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JtD
08-27-2006, 12:38 AM
I have come across this type of comment all too often latetly:

"E-retention for B'n'Z planes is porked."

Could you please enlight me:
What features exactly make a plane a B'n'Z plane?
What exactly is wrong with E-retention?

JtD
08-27-2006, 12:38 AM
I have come across this type of comment all too often latetly:

"E-retention for B'n'Z planes is porked."

Could you please enlight me:
What features exactly make a plane a B'n'Z plane?
What exactly is wrong with E-retention?

Treetop64
08-27-2006, 12:42 AM
Oh, here we go...

(dons flame-******ant suit)

ColoradoBBQ
08-27-2006, 01:32 AM
There's nothing wrong with E-rentention in-game. It just the problem of pilots wondering why Zeroes and Ki-61s could keep up with their F4Us and P-38s in zoom climbs.

CMHQ_Rikimaru
08-27-2006, 01:32 AM
I will just give u hints : FW190, P47, a5FN, dive, zoom climb. Now use ur brainhttp://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

JtD
08-27-2006, 03:13 AM
I was asking for more precise information. That's why I used the term "exactly" in each of my questions in the first post.

KaleunFreddie
08-27-2006, 03:18 AM
E-stuff is over-rated... sooner or later they going to have to turn and fight. This is where they'll lose coz they haven't been practising.
http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

DuxCorvan
08-27-2006, 04:24 AM
It means that AI planes gain and retain energy better than human controlled planes. If you add that AI planes don't break apart or suffer compressibility due to speed, the result is that true life BnZ tactics don't work against AI.

I mean, you are in a P-47, and you see a group of Zeros beneath you. You dive towards them, while they are climbing like rockets from 0 to 100 in a nanosecond -because that's how supervitamined AI works now.

You make a pass, and use your energy again to gain altitude and distance and try a second chance, but... you can't, because Zeros are climbing faster than you even if they never dived: the awesome AI power boost makes them gain energy right from their butts.

So they're higher and higher, without losing significant speed. If you try to chase them upwards, you energy bleeds as a hole in your femoral arteria. That's normal, you're in a human controlled heaaaavy P-47, and they're in light Zeroes, which besides are AI -that means they're filled with helium.

So now they have tactical advantage. They come down and chase you. So what would a WW2 Thunderbolt pilot do? Run!!! You have a very heavy, powerful and robust aircraft. So... dive!!! In real life, lighter Zeros couldn't catch you in the initial stages of a dive, because of them being so light.

After a while they should be able to match your speed, but by then, speed should be too high for them not to lose control or break apart.

But they don't! They catch you and fry you.

So here it is, you've lost in a win-win situation, because the only advantages of your BnZ plane are completely cancelled by the cheating abilities given to AI.

What sense has to fly a pure BnZ aircraft -which sacrifices maneuverability for speed and diving tactics- when any Turn'n'Burn aircraft can do the same and counter your tactics, and still turn better, if it is controlled by AI?

This kind of things is what discourages we offline players -at least those who seek for immersion, not merely skill challenges- lately.

BiscuitKnight
08-27-2006, 04:45 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by DuxCorvan:
It means that AI planes gain and retain energy better than human controlled planes. If you add that AI planes don't break apart or suffer compressibility due to speed, the result is that true life BnZ tactics don't work against AI.

I mean, you are in a P-47, and you see a group of Zeros beneath you. You dive towards them, while they are climbing like rockets from 0 to 100 in a nanosecond -because that's how supervitamined AI works now.

You make a pass, and use your energy again to gain altitude and distance and try a second chance, but... you can't, because Zeros are climbing faster than you even if they never dived: the awesome AI power boost makes them gain energy right from their butts.

So they're higher and higher, without losing significant speed. If you try to chase them upwards, you energy bleeds as a hole in your femoral arteria. That's normal, you're in a human controlled heaaaavy P-47, and they're in light Zeroes, which besides are AI -that means they're filled with helium.

So now they have tactical advantage. They come down and chase you. So what would a WW2 Thunderbolt pilot do? Run!!! You have a very heavy, powerful and robust aircraft. So... dive!!! In real life, lighter Zeros couldn't catch you in the initial stages of a dive, because of them being so light.

After a while they should be able to match your speed, but by then, speed should be too high for them not to lose control or break apart.

But they don't! They catch you and fry you.

So here it is, you've lost in a win-win situation, because the only advantages of your BnZ plane are completely cancelled by the cheating abilities given to AI.

What sense has to fly a pure BnZ aircraft -which sacrifices maneuverability for speed and diving tactics- when any Turn'n'Burn aircraft can do the same and counter your tactics, and still turn better, if it is controlled by AI?

This kind of things is what discourages we offline players -at least those who seek for immersion, not merely skill challenges- lately. </div></BLOCKQUOTE>

Thanks, Corvan, your answer helps me, as well. I'm assuming this is why the other day an AI P-40 was able to climb to 5000 metres with ease while my Bf-110 was struggling?

JtD
08-27-2006, 04:58 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by BiscuitKnight:

Thanks, Corvan, your answer helps me, as well. I'm assuming this is why the other day an AI P-40 was able to climb to 5000 metres with ease while my Bf-110 was struggling? </div></BLOCKQUOTE>

No, this is because the 110 isn't modelled to best specs. Flies like a pregnant whale where is should fly like a dolphin.

BiscuitKnight
08-27-2006, 05:15 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by JtD:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by BiscuitKnight:

Thanks, Corvan, your answer helps me, as well. I'm assuming this is why the other day an AI P-40 was able to climb to 5000 metres with ease while my Bf-110 was struggling? </div></BLOCKQUOTE>

No, this is because the 110 isn't modelled to best specs. Flies like a pregnant whale where is should fly like a dolphin. </div></BLOCKQUOTE>

Really? I'm curious about how the Bf-110 was modelled - I posted a thread that so far no one's replied to, asking about its performance. Still, the P-40 was chasing an AI Bf-110, and despite those two circling like crazy, I wasn't gaining on them and I was spending all my energy climbing, not turning.

Xiolablu3
08-27-2006, 05:16 AM
I think the idea is that the heavy planes like the FW190/P47/P51 dont have enough of a weight advantage.

This means

1: They dont speed up fast enough in dives. (Heavier plane should reach its terminal velocity faster)
2: Their zoom climb is not much better than the much lighter planes.
3. BAsically, any advantage they gain from being heavier is not modelled very well, whereas their disadvatntages, such as poor climb, poor slow speed turn etc are all mdelled.

Whether this is true or not I am not sure, but I can see that the FW190 doesnt seperate from the Spitfire very fast in a dive.

As far as zoom climb goes,Maybe many of these pilots pass though the zoom climb into powered climb, and wonder why they are caught?

JtD
08-27-2006, 05:21 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by DuxCorvan:

I mean, you are in a P-47, and you see a group of Zeros beneath you... </div></BLOCKQUOTE>

Ok, I simulated this in the QMB. I was in a D-27 and four veteran A6M5b started with disadvantage on the Pacific island map at 3000 meters. I dived past them, zoomed up, turned around, shot one down, zoomed up, turned around, shot one down, extended, came back, chased one, shot it down, headed towards the last, flew past him, zoomed up, turned around, shot him up and finally down. Seems to work for me, nowhere near your description.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">In real life, lighter Zeros couldn't catch you in the initial stages of a dive, because of them being so light. </div></BLOCKQUOTE>

Only if you are entering the dive at high speeds. At slow speeds, acceleration is more about power/weight, even in dives. The A6M has advantages over the P-47 there.

The fact that AI ignore dive limits is frustrating indeed. http://forums.ubi.com/groupee_common/emoticons/icon_mad.gif

Thanks for the input. http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

ICDP
08-27-2006, 05:21 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Xiolablu3:
I think the idea is that the heavy planes like the FW190/P47/P51 dont have enough of a weight advantage.

This means

1: They dont speed up fast enough in dives. (Heavier plane should reach its terminal velocity faster)
2: Their zoom climb is not much better than the much lighter planes.
3. BAsically, any advantage they gain from being heavier is not modelled very well, whereas their disadvatntages, such as poor climb, poor slow speed turn etc are all mdelled.

Whether this is true or not I am not sure, but I can see that the FW190 doesnt seperate from the Spitfire very fast in a dive.

As far as zoom climb goes,Maybe many of these pilots pass though the zoom climb into powered climb, and wonder why they are caught? </div></BLOCKQUOTE>

I agree with this theory. In my experience the Heavier fighters should accelerate slightly better in a dive and have slightly better E retention. The lighter fighter should bleed energy slightly more in heavy manouvering. At the moment the lighter fighters can zoom with the heavier fighters for too long.

I know that some people expcect to just point the nose down in a Fw190 or P51 and leave their opponent standing. I don't go with this belief but a slight improvement in the areas I outlined would bring things closer to what IMHO is a closer rendition of historical records. Admitedly these are only opinions and I wouldn't dare try to pedal them as unalterable facts.

JtD
08-27-2006, 05:33 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by BiscuitKnight:

Really? I'm curious about how the Bf-110 was modelled - I posted a thread that so far no one's replied to, asking about its performance. </div></BLOCKQUOTE>

If I had test data, I'd share. My opinion is based on the fact that technical data and reports do not make sense if you accept the FM as correct. It is a rather high powered plane with rather low wingloading, yet in a maneuvering battle it won't survive against planes it historically was superior to (in this type of battle), say the Beaufighter.

Xiolablu3
08-27-2006, 05:41 AM
I think right away that we have to ignore the AI abilities. They just do things which are too strange.

Maybe we could limit the discussion to online only?

JtD
08-27-2006, 05:52 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Xiolablu3:

1: They dont speed up fast enough in dives. (Heavier plane should reach its terminal velocity faster) </div></BLOCKQUOTE>

Let me post this again:
http://mitglied.lycos.de/jaytdee/d001.JPG

An in game dive comparism of Spit IX and FW 190A in an full power dive from 7000 meters. Dive angle was 30?. This results in a raw dive acceleration of sin 30?*9,81m/s²= 4.905 m/s².

This acceleration is reached exactly when the plane passes it's top speed at the current altitude. Since the FW is faster than the Spit, so it reaches this limit at higher speeds. Below that 4.905 figure, the power/weight ratio is important, a lighter, more powerful plane (Spit) will accelerate better. Above that speed, weight/drag becomes commanding and the heavier plane with less drag (FW) accelerates better. So much for physics.

Good news: It works just like that in game.

I can also tell you one thing:
If two planes with the same top speed fly level at the same alt at the same speed, which is below their top speed, zoom up, the one with the better power/weight will end up higher. No free lunch in physics.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">2: Their zoom climb is not much better than the much lighter planes. </div></BLOCKQUOTE>

This totally depends on the speed. Also, I tested a P-51 to have a 1% better power off zoomclimb with full tanks than with half full ones, so it is modelled to some extend. Considering the energy retention is 90% and 91%, there isn't much room for improvements anyways.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">3. BAsically, any advantage they gain from being heavier is not modelled very well, whereas their disadvatntages, such as poor climb, poor slow speed turn etc are all mdelled. </div></BLOCKQUOTE>

Well, my question would be:
3. What advantages and disadvantages exactly should you have from flying a heavier plane?

JtD
08-27-2006, 05:59 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by ICDP:
...The lighter fighter should bleed energy slightly more in heavy manouvering... </div></BLOCKQUOTE>

Cherry picking, sorry. But:

The lighter fighter should, in general, bleed less E in heavy maneuvering. It doesn't need as much lift as the heavy one and therefore it does not create as much drag. Drag is where the energy goes.

I think you also meant to say that all that E stored in the heavier fighter should help it through a few maneuvers without slowing it down all so much...I gotta think about that.

Brain32
08-27-2006, 06:01 AM
I mainly find dive and zoom characteristics of Fw190A's EXTREMELY poor. The sheer fact that you have to be at 700km/h+ to start pulling away from a Spitfire is downright ridiculous. Spitfire was not only lighter but also draggy comparing to FW190A so this really does not make sense.
I have yet to be caught in a dive in 51/47/38/Tempest by anything but a FW190D9, maybe K4?

Taylortony
08-27-2006, 06:03 AM
What's wrong about E-retention?

You need some ruf***e mate, that should clear your problem up and get you back to being regular http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

Xiolablu3
08-27-2006, 06:03 AM
I only posted those things bcasue I gather thats what some people are coplaining about. I dont necesarily think those things, I really hav no idea if they are correct or not. I have trouble reading those graphs which people post, so I am not the best person to work this out.

I will try and answer your point 3. fromt eh perspective of the average Joe who knows nothing about physics or Plane design http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

I would expect

Better dive because the heavier plane picks up speed faster, maybe?

Better zoom climb becasue of the 'pendalum' effect, a heavier plane will 'swing' better than a lighter plane. (try a pendalum with a piece of string and it doesnt work, attach a weight to it and it swings (zooms) very well.

Hmm thats about all I can think of now.

Xiolablu3
08-27-2006, 06:06 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by JtD:

I think you also meant to say that all that E stored in the heavier fighter should help it through a few maneuvers without slowing it down all so much...I gotta think about that. </div></BLOCKQUOTE>

I would *think* that in this situation it would depend if the plane was diving or climbing. Straight line I am not so sure. If the plane was diving then the hard manouvres would slow it down even faster. If it was diving thn the weight wouild help it through the hard manouvres a little.

Am I correct? (probably not http://forums.ubi.com/images/smilies/16x16_smiley-tongue.gif)

JtD
08-27-2006, 06:06 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Brain32:
I mainly find dive and zoom characteristics of Fw190A's EXTREMELY poor. The sheer fact that you have to be at 700km/h+ to start pulling away from a Spitfire is downright ridiculous. Spitfire was not only lighter but also draggy comparing to FW190A so this really does not make sense. </div></BLOCKQUOTE>

600 is enough, even at high alt. At lower alts, 500 will already do the trick.

KraljMatjaz
08-27-2006, 06:10 AM
let me just repost what have I posted in the "why don't you like P-51" thread:

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by KraljMatjaz:
this thread may well be conneced with one of the big flaws of this 'sim': energy retention.

BnZ fighters are simply bleeding too much compared to TnB ones. that's why P51 NEVER (but in a single initial surprise dive from 1k alt advantage) can utilise it's better maneouverability at high speeds. ironically it is more maneouverable until it keeps flying straight. as soon as she tries to turn (let it be a gentle turn at 700 or 800kph) she'll bleed enormously and allow 109 to connect and do the job. many other examples are F6F vs A6M5, Fw190 vs Spit, P51 vs everything, P47 vs everything, F4U vs everything...

US fighters in this sim are mostly bnz that's why they are the ones that suffer most from this error. now throw in a bit of wobbling and a lacking DM (ammo boxes, hydrawlics, glycol coolant,.......) that lowers the efficiency of .50cals, and you have planes that require true masochists to pilot them. do u see how P40s and, a little bit sarcasticaly, P-39 are popular in this sim?

salute to all US planes pilots that do manage to do well in them by not always having 5k alt advantage (which I'm quite sure US pilots didn't always have, not on Pacific nor in ETO).

now all repeat after me:

"Oleg please in BOB do the energy retention right." </div></BLOCKQUOTE>

let's put the cards on the table now:

bnz fighters have no real options against tnb fighters but to run their *** out towards friendly aaa and screaming for help (assuming of course they met on a same alt - having 2k alt advantage was smart in ww2 and here, but presents a nice excuse for poor plane. u can do well in every plane with 2k advantage).

yes a group of 190As can be succsessful versus spitsIX only due to better armament which allows them to drag and bag all the spits before they manage to do the same, and in great numbers, 1v1 fw should immediately dive and run before it's too late.

tnb fighters simply retain E to well compared to bnz. how on earth am I about to use my better high speed manoeuvering in P51 versus 109 if I bleed all my speed in first 90 degrees of turning? i doubt p-51 was THAT bad at 1v1 same alt. same goes for f4u, f6f vs A6M5, fw190 etc etc etc.

all the historical reports claiming P51 could turn inside 109 are correct becuse they are reffering to turning at hihg speeds.


the trend of fighter developement toward the end of the war was tending towards bnz planes. f8f was greatly influenced by 190, as was La11.

another example (which I already mentioned in one of previous posts) is, ta..da.., the milion times heard Fw190A4 versus SpitV.

we may have a derated Fw and a 1942 spitV while we should actualy have a 9lb boost 41 one, but A4 still dominates the spit. however, the fw was known to have aproximately same optimal climbing speed but much steeper climbing angle and was getting away from spit in a steep sustained climb, and spit couldn't follow, because if he would pull up even further to get firing solution, he would stall.

in this sim they both climb at approximately same angle, but fw is faster and all you do is increase the distance between the planes (which is enough to get advantage over him though).

Xiolablu3
08-27-2006, 06:17 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by KraljMatjaz:
how on earth am I about to use my better high speed manoeuvering in P51 versus 109 if I bleed all my speed in first 90 degrees of turning?. </div></BLOCKQUOTE>

Good post, but a lot of speculation.

Can you be sure that this is not in fact correct? Just complaining about it becaue planes with a low wing loading are far better at dogfighting, does not necesarrily make it wrong.

JtD
08-27-2006, 06:20 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Xiolablu3:

Better dive because the heavier plane picks up speed faster, maybe?

Better zoom climb becasue of the 'pendalum' effect, a heavier plane will 'swing' better than a lighter plane. (try a pendalum with a piece of string and it doesnt work, attach a weight to it and it swings (zooms) very well. </div></BLOCKQUOTE>

In a vacuum, freefalling light and heavy objects will reach the same dive acceleration. The essential differences for planes are:
1) They got an engine. (power)
2) They don't fly in vacuum. (drag)

So IF the heavier plane accelerates better in a dive depends on it's power and drag compared to the lighter plane. As indicated above, a lot of power helps at low speeds, and little drag helps at high speed - both in relation to the weight.
At low speeds, where drag is neglectable, the plane with better power/weight ratio will outaccelerate the other. This, in most cases, is not the heavier plane. At high speeds, where drag is very important and engine power doesn't count for much, the plane with the better weight/drag ratio will pull ahead. This, in most cases, is the heavier plane.

The advantages of rather heavy planes come into play when you dive to a very high speed, and zoom up from there again. You simply lose a smaller percentage of your E to drag, because you got more total E.

KaleunFreddie
08-27-2006, 06:25 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by JtD:
In a vacuum, freefalling light and heavy objects will reach the same dive acceleration. </div></BLOCKQUOTE>

http://forums.ubi.com/images/smilies/11.gif http://forums.ubi.com/images/smilies/11.gif http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif http://forums.ubi.com/images/smilies/16x16_smiley-tongue.gif === WRONG WRONG WRONG....

Go back to 1st year physics, Do not collect $200 .. http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

Xiolablu3
08-27-2006, 06:33 AM
So the idea is that you MUST at all cost stay very fast in the heavier (B&Z) plane for this to take effect?

What would you say is a good speed? 500kph? I know it will be different for all planes but as a general ballpark figure for the P51/FW190/P47 etc?

I think what you are saying is that - If I see a SPit coming up behind me in a FW190 and I am travelling at 300-400k, the SPit will actually catch up in a dive, until I hit that speed of say 500-550kph?

Xiolablu3
08-27-2006, 06:34 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by KaleunFreddie:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by JtD:
In a vacuum, freefalling light and heavy objects will reach the same dive acceleration. </div></BLOCKQUOTE>

http://forums.ubi.com/images/smilies/11.gif http://forums.ubi.com/images/smilies/11.gif http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif http://forums.ubi.com/images/smilies/16x16_smiley-tongue.gif === WRONG WRONG WRONG....

Go back to 1st year physics, Do not collect $200 .. http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif </div></BLOCKQUOTE>

So tell us the answer pls, dont just write that its wrong. http://forums.ubi.com/groupee_common/emoticons/icon_rolleyes.gif

We are trying to work stuff out here, playing cat and mouse doesnt help at all.

JG4_Helofly
08-27-2006, 06:35 AM
Hmmm... good question. I think the probem is that heavy planes do not gain enough distance in a dive also if your initial speed is high.
Here is a test with numbers: http://www.beim-zeugmeister.de/zeugmeister/index.php?id=24&L=1

b) In the dive:

The comparaison was conducted with military power, about 20% dive angle and with an alt difference of 2000m. The result was that the fw 190 A2 gained several hundred meters at all height. The steeper and longer the dive the greater the advantage.But It also showed that the fw 190A2 reached slower it's maximum speed compared to the bf 109.

The bf 109 was a F4 in this test.

I did a test with a friend. We reproduced exactly the same situation. We flew at maximum horizontal speed. The result was that with auto prop the fw 190 was not able to create a seperation from the f4. With manual prop the distance was 100m. Against a spit Vb it was 150-190m.

An other Problem is that the advantage is particulary not during the inital stages of the dive like it was in RL but the other way around.

This make it impossible to dive away from an ennemy, also with half a roll dive because all planes have instant 100% effectiv ailerons without any delay.

JtD
08-27-2006, 06:40 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Xiolablu3:

I would *think* that in this situation it would depend if the plane was diving or climbing. </div></BLOCKQUOTE>

Well, I have made up my mind and the answer is:

It depends. http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif

But in true heavy maneuvering, pulling to the max g or max AoA or so, the advantage almost immediately lies with the lighter plane.

Downwards combat in general favours planes with a low power/weight, while upwards combat favours planes with a good power/weight ratio. So a heavy plane can draw some reserves from that, but it will only delay it's doom if it keeps trying to outmaneuvre it's opponent.

If I find a decent test procedure I can probably tell a bit more, and also reply to KraljMatjaz, who raised a few good questions.

JtD
08-27-2006, 06:44 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by KaleunFreddie:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by JtD:
In a vacuum, freefalling light and heavy objects will reach the same dive acceleration. </div></BLOCKQUOTE>

=== WRONG WRONG WRONG.... </div></BLOCKQUOTE>

Go on, tell me. In the meantime watch this (http://www.youtube.com/watch?v=m6zNEsfuySU).

KraljMatjaz
08-27-2006, 06:45 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Xiolablu3:
Good post, but a lot of speculation.

Can you be sure that this is not in fact correct? Just complaining about it becaue planes with a low wing loading are far better at dogfighting, does not necesarrily make it wrong. </div></BLOCKQUOTE>

again, planes with lower wingloading, they are more manoeuverable and they should be. at slow speeds, not at high. they are not nor they should be. i am not speaking about maneouverability, it's ok. 109 is according to history more maneouverable at slow speeds, p51 is at high. but this high speed advantage doesn't really matter if we can't really have high speed dogfights. only matchup that does allow a bit of high speed dogfighting is A8 vs 47D or D-27. very good matchup imo.

at 600 kph any wing in game provides sufficient lift to pull 10 g turn, any of them, since wing is really stiffed in the air (for example think about V1 wingloading and it's size). if wings of bnz at slow speeds provided such a low lift, how then is it possible for a fw190 to take off with 1000 and even with 1800 kg bombs? or p51 with 1000, not to mention f4u?

Xiolablu3
08-27-2006, 06:52 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by KraljMatjaz:
if wings of bnz at slow speeds provided such a low lift, how then is it possible for a fw190 to take off with 1000 and even with 1800 kg bombs? or p51 with 1000, not to mention f4u? </div></BLOCKQUOTE>

http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif I am afraid this is totally over my head, I have no idea.

Over to the others http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

ICDP
08-27-2006, 06:57 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by JtD:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by ICDP:
...The lighter fighter should bleed energy slightly more in heavy manouvering... </div></BLOCKQUOTE>

Cherry picking, sorry. But:

The lighter fighter should, in general, bleed less E in heavy maneuvering. It doesn't need as much lift as the heavy one and therefore it does not create as much drag. Drag is where the energy goes.

I think you also meant to say that all that E stored in the heavier fighter should help it through a few maneuvers without slowing it down all so much...I gotta think about that. </div></BLOCKQUOTE>

I should have been more explicit im my post. I meant to say The lighter fighter(s) should bleed energy slightly more in heavy manouvering than they do currently. They most definately should not bleed energy quicker than a heavy fighter in manouvers.

Also the power to weight ratio for the MkIXc and Fw190A5 are remarkably similar. Around 4.7 for the Spitfire and around 4.9 for the Fw190A5. So the Spitfire should keep up with the Fw190A in a dive for a very short time only. It should not however outaccelerate it at anytime during a dive IMHO.

KraljMatjaz
08-27-2006, 07:04 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Xiolablu3:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by KraljMatjaz:
if wings of bnz at slow speeds provided such a low lift, how then is it possible for a fw190 to take off with 1000 and even with 1800 kg bombs? or p51 with 1000, not to mention f4u? </div></BLOCKQUOTE>

http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif I am afraid this is totally over my head, I have no idea.

Over to the others http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif </div></BLOCKQUOTE>

well I guess it's way too much for any of us. we will simply have to wait another decade or so until there will be computers strong enough to calculate precisely actual flow of the air around the planes, and planes to be modelled with their actual mass distribution and power output.

hell even WW2 pilots contradicted eachother in their reports, how couldn't we.

cheers

JtD
08-27-2006, 07:12 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by JG4_Helofly:
...I did a test with a friend... </div></BLOCKQUOTE>

Intersting. Sadly, the report itself doesn't state details of the tests. But I figure they are still available for your test. http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

Could you possibly tell me:

Which version of FB did you use?
What alt did you do your tests at?
Which loadout did you select and how much fuel did you take?
What radiator settings did you use?
Do you happen to have a track of this?

JG4_Helofly
08-27-2006, 07:19 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by ICDP:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by JtD:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by ICDP:
...The lighter fighter should bleed energy slightly more in heavy manouvering... </div></BLOCKQUOTE>

Cherry picking, sorry. But:

The lighter fighter should, in general, bleed less E in heavy maneuvering. It doesn't need as much lift as the heavy one and therefore it does not create as much drag. Drag is where the energy goes.

I think you also meant to say that all that E stored in the heavier fighter should help it through a few maneuvers without slowing it down all so much...I gotta think about that. </div></BLOCKQUOTE>

I should have been more explicit im my post. I meant to say The lighter fighter(s) should bleed energy slightly more in heavy manouvering than they do currently. They most definately should not bleed energy quicker than a heavy fighter in manouvers.

Also the power to weight ratio for the MkIXc and Fw190A5 are remarkably similar. Around 4.7 for the Spitfire and around 4.9 for the Fw190A5. So the Spitfire should keep up with the Fw190A in a dive for a very short time only. It should not however outaccelerate it at anytime during a dive IMHO. </div></BLOCKQUOTE>

Well, probably true but at slow speed. At high speed the drag advantage and the greater mass would overtake the power to weight ratio variable.

We have also an other problem. In the f4 vs a2 report it was said that the roll advantage in doghfight is extremly noticeable. Most time the fw 190 did a half a roll dive to escape. The spit was not able to follow this manoeuvre quick enough to get a fire solution.
In the game the spit and all other planes have 100% controle effectiveness in 0.01 sec. There is no delay no inertia effect and the pilot can put the stick at maximum instantly. It was known that planes with larges wings was not that reactiv compared to fw 190 wings for exemple.
That makes it impossible to use the roll advantage in game because all planes react so well and instantly to controle inputs.
I remember that we had a patch in which we had noticeable inertia effects but there were many complaines about it because it made it more difficult to aime and to escape with extrem manoeuvres and in the next patch it was removed.

(This is my opinion)

JtD
08-27-2006, 07:26 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by ICDP:

I should have been more explicit im my post. I meant to say The lighter fighter(s) should bleed energy slightly more in heavy manouvering than they do currently. They most definately should not bleed energy quicker than a heavy fighter in manouvers.

Also the power to weight ratio for the MkIXc and Fw190A5 are remarkably similar. Around 4.7 for the Spitfire and around 4.9 for the Fw190A5. So the Spitfire should keep up with the Fw190A in a dive for a very short time only. It should not however outaccelerate it at anytime during a dive IMHO. </div></BLOCKQUOTE>

Lol, I am too focussed. http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif

I'd now like to throw in the what came first - egg or chicken argument...are planes that bleed little E used as turnfighters or are turnfighters bleeding little E?

The power/weight ratio of the Spit and the FW do vary a lot with the altitude. At higher altitudes, the Merlin 66 actually produces more power than the BMW. The Spit is considerably lighter and so you are left with a very notable power/weight advantage for the Spit. Bit different down low.

JG4_Helofly
08-27-2006, 07:31 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by JtD:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by JG4_Helofly:
...I did a test with a friend... </div></BLOCKQUOTE>

Intersting. Sadly, the report itself doesn't state details of the tests. But I figure they are still available for your test. http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

Could you possibly tell me:

Which version of FB did you use?
What alt did you do your tests at?
Which loadout did you select and how much fuel did you take?
What radiator settings did you use?
Do you happen to have a track of this? </div></BLOCKQUOTE>

The settings were:
Rad closed
prop auto and manual
alt was 3000-1000 and 5000-3000 (no noticeable difference)
fuel was 100% with standard loadout
i don't know if i can find the track
and the version was 4.04m

DuxCorvan
08-27-2006, 07:38 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by JtD:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by KaleunFreddie:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by JtD:
In a vacuum, freefalling light and heavy objects will reach the same dive acceleration. </div></BLOCKQUOTE>

=== WRONG WRONG WRONG.... </div></BLOCKQUOTE>

Go on, tell me. In the meantime watch this (http://www.youtube.com/watch?v=m6zNEsfuySU). </div></BLOCKQUOTE>

Everyone -I hope- knows Newton and Galileo. http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

In the vacuum, objects fall with the same acceleration (in Earth, 9,8 m/s2), asuming they start from zero, or at the same speed. An object impulsed downwards at 500 km/h won't obviously reach the ground at the same time that one which is simply falling by gravity. Now well, diving planes aren't just falling.

Anyway, planes can't fly in the vacuum. Without air, both wings and propellers are useless. http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

VW-IceFire
08-27-2006, 08:05 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Brain32:
I mainly find dive and zoom characteristics of Fw190A's EXTREMELY poor. The sheer fact that you have to be at 700km/h+ to start pulling away from a Spitfire is downright ridiculous. Spitfire was not only lighter but also draggy comparing to FW190A so this really does not make sense.
I have yet to be caught in a dive in 51/47/38/Tempest by anything but a FW190D9, maybe K4? </div></BLOCKQUOTE>
Brain I have to call that out. IT depends alot on the Spitfire involved. In reading about the Spitfire IX and Spitfire VIII types...diving away from combat was less likely to work in a FW190A as it had against the Mark V. The thing is that the anecdote about FW190 pilots just diving away and leaving the Spitfires behind was made and is only specifically true for Mark V's. I've never read about the VIII or IX having the same problem.

I think its good that JtD has called this issue out. I still believe, like some of you, that the E-retention based on weight may be a little off...but I think that what JtD is saying is also true...its not as off by as much as some of us like to think it is.

Ratsack
08-27-2006, 08:11 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by KaleunFreddie:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by JtD:
In a vacuum, freefalling light and heavy objects will reach the same dive acceleration. </div></BLOCKQUOTE>

http://forums.ubi.com/images/smilies/11.gif http://forums.ubi.com/images/smilies/11.gif http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif http://forums.ubi.com/images/smilies/16x16_smiley-tongue.gif === WRONG WRONG WRONG....

Go back to 1st year physics, Do not collect $200 .. http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif </div></BLOCKQUOTE>

I want popcorn for this explanation.

cheers,
Ratsack

carguy_
08-27-2006, 08:31 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by KraljMatjaz:
tnb fighters simply retain E to well compared to bnz. how on earth am I about to use my better high speed manoeuvering in P51 versus 109 if I bleed all my speed in first 90 degrees of turning? i doubt p-51 was THAT bad at 1v1 same alt. same goes for f4u, f6f vs A6M5, fw190 etc etc etc.
</div></BLOCKQUOTE>

Overall your post descibes what I think most B&Zers are complaining about.The P51 part is particulary annoying and applies to all pure B&Zers like you said.In a P51D,FW190A gentle scissors make you bleed so much speed,that the enemy you just surprised is at a similar E state and bangs you rightaway.I do this to Mustangs while flying the 109 and I am done the same by Spits/La while flying the FW190A.

I think that this is easily visible in planes that have both B&Z and T&B qualities.For example the Bf/Me109 and P47 are both good turners and even better B&Zers.Due to this they suffer only in part of what pure B&Zers suffer.


I mean take a Spit IX,exceed 350km/h,take her to a gentle horizontal turn and watch how she loses speed - hardly any.
Do the same in a P51D/FW190A and watch the speed bleed at about 15km/h every two seconds.

JG4_Helofly
08-27-2006, 08:32 AM
every one gives his point of view about the problem, but have we any report or such things to resolve this problem? Or maybe it is possible to calculate dive acceleration for each plane with enough information.

Is it possible to solve the prob or can we only speculate and interpret some unprecise reports?

Brain32
08-27-2006, 08:38 AM
Ice Fire, didn't you see that test involving FW190A3 and SpitMkIX? It said:
"The FW.190 is faster than the Spitfire IX in a dive, particularly during the initial stage. This superiority is not as marked as with a SpitfireVb"
Not as marked but still superiour http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif
According to the measurement robban75 http://forums.ubi.com/images/smilies/11.gif made in v402 Antons have a lot to hope for when it comes to dive acceleration, while MkVIII pwns them, MkIX only starts to lag behind at speeds nearing 700Km/h this is what I find pretty ridiculous. The Spitfire that could indeed mess with the Antons in a dive was MkXIV, not MkIX.
Link to v402 testing: http://www.acompletewasteofspace.com/modules.php?name=F...ile=viewtopic&t=7760 (http://www.acompletewasteofspace.com/modules.php?name=Forums&file=viewtopic&t=7760)

Xiolablu3
08-27-2006, 08:42 AM
I think its possibly an engine limitation Helofly.

It must be very very hard to program exact characteristic into different planes in some cases.

For example, the fact that the FW190 vs SpitV. The FW190 extends away from from the Spitfire V in a dive. This is especially true in the early stages.

Too program the 'early stages' bit into the flight model of the FW190 must be particularly hard.

BTW this is a guess, I have no evidence.

HellToupee
08-27-2006, 09:15 AM
as for heavyer planes retaining more speed in manovers, why?

what goes around a corner faster a bus or a lotus, a b25 is heavyer than a 190, why cant i outdive them and retain my speed in game wah!

KaleunFreddie
08-27-2006, 09:27 AM
Whoops sorry ... I was thinking Momentum - wrong theory http://forums.ubi.com/images/smilies/35.gif http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif

VW-IceFire
08-27-2006, 09:45 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Brain32:
Ice Fire, didn't you see that test involving FW190A3 and SpitMkIX? It said:
"The FW.190 is faster than the Spitfire IX in a dive, particularly during the initial stage. This superiority is not as marked as with a SpitfireVb"
Not as marked but still superiour http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif
According to the measurement robban75 http://forums.ubi.com/images/smilies/11.gif made in v402 Antons have a lot to hope for when it comes to dive acceleration, while MkVIII pwns them, MkIX only starts to lag behind at speeds nearing 700Km/h this is what I find pretty ridiculous. The Spitfire that could indeed mess with the Antons in a dive was MkXIV, not MkIX.
Link to v402 testing: http://www.acompletewasteofspace.com/modules.php?name=F...ile=viewtopic&t=7760 (http://www.acompletewasteofspace.com/modules.php?name=Forums&file=viewtopic&t=7760) </div></BLOCKQUOTE>
Not as marked says to me that its much closer. There are at least a few combat reports of chasing FW190s into dives and catching them on the bottom. I am glad that you replied...I'm always looking for the best data.

Jaws2002
08-27-2006, 09:46 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by JtD:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by ICDP:

I should have been more explicit im my post. I meant to say The lighter fighter(s) should bleed energy slightly more in heavy manouvering than they do currently. They most definately should not bleed energy quicker than a heavy fighter in manouvers.

Also the power to weight ratio for the MkIXc and Fw190A5 are remarkably similar. Around 4.7 for the Spitfire and around 4.9 for the Fw190A5. So the Spitfire should keep up with the Fw190A in a dive for a very short time only. It should not however outaccelerate it at anytime during a dive IMHO. </div></BLOCKQUOTE>

Lol, I am too focussed. http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif

I'd now like to throw in the what came first - egg or chicken argument...are planes that bleed little E used as turnfighters or are turnfighters bleeding little E?

The power/weight ratio of the Spit and the FW do vary a lot with the altitude. At higher altitudes, the Merlin 66 actually produces more power than the BMW. The Spit is considerably lighter and so you are left with a very notable power/weight advantage for the Spit. Bit different down low. </div></BLOCKQUOTE>

You completely ignore the drag, and that's what decides who wins.

Just look at WW1 aircraft. The Germans dominated with small engines specially because their aircraft were much less dragy.
The drag is the factor that makes the difference in the hammer/feather example.

HellToupee
08-27-2006, 09:52 AM
and drag is less of a factor at high alt with thinner air, and less of a factor at the lower speed end.

carguy_
08-27-2006, 09:53 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by HellToupee:
what goes around a corner faster a bus or a lotus, a b25 is heavyer than a 190, why cant i outdive them and retain my speed in game wah! </div></BLOCKQUOTE>

Because the B25 has a monster of a drag,foo!

MEGILE
08-27-2006, 10:08 AM
Anyone have a track of a Spitfire catching a focke wulf in a dive?
Please post it, so we can critique it

Jaws2002
08-27-2006, 10:08 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by JG4_Helofly:
Hmmm... good question. I think the probem is that heavy planes do not gain enough distance in a dive also if your initial speed is high.
Here is a test with numbers: http://www.beim-zeugmeister.de/zeugmeister/index.php?id=24&L=1

b) In the dive:

The comparaison was conducted with military power, about 20% dive angle and with an alt difference of 2000m. The result was that the fw 190 A2 gained several hundred meters at all height. The steeper and longer the dive the greater the advantage.But It also showed that the fw 190A2 reached slower it's maximum speed compared to the bf 109.

The bf 109 was a F4 in this test.

I did a test with a friend. We reproduced exactly the same situation. We flew at maximum horizontal speed. The result was that with auto prop the fw 190 was not able to create a seperation from the f4. With manual prop the distance was 100m. Against a spit Vb it was 150-190m.

An other Problem is that the advantage is particulary not during the inital stages of the dive like it was in RL but the other way around.

This make it impossible to dive away from an ennemy, also with half a roll dive because all planes have instant 100% effectiv ailerons without any delay. </div></BLOCKQUOTE>

This test was made in december 1941, with FW-190A2 with a <span class="ev_code_YELLOW">BMW-801C</span> engine. This engine was producing 1500HP compared with over 1700HP in all BMW-801D engines. On top of that the engine was very unreliable and not ready for operation in that form. They did a lot of changes in the cowling, internal airflow and generally in the cooling area after that test.

Look at page 7:
http://www.beim-zeugmeister.de/zeugmeister/index.php?id=25&L=1

What we have in game should be a very different animal.

WWMaxGunz
08-27-2006, 10:09 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by JtD:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by ICDP:
...The lighter fighter should bleed energy slightly more in heavy manouvering... </div></BLOCKQUOTE>

Cherry picking, sorry. But:

The lighter fighter should, in general, bleed less E in heavy maneuvering. It doesn't need as much lift as the heavy one and therefore it does not create as much drag. Drag is where the energy goes. </div></BLOCKQUOTE>

And there I was thinking that conversion of kinetic energy to potential in the raising of
mass through a gravity field was some kind of major factor. Silly me.

It works with pendulums but then they don't have props.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">I think you also meant to say that all that E stored in the heavier fighter should help it through a few maneuvers without slowing it down all so much...I gotta think about that. </div></BLOCKQUOTE>

Well it does have more energy and depending on drag, wings and such it may use more to make
those maneuvers.

From Robert Shaw's Fighter Combat back in the Appendix chapter on Energy Maneuverability he
does discuss Zoom Climb with Specific Energy and Apecific Excess Power. In the Specific
Energy equation he notes that 'aircraft weight has been eliminated and does not enter into
ideal-zoom calculations' then 'In reality, however, this is not quite the case.', the amount
of energy gained or lost in the zoom (going to zero speed and max height) depends on the
average value of Specific Excess Power during the climb. "To illustrate this concept,
assume two fighters are identical in all respects, except one is heavier (maybe it is
carrying more internal fuel). If they begin zooms at the same speed and altitude (i.e.,
same Es *my note, same Specific Energy*, WWMG), Equation 4 *my note, Specific Excess Power
Equation, WWMG* shows that the lighter fighter will have greater Ps *my note, Specific
Excess Power, WWMG*, will therefore add more energy during the zoom, and will utimately
zoom higher than the heavy fighter. Ps as well as energy state must, therefore, be taken
into account when calculating the zoom capability, or "true energy height" of a fighter."

MY note here:
If you don't zoom to less than best sustained climb speed then the heavier plane with all
other things equal will win out as the extra kinetic better overcomes the extra drag at
higher speed. And I think that is what WWII zoom climb as referred by pilots is really about.
The heavier plane will be moving faster at the bottom of the highspeed dive and if he can
hold onto speed in the transition (a big if and depends on plane as well as pilot) then he
will have the better zoom.

This don't refer to anyone specifically though from posts I *can* name a few;
---------------------------------------------------------------------------------------------
To play the margins one has to know them and not just go by trueisms.
It's not just what works but HOW, which does not include every half-fast stick pull doable
by I can't say how many players who somehow expect good results from bad practices.

WWMaxGunz
08-27-2006, 10:17 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by KraljMatjaz:

we may have a derated Fw and a 1942 spitV while we should actualy have a 9lb boost 41 one, but A4 still dominates the spit. however, the fw was known to have aproximately same optimal climbing speed but much steeper climbing angle and was getting away from spit in a steep sustained climb, and spit couldn't follow, because if he would pull up even further to get firing solution, he would stall. </div></BLOCKQUOTE>

Please show the quote and source or give the source.

Where does it say that best climb of the FW is better than best climb of the Spitfire?

I've seen ONE document where those words were used and the two statements you show are not
connected except by assumption of some readers. Not fact, assumption. In the comparison
tests at Duxford the climbs were done at 400 kph, not best climb for either plane.

WWMaxGunz
08-27-2006, 10:26 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by KraljMatjaz:
at 600 kph any wing in game provides sufficient lift to pull 10 g turn, any of them, since wing is really stiffed in the air (for example think about V1 wingloading and it's size). if wings of bnz at slow speeds provided such a low lift, how then is it possible for a fw190 to take off with 1000 and even with 1800 kg bombs? or p51 with 1000, not to mention f4u? </div></BLOCKQUOTE>

Different airfoils and changes in AOA? http://forums.ubi.com/images/smilies/10.gif

HuninMunin
08-27-2006, 10:32 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by DuxCorvan:

Anyway, planes can't fly in the vacuum. Without air, both wings and propellers are useless. http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif </div></BLOCKQUOTE>

The Me-163 can http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif http://forums.ubi.com/images/smilies/16x16_smiley-happy.gif

Kettenhunde
08-27-2006, 10:36 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">If they begin zooms at the same speed and altitude </div></BLOCKQUOTE>


Problem is that two fighters of differing weights are usually not at the same speed or height when they begin the zoom generally due to the effect of weight.

Effect of weight on turning:

http://img127.imagevenue.com/loc302/th_96048_weight_effect_on_vert_turn_122_302lo.JPG (http://img127.imagevenue.com/img.php?image=96048_weight_effect_on_vert_turn_122 _302lo.JPG)http://img156.imagevenue.com/loc347/th_96073_Radial_accellerations_in_a_Loop_122_347lo .JPG (http://img156.imagevenue.com/img.php?image=96073_Radial_accellerations_in_a_Loo p_122_347lo.JPG)http://img127.imagevenue.com/loc302/th_96082_orientation_of_lift_122_302lo.JPG (http://img127.imagevenue.com/img.php?image=96082_orientation_of_lift_122_302lo. JPG)

All the best,

Crumpp

WWMaxGunz
08-27-2006, 10:40 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by VW-IceFire:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Brain32:
I mainly find dive and zoom characteristics of Fw190A's EXTREMELY poor. The sheer fact that you have to be at 700km/h+ to start pulling away from a Spitfire is downright ridiculous. Spitfire was not only lighter but also draggy comparing to FW190A so this really does not make sense.
I have yet to be caught in a dive in 51/47/38/Tempest by anything but a FW190D9, maybe K4? </div></BLOCKQUOTE>
Brain I have to call that out. IT depends alot on the Spitfire involved. In reading about the Spitfire IX and Spitfire VIII types...diving away from combat was less likely to work in a FW190A as it had against the Mark V. The thing is that the anecdote about FW190 pilots just diving away and leaving the Spitfires behind was made and is only specifically true for Mark V's. I've never read about the VIII or IX having the same problem. </div></BLOCKQUOTE>

If the 190 rolls 180 and uses his lift to change direction to down then hey he should be able to
leave the slower rolling Spit-any well behind. Gravity may be stronger than prop thrust but the
lift and kinetic that allows zoom also allows a plane to slingshot into a dive. How many extra
seconds before the Spit can roll over? How far past the FW that has already been headed in the
other direction? Only minus I can think for the FW is the not-great transition which with
gravity assist I think was no problem.

BfHeFwMe
08-27-2006, 10:41 AM
Don't discount game world limitations other than purely physics modeling. For example Med theatre allies ran ground attack sorties from 5000', dive, attack, destroy, climb. You could never spot and distinguish targets from that altitude in sim if you had to filter them out from the masses of objects that are missing. Your lucky if you can see them, let alone identify.

Same goes with airbattles, my gut feel is we tend to fight far to close in because of the horrid visuals nullifying the ability to high speed fight for most.

Kettenhunde
08-27-2006, 10:58 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Where does it say that best climb of the FW is better than best climb of the Spitfire? </div></BLOCKQUOTE>

The report exerpts and best climb speed from the POH's:

http://img138.imagevenue.com/loc581/th_97878_SpitV_climb_122_581lo.JPG (http://img138.imagevenue.com/img.php?image=97878_SpitV_climb_122_581lo.JPG)http ://img129.imagevenue.com/loc343/th_97883_Spit_IX_Climb_122_343lo.JPG (http://img129.imagevenue.com/img.php?image=97883_Spit_IX_Climb_122_343lo.JPG)ht tp://img126.imagevenue.com/loc535/th_97888_spit22_122_535lo.jpg (http://img126.imagevenue.com/img.php?image=97888_spit22_122_535lo.jpg)http://img130.imagevenue.com/loc420/th_97904_spit19_122_420lo.JPG (http://img130.imagevenue.com/img.php?image=97904_spit19_122_420lo.JPG)

The FW190A's Best Climb Speed:
http://img44.imagevenue.com/loc539/th_98073_190bestclimbspeed2_122_539lo.jpg (http://img44.imagevenue.com/img.php?image=98073_190bestclimbspeed2_122_539lo.j pg)

All the best,

Crumpp

JG14_Josf
08-27-2006, 11:29 AM
Hail,

I've banned myself from this forum for years. I'd like to discuss this topic. If anyone asks me to leave or calls me a Nazi, then, I'll ban myself again.

I've been asked to leave here (http://www.acompletewasteofspace.com/modules.php?name=Forums&file=viewtopic&t=7876)

A.
High mass does accelerate faster in earth€s gravity because higher mass causes gravity. Science has yet to explain gravity so anyone claiming absolute knowledge on the subject aught to write up their own theory for peer review.

B. Drag is least during unloaded flight where the wings do not generate acceleration up or down. THEREFORE all acceleration tests should be done while flying straight up or straight down.

C. It isn't coincidental that Energy Fighting (NOT the game term - BnZ) is VERTICAL fighting. Drag is least in the vertical.

D. WWII prop fighters cannot add any energy up or down. The most a prop fighter can do is eliminate drag up or down. In other words: If the prop fighter cannot lift the mass of the plane against gravity, then, the prop fighter will not add any greater altitude vertically than the theoretical Energy Height (no drag) with or without a motor. Therefore in vertical maneuvering the power to weight advantage is nothing. Power against drag is everything. More power to move air by engine power and power to move air by momentum (mass times velocity) is ENERGY POWER. Therefore in vertical maneuvers the high horsepower, high mass, and low drag planes dominate. Therefore Energy Fighting (vertical maneuvering) advantages favor high horsepower, high mass, and low drag planes over low horsepower, low mass, and high drag planes.

E. Aircraft size (displacement)is as much a factor as shape in determining drag performance.

Example: A 1/10th scale plane with the same exact power to weight as the full size plane will turn a much tighter turn.

If anyone wants to discuss this topic (actually wants to figure out answers), then, it may help to get each contradiction resolves one at a time.

The effect of mass on gravity in a vacuum is a good start. The real effect is insignificant.

The effect of mass on drag is another good start. The real effect is not insignificant.

If someone does wish to discuss this topic with me, then, please consider reading the link. If anyone wants me to stop then please say so I prefer to stop trying to penetrate the bullcrap as that resistance is unlimited - especially when the moderators shovel it.

Let me know sooner rather than later - please.

I can ban myself from this forum for another couple of years or longer.

NP

&lt;S&gt;

P.S. What is wrong about E-retention?

My OPINION:

High Engine Power, High Mass, and Low Drag planes - like FW, P-47, and Mustang do not gain or retain velocity in the vertical in the game compared to how those planes reportedly (consitantly) did in reality.

As if the game adds acceleration by adding prop thrust that is greater than plane mass. As if power to weight is modeled as a factor affecting vertcial acceleration.

You guys who absolutely must resort to misdirection tactics during discussions and thereby turn a reasonable discussion into an arugment can stuff it and by all means blame me for my attitude - it has been earned.

P.P.S. REPEAT - make my day, anyone, ask me to stop posting politely. I will stop.

Xiolablu3
08-27-2006, 12:01 PM
Calm down, calm down! (said in a liverpool accent http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif)

I am enjoying this debate, and learning as we go. Please carry on.

SithSpeeder
08-27-2006, 12:07 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> <BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">
Originally posted by DuxCorvan:

Anyway, planes can't fly in the vacuum. Without air, both wings and propellers are useless. Wink </div></BLOCKQUOTE>
The Me-163 can </div></BLOCKQUOTE>

"Fly" implies controlled flight. An Me-163 could NOT fly in a vacuum because it has no thruster system to maintain its direction--it relies on airfoils to do that.

* _54th_Speeder *

***
Why yes, yes I AM a rocket scientist.
***

NonWonderDog
08-27-2006, 12:13 PM
I don't get you people.

KE = 1/2*m*v^2
PE = m*g*h

In a total conversion of kinetic to potential energy, v = sqrt(2*g*h); h = v^2/(2*g)

Regardless of any relativistic effects you might want to throw in (seriously Josf, part A there is nonsense) MASS DOESN'T MATTER TO KINETIC/POTENTIAL ENERGY CONVERSION!

Mass only matters in the way it affects drag and the overcoming of drag.

The MAIN effect of mass is to INCREASE drag. More weight means more lift for the same flight conditions, and lift induces drag. This is true at any speed, but especially true at low speed.

The SECONDARY effect of mass is to OVERCOME drag. The more massive the object, the greater its momentum. Drag, being a force, is a partial derivative of momentum. Drag increases with approximately the square of velocity (I know I'm oversimplifying), so this effect is only noticable at high speed.


There is NO reason whatsoever for a heavier plane to be more maneuverable than an equivalent lighter plane. In fact, the opposite is true. In heavy maneuvering the heavy plane will need more lift. At high angles of attack, drag increases much more quickly than lift. Although the weight serves to overcome drag, it ALSO serves to overcome LIFT.

Weight doesn't directly matter. What matters is the L/D ratio of the wing at the angle of attack needed to generate the required load factor. For two otherwise identical planes, the heavier plane will have a WORSE L/D ratio than the lighter plane at the same loading in nearly all cases.

Weight increases terminal velocity, but has no other benefit.

If you still refuse to believe, then tell me: why didn't Willi Messerschmitt add lead weights to the Bf-109 to improve its "energy retention"?

KraljMatjaz
08-27-2006, 12:16 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by WWMaxGunz:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by KraljMatjaz:

we may have a derated Fw and a 1942 spitV while we should actualy have a 9lb boost 41 one, but A4 still dominates the spit. however, the fw was known to have aproximately same optimal climbing speed but much steeper climbing angle and was getting away from spit in a steep sustained climb, and spit couldn't follow, because if he would pull up even further to get firing solution, he would stall. </div></BLOCKQUOTE>

Please show the quote and source or give the source.

Where does it say that best climb of the FW is better than best climb of the Spitfire?

I've seen ONE document where those words were used and the two statements you show are not
connected except by assumption of some readers. Not fact, assumption. </div></BLOCKQUOTE>

oh, please. here:

http://img138.imagevenue.com/loc581/th_97878_SpitV_climb_122_581lo.JPG

thanks to kettenhunde, I really am not in a mood to search over my utterly messed up hard drive http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif.

Saburo_0
08-27-2006, 12:17 PM
Very Good and interesting discussion. Thank you all and please continue!
http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

tigertalon
08-27-2006, 12:30 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by NonWonderDog:
I don't get you people.

KE = 1/2*m*v^2
PE = m*g*h

In a total conversion of kinetic to potential energy, v = sqrt(2*g*h); h = v^2/(2*g)

Regardless of any relativistic effects you might want to throw in (seriously Josf, part A there is nonsense) MASS DOESN'T MATTER TO ENERGY CONVERSION!

Mass only matters in the way it affects drag and the overcoming of drag.

The MAIN effect of mass is to INCREASE drag. More weight means more lift for the same flight conditions, and lift induces drag. This is true at any speed.

The SECONDARY effect of mass is to OVERCOME drag. The more massive the object, the greater its momentum. Drag, being a force, is a partial derivative of momentum. Drag increases with approximately the square of velocity (I know I'm oversimplifying), so this effect is only noticable at high speed.


There is NO reason whatsoever for a heavier plane to be more maneuverable than an equivalent lighter plane. In fact, the opposite is true. In heavy maneuvering the heavy plane will need more lift. At high angles of attack, drag increases much more quickly than lift. Although the weight serves to overcome drag, it ALSO serves to overcome LIFT.

Weight doesn't directly matter. What matters is the L/D ratio of the wing at the angle of attack needed to generate the required load factor. For two otherwise identical planes, the heavier plane will have a WORSE L/D ratio than the lighter plane at the same loading, ALWAYS.

Weight increases terminal velocity, but has no other benefit.

If you still refuse to believe, then tell me: why didn't Wili Messerschmidt add lead weights to the Bf-109 to improve it's "energy retention"? </div></BLOCKQUOTE>

You are wrong.

Mass does matter to energy retention. Why? What do you think, if you fire a handgun bullet and a 125mm HEAT shell with equal muzzle velocity into a watter, which one will stop first?

Your post is correct only if you assume all aircraft weight the same. But they don't.

If you freefall drop two cubes (or balls), one twice larger than the other (so 8 times more weight), the heavier will drop faster, as it has only 4 times the drag. Bigger objects have lower drag/mass ratio than small ones.

With large cube it's the same as you would glue together 8 small ones. And if it falls face down, it's obvious that rear 4 cubes don't contribute to drag.

mass increases as L^3 (where L is characteristic dimension of an object) while drag does as L^2.

So if you take a P47 and a 1:12 model of P47 with equal Power/weight, the large one will retain energy WAY better. Catch my drift?

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by NonWonderDog:
If you still refuse to believe, then tell me: why didn't Wili Messerschmidt add lead weights to the Bf-109 to improve it's "energy retention"? </div></BLOCKQUOTE>

because it would be a small benefit for ruining handling, climb rate, range etc. of a plane.

Still: if you take a 109 with and one without a bomb, get them into a level flight with same speed, switch off the engines and pull them into climb, the one with the bomb will climb higher than the other one.

Xiolablu3
08-27-2006, 12:32 PM
Lighter is OBVIOUSLY better for a fighter, I think we all know that.

The P51H was a remod of the P51D to try adn get the weight down.

The SPitfire was studied in order to better understand why the P51 was so much heavier than the Spitfire.

I think we should get back to the basics again.

Just what benefits do people expect from a heavier fighter? My suggestions were just uninformed guesses I know little about this subject. So could someone with more knowledge state :-

Just what benefits are we expecting from a heavier fighter?

tigertalon
08-27-2006, 12:37 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Xiolablu3:
Lighter is OBVIOUSLY better for a fighter, I think we all know that. </div></BLOCKQUOTE>

Isn't this just a false assumption a lot of people are categoricaly trying to protect just because it "seems logical"?

Kettenhunde
08-27-2006, 12:39 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">There is NO reason whatsoever for a heavier plane to be more maneuverable than an equivalent lighter plane. In fact, the opposite is true. The heavier plane will have a greater terminal velocity, but few other benefits. </div></BLOCKQUOTE>

You should probably read this link below. While you€re correct that weight shrinks the envelope, the relationship becomes more complicated in maneuvering flight. Not all conditions of maneuvering flight dictate weight is a bad thing.

The lighter aircraft gains on the up vector but the heavier aircraft gains on the down vector in a loop for example. This includes radius and rate changes that are advantageous. At the top of the loop, the heavier aircraft will €œoutturn€ the lighter one. On the down vector the heavier aircraft can also €œturn tighter€ than the lighter one if the pilot chooses. If he matches the lighter aircraft rate and radius then he will have more energy in the up vector.

The advantages are reversed in the loop for the lighter aircraft. So it is not to say the heavier aircraft will always out loop the lighter. Just that each gains advantages in different portions of the maneuver. The actual relative maneuvering performance is dependant upon power available to power required. It is possible to have a heavier aircraft match or improve the steady state turn performance of a lighter variant of the same model provided a suitable increase in power available occurs. All it takes is good engineering.

http://forums.ubi.com/eve/forums/a/tpc/f/23110283/m/851...801090674#9801090674 (http://forums.ubi.com/eve/forums/a/tpc/f/23110283/m/8511049574?r=9801090674#9801090674)

You can observe the effects of a power increase by examining the results of the USN F2F steady state turn testing.

http://www.onpoi.net/ah/pics/users/503_1154714942_effectofthrust.jpg

While the lower powered aircraft can actually fly at a slower speed at no point in the envelope can it outturn the higher powered variant.

Adding weight in and of itself is in no way desirable. However adding thrust in proportion to weight is not a bad thing at all.

All the best,

Crumpp

msalama
08-27-2006, 12:42 PM
An interesting discussion indeed. S! and please continue http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

Xiolablu3
08-27-2006, 01:04 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by tigertalon:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Xiolablu3:
Lighter is OBVIOUSLY better for a fighter, I think we all know that. </div></BLOCKQUOTE>

Isn't this just a false assumption a lot of people are categoricaly trying to protect just because it "seems logical"? </div></BLOCKQUOTE>

If this is so then whats the point of hte whole P51H program to try and get the plane lighter by studying the Spitfire? Was this a complete waste of time?

http://www.mustangsmustangs.net/p-51/p51variants/P-51H.shtml

I am pretty sure that lighter is better for a fighter otherwise, as was said before, Willi would have added weight to his 109. The SPitfire would have added weights in the body, etc.

tigertalon
08-27-2006, 01:12 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Xiolablu3:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by tigertalon:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Xiolablu3:
Lighter is OBVIOUSLY better for a fighter, I think we all know that. </div></BLOCKQUOTE>

Isn't this just a false assumption a lot of people are categoricaly trying to protect just because it "seems logical"? </div></BLOCKQUOTE>

If this is so then whats the point of hte whole P51H program to try and get the plane lighter by studying the Spitfire? Was this a complete waste of time?

http://www.mustangsmustangs.net/p-51/p51variants/P-51H.shtml

I am pretty sure that lighter is better for a fighter otherwise, as was said before, Willi would have added weight to his 109. The SPitfire would have added weights in the body, etc. </div></BLOCKQUOTE>

I agree with "lighter is better" once you have an existing airframe. But overall it aint. Why weren't then all fighters from WW2 ultra light biplanes? I'm pretty sure Fw190 was better fighter than I-153 alhough it weighted more than twice as much.

Plus I think we all agree late war fighters were better than early ones although they were heavier.

Now a hypothetical question for us all:

If you had an option to take a ww2 fighter or to take it's exact copy that would be, let's say 1.5 times bigger, which one would you take?

I'd take a big one, no question about it. Well, yes, in this sim it would be the small, but IRL it would be the large one. http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

JG14_Josf
08-27-2006, 01:13 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">seriously Josf, part A there is nonsense </div></BLOCKQUOTE>

If the words written are misunderstood by the reader, then, who is responsible for the error?

Part A is nonsense?

Part A:

A.
High mass does accelerate faster in earth€s gravity because higher mass causes gravity. Science has yet to explain gravity so anyone claiming absolute knowledge on the subject aught to write up their own theory for peer review.

Absolute knowledge:

"part A there is nonsense"

Absolute knoweldge?

Note: I propose ideas and ask for proof if the ideas (presented as fact) are nonsense.

How fast will the earth accelerate toward the moon if both objects stopped now?

If the question is nonsense, then, I need to ask for a definition of nonsense.

If the question is not nonsense, then, the accusation is exposed for what it is - intended or not.

Why not just cut the bullcrap and say:

Josf is STUPID.

I can take it, then, show exactly how stupid Josf is and we can both move on. Everyone else can add or subtract from the actual perception of the actual facts (peer review).

If you misunderstand the statement, then, please ignore it or ask for clarification.


Example:

"anyone claiming absolute knowledge on the subject aught to write up their own theory for peer review."

If anyone possesses absolute knowledge concerning the relationship between mass and gravity (the statement that is attacked as being nonsense), then, prove it - otherwise move on to something that can be discussed rationally in the effort to get closer to the truth rather than farther away from the truth by misdirection and innuendo.

Calm down?

I am calm. If you misunderstand the reason for my defensive words, then, perhaps you are one of those people who enjoy the consistent misdirection that occurs on nearly every topic argued on this board (an many other boards). I'm asking for clarification (in response to misdirection).

I do not enjoy misdirection and I see only one way to battle against it i.e. expose it immediately, consistently, and avoid it when exposure does not work. I've done this consistently as a discipline for many years and it certainly does work in avoiding misdirection and argument. I've avoiding misdirection and argument for years. I can avoid it again.

Who wants to argue? Raise you hand and let me know I am unwelcome. I will leave. That is a calm and conscious decision; a no brainer - simple and easy to understand. If you do not understand than raise your hand, I can explain it, or simply ask me to leave. Don't expect me to calm down since I am not at all un-calm.

I could be misunderstanding the meaning of the word calm like my obvious minsuderstanding of the term gravity and mass.

Where exactly does the vocabulary contend with reality?

What is wrong about E-retention?

"MASS DOESN'T MATTER TO KINETIC/POTENTIAL ENERGY CONVERSION!"

The bold type above are words. Those words can be percieved as a stand alone statement or as a statement in context. Either way the fact is that mass matters in a relative manner. The relative insignificance of or 'how much' mass matters, in a vacuum, has already been noted by my earlier post as a matter of fact.

None of the above text, in context, would be required if the poster did not call into question the validity of my statement by using the word NONSENSE.

"Mass only matters in the way it affects drag and the overcoming of drag."

The word 'only' is an absolute term. Disregarding the fact that mass does matter (insignificantly)because mass is proportional to gravity (in some manner not known in science but definitely measurable), disregarding that fact, the effort to understand reality moves, by the poster, to the subject of drag.

I've already noted the need to do this.

"There is NO reason whatsoever for a heavier plane to be more maneuverable than an equivalent lighter plane."

The subject is:

"What is wrong about E-retention?"

If my suggestion to focus on vertical energy retention study (Energy Fighting)is ignored and the topic moves toward turn performance or vector maneuvering that is not confined to vertical vectors, then, please consider noting the following chart:

http://mysite.verizon.net/res0l0yx/IL2Flugbuch/Corner%20time.jpg

That is a EM (Energy Maneuverability) chart constructed by John Boyd with the help of Chuck Yeager as they tested and recorded relative performace between a capture Mig-15 and the F-86.

Note the white area.

If the discussion moves from vertical performance where wing lift is not a factor of drag and the discussion moves into lift drag factored performance, then, the white area cannot be ignored without moving into wishful thinking - in my opinion.

I can add "in my opinion" in every sentence I write however that would be adding even more text to an already large post and that would tend to divert from the topic:

What is wrong about E-retention?

NonWonderDog
08-27-2006, 01:15 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by tigertalon:
You are wrong.

Mass does matter to energy retention. Why? What do you think, if you fire a handgun bullet and a 125mm HEAT shell with equal muzzle velocity into a watter, which one will stop first?

Your post is correct only if you assume all aircraft weight the same. But they don't.

If you freefall drop two cubes (or balls), one twice larger than the other (so 8 times more weight), the heavier will drop faster, as it has only 4 times the drag. Bigger objects have lower drag/mass ratio than small ones.

With large cube it's the same as you would glue together 8 small ones. And if it falls face down, it's obvious that rear 4 cubes don't contribute to drag.

mass increases as L^3 (where L is characteristic dimension of an object) while drag does as L^2.

So if you take a P47 and a 1:12 model of P47 with equal Power/weight, the large one will retain energy WAY better. Catch my drift?
</div></BLOCKQUOTE>

All right, sure. A larger plane with the same density (a reasonable approximation) will have a lower ratio of parasitic drag to mass. AND?

While this will accent differences in unloaded dives (and while were at it: there is no tactical benefit of a vertical dive -- it doesn't last long enough to gain you any separation and you'd have to pull out of it at the end and destroy your speed advantage through the HUGE induced drag of your heavy plane), it means little in maneuvering.

Sure, in high-speed level flight you might have 75% more parasitic drag than induced drag, but that still has nothing to do with maneuvering. Induced drag increases quickly with load factor, and DEFINITELY dominates at 5G. A heavier plane will have MORE induced drag per G of loading than a lighter plane, and size has little effect on that. (There would be a different Reynolds number. It would even be the biggest difference between your model P-47 and the full-scale one. The difference between a Me-109 and a P-47 in this regard, however, is negligable.)


<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Kettenhunde:
The lighter aircraft gains on the up vector but the heavier aircraft gains on the down vector in a loop for example. This includes radius and rate changes that are advantageous. At the top of the loop, the heavier aircraft will €œoutturn€ the lighter one. On the down vector the heavier aircraft can also €œturn tighter€ than the lighter one if the pilot chooses. If he matches the lighter aircraft rate and radius then he will have more energy in the up vector.

The advantages are reversed in the loop for the lighter aircraft. So it is not to say the heavier aircraft will always out loop the lighter. Just that each gains advantages in different portions of the maneuver. The actual relative maneuvering performance is dependant upon power available to power required. It is possible to have a heavier aircraft match or improve the steady state turn performance of a lighter variant of the same model provided a suitable increase in power available occurs. All it takes is good engineering.
</div></BLOCKQUOTE>

None of that has anything at all to do with energy retention. The heavier plane still loses more energy from induced drag if it turns at the same load factor.

The weight of the plane does not have the effect you state in the verticle loop situation. Although the weight vector may be bigger for the heavier plane, mass and weight are directly proportional. Weight, a force, is a partial derivative of momentum, not velocity. At the same speed, parasitic drag would have less effect on the heavy plane, but the effect of induced drag would be greater.

NonWonderDog
08-27-2006, 01:23 PM
Josf, really. Do we need to include the attraction of the Earth to the aircraft dependent on its mass? Do we need to include the distortion of space time and the slowing of an object in a relativistic sense as created by its mass?

If not, we can safely disregard the effect of the mass of an object in freefall in a vacuum. Two objects of different mass, in a vacuum, will fall towards Earth at the same rate. It is not necessary or helpful in the least to clarify that this is only true if (A) the mass of the object is less than 1% of Earth, (B) the objects are falling at a velocity less than .7c, (C) the objects are small enough that gravity gradient does not affect them, and (D) the object in question is not so small as to be unobservable due to Heisenberg's Uncertainty Principle.

Part A there may not be absolute nonsense, but it is without a doubt obfuscation. If something has an effect so small it cannot even be OBSERVED, what is the point in mentioning it?

tigertalon
08-27-2006, 01:24 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by NonWonderDog:
All right, sure. A larger plane with the same density (a reasonable approximation) will have a lower ratio of parasitic drag to mass. AND?

While this will accent differences in unloaded dives (and while were at it: there is no tactical benefit of a vertical dive -- it doesn't last long enough to gain you any separation and you'd have to pull out of it at the end and destroy your speed advantage through the HUGE induced drag of your heavy plane), it means little in maneuvering.

Sure, in high-speed level flight you might have 75% more parasitic drag than induced drag, but that still has nothing to do with maneuvering. Induced drag increases quickly with load factor, and DEFINITELY dominates at 5G. A heavier plane will have MORE induced drag per G of loading than a lighter plane, and size has little effect on that. (There would be a different Reynolds number. It would even be the biggest difference between your model P-47 and the full-scale one. The difference between a Me-109 and a P-47 in this regard, however, is negligable.)
</div></BLOCKQUOTE>

Of course I agree heavier plane is harly as maneouverable as light one. Still, I'd rather be in a F6F (IRL that is, not PF!!) than A6M. In energy fighting heavier (not being "heavied" on purpose, but larger, heavier) fighter should dominate, as with the 'same effective density' it will be loosing less E durign zoom climbs and dives as opposed to ligher, more maneouverable fighters.

Still, I agree, in pure maneouvering light one will prevail. But in this case I think all WW2 airforces would be using biplanes and Ki-27 like planes in 1945. IIRC they didn't, they all tended towards heavier, energy fighters.

NonWonderDog
08-27-2006, 01:28 PM
OK, tigertalon, that is true. The difference, however, is marginal. What benefit there is in 1G climbs and dives (and there is a benefit, I'm not disputing that) is offset by the act of pitching the plane up or down. If you enter a zoom climb at 4G you can hardly expect your plane's weight to carry you beyond an adversary. If you enter the climb at 2G, sure, it's possible. Coming out of a BnZ pass, though, you'll be pulling MUCH more than 2G.

But the benefit in this case is due to differences in size! The large wings don't generate as much of the extra induced drag that would normally be associated with the extra mass. Except at very high speed the only effects of the extra mass are negative, and it takes energy to get to high speed.


I would say that planes got bigger and heavier in WWII so that they could (A) carry more powerful engines, (B) carry more fuel, and (C) carry more powerful weapons. It wasn't so they could go faster in dives.

JtD
08-27-2006, 01:30 PM
Um, somehow looks like I opened pandoras box with my little physics excerpts...

For today just let me add:

The advantage of an heavier plane solely lies with the intial E it has. At the same speed and alt but with heavier weight, it has more E. After that point, extra weight offers NO bonuses. The easiest comparism would be a planes with a full vs. the same plane with an empty fuel tank. After starting with an E advantage directly proportional to it's weight advantage, the heavier plane will bleed more E in about every maneuver while gaining the same E from the same engine as the lightweight plane. In the end it means it will lose the E advantage.

Xiolablu3
08-27-2006, 01:31 PM
Lol Josef, you seem a bit worked up about things.

Take a chill pill, brother. http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

The subject of energy rentention aint worth a heart attack http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

Xiolablu3
08-27-2006, 01:33 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by tigertalon:
Still, I'd rather be in a F6F (IRL that is, not PF!!) than A6M. . </div></BLOCKQUOTE>

I totally agree with this statement. In the game too, the F6F is much better than the Zero.

The zero is terrible at rolling and also at high speed manouvring. I think the ingame battle between these 2 is excellent, with the F6F being much better if you are a veteran pilot.

DuxCorvan
08-27-2006, 01:34 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by HuninMunin:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by DuxCorvan:

Anyway, planes can't fly in the vacuum. Without air, both wings and propellers are useless. http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif </div></BLOCKQUOTE>

The Me-163 can http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif http://forums.ubi.com/images/smilies/16x16_smiley-happy.gif </div></BLOCKQUOTE>

Yes, it may be able because of the sheer thrust of its rocket engine, but wings wouldn't provide any lift. If thrust was superior to weight, it could 'hover' for some time, but I wouldn't like to be the pilot when fuel is out and the thing falls like a stone.

HellToupee
08-27-2006, 01:48 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by tigertalon:
I agree with "lighter is better" once you have an existing airframe. But overall it aint. Why weren't then all fighters from WW2 ultra light biplanes? I'm pretty sure Fw190 was better fighter than I-153 alhough it weighted more than twice as much.
</div></BLOCKQUOTE>

because fittinga 2000hp engine and cannons simply isnt possible to a ultralight, why did the spitfire get heavyer? because they had to add bigger more powerful engines each time requiring a stronger airframe and other additions. Its very easy to add weight, u want a heavy plane build it out of lead or steal or wood or something not light weight aluminum.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">
Plus I think we all agree late war fighters were better than early ones although they were heavier. </div></BLOCKQUOTE>

and planes like the bearcat where designed to be light as possible with biggest engine it could mount. Pretty sure it weighed less than a p47 and p38.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">
If you had an option to take a ww2 fighter or to take it's exact copy that would be, let's say 1.5 times bigger, which one would you take?

I'd take a big one, no question about it. Well, yes, in this sim it would be the small, but IRL it would be the large one. http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif </div></BLOCKQUOTE>

and why would you take it? What advantages to u think it would have.

fordfan25
08-27-2006, 02:55 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by ColoradoBBQ:
There's nothing wrong with E-rentention in-game. It just the problem of pilots wondering why Zeroes and Ki-61s could keep up with their F4Us and P-38s in zoom climbs. </div></BLOCKQUOTE>or in zoom dive http://forums.ubi.com/images/smilies/51.gif

BfHeFwMe
08-27-2006, 02:55 PM
The P-38's PORKED!!!

http://forums.ubi.com/images/smilies/16x16_smiley-mad.gif

fordfan25
08-27-2006, 02:58 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by JtD:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by DuxCorvan:

I mean, you are in a P-47, and you see a group of Zeros beneath you... </div></BLOCKQUOTE>

Ok, I simulated this in the QMB. I was in a D-27 and four veteran A6M5b started with disadvantage on the Pacific island map at 3000 meters. I dived past them, zoomed up, turned around, shot one down, zoomed up, turned around, shot one down, extended, came back, chased one, shot it down, headed towards the last, flew past him, zoomed up, turned around, shot him up and finally down. Seems to work for me, nowhere near your description.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">In real life, lighter Zeros couldn't catch you in the initial stages of a dive, because of them being so light. </div></BLOCKQUOTE>

Only if you are entering the dive at high speeds. At slow speeds, acceleration is more about power/weight, even in dives. The A6M has advantages over the P-47 there.

The fact that AI ignore dive limits is frustrating indeed. http://forums.ubi.com/groupee_common/emoticons/icon_mad.gif

Thanks for the input. http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif </div></BLOCKQUOTE>O my he can shoot down AI planes ...well that proves everything lol http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

tigertalon
08-27-2006, 03:28 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by HellToupee:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">
If you had an option to take a ww2 fighter or to take it's exact copy that would be, let's say 1.5 times bigger, which one would you take?

I'd take a big one, no question about it. Well, yes, in this sim it would be the small, but IRL it would be the large one. http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif </div></BLOCKQUOTE>

and why would you take it? What advantages to u think it would have. </div></BLOCKQUOTE>

Exactly the same advantages a P-47 would have above, let's say a P-35.

(keep in mind that by scaling an AC up the engine is scaled up and therefore powered up too)

JG4_Helofly
08-27-2006, 03:56 PM
It would be very nice if Oleg would help us a bit in his free time http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif I mean, he should know how it works.

DuxCorvan
08-27-2006, 04:38 PM
Yeah, I'm sure Oleg hired a Physics Nobel Prize to design aircraft FMs... http://forums.ubi.com/groupee_common/emoticons/icon_razz.gif

Come on, you know SOMETHING is wrong. And it is: AI doesn't follow the rules we do.

Online fights, while not perfect, and despite some over/under-modeling, are more or less *similar* to RL, or at least, *plausible* or *believable*.

Offline fighting is a joke, an UFO festival. And I don't need proof, nor digging Einstein out of his tomb with a chalk and a blackboard. It's OBVIOUS to any serious offline player.

HuninMunin
08-27-2006, 04:46 PM
The Thing that is wrong is that all our planes are modelled within an engine that was designed to simulate ONE russian ground attack aircraft to beginn with.
It does not have a proper high alt modell and it simulates all FMs on modiefied IL-2s.
Thats why some things are off in plane to plane comparsion.

Kettenhunde
08-27-2006, 05:12 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">None of that has anything at all to do with energy retention. The heavier plane still loses more energy from induced drag if it turns at the same load factor.

The weight of the plane does not have the effect you state in the vertical loop situation. Although the weight vector may be bigger for the heavier plane, mass and weight are directly proportional. Weight, a force, is a partial derivative of momentum, not velocity. At the same speed, parasitic drag would have less effect on the heavy plane, but the effect of induced drag would be greater. </div></BLOCKQUOTE>

I am sorry but weight does affect the aircraft in exact manner I stated. My statement is right out of the USN Flight Training Manual. When the vector of lift is below the horizon, weight contributes to thrust allowing better turn performance. Power available to power required being the fundamental relationship for turn performance.

Induced drag is not nearly the force you think it is at high speeds or in a turn. While it's coefficient rises dramatically, the power or rate of work is more like a wall that suddenly rises at the edge of the stall.

http://www.av8n.com/how/htm/4forces.html#sec-coeff-force-power

Coefficient of induced drag vs angle of attack:

http://www.av8n.com/how/htm/4forces.html#fig-coeff-alpha

Coefficient of induced drag vs airspeed:

http://www.av8n.com/how/htm/4forces.html#fig-coeff-ias

Force or capacity to do work of induced drag over airspeed:

http://www.av8n.com/how/htm/4forces.html#fig-force-ias

And finally the power or rate at which that force is applied:

http://www.av8n.com/how/htm/4forces.html#fig-power-ias

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">In the mushing regime, most of the drag is induced drag. As you go slower and slower, induced drag increases dramatically and parasite drag becomes almost negligible. </div></BLOCKQUOTE>

http://www.av8n.com/how/htm/4forces.html#sec-induced-vs-parasite

The power of induced drag is like a wall that occurs on the backside of the lift curve in the mushing realm.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Nothing magical happens at the critical angle of attack. Lift does not go to zero; indeed the coefficient of lift is at its maximum there. Vertical damping goes smoothly through zero as the airplane goes through the critical angle of attack, and roll damping goes through zero shortly thereafter. An airplane flying 0.1 degree beyond the critical angle of attack will behave itself only very slightly worse than it would 0.1 degree below. </div></BLOCKQUOTE>

Maximum turn performance occurs at CL max. Not on the other side of the lift curve where the power of induced drag becomes a factor.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">If we go far beyond the critical angle of attack (the €œdeeply stalled€ regime) the coefficient of lift is greatly reduced, and the coefficient of drag is greatly increased.
</div></BLOCKQUOTE>

It only when the heavier aircraft exceeds CL max and drops on the backside of the lift curve that induced drag would be a mitigating factor.

http://www.av8n.com/how/htm/spins.html#sec-stall-cause-effect

All the best,

Crumpp

p1ngu666
08-27-2006, 08:08 PM
WW2 aircraft and nearly all aircraft got/get heavier to carry more stuff or tobe more "useful" and operationaly effective. mostly bigger guns, engines (to go faster/climb better) nav equipment, fuel, armour, ordinancy, visability aswell..

the problem we have ingame is that the airframes are much different, so its not a "fair test", specialy our combat.

the problem is howto pinpoint the amount of advantage/disadvantage that you should have.

oh and our spitvb has 9lb boost speed (hence mega slow) but 16lb boost climb. at 9lb boost climb the 190a4 is easily better.

i can see how the heavier plane has the advantage going down, but that doesnt seem like a viable long term solution to me

WWMaxGunz
08-27-2006, 10:20 PM
All fine Crumpp but simple fact is that same plane but heavier does need more lift and that
need is multiplied with G's in a turn. More lift needs more AOA gets more induced drag.

horseback
08-27-2006, 10:23 PM
I think one factor is being ignored here. The assumption seems to be that it is just a matter of wieght, that the Z&B a/c are the same in terms of drag.

However, it is my understanding that these a/c had fairly sophisticated shapes and streamlining to optimise their power, even the bulbous P-47. Their designers wouldn't have bothered with all the extra weight otherwise.

The Mustang, which was much heavier than a Spitfire Mk IX, yet used the same engine, was generally faster. Similarly, the P-47, which was s good bit heavier than the Hellcat, was also faster, even though it used essentially the same engine. Both of these AAF aircraft were optimized for speed up high.

It stands to reason that if they go faster in the horizontal, when they drop their noses a bit they should pick up speed a good bit faster than the 'higher lift but draggier' turn and burn types. They are heavier in proportion to their size, they are smoother and more efficient at high speeds, and they should reach terminal speed much sooner than the lightweights. If I can out accelerate those nifty Japanese sports cars going downhill in my (heavier) little pickup truck, just think what I could do if it were aerodynamically more efficient...

They should also be able to translate all that extra momentum into a more efficient transition to level flight or zoom climb, allowing their pilots to take and hold the initiative..

The historical record indicates that they did these things consistantly, else we'd still be using biplanes (picture a jet powered CR 42, anyone?).

In-game, the speed/E scrubs off of these types faster than a porn star sheds her knickers, while the higher drag/lift types seem to be able not only to save it, but earn interest.

cheers

horseback

fordfan25
08-27-2006, 10:34 PM
But you do not know to power of the dark side.

WWMaxGunz
08-27-2006, 10:42 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by KraljMatjaz:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by WWMaxGunz:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by KraljMatjaz:

we may have a derated Fw and a 1942 spitV while we should actualy have a 9lb boost 41 one, but A4 still dominates the spit. however, the fw was known to have aproximately same optimal climbing speed but much steeper climbing angle and was getting away from spit in a steep sustained climb, and spit couldn't follow, because if he would pull up even further to get firing solution, he would stall. </div></BLOCKQUOTE>

Please show the quote and source or give the source.

Where does it say that best climb of the FW is better than best climb of the Spitfire?

I've seen ONE document where those words were used and the two statements you show are not
connected except by assumption of some readers. Not fact, assumption. </div></BLOCKQUOTE>

oh, please. here:

http://img138.imagevenue.com/loc581/th_97878_SpitV_climb_122_581lo.JPG

thanks to kettenhunde, I really am not in a mood to search over my utterly messed up hard drive http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif. </div></BLOCKQUOTE>

You show a tiny picture of what looks like words on a page except nothing of it is readable.

WWMaxGunz
08-27-2006, 10:58 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by JG14_Josf:
A.
High mass does accelerate faster in earth€s gravity because higher mass causes gravity. Science has yet to explain gravity so anyone claiming absolute knowledge on the subject aught to write up their own theory for peer review.
</div></BLOCKQUOTE>

LMAO! In the face of Galileo, Newton and Einstein you claim THAT?

Peer review? Ever heard of the LAW OF GRAVITY?

It's good enough to closely calculate from orbital mechanics to falling objects.

All masses attract by exact formula known well over 200 years now at less than relativistic
speeds. The more complete theory of General Relativity which explains gravity even at
relativistic speeds is very close to 100 years old and used to make uncanny predictions even
to the sub-atomic.

But since none of those men are GOD it must all be bulls#it, huh?

Attraction between masses is total mass of both.
Take Earth and the Moon. Both rotate around a point about 100 ft between Earth center and
Lunar center. They rotate around each other but since Earth is some 8,000 MILES wide you
won't notice the 100 FEET. It only requires Newton's formulae to do that, the error is
knowing PRECISE masses of Earth and Moon which through orbital observation we can closely
guess.

Attraction between masses is TOTAL of both.
What is ratio of these two total masses?
A) Earth plus 2000 kg plane.
B) Earth plus 4000 kg plane.
The ratio is so close to ONE it is not worth calculating the difference.

We round off acceleration due to gravity at or near Earth surface to less than 10,000 places
so for all PRACTICAL purposes, both planes have the same acceleration due to gravity.

Review that.

Kettenhunde
08-27-2006, 11:26 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">All fine Crumpp but simple fact is that same plane but heavier does need more lift and that
need is multiplied with G's in a turn. More lift needs more AOA gets more induced drag. </div></BLOCKQUOTE>

Certainly.

However the power of induced drag does not become a factor until the aircraft is on the backside of the lift curve in the mushing realm. The heavier aircraft also has more momentum but will certainly bleed more E when it does hit the induced drag wall.

So to characterize the heavier aircraft as bleeding more energy is not necessarily the case depending on how the pilot flies the aircraft.

Now that being said, the heavier aircraft also has smaller envelope as long as the vector of lift is above the horizon. In the majority of the conditions of flight, the vector is above the horizon. Especially when using angle tactics.

When the vector of lift is below the horizon weight acts to increase the envelope by enhancing thrust. This becomes most useful in energy tactics where it is more common to have the vector of lift orientated below the horizon in the vertical.

Weights reduces the load factor limits, lift limits of the envelope, and negatively effects all parameters of flight. Adding thrust raises the sustainedload factor limits with in the structural limits and also raises the lift limits. It positively effects all parameters of flight. Propeller aircraft gain most of their thrust lift benefits at low speed in proportion to the thrust coefficient.

So adding weight with a proportional gain in thrust is not necessarily a performance robbing measure. These design engineers were much smarter than any of us on their own designs and very much knew what they were doing.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">You show a tiny picture of what looks like words on a page except nothing of it is readable. </div></BLOCKQUOTE>

Click on the original I posted. It is a thumbnail linked to the document excerpt.

All the best,

Crumpp

NonWonderDog
08-27-2006, 11:55 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Kettenhunde:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">None of that has anything at all to do with energy retention. The heavier plane still loses more energy from induced drag if it turns at the same load factor.

The weight of the plane does not have the effect you state in the vertical loop situation. Although the weight vector may be bigger for the heavier plane, mass and weight are directly proportional. Weight, a force, is a partial derivative of momentum, not velocity. At the same speed, parasitic drag would have less effect on the heavy plane, but the effect of induced drag would be greater. </div></BLOCKQUOTE>

I am sorry but weight does affect the aircraft in exact manner I stated. My statement is right out of the USN Flight Training Manual. When the vector of lift is below the horizon, weight contributes to thrust allowing better turn performance. Power available to power required being the fundamental relationship for turn performance.
</div></BLOCKQUOTE>

Yes, but this should be true to exactly the same extent no matter the weight of the plane. You shouldn't see a greater effect in a heavier plane, becase the heavy plane has exactly enough extra momentum to cancel it out. Heavier planes don't somehow maneuver better than lighter planes when they're pointed towards the ground.

At maximum turn rate, as you referenced before, the heavier plane will simply not turn as tightly. I thought this went without saying, and you shouldn't be trying to turn as hard as possible in an "energy fighter" anyway.

What I said, was that if two planes are both to maintain the same load factor ("Gs"), and one is heavier than the other, the heavier plane will have greater induced drag due to the extra lift required to overcome the weight. This is all undeniably true unless the load factor desired is so great that the the heavier plane will STALL before reaching it. The light plane still maneuvers better. Even in a dive.


I think you're misinterpreting the induced drag/airspeed graph. This graph is at a constant 1 G. Induced drag increases at low speed because AoA must increase at low speed in order to maintain 1 G. That is the ONLY reason. Increasing AoA in order to turn has EXACTLY the same effect on induced drag coefficients. You'll in fact have MORE induced drag in the turning case (in an absolute sense) BECAUSE the plane has a greater airspeed. The ratio of induced to parasitic drag will be less than if you're stuggling to stay in the air at minimum controllable speed, but I can't see how that makes a difference.

As for drag power? The usual formula when dealing with aircraft is P = F * V. For drag power, that's Drag * airspeed. High drag * High airspeed &gt; High drag * low airspeed. I really think you're misinterpreting those graphs.

Assuming a constant coefficient of lift (we're going to be at Cl_max at both level stall speed and max turn at any speed), induced drag power increases with the CUBE of airspeed. This is very different than in level flight, where induced drag power decreases with 1/airspeed. The second case is what is displayed on those graphs.

Xiolablu3
08-28-2006, 12:14 AM
I think its safe to say that to get a game engine to simulate all these things would be a massive undertaking requiring NASA computers.

All in all the 6 year old IL2 engine does a pretty good job, dont you think? http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

I would have to say its an amzing feat of programming even in its current state of outdatedness (is that a word?)

NonWonderDog
08-28-2006, 12:24 AM
I think the sim does most if not all of what we've touched on. None of it is very difficult math. The sim might use approximations in some formulas instead of working everthing out, but I don't see anything that's really computationally intensive.

I also heavily dispute the idea that engineers were trying to add mass in proportion to thrust. That is absurd. The engineers were absolutely trying to add as much engine, ammo, and armor as they could with the least amount of weight. If the P-47 could have been made lighter without sacrificing speed, armament, durability, or cost, they would have damn well made it lighter. It would have flown farther, climbed faster, turned tighter, and turned with less speed loss. I don't see how a couple mph maximum dive speed (probably beyond Vne anyway) and maybe a couple percent off of zoom climb decelleration mattered more than that.

Xiolablu3
08-28-2006, 12:35 AM
I have to agree. I think climb speed is more important than dive speed to a fighter.

Especially an air superiorty fighter like the 109/La5/Spitfire, where performance is the most important thing.

Just my opinon.

HellToupee
08-28-2006, 12:45 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by tigertalon:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by HellToupee:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">
If you had an option to take a ww2 fighter or to take it's exact copy that would be, let's say 1.5 times bigger, which one would you take?

I'd take a big one, no question about it. Well, yes, in this sim it would be the small, but IRL it would be the large one. http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif </div></BLOCKQUOTE>

and why would you take it? What advantages to u think it would have. </div></BLOCKQUOTE>

Exactly the same advantages a P-47 would have above, let's say a P-35.

(keep in mind that by scaling an AC up the engine is scaled up and therefore powered up too) </div></BLOCKQUOTE>

p47s engine power was the reason for its advantages no its weight, and the p47 was as heavy as it was because of its engine setup, if the 47 had the engine of the 35 it probly wouldnt even get off the ground.

dieg777
08-28-2006, 01:47 AM
I just wonder how many can apply the theoretical best rates of climb and turn rates during an intense dogfight to get maximum theoretical advantage from their aircraft, Im sure that the majority are like myself who get caught up in the fight and allow the plane to drift outside this envelope.

BBB_Hyperion
08-28-2006, 02:23 AM
What about wrong high speed drag modeling ?
Max dive speed duo high speed drag (prop rotating flat disc) ?
Acceleration process on auto pitch wrong ?
Full throttle dive unrealistic ?

tigertalon
08-28-2006, 04:40 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by HellToupee:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by tigertalon:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by HellToupee:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">
If you had an option to take a ww2 fighter or to take it's exact copy that would be, let's say 1.5 times bigger, which one would you take?

I'd take a big one, no question about it. Well, yes, in this sim it would be the small, but IRL it would be the large one. http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif </div></BLOCKQUOTE>

and why would you take it? What advantages to u think it would have. </div></BLOCKQUOTE>

Exactly the same advantages a P-47 would have above, let's say a P-35.

(keep in mind that by scaling an AC up the engine is scaled up and therefore powered up too) </div></BLOCKQUOTE>

p47s engine power was the reason for its advantages no its weight, and the p47 was as heavy as it was because of its engine setup, if the 47 had the engine of the 35 it probly wouldnt even get off the ground. </div></BLOCKQUOTE>

Exactly! If we assume a P-47 is roughly a scaled up version of P-35 (a very rough approximation, I know), It SHOULD have larger (eg. stronger) engine. I'm assuming that from the very first post regarding this matter. And I would, still, rather be in a P-47 than in P-35.

What you are saying is like: If propeller of a p-35 was fitted on a p-47, it would not even take off from the ground. You bet it wouldn't, that's why I was talking about scaling up ENTIRE arplane (together with engines, wings, propellers, etc etc etc).

KraljMatjaz
08-28-2006, 04:59 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by WWMaxGunz:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by KraljMatjaz:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by WWMaxGunz:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by KraljMatjaz:

we may have a derated Fw and a 1942 spitV while we should actualy have a 9lb boost 41 one, but A4 still dominates the spit. however, the fw was known to have aproximately same optimal climbing speed but much steeper climbing angle and was getting away from spit in a steep sustained climb, and spit couldn't follow, because if he would pull up even further to get firing solution, he would stall. </div></BLOCKQUOTE>

Please show the quote and source or give the source.

Where does it say that best climb of the FW is better than best climb of the Spitfire?

I've seen ONE document where those words were used and the two statements you show are not
connected except by assumption of some readers. Not fact, assumption. </div></BLOCKQUOTE>

oh, please. here:

http://img138.imagevenue.com/loc581/th_97878_SpitV_climb_122_581lo.JPG

thanks to kettenhunde, I really am not in a mood to search over my utterly messed up hard drive http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif. </div></BLOCKQUOTE>

You show a tiny picture of what looks like words on a page except nothing of it is readable. </div></BLOCKQUOTE>

thanks WWMaxGuns, for making me ordering up a bit my hd http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif.

here it is:

http://img.photobucket.com/albums/v662/aegeeaddict/image003_1.jpg

still 'assumption of some readers'?

WWMaxGunz
08-28-2006, 07:18 AM
Here is a link to the text:
http://www.simhq.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=98;t=007998

Direct text for those who can't bother to link:
------------------------------------------------------------------------------------------
I flew the Spitfires and the P-51 against a pilot who flew the 190 like a Hun.
.............
But the things I discovered about the comparative of the Spitfire IXB proved invaluable to
me in the next two years. In level flight and high speed the 190 flies slightly nose down.
With a higher wing loading than the Spitfire, the 190's maximum rate of climb was attained
at an air speed of about 240 miles an hour. The Spitfire IXB's maximum climb rate was
attained at 160 miles an hour. Thus, if you were foolish enough to try to follow the 190
in full throttle climb at the same angle, you soon find that he was above you. On the
other hand, if you pulled away and held the Spitfire at an airspeed of 160, you would climb
at a much steeper angle and end up with a height advantage.
---------------------------------------------------------------------------------------------
Source: "Lucky 13", Hugh Godefroy
Stoddart 1987
pp. 155-157

Did the FW have best climb at 240mph (384kph) or did the other pilot push the run to 240mph
because as in the cross-channel fights that is how the FW pilots flew, it gives the FW a
major climb advantage over Spitfires trying to keep up... they just can't. He tried and no luck.
The planes flew together so they could see the difference


But tell me that the Spit VB has best climb at 240 mph. Spit VB going 240 mph will climb even
less than Spit IXB. It is about excess power at speed. Yeah sure the Spit VB did not keep up
is certain. Even the IXB did not.

You really want to compare best climb rates? Compare the actual test flights data Rechlin to
RAEE and don't play games with words. The figures are available... well no Ring's Pro Docs
page doesn't work for me any more.

KraljMatjaz
08-28-2006, 07:37 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by WWMaxGunz:
well no Ring's Pro Docs
page doesn't work for me any more. </div></BLOCKQUOTE>

lol it was ME who posted an unedited scan of an original ww2 BRITISH test of a GERMAN plane (to rule out the bias), and all you can do is throw a link to a forum from 2004 (a bloody 60 years AFTER the acutal events) where a few enthusiasts that have, at best, seen some ww2 warbirds remotely, let a lone fly one in combat (mock or real) discuss the topic.

plus it NOWHERE says that speeds used for climbing in the test my document is from, are 240 mph. it is your assumption (and it was you who accused others to assume exactly what upper document states clearly).

what are you gonna claim next, that despite all evidence fw190 actualy had 6 wings and no guns?

i'm out of this one.

WWMaxGunz
08-28-2006, 09:22 AM
No. AFAIK best climb in FW is 280kph yet the pilot who flew the Spits gives 240mph which
puts a light on the speed of the FW in the climb test.

It does NOT say in the comparison sheet that the climbs were done at 280kph either. Those
were combat comparison. You let enemy get much faster than you while you climb at lowspeed
and he will show you the meaning of zoom in short enough order.

It matters not anyway. Depending on which engine the Spit VB had the best sustained climb
at full power and best alt could be 2700 ft/min clear to 4700 ft/min just on a quick look.
I remember posts a long time ago on this same Farnsborough test that the Spit VB used was
the second serial Spit VB produced and had been worn out through long tests before.

So wave the single-case report all you want, but let's see real test data and not just the
cherry-picked favorites from the fanboys. Long ago here I learned to watch that each group
knows which planes by serial number were dogs or special hacks both good and bad and just
plain prototypes. If I go over to CWOS I bet I can come out with solid averages.

Till then there is someone who has had the data long time now and last time this same
subject of the same words in the same report came up he made the answers knowing just
which planes with just which engines and even to the props the sim models are to say
the climbs with speed and alt.

Kettenhunde
08-28-2006, 09:48 AM
Hi nonwonderdog,

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">NWD says:
Yes, but this should be true to exactly the same extent no matter the weight of the plane. You shouldn't see a greater effect in a heavier plane, becase the heavy plane has exactly enough extra momentum to cancel it out. </div></BLOCKQUOTE>

When the vector of lift is below the horizon weight does add to thrust. Heavier weight = more thrust.

It is no different than the benefits of the lighter plane when the vector of lift is above the horizon, correct.

So each aircraft has its advantages and disadvantages.

http://www.onpoi.net/ah/pics/users/503_1156778272_orientationoflift.jpg

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">NWD says:
I think you're misinterpreting the induced drag/airspeed graph. </div></BLOCKQUOTE>

The graphs and text are open for all to see. I posted the links. It is the way I was taught and I do not think I am misinterpreting anything.

I think you€re confused. Let€s eliminate that by defining our topic so we can move on. There are two very different topics you and I are discussing. Do not blend and confuse the two. You keep trying to apply the effects of weight to a level turn. As I stated earlier the advantages do not apply to a level turn. They apply only when the vector of lift is below the horizon.

http://www.onpoi.net/ah/pics/users/503_1156778626_weighteffectonvertturn.jpg

The second topic is applicable to level turn but has nothing to with weight differences. It is simply the role of induced drag in a turn. When the vector of lift is orientated above the horizon the heavier aircraft will produce more induced drag. However the effects of induced drag is overestimated and it does not become a major factor until the aircraft exceeds CL max and enters the backside of the lift curve.

Load factor will increase the influence of induced drag. However this effects all airplanes proportionally. Turn performance is based on fundamental relationship of power available to power required. Planes will out perform one another based on this relationship.

Wing loading is a simplified reflection of this relationship.

http://www.onpoi.net/ah/pics/users/503_1156779453_turnperformance.jpg

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">NWD says:
Increasing AoA in order to turn has EXACTLY the same effect on induced drag coefficients. </div></BLOCKQUOTE>

Correct. However we are not discussing coefficients but the rate of work or power. The power becomes a wall on the backside of the lift curve after CLmax. Again that is a direct quote from an engineering source.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Nothing magical happens at the critical angle of attack. Lift does not go to zero; indeed the coefficient of lift is at its maximum there. Vertical damping goes smoothly through zero as the airplane goes through the critical angle of attack, and roll damping goes through zero shortly thereafter. An airplane flying 0.1 degree beyond the critical angle of attack will behave itself only very slightly worse than it would 0.1 degree below. </div></BLOCKQUOTE>

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">If we go far beyond the critical angle of attack (the €œdeeply stalled€ regime) the coefficient of lift is greatly reduced, and the coefficient of drag is greatly increased. </div></BLOCKQUOTE>

http://www.av8n.com/how/htm/spins.html#sec-spin


<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">NWD says:
MORE induced drag in the turning case (in an absolute sense) BECAUSE the plane has a greater airspeed. </div></BLOCKQUOTE>

Not correct. Remember the faster the velocity the smaller the role induced drag plays in the overall drag picture.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">NWD says:
induced drag power increases with the CUBE of airspeed. </div></BLOCKQUOTE>

Drag increases with the cube of airspeed. The largest component of drag at high speeds is parasitic drag. The aircraft with the smaller flat plate area has the advantages at high speeds.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">At high airspeeds, parasite drag is dominant and induced drag becomes almost negligible. </div></BLOCKQUOTE>

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">In the high-speed regime (which includes normal cruise), the power required increases rapidly with increasing airspeed. Eventually it grows almost like the cube of the airspeed. The reason is easy to see: parasite drag is the dominant contribution to the coefficient of drag in this regime, and is more-or-less independent of airspeed.5 </div></BLOCKQUOTE>

http://www.av8n.com/how/htm/4forces.html#sec-induced-vs-parasite

The influence of induced drag only becomes a factor on the backside of the lift curve. This means the pilot has pulled the stick too hard in our turn moving the wing past CL max. All the components of drag will greatly increase with the power of induced drag moving to the dominate power and the aircraft will slow down dramatically.

As long as he flies to the limit of CLmax or stays on the frontside of the curve, the power of induced drag is not the dominate force.

All the best,

Crumpp

WWMaxGunz
08-28-2006, 09:52 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Kettenhunde:
However the power of induced drag does not become a factor until the aircraft is on the backside of the lift curve in the mushing realm. The heavier aircraft also has more momentum but will certainly bleed more E when it does hit the induced drag wall.
</div></BLOCKQUOTE>

From Ugly Kid I have that at high speed the induced drag is like 1-2% of total drag.
That is when form and parasite drag are at the high end.

But turns, the speed varies widely. Still there is a maximum G's sustained flat turn for any
plane where the total drag does equal thrust. The speed of that turn being much less than the
top speed of the plane I can only guess that induced drag is indeed a real factor. How much
less thrust is required to fly straight and level at the same speed?

What I don't know are the factors, only some of the behaviours of the equations. To cause a
3+ ton plane to change direction 180 degrees is going to take a lot of energy but then how
quickly by that performance envelope does give time to spread the cost out. I do know that
the heavier planes generally had much more power and yet I don't see that they had more G's
available in hardest sustained turns if you see what I am pointing to.

And I very much know about the nose-low turns using gravity assist. Long time ago I saw on
Delphi the old-timer-simmers kept posting over and over about noobs making nose high flat
turns and then complaining about results. I've gone nose low and cut across the circle of
supposed better turning planes more times than I can count. But then I've also zoomed up
a ways to lose speed, rolled a bit and nose-lowed right onto targets as well. It beats the
H outta pulling extra stick and just blowing speed for no gain. Gravity can assist me nose
a little down or nose very much up as long as it's coming right down. This is where I think
that heavy planes with high roll rate really maneuver best.

JG14_Josf
08-28-2006, 09:57 AM
To Whom It May Concern:

First: I am calm so no matter how many times a poster believes otherwise, well, that poster will be left wanting something that does not exist.

Second: I notice how WWMaxGunz is allowed to express words that appear to be less than calm and no one points the finger at him.

Third: The subject of mass affects on gravity is scientifically proven and therefore anyone who claims that a smaller mass object will fall at the same speed as a larger mass object is incorrect. The significance of that fact can be ignored in the study of Air Combat. The significance of that fact cannot be ignored in science, since, it is a fact.

Fourth: If anyone must point fingers at the stupid people who cannot or will not understand scientific realities, then, point those fingers at the people who cannot or will not understand scientific realities. Look in the mirror.

Fifth: The following is not supported with physical evidence:

€œBut the things I discovered about the comparative of the Spitfire IXB proved invaluable to me in the next two years. In level flight and high speed the 190 flies slightly nose down. With a higher wing loading than the Spitfire, the 190's maximum rate of climb was attained at an air speed of about 240 miles an hour. The Spitfire IXB's maximum climb rate was attained at 160 miles an hour. Thus, if you were foolish enough to try to follow the 190 in full throttle climb at the same angle, you soon find that he was above you. On the other hand, if you pulled away and held the Spitfire at an airspeed of 160, you would climb at a much steeper angle and end up with a height advantage.€ (WWMaxGunz quoting €œLucky 13€, Hugh Godefroy)

An airplane arrives at the maximum climb rate when the plane gains the most altitude in the shortest time i.e. gaining the most energy going up in the shortest time. The forward vector velocity at the best climb rate is determined by AOA and or maximum lift possible generated by the wings at a given speed. If the plane is at less than maximum lift (AOA too shallow) the plane goes faster forward and slower vertically. If the plane is pitched up beyond maximum lift (AOA to steep) the plane goes slower on the forward vector and slower on the vertical vector. The best climb angle is steeper than best climb rate and at a slower air speed.

Here is an important thing to understand. There is not much room between the AOA on the wing at Maximum Lift and the AOA on the wing at stall. That ROOM is the mush envelope.

Take this:

€œWith a higher wing loading than the Spitfire, the 190's maximum rate of climb was attained at an air speed of about 240 miles an hour. The Spitfire IXB's maximum climb
rate was attained at 160 miles an hour.€

The difference between Maximum (continuous) rates of climb is the difference between Maximum lift for the wings at that speed. Going past Maximum lift (slower and higher angle of climb) causes the plane to stall (The back side of the curve as reported by Crumpp). Therefore the stall speed difference (unless one wing has a much larger mush envelope = easier handling) according to the Quote is 240 €" 160 mph = 80 mph or 128.747 km/h

What is not quoted is the actual climb rate (actual maximum energy gaining capability going up).

Here are the quotes in the official documents published by the British Air Force during WWII:

€œClimb:
The climb of the Fw190 is superior to that of the Spitfire VB at all heights. The best speeds for climbing are approximately the same, but the angle of the Fw190 is considerably steeper. Under maximum continuous climbing conditions the climb of the Fw190 is about 450 ft/min better up to 25,000 feet [7,620 m]. With both aircraft flying at high cruising speed and then pulling up into a climb, the superior climb of the Fw 190 is even more marked. When both aircraft are pulled into a climb from a dive, the Fw 190 draws away very rapidly and the pilot of the Spitfire has no hope of catching it.€

Note: What is wrong about E-retention?

Possible answer: The flight model is wrong for both E generation and E-retention (you can€t retain what you don€t have).

Example: Spitfires in the game act like low boost planes in level flight and high boost planes during climb. That is a clue.

Example: Two similar planes (Spitfire and FW190) are modeled with very different maximum climb rate speeds.

Maybe Oleg uses WWMaxGunz historical example and maybe Oleg threw out the WWII era British documents recording side by side relative combat performance tests. The two historical examples are widely different:

One WWII pilot:

Spitfire 160 mph
FW 190 €˜about€ 240 mph

Actual examples of the planes tested are not reported.

WWII Official British Air Force test results:

Fw 190A-3 (de-rated) 450 ft/m better @ €œconsiderably€ steeper climb angle

Spitfire VB (9lb boost) 450 ft/m lower climb rate (energy generation in the vertical) @ €œconsiderably€ shallower climb angle

Both planes are flown at approximately the same forward (indicated/true) air speed.

Repeat:

80 mph difference [128 km/h] according to one source for speed to fly to get €œmaximum climb rate€

Approximately the same air speed to get €œthe best speeds for climbing€ according to another source

Note: If a plane is modeled, or one is actually in the air flying, with a maximum continuous lifting capacity at a shallow angle of attack, then, that plane stalls soon after adding more angle of attack. If the plane does not stall soon after adding more angle of attack after maximum lift angle of attack, then, that plane has a WIDE mushing envelope like a Hang Glider.

Hang Gliders can fly very slow and still go up. That is a bit off topic like climb performance in an E-retention thread.

What comes down €" must first go up.

Restate the obvious:

I€m not the one who started arguing the effect of mass on gravity. Science has answered that question well (so far) and mass affects gravitational acceleration €" end of story?

Planes slow down because planes contact air molecules and planes slow down when going against gravitational acceleration (up). Power required is determined by mass, gravity, and contact with air mass. Mass does not slow down unless something slows mass down. Gravity slows down all mass at almost the exact same rate so a plane can be very massive or very light and gravity slows both down at relatively the same rate when those planes go up at the same angle.

Air mass slows light planes down faster than Air mass can slow down heavy planes. Air mass slows down light planes with big draggy wings, big radiators, and flatter windscreens faster than air mass can slow down massive planes with small draggy wings, prop driven radiators, and steeply slanted wind screens. That is fact.

The higher mass, smaller, cleaner, less draggy plane will not be slowed down by air mass as quickly as lower mass, larger, more draggy, plane. In other words: The Fw190 did, in fact, retain energy better in WWII than the Spitfire i.e. zoom higher vertically.

Fw 190s, P-47s, and Mustang also gained energy faster vertically down compared to low mass big wing draggy planes for much the same reasons €" in fact.

Of course that is not just my opinion.

Example:

€œIt was concluded that the Fw 190 pilot trying to €œmix it€ with a Spitfire in the classic fashion of steep turning was doomed, for at any speed - even the German fighter€s stalling speed - it would be out-turned by its British opponent. Of course, the Luftwaffe was aware of this fact and a somewhat odd style of dogfighting evolved in which the Fw 190 pilots endeavoured to keep on the vertical plane by zooms and dives, while their Spitfire-mounted antagonists tried everything in the book to draw them on to the horizontal. If the German pilot lost his head and failed to resist the temptation to try a horizontal pursuit curve on a Spitfire, as likely as not, before he could recover the speed lost in a steep turn he would find another Spitfire turning inside him! On the other hand, the German pilot who kept zooming up and down was usually the recipient of only difficult deflection shots of more than 30 deg. The Fw 190 had tremendous initial acceleration in a dive but it was extremely vulnerable during a pull-out, recovery having to be quite progressive with care not to kill the speed by €œsinking€? (Eric Brown, Wings of the Luftwaffe)€

Note the term €œsinking€ which is: High Speed Stall or AOA beyond max lift.

What is €˜sinking€? It is one example of Energy Bleed at very high angles of attack past maximum lift angle of attack and before full stall angle of attack.

Note if a wing is flying faster than corner velocity, then, the wing will generate much more lift than the weight of the plane. If the pilot can pull the stick above corner velocity, then, the pilot blacks out or the wings rip off €" the plane cannot stall unless the wing goes beyond max lift AoA. Therefore €˜sinking€ cannot happen at speeds much over corner velocity without subjecting the pilot and the plane to extreme g force. Therefore the €˜sinking€ referred to by Capt. Eric Brown (human being who flew the FW190 and the Spitfire in WWII) €˜sinking€ must be at, near, or under corner speed.

Note: What is wrong about E-retention?

Light planes are modeled as if thrust to weight is the only determining factor factored into calculating acceleration.

Example:

From Fighter Combat by Robert Shaw
page 407

"One further method of increasing fighter acceleration is by the use of gravity: a steep dive will often multiply acceleration many times. Such a dive may follow unloading, which causes the aircraft to fly a ballistic trajectory resulting in gradually steepening dive angles. If altitude is available, however, a sharp pull-down to a steep dive attitude, followed by unloading, produces the most rapid long-term dive acceleration. Discounting the effects of thrust, the acceleration of an aircraft in a dive is a function of its "density," that is, its ratio of weight (actually its mass) to drag. When two fighters are similar in all respects except that one is heavier, the heavier aircraft will accelerate faster in a dive and, assuming structural considerations allow, will have a faster terminal velocity. Likewise, with two fighter of the same weight, the cleaner one (i.e. the one with less drag) will dive better. (This is why a brick falls faster than a feather in air.")

Drag does not stop affecting mass in level flight or during zoom climbs.

Example:

"Actual combat accounts of the successful use of energy tactics are rather rare, but the following example is a beauty. Here John Godfrey's P-51B Mustang has probably 20 percent lower wing loading than the German Focke-Wulf 190D9 opponent, and Godfrey increases his turn advantage further by skill full use of flaps. The Focke-Wulf, however, may have 20 percent better power loading. Here are two masters at work:"

From page 163
Figher combat

"...Around and around we went. Sometimes the FW got in close, and other times, when I'd drop my flaps to tighten my turn, I was in a position to fire; but the German, sensing my superior position, kept swinging down in his turn, gaining speed and quickly pulling up, and with the advantage in height he would then pour down on my tail..."

Another example:

page 184
Double inferior conditions
------------------------------------------
Climbing extension/pitch-back tactics cannot be expected to work for the inferior fighter in this scenario, since the opponent has a Ps advantage. The other energy tactics discussed, which are intended to bleed the bogey's energy with a nose-to-tail turn...can still be effective against an inexperienced or careless opponent.
The following episode, found in Thunderbolt! by the World War II USAAF ace Robert S. Johnson, is one of the best examples available of the use of energy tactics (diving extension/pitch back) to defeat a double-superior opponent. The encounter described is a mock combat engagement over England between Johnson (P-47C) and an unidentified RAF pilot in a new Spitfire IX. The Spitfire had about a 25 percent better power loading and nearly a 25 percent lower wing loading. The Thunderbolt's only performance advantages were faster top speed, greater acceleration in a dive (because of the P-47s heavier weight and higher density), and better roll performance.) Johnson, undoubtedly one of the greatest natural fighter pilots of all time, used his roll performance defensively to allow himself the chance to build an energy advantage in a diving extension.

We flew together in formation, and then I decided to see just what this airplane had to its credit.
I opened the throttle full and the Thunderbolt forged ahead. A moment later exhaust smoke poured from the Spit as the pilot came after me. He couldn't make it; the Jug had a definite speed advantage. I grinned happily; I'd heard so much about this airplane that I really wanted to show off the Thunderbolt to her pilot. The Jug kept pulling away form the Spitfire; suddenly I hauled back on the stick and lifted the nose. The Thunderbolt zoomed upward; soaring into the cloud-flecked sky. I looked out and back: the Spit was straining to match me, and barely able to hold his position.
But my advantage was only the zoom-once in steady climb, he had me. I gaped as smoke poured from the exhausts and the Spitfire shot past me as if I were standing still. Could that plane climb! He tore upward in a climb I couldn't match in the Jug. Now it was his turn; the broad elliptical wings rolled, swung around, and the Spit screamed in, hell-bent on chewing me up.
This was going to be fun. I knew he could turn inside the heavy Thunderbolt; if I attempted to hold a tight turn the Spitfire would slip right inside me. First rule in this kind of fight: don't fight the way your opponent fights best. No sharp turns; don't climb: keep him at your own level.
We were at 5,000 feet, the Spitfire skidding around hard and coming in on my tial. No use turning: he'd whip right inside me as if I were a truck loaded with cement, and snap out in firing position. Well, I had a few tricks, too.
The P-47 was faster, and I threw the ship into a roll. Right here I had him. The jug could out roll any plane in the air, bar none. With my speed, roll was my only advantage, and I made full use of the manner in which the Thunderbolt could whirl. I kicked the Jug into a wicked left roll, horizon spinning crazily, once, twice, into a third. As he turned to the left to follow, I tramped down on the right rudder, banged the stick over to the right, around and around we went, left, right, left, right. I could whip through better than two rolls before the Spitfire even completed his first. And this killed his ability to turn inside me. I just refused to turn. Every time he tried to follow me in a roll, I flashed away to the opposite side, opening the gap between our two planes.
Then I played the trump. The Spitfire was clawing wildly through the air, trying to follow me in a roll, when I dropped the nose. The Thunderbolt howled and ran for the earth. Barely had the Spitfire started to follow-and I was a long way ahead of him by now - when I jerked back on the stick and threw the Jug into a zoom climb. In a straight or turning climb, the British ship had the advantage. But coming out of a dive, there's not a British or a German fighter that can come close to a Thunderbolt rushing upward in a zoom. Before the Spit pilot knew what had happened, I was high above him, the Thunderbolt hammering around. And that was it - for in the next few moments the Spitfire flier was amazed to see a less maneuverable, slower-climbing Thunderbolt rushing straight at him, eight guns pointed ominously at his cockpit.€ (Shaw quoting Johnson)

The next thing that will be argued against vertical energy performance and e-retention error, and argued by people who will not or cannot refrain from misdirection, hyperbole, Straw Man arguments, and other maneuvers away from the topic is the argument that re-defines the word €œvertical€. Vertical means straight up or straight down

Any zoom climb that is not pure vertical (unloaded) introduces wing lift drag and will therefore reduce the altitude gained during the zoom. The focus should be zeroed in on a term called Energy Height which is the maximum calculated height a plane will zoom straight up if nothing slows it down based upon velocity and starting altitude. In other words how much will gravity slow down any object (regardless of mass) going straight up at a specific starting speed and at a specific altitude (the formula does not account for the insignificant affect of mass on gravitational acceleration).

One more note:

If the Fw 190 has a higher rate of climb and a higher rate of climb at an air speed that is 80 mph (128 km/h) faster, then, the Fw 190 will gain altitude faster and gain horizontal separation much faster.

Example:

450 ft/m better maximum climb rate
80 mph faster air speed.

In two minutes the Fw 190 is 900 [274 m] ft higher and 2.6 miles [1,448 km] horizontal separation.

80 miles per hour difference is more than one mile a minute faster.

Something definitely does not compute.

Kettenhunde
08-28-2006, 10:09 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">I do know that
the heavier planes generally had much more power and yet I don't see that they had more G's
available in hardest sustained turns if you see what I am pointing to. </div></BLOCKQUOTE>


Hi WWMaxGunz,

Weight affects all parameters of flight. More weight decreases the load factor limits. Again this can offset or mitigated by an appropriate increase in power available. Adding horsepower is not the only method to increase power available either. Large gains can be made quickly and cheaply just by drag reduction.

Weight in and of itself though is bad for a design.

Thing to remember is that designs are not one characteristic. They are complicated systems engineered to do a task. Their designers were very smart and capable. In general the largest discriminator is when the aircraft was designed. IMHO, the largest advances in WWII in aircraft design were in the realm of stability and control.

If you want an interesting topic to explore just examine the similarities of the Spitfire/109 and the FW190/P51 stability and control. In just a few short years large advances were made.

All the best,

Crumpp

JtD
08-28-2006, 10:12 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by JG4_Helofly:
The settings were:
Rad closed
prop auto and manual
alt was 3000-1000 and 5000-3000 (no noticeable difference)
fuel was 100% with standard loadout
i don't know if i can find the track
and the version was 4.04m </div></BLOCKQUOTE>

Thanks, I might give that a try soon. Have you found the track?

What I found a little disturbing is the fact the entire test is only 5.8 km and probably just 35 seconds long. Several hundred meters advantage therefore mean a huge advantage for the FW.

WWMaxGunz
08-28-2006, 10:17 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Kettenhunde:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">NWD says:
MORE induced drag in the turning case (in an absolute sense) BECAUSE the plane has a greater airspeed. </div></BLOCKQUOTE>

Not correct. Remember the faster the velocity the smaller the role induced drag plays in the overall drag picture.

</div></BLOCKQUOTE>

Many times I have seen the like of this on aero sites and in books discussing flight. It took
me a while to figure out that there is the hidden part that with more speed you use less AOA
than at lower speed at least to stay in level flight.

If the same plane with more load has to go faster in the same banked flat turn then can you
also say it will have less AOA? I think not. More like faster with same AOA in order to
make the lift to support that bank angle possibly? In which case there will be some extra
induced drag as the induced drag does increase with square of speed. But how large that does
play of the total I can't say.

sudoku1941
08-28-2006, 10:59 AM
The hard part about this is trying to figure out exactly what's off; good luck, when the development team won't share their numbers or sources with you. This hampers an open discussion immeasurably.

The easy part is in discovering that it IS so badly off. But, as someone noted up above, that part is OBVIOUS: you see it the first time a plane does a 180 break turn relative to your course and catches you up way too quickly; you see it in reviewing .ntrks and watching planes (AI, mostly) actually pivot on their CoG; you see it in the way some planes can stand on their noses, with a stable gun platform, for an eternity when you try to sap them of their energy, and you see it when you compare the relative merits of T&B vs. B&Z tactics. Clearly this sim's "computations" favor the T&B.

Xiolablu3
08-28-2006, 11:06 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by sudoku1941:
The hard part about this is trying to figure out exactly what's off; good luck, when the development team won't share their numbers or sources with you. This hampers an open discussion immeasurably.

The easy part is in discovering that it IS so badly off. But, as someone noted up above, that part is OBVIOUS: you see it the first time a plane does a 180 break turn relative to your course and catches you up way too quickly; you see it in reviewing .ntrks and watching planes (AI, mostly) actually pivot on their CoG; you see it in the way some planes can stand on their noses, with a stable gun platform, for an eternity when you try to sap them of their energy, and you see it when you compare the relative merits of T&B vs. B&Z tactics. Clearly this sim's "computations" favor the T&B. </div></BLOCKQUOTE>

You have obviously experine dogfighting in high performance prop planes to make such bold statements.

Many times you hear W2 pilots talking about 'hanging on their props', maybe this is what they meant?

We need someone who has flown hi performance prop planes to say if this is wrong or not, as someone who hasnt, can never be sure.

horseback
08-28-2006, 11:23 AM
Clearly, a number of aircraft in this sim are experiencing E-retention disfunction...

They need some little blue pills.

cheers

horseback

Kettenhunde
08-28-2006, 11:41 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> In which case there will be some extra
induced drag as the induced drag does increase with square of speed. But how large that does
play of the total I can't say. </div></BLOCKQUOTE>

Your correct on the effect somewhat. Please be more specific on the condition of flight.

However total drag changes with the square of speed. Induced drag is just one component of that total drag picture. It's significance changes based on the condition of flight.

All the best,

Crumpp

NonWonderDog
08-28-2006, 12:28 PM
...and posting graphs that show that induced drag is insignificant in level flight at very high speed does nothing to help your argument. Even when you post them twice. The very high speeds where most graphs show induced drag as insignificant are usually transonic, by the way, and the transonic wave drag this creates increases with angle of attack similarly to induced drag.

Even when diving, if a heavy plane has to turn at the same load factor as a lighter plane it needs more lift than the lighter plane. This is just due to momentum, and aligning your thrust and weight vectors does nothing to change momentum. Induced drag increases with the square of lift. Thus, a heavy plane will incur more of a drag penalty to turning than will a lighter plane. It doesn't matter if induced drag will not be the dominant part of the overall drag in a high speed spiral dive at low load factor, the heavy plane still has more of it.

Kettenhunde
08-28-2006, 12:45 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">...and posting graphs that show that induced drag is insignificant in level flight at very high speed does nothing to help your argument. </div></BLOCKQUOTE>


You should probably read it again.

All the best,

Crumpp

Haigotron
08-28-2006, 01:32 PM
sometimes my bowels have 0 E-retention...

watch out world...

sudoku1941
08-28-2006, 03:17 PM
Xiolablu posts:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">You have obviously experine dogfighting in high performance prop planes to make such bold statements.

Many times you hear W2 pilots talking about 'hanging on their props', maybe this is what they meant?

We need someone who has flown hi performance prop planes to say if this is wrong or not, as someone who hasnt, can never be sure.
</div></BLOCKQUOTE>

Well, you're right on this point, but the same point also invalidates the opinions of some members of the dev team, too. As for "real WWII experience", that leaves out likely every single person who's ever played the sim.

So, while the point is correct, it certainly is a major fanboi tactic designed to stifle debate. Clearly we also have other documents and historical records, as well as first-person accounts to also shed some light, however dimmed by the passage of time, on these phenomena.

As I said, to most of us, it's rather obvious. To others, who already have made up their minds that Oleg can't possibly be wrong about anything; despite the fact that his (how many?) versions of Earth Flight Physics show the same aircraft wildly changing flight properties; these people will always assume the fault lies with the observer. And, with the IL-2 dev team always staying mum about their sources and their numbers, you can't really get to the truth anyway, can you?

joeap
08-28-2006, 04:27 PM
Guys what exactly does "hanging on the prop" refer too? The pilot's own plane or the opponents? Whatever, my limited experience in roller coasters, and as a passenger in commercial jets, (yes I know) leads me to say how often perception of events at such speeds can be different from what the words convey. Especially on this forum where it seems to mean helicopter like behaviour. I could see two planes climbing and having very little relative motion next to each other for example.

sudoku1941
08-28-2006, 06:11 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by joeap:
Guys what exactly does "hanging on the prop" refer too? The pilot's own plane or the opponents? Whatever, my limited experience in roller coasters, and as a passenger in commercial jets, (yes I know) leads me to say how often perception of events at such speeds can be different from what the words convey. Especially on this forum where it seems to mean helicopter like behaviour. I could see two planes climbing and having very little relative motion next to each other for example. </div></BLOCKQUOTE>

"Hanging on the prop" refers to being nose up very near to stall speed; you kind of "wallow" and "hang" there suspended; then, either you lower the nose, stall, spin, or if you can maintain enough control, hammerhead, jackknife or perhaps even tailslide some, because in the end gravity wins. I suppose the idea for the term comes from that feeling of "no visible means of support" and the inherent instability of the plane in that particular situation.

WWMaxGunz
08-29-2006, 04:53 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Kettenhunde:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> In which case there will be some extra
induced drag as the induced drag does increase with square of speed. But how large that does
play of the total I can't say. </div></BLOCKQUOTE>

Your correct on the effect somewhat. Please be more specific on the condition of flight. </div></BLOCKQUOTE>

Let's just compare a plane in a 2G turn with the same plane but loaded 25% heavier in a 2G turn.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">However total drag changes with the square of speed. Induced drag is just one component of that total drag picture. It's significance changes based on the condition of flight. </div></BLOCKQUOTE>

Now THAT'S something I can chew! Very good! Yet still I think that with extra G's of a turn
that ration induced to total drag is more than level flight at same speed. I am sure or that
actually but right now I don't want to go searching and typing links. The G's are loading,
in level flight the same loading as extra mass *at the same speed as in the turn* would force
a higher AOA which would increase the induced drag component without increasing the other
drag components... well maybe parasitic drag as the fuselage becomes angled?

How about take the 2G turn example and compare to level flight again same planes?

gmot_ka
08-29-2006, 05:31 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by JtD:

In a vacuum, freefalling light and heavy objects will reach the same dive acceleration. The essential differences for planes are:
1) They got an engine. (power)
2) They don't fly in vacuum. (drag)

So IF the heavier plane accelerates better in a dive depends on it's power and drag compared to the lighter plane. As indicated above, a lot of power helps at low speeds, and little drag helps at high speed - both in relation to the weight.
At low speeds, where drag is neglectable, the plane with better power/weight ratio will outaccelerate the other. This, in most cases, is not the heavier plane. At high speeds, where drag is very important and engine power doesn't count for much, the plane with the better weight/drag ratio will pull ahead. This, in most cases, is the heavier plane.

The advantages of rather heavy planes come into play when you dive to a very high speed, and zoom up from there again. You simply lose a smaller percentage of your E to drag, because you got more total E. </div></BLOCKQUOTE>

This post is completle right! It explains the basic facts which are importand for accelaration of a plane in a dive.

Kettenhunde
08-29-2006, 06:43 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Let's just compare a plane in a 2G turn with the same plane but loaded 25% heavier in a 2G turn. </div></BLOCKQUOTE>

Hi WWMaxguns,

You will find out weight in and of itself is a bad thing as long as the vector of lift is pointed above the horizon. Weight reduces all parameters of flight and shrinks the envelope.

The heavier plane exhibits more induced drag.

Here try this link. It explains momentum effects as well as accelerations. In fact the example is at 2 G IIRC:

http://www.auf.asn.au/groundschool/umodule1b.html

However as it is has also been stated, very rarely will you find an increase in weight in a fighter design without an appropriate increase in power. So don't think of these aircraft in terms of only one characteristic.

Effects on CL and AoA from an increase in thrust:

http://www.onpoi.net/ah/pics/users/503_1156852124_thrustonlift.jpg

Thrust directly affects the load factor limits in a steady state turn and indirectly affects the lift limits. So it expands the envelope in that direction. It does not affect structural limits. It therefore can mitigate some of the effects of weight. However it takes a larger proportional increase in power to overcome an increase in weight. It is typical to see for every 4-5% gain in weight a 25-30% increase in power.

http://www.onpoi.net/ah/pics/users/503_1156852270_emdiagram.jpg

Understand though a propeller aircraft receives more thrust effects the slower it goes due to the Tc decreasing with speed.

http://www.onpoi.net/ah/pics/users/503_1156852292_f2a3cl.jpg

You can see the trend of increasing weight and power with just about any design of the war.

All the best,

Crumpp

WWMaxGunz
08-29-2006, 07:07 AM
I thank ye much for the link, the info and sep the turn performance diagram. It's most all
things I've gone over before but still gonna take time to find what I want.

I about nose low helping and extra mass adding more to at least some factors. I've been at
the 'trading height for energy' level since long ago and I do know that it's height x mass.
If the plane is falling then that's also cutting the wingloading, increasing powerloading.

I just wanted to simplify the case and not bring in extras yet I understand that there is
danger of someone running off to make a blanket 'heavier planes vs lighter planes' kind of
pseudo-rule.

Just for (my) fun, that 5% extra weight with say 30% extra power gets how much better...
well I guess for performance too much depends on what speed, etc, there already is and
the wings ad nauseum so maybe example noted as somewhat but not as a rule typical?

Viper2005_
08-29-2006, 07:08 AM
There is a lot of confusion in this thread. For example:

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">
Drag increases with the cube of airspeed. The largest component of drag at high speeds is parasitic drag. The aircraft with the smaller flat plate area has the advantages at high speeds. </div></BLOCKQUOTE>

No. Drag increases with the square of airspeed.

Power requirement increases with the cube of airspeed.

Remember our friends the lift and drag equations

L = Q * Cl * S
D = Q * Cd * S

Where Q = * roh * v²

L and D are forces.

Work done = Force * Distance

Power = Rate of doing Work.

Thus it should be obvious by inspection that since the distance covered per unit time varies directly with velocity, power requirement will vary as the cube of velocity.

(At a simple level it may be said that the piston engine lost out to the turbojet because it produces power, the requirement for which varies as the cube of velocity, whilst the turbojet produces thrust, the requirement for which varies with the square of velocity.)

Now let's move backwards and cover this statement:

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">
Remember the faster the velocity the smaller the role induced drag plays in the overall drag picture. </div></BLOCKQUOTE>

This is an unfortunate misunderstanding based upon skimming through textbooks.

Let's look at the lift equation again.

L = Q * Cl * S

Since we want to maintain level flight, L = M * g = constant

S is of course constant in most aeroplanes.

Thus, we may say that since L = M * g = constant, Q * Cl must also be a constant.

Therefore, in level flight, since Q varies as the square of velocity, it follows that Cl must vary as the inverse square of velocity in order that the product of Q and Cl remains constant.

Since induced drag varies directly with Cl, in level flight it follows that induced drag varies with the inverse square of velocity.

Meanwhile of course the lift independent drag coefficient is constant, and the geometry of the aeroplane is constant, and so since Q varies with the square of velocity it follows that the lift independent drag force also varies with the square of velocity.

That's straight and level flight, where L is held constant.

We're talking about turns, where the object of the exercise is to increase L.

The power requirement for flight is minimised at the angle of attack which maximises (Cl^3/Cd^2). In level flight this is generally pretty close to Vy for obvious reasons.

When making a sustained level turn in a piston engined aeroplane obviously we want to minimise power requirement, and so we continue to fly at that angle of attack, and simply increase speed so that we have some excess lift. This excess allows us to tilt the lift vector whilst still maintaining the vertical component of lift equal to the weight of the aeroplane.

Thus, if the g meter in the aeroplane reads 4 g, minimum power requirement will be attained by flying at roughly 2*Vy.

Since L * cos(˜) = W it follows that cos(˜) = W/L = 0.25 and therefore ˜ = arccos(0.25).

Thus, the bank angle is 75.52º.

It is then possible to calculate the horizontal component of lift (since the vertical component of lift is known to be M * g). We may eliminate M and produce an answer in terms of g. The vertical component of lift is 1 g, whilst the total lift is 4 g. The horizontal component may be arrived at thanks to Pythagoras, and is ˆ15 g, which is about 3.87 g if you prefer. This figure may then be used to compute turn radius using a = v²/r. Then it's a simple matter to work out the circumference of the turning circle and divide that distance by v to compute turn time, which may be simply converted to turn rate.

Note that IL2c's doghouse plot uses the horizontal component of g as its basis for comparison rather than the total g, which is an important distinction.

Most WWII fighter aeroplanes can't sustain a 4 g level turn since they just don't have enough power. So they tend to descend. It's still important to fly at the right speed, because this will minimise rate of descent...

<span class="ev_code_red">Having dealt with the maths, it should be obvious that since we're flying at constant alpha, the lift induced drag coefficient is constant. Therefore, the lift induced drag varies as the square of velocity, rather than as the inverse square of velocity as would be the case in straight and level flight.</span>

WWMaxGunz
08-29-2006, 07:41 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Viper2005_:
Having dealt with the maths, it should be obvious that since we're flying at constant alpha, the lift induced drag coefficient is constant. Therefore, the lift induced drag varies as the square of velocity, rather than as the inverse square of velocity as would be the case in straight and level flight. </div></BLOCKQUOTE>

Now there is some conjuring!

It explains much about speed bleed when trying to close with a target in a turn. If you are
twice as fast then you have four times the induced drag just for starts, and I guess four times
the form drag whereas in a straight chase you have less induced with more form drag... given
the same planes and etc cautions of apples and oranges.

So mass is a linear factor in all this without going into heavier means you must go faster?

p1ngu666
08-29-2006, 08:14 AM
scary maths http://forums.ubi.com/images/smilies/16x16_smiley-surprised.gif

can i sumerise in more simple terms?

assuming 2 equal planes, apart from weight...

in a turn, if the nose is pointing up, heavier is worse off, if nose below the horizon then the weight acts as extra thrust, but its still got the extra weight to heft about.

the heavier plane should dive better?

and "zoom" better

and retain energy better as long as there is just smooth, subtle movements

if it tries hard, or sudden movements, it will lose lots of energy, or fail the movements..

so in combat (light vs heavy, same airframe and power..)

the heavy plane should try and keep the fight fast, should do diving turns and split S's, and should try to zoom climb...

the light plane should try and keep the fight slower, so the heavier plane is more comprimised. it should try and outclimb the heavier plane in sustained climb. it should be able to change direction and turn better. it should accelorate better, and probably be a smidge faster.

imo, the lighter fighter looks more likely to win, so theres little point ballesting up a aircraft just to make it heavier.

Xiolablu3
08-29-2006, 08:22 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by p1ngu666:

imo, the lighter fighter looks more likely to win, so theres little point ballesting up a aircraft just to make it heavier. </div></BLOCKQUOTE>

Thats what I would think.

It seems to be supported by the fatc that fighter plane manufactorers are always trying to get a lighter plane.

Kettenhunde
08-29-2006, 08:24 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">In the high-speed regime (which includes normal cruise), the power required increases rapidly with increasing airspeed. Eventually it grows almost like the cube of the airspeed. The reason is easy to see: parasite drag is the dominant contribution to the coefficient of drag in this regime, and is more-or-less independent of airspeed.5 We pick up two factors of V from equation 4.1 and one from equation 4.4. Knowing this cube law is useful for figuring out the shape of your airplane€s power curve (section 7.6.2), and for figuring out how big an engine you need as a function of speed (section 7.6.4) and altitude (section 7.6.5). </div></BLOCKQUOTE>

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Eventually it grows almost like the cube of the airspeed. </div></BLOCKQUOTE>

http://www.av8n.com/how/htm/4forces.html#sec-induced-vs-parasite

What we have here is "condition of flight" confusion. In the context of my post you will see the discussion is about the power of induced drag on the backside of the lift curve at the stall piont.

There it acts like a wall which you have actually illustrated the concept and differences rather well. In your example the aircraft has exceeded the Power Available to Power required limits and is not in a steady state turn. Your application is more applicable to instantaneous turns which is a different subject.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Having dealt with the maths, it should be obvious that since we're flying at constant alpha, the lift induced drag coefficient is constant. Therefore, the lift induced drag varies as the square of velocity, rather than as the inverse square of velocity as would be the case in straight and level flight. </div></BLOCKQUOTE>

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Remember the faster the velocity the smaller the role induced drag plays in the overall drag picture. </div></BLOCKQUOTE>

Holds true on the front side of the curve under the conditons of flight under discussion.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Most WWII fighter aeroplanes can't sustain a 4 g level turn since they just don't have enough power. </div></BLOCKQUOTE>

Correct. You will get more representative results if you do your calculations within the envelope.

All the best,

Crumpp

Kettenhunde
08-29-2006, 08:26 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">imo, the lighter fighter looks more likely to win, so theres little point ballesting up a aircraft just to make it heavier. </div></BLOCKQUOTE>


That is not being questioned in the discussion. Weight is not good thing. However these designs are not one characterstic. Their designers were very capable and very much understood the pitfalls of weight creep along with methods to mitigate it.

All the best,

Crump

Viper2005_
08-29-2006, 08:27 AM
If you quadrouple the mass of your aeroplane you'll end up flying twice as fast at any given alpha/load factor combination.

Of course, real air combat isn't constructed from nice simple constant lift or constant alpha profiles, and prop efficiency effects can have an impact at the low and high speed edges of the envelope. But the general concepts work quite well.

If you put lots of knots on the ASI then you need to be more gentle with the stick, otherwise you'll command lots of lift, produce lots of drag and lose a lot of energy (unless you've got bags of power of course).

Induced drag is very important at higher lift coefficients. Zero lift drag is very important at lower lift coefficients.

In any given turn, the lift coefficient required will vary directly with the wing loading. So, all things being equal, if you've got a high wing loading you should expect to bleed a lot of energy if you pull hard; induced drag is your enemy, and turns are going to be expensive.

If you've got a low wing loading, you should expect to bleed less energy if you pull hard. The chances are that you should be more worried about losing energy to zero lift drag. Therefore high speed dives are likely to be more costly.

Of course, a high aspect ratio wing will do better than a low aspect ratio wing so far as lift induced drag is concerned, so that something like the Ta-152 may reasonably be expected to punch above its weight.

Meanwhile, a thin wing is likely to produce less zero lift drag than a thicker wing, and so the Spitfire may be expected to punch above its weight in a dive.

In fact, if you look at the total energy of a Spitfire in a dive, you'll see that it only starts to lose out when recovery action is taken.

http://www.spitfireperformance.com/sd2011.jpg

Induced drag, not zero lift drag, is the real killer. Which you might expect, since the Spitfire has washout and therefore isn't as efficient with regards to lift induced drag as you might expect given its eliptical planform.

Kettenhunde
08-29-2006, 08:42 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">So, all things being equal, if you've got a high wing loading you should expect to bleed a lot of energy if you pull hard; induced drag is your enemy, and turns are going to be expensive. </div></BLOCKQUOTE>

Correct and not the condition of flight under discussion in my post which you quote out of context.

As there are many other factors involved that is not to say a properly designed aircraft will lose excessive amounts of energy. Designers are well aware of these characteristics.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">If you've got a low wing loading, you should expect to bleed less energy if you pull hard. The chances are that you should be more worried about losing energy to zero lift drag. Therefore high speed dives are likely to be more costly. </div></BLOCKQUOTE>

Exactly. Designers are also aware of the pitfalls in these design choices and can take measures to mitigate them as well.

All the best,

Crumpp

Viper2005_
08-29-2006, 08:48 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">There it acts like a wall which you have actually illustrated the concept and differences rather well. In your example the aircraft has exceeded the Power Available to Power required limits and is not in a steady state turn. Your application is more applicable to instantaneous turns which is a different subject. </div></BLOCKQUOTE>

I used 4 g simply in order to make the maths easy because 4^0.5 = 2.

Of course you can have a sustained descending turn as long as you've got altitude to burn. IRL the atmosphere isn't isotropic and so you'll see power changes and velocity changes on the way down, but this sort of spiral descent is a somewhat different class of manoeuvre from the classic instantaneous turn in which kinetic rather than potential energy is expended.

Induced drag is only unimportant if you're operating at low Cl.

Note that when you maximise (Cl^3/Cd^2) you'll find that induced drag is dominant since induced drag = zero lift drag when (Cl/Cd) is maximised. Even at high speed, I'll try to turn at this ((Cl^3/Cd^2)max) Cl because it gives me the most value for money in a power limited aeroplane.

NB, in this context I'm talking about the Cl and Cd of the aeroplane as a whole.

Thrust limited jets will tend to attempt to turn at (L/D)max, so that neither zero lift nor induced drag is dominant.

Jets with bags of excess thrust will tend to go for sustained turns at a higher Cl and lower speed because they are structure or pilot limited when thrust = drag at (L/D)max.

Kettenhunde
08-29-2006, 09:03 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Of course, real air combat isn't constructed from nice simple constant lift or constant alpha profiles, and prop efficiency effects can have an impact at the low and high speed edges of the envelope. But the general concepts work quite well. </div></BLOCKQUOTE>

Exactly. In fact your standard turn relationship does not factor in thrust effects at all. They must be dealt with using seperate corrections.

http://www.onpoi.net/ah/pics/users/503_1156863277_turnperformancebasis.jpg

http://www.onpoi.net/ah/pics/users/503_1156863201_contents.jpg

This is a mistake many make in using the standard turn forumlation for simple calculations. Here we can see the measured differences between standard calculations and the effects of thrust:

http://www.onpoi.net/ah/pics/users/503_1156863179_thrusteffectscalculationsvsthrust.j pg

All the best,

Crumpp

JG14_Josf
08-29-2006, 09:19 AM
For those who are curious (rather than those who already know everything):

A €˜theory€ pervades (apparently) that goes something like this:

A light WWII fighter plane will accelerate up to max level speed faster than the same plane loaded heavy, therefore, in a dive the light plane will accelerated up to that velocity faster than the heavy plane.

I can€t know if that is the theory since that theory has yet to be spelled out.

If the question is: What is wrong with E-retention?

Presumably in the game

The answer cannot include error in gaining E

Presumably energy

Acceleration is the only way to gain E

Gravity, thrust (lift from the props), and wing lift is the only way to accelerate.

Lift generated by the prop is the primary force causing acceleration. Lift generated by the wings multiplies the lift generated by the prop so LIFT is not a primary source of acceleration.

Gravity can only add acceleration without the prop if the plane is dropped or launched from altitude.

E or Energy can only be gained with prop lift.

WWII fighter planes cannot lift the weight of the plane with the prop.

WWII fighter planes cannot accelerate the plane vertically AT ALL. The power to lift with the prop is less than the power accelerating the plane downward. There is no going up AT ALL with the prop. Going up AT ALL requires energy of motion and multiples of that energy on the lift vector. The wings are inclined planes that multiply forward vector energy into lift vector force.

If the question is: What is wrong with E-retention?

Then: The answer requires knowledge concerning what makes the planes go and what makes the planes stop going.

If the answer does not include knowledge concerning what makes the plane go and what makes the plane stop going, then, the answer will be wrong.

Experiment:

Two almost identical WWII airplanes

Both planes have no fuel.

Both planes are dropped from their 10,000 meter airport.

One WWII airplane is gutted to super light weight

The other WWII airplane is filled with super heavy ridiculously heavy stuff.

Which plane hits the ground first? Which plane accelerates faster?

The answers that the professors of vast wisdom have so far dodged the question or have given ridiculous answers (see my previous thread linked in my first post).

I think the ridiculous answer given alluded to (indirectly) an insignificant difference in acceleration between the heavy and the light plane during a no engine dive performance test. That poster listed his formula and the results. That post is now corrupted on that forum with stuff like this *&^*&*(

That presumption and that formula is patently false since the light plane could get so light as to go up from 10,000 meters and the heavy plane could get so heavy as to accelerate the earth to the plane. In other words the affect of mass on dive performance is significant.

If that is not understood as fact, then, the answer to the E-retention question will be difficult if not impossible to answer accurately.

NO€¦I do not know the answer definitively or I would not be wasting my time here trying to find the answer among those who should be interested in finding the answer as they state that desire themselves. Either the desire is true or it is not. If it is not true then some other desire inspires people to post here €" I have my own theory on that.

Back to this: What is wrong with E-retention?

Here is a clue: (like the clue where the Spitfires in the game have high boost engines in a climb and a low boost engine in level flight)

Clue:

The light plane will reach terminal velocity when drag equals aircraft weight.

Terminal velocity can be zero at 10,000 meters for a WWII plane skin filled with helium.

My critics duck this experiment OUT OF HAND without even looking at the significance of this fact.

A WWII plane skin having the same exact size and shape of the WWII exact copy has the same numbers for Form Drag and Wetted area. In the dive experiment the factor of lift coefficient is a non-factor since the planes travel vertically down = no lift = no induced drag.

The super light WWII plane can have a terminal velocity of zero at 10,000 meters where aircraft weight is equal to drag. What is needed to see this clearly, in my opinion, is an understanding of the term €œDisplacement€.

Back to the experiment to see what €œDisplacement€ is or is not:

This time our experiment includes a new device that can change the two aircraft weights from 0 to infinity. We have weight on a slider.

We adjust the slider until both WWII planes are hovering like balloons at 10,000 meters.

The WWII airplanes displace exactly the amount of air mass by unit weight that would fill these WWII airplanes. In other words the volume of the WWII airplanes hovering at 10,000 meters weighs the same as the same volume of air at 10,000 meters.

Slide one of the WWII airplane weight sliders to a lower weight and that plane accelerates up. Slide the other weight slider to a higher weight and that plane accelerates down.

Both planes are the same exact size and shape and both planes are exact copies of WWII air planes. The only difference between these planes and actual WWII air planes is that weight is on a slider.

I€ll end this €˜contribution€ since it is long with this:

When weight equals drag, then, acceleration stops therefore the lighter plane accelerates slower because drag equals weight at lower values for drag and a WWII plane going down in gravity can only be slowed down by air mass drag or €" displacement. The lighter plane in a dive accelerates slower that the heavy plane because the lighter plane is lighter.

More experimentation later if the opportunity to do so appears to be welcome.

If not, then, I€ll have more evidence to support my forum troll theory.

I expect to see "projection" and "Transference". That will not be tolerated. If a poster accuses me of being a troll, then, prove it. If not, then, look in the mirror to find the real troll. These defensive words are necessary in defense against trolls according to me. I can waste my time elsewhere if my time here is a waste according to you. Just say the words - please leave. End of the troll by mutual agreement. Thank you very much.

Kettenhunde
08-29-2006, 09:23 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Induced drag is only unimportant if you're operating at low Cl. </div></BLOCKQUOTE>


No one is claiming it is unimportant. However it does not have as large an effect on the front side of the curve. In other words you€re "pulling hard" is pulling to the backside of the curve beyond CLmax.

On the front side the aircraft is not working as hard. Basically if the pilot only pulls to the top of the lift curve he does not pay that excessive price for higher wing loading. He still pays more than a lighter aircraft with the same power loading but not nearly the penalty he pays by passing CLmax on the backside.

Again aircraft are a system and examining the effects of only portion of that system can lead to erroneous conclusions.

As for the comments on wing efficiency. There is very little appreciable differences in wing efficiency in most WWII designs. Designers were very much aware of the benefits of wing efficency. It is very easy to manipulate a wing to achieve a desired efficency. Here we can see a rectangular wing properly designed being compared with an ellipse with no washout:

http://www.onpoi.net/ah/pics/users/503_1156863229_induceddrag.jpg

All the best,

Crumpp

Kettenhunde
08-29-2006, 09:29 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Of course you can have a sustained descending turn as long as you've got altitude to burn </div></BLOCKQUOTE>


By definition then it is not a steady state turn. Different condition of flight.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Thrust limited jets will tend to attempt to turn at (L/D)max, so that neither zero lift nor induced drag is dominant. </div></BLOCKQUOTE>

Jet thrust characteristics are not really applicable to propeller aircraft thrust development.

All the best,

Crumpp

Viper2005_
08-29-2006, 09:35 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Kettenhunde:
In fact your standard turn relationship does not factor in thrust effects at all. They must be dealt with using seperate corrections.

This is a mistake many make in using the standard turn forumlation for simple calculations. Here we can see the measured differences between standard calculations and the effects of thrust:
</div></BLOCKQUOTE>

By this I take it you really mean prop wash effects. In my limited experience they are only of any great significance at low speed. At high speed, prop wash velocity tends to be pretty low because the mass flow through the prop disk is high. Since aircraft speed is high, the effect of propwash upon lift is pretty insignificant. As a rough rule of thumb I'd say that propwash really starts to become important at speeds at or below Vy. If you're juddering along at the stall in a P-38 I can see propwash effects making a very big difference. OTOH, in a high speed sustained turn in a P-51 I think you could neglect them...

Horses for courses etc.

The big trouble is that the more detailed the mathematical model, the more difficult it is for everybody to understand. Heaven help us if somebody opens the can of worms marked "AEROELASTIC EFFECTS"... http://forums.ubi.com/images/smilies/1072.gif

Viper2005_
08-29-2006, 09:38 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Kettenhunde:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Of course you can have a sustained descending turn as long as you've got altitude to burn </div></BLOCKQUOTE>


By definition then it is not a steady state turn. Different condition of flight.

All the best,

Crumpp </div></BLOCKQUOTE>

Depends upon your frame of reference. It's steady state in that rate of descent is constant, speed is constant and turn rate is constant.

If you assume an isotropic atmosphere and hold g constant then you're fine.

The classic steady state turn where thrust = drag and vertical component of lift is equal to weight is only itself steady state if you make a variety of interesting assumptions. For a start, you've got to neglect fuel burn.

JG14_Josf
08-29-2006, 09:48 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">On the front side the aircraft is not working as hard. Basically if the pilot only pulls to the top of the lift curve he does not pay that excessive price for higher wing loading. He still pays more than a lighter aircraft with the same power loading but not nearly the penalty he pays by passing CLmax on the backside. </div></BLOCKQUOTE>

If I may add:

Two planes exactly the same where one is heavier than the other side by side at max level speed and both planes turn at ClMax:

Both planes do not start out with the same energy.

The heavier plane starts out with more energy to burn since both planes are side by side at the same altitude and the same speed.

Both planes do not roll to the same bank angle to maintain level turn performance (no acceleration up or down subtracting or adding to gravity).

Both planes remain on the front side, at least, or at exactly CLMax (the angle of attack that generates the most lift) and both pilots manage to pilot the planes exactly the same i.e. the same error off CLMax and neither pilot 'sinks' the plane and both pilots have the same exact G tolerance, and both pilot maintain exactly the same G force during the turns.

NOW...which plane stalls first or, in other words, does the heavy plane with more energy "BLEED" more energy faster than the lighter plane or visa versa. The lighter plane starts out with less energy; of course.

Which plane stalls first?

Please be so kind as to answer the question definitively with mathematical proof.

Additional, extra point, question:

Which plane has the lower corner velocity?

P.S. I don€t know the answer definitively therefore I am asking. I have my guess. If anyone doesn€t answer the question definitively, then, the answer remains a guess.

P.P.S. The answer may offer a clue to answer this question definitively:

What is wrong with E-retention?

Kettenhunde
08-29-2006, 09:53 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Depends upon your frame of reference. </div></BLOCKQUOTE>


Exactly. Your illustration is from a different frame of reference. Steady state turns is a definable condition of flight in aeronautics.

http://www.answers.com/topic/steady-state

All the best,

Crumpp

Viper2005_
08-29-2006, 10:06 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Kettenhunde:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Induced drag is only unimportant if you're operating at low Cl. </div></BLOCKQUOTE>


No one is claiming it is unimportant. However it does not have as large an effect on the front side of the curve. In other words you€re "pulling hard" is pulling to the backside of the curve beyond CLmax.

On the front side the aircraft is not working as hard. Basically if the pilot only pulls to the top of the lift curve he does not pay that excessive price for higher wing loading. He still pays more than a lighter aircraft with the same power loading but not nearly the penalty he pays by passing CLmax on the backside.
</div></BLOCKQUOTE>

I agree that a piston engined aeroplane should not be pulled to the back side of the power curve. However, I would point out that the back side of the power curve is reached long before Clmax.

The back side of the power curve is reached the second you pull beyond (Cl^3/Cd^2)max. For example, consider NACA4412.
α 0º, Cl 0.38, Cd 0.010
α 2º, Cl 0.60, Cd 0.010
α 4º, Cl 0.80, Cd 0.012
α 6º, Cl 1.00, Cd 0.014
α 8º, Cl 1.15, Cd 0.017
α 10º, Cl 1.27, Cd 0.022
α 12º, Cl 1.36, Cd 0.030
α 14º, Cl 1.35, Cd 0.042
α 16º, Cl 1.25, Cd 0.059

(Cl/Cd)max is at about 6º α.
(Cl^3/Cd^2)max is at about 8º α.
Clmax is at about 12º α

Data taken from KERMODE, A. C. (1996) MECHANICS OF FLIGHT. 10th edition, Harlow: Longman.

Kettenhunde
08-29-2006, 10:12 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">In my limited experience they are only of any great significance at low speed. </div></BLOCKQUOTE>

Sure, due to Tc:

http://www.onpoi.net/ah/pics/users/503_1156852292_f2a3cl.jpg

http://www.onpoi.net/ah/pics/users/503_1156863179_thrusteffectscalculationsvsthrust.j pg

http://www.onpoi.net/ah/pics/users/503_1156852124_thrustonlift.jpg

All the best,

Crumpp

Kettenhunde
08-29-2006, 10:14 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">However, I would point out that the back side of the power curve is reached long before Clmax. </div></BLOCKQUOTE>


Your confusing curves.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">No one is claiming it is unimportant. However it does not have as large an effect on the front side of the curve. In other words you€re "pulling hard" is pulling to the backside of the curve beyond CLmax.

On the front side the aircraft is not working as hard. Basically if the pilot only pulls to the top of the lift curve he does not pay that excessive price for higher wing loading. He still pays more than a lighter aircraft with the same power loading but not nearly the penalty he pays by passing CLmax on the backside. </div></BLOCKQUOTE>

I apologize for not making it more clear that I was refering to the lift curve.

All the best,

Crumpp

Kettenhunde
08-29-2006, 10:17 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">I agree that a piston engined aeroplane should not be pulled to the back side of the power curve. However, I would point out that the back side of the power curve is reached long before Clmax. </div></BLOCKQUOTE>


Depends on the airplane, power available, and condition of flight.

Speaking in terms of the power curve, if we look at the following diagram for an aircraft maintaining a 60 degree bank the area of least penalties is between the red lines labeled "good". Anything outside of those lines and we begin to pay an increased penalty including induced drag to maintain flight. We cannot maintain steady state performance at 60 degree bank either.

http://www.onpoi.net/ah/pics/users/503_1156869119_beststeadystateturn.jpg

Your calculations are somewhere above the power required line.

Of course a heavier aircraft will pay a higher price in these zones than a lighter one of the same design.

However, in different designs you have to examine the whole aircraft as a system to determine the relative penalties.

All the best,

Crumpp

Viper2005_
08-29-2006, 10:21 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Kettenhunde:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Depends upon your frame of reference. </div></BLOCKQUOTE>


Exactly. Your illustration is from a different frame of reference. Steady state turns is a definable condition of flight in aeronautics.

http://www.answers.com/topic/steady-state

All the best,

Crumpp </div></BLOCKQUOTE>

Actually, my illustration just doesn't care about engine power. Put me in a glider and I can still pull a tight turn. If I apply 60º of bank I'll still get 2 g. However, if I want to maintain constant speed I'll need to descend as I turn.

Put me in a high performance aerobatic aeroplane and I'll probably be able to climb whilst turning at 2 g.

The constant altitude, constant speed turn is a special case, but it's not actually steady state because my I'm losing weight all the time due to fuel burn.

Of course, if we return to the glider, I can make that steady state quite easily; just put the aeroplane in air which is rising at the same rate as the glider is descending. Simple. Well, at least until you remember that I'm losing weight all the time as I breathe out water vapour and CO2...

The fact is that steady state is just a mathematical trick used to save on hard work. It's not right - it's just not far enough wrong to matter most of the time when used properly.

Viper2005_
08-29-2006, 10:39 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Kettenhunde:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">However, I would point out that the back side of the power curve is reached long before Clmax. </div></BLOCKQUOTE>
Your confusing curves.
</div></BLOCKQUOTE>

I'm saying that if you pull beyond (Cl^3/Cd^2)max that you're paying too much for your lift IMO because you are on the back side of the power curve.

If you only pull to (Cl^3/Cd^2)max then at constant altitude you'll bleed down to a maximum rate sustained turn.

Lift starts to get expensive as soon as you pull beyond (L/D)max. Beyond the minimum power requirement alpha, lift is very expensive.

There is no reason for pulling beyond Cl max if you're trying to turn tightly. In fact, pulling all the way to Clmax is probably not a good idea because unless you're in totally flat air you're likely to find that turbulence causes your aeroplane to depart.

Kettenhunde
08-29-2006, 11:10 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">The constant altitude, constant speed turn is a special case, but it's not actually steady state because my I'm losing weight all the time due to fuel burn. </div></BLOCKQUOTE>


Certainly. However each weight point is seperate calculation point to form a curve if you were looking to see the effects of weight reduction due to fuel consumption.

Constant speed, constant altitude, constant power, and constant bank is the definition of a steady state turn.

http://www.onpoi.net/ah/pics/users/503_1156871308_steadystateturn.jpg

I edited my earlier post to better illustrate the area of induced drag production under discussion in terms of the power curve for you.

All the best,

Crumpp

Kettenhunde
08-29-2006, 11:13 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">There is no reason for pulling beyond Cl max if you're trying to turn tightly. In fact, pulling all the way to Clmax is probably not a good idea because unless you're in totally flat air you're likely to find that turbulence causes your aeroplane to depart. </div></BLOCKQUOTE>


Exactly! That is thinking behind some of the higher wingloaded designs for fighters too. The concept is sacrifice wing size for the speed benefits and reduced parasitic drag. Thrust is generally used to mitigate the compromise of reduced wing area and regain some of the lost envelope from weight. Remember thrust is not just about engine horsepower but also drag among other factors.

As long as the pilot does not exceed CLmax this is effective. If he exceeds these limits then this is a very bad choice in design engineering for a fighter.

Again we have to look at the aircraft as a system.

All the best,

Crumpp

Viper2005_
08-29-2006, 11:21 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Kettenhunde:
Depends on the airplane, power available, and condition of flight.

Speaking in terms of the power curve, if we look at the following diagram for an aircraft maintaining a 60 degree bank the area of least penalties is between the red lines labeled "good". Anything outside of those lines and we begin to pay an increased penalty including induced drag to maintain flight. We cannot maintain steady state performance at 60 degree bank either.

http://www.onpoi.net/ah/pics/users/503_1156869119_beststeadystateturn.jpg

Your calculations are somewhere above the power required line.
</div></BLOCKQUOTE>

Actually in the case of this diagram, if we fly at 60º bank with full power at about 150 mph TAS we've got around 10 thrust horsepower excess power to play with.

OTOH this: http://p.airliners.net/photos/small/5/7/6/0738675.jpg is hardly a WWII fighter...

Kettenhunde
08-29-2006, 11:47 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Actually in the case of this diagram, if we fly at 60º bank with full power at about 150 mph TAS we've got around 10 thrust horsepower excess power to play with. </div></BLOCKQUOTE>

Exactly. However that is irrelevant to our steady state turn. We would have to reduce throttle in the dark grey area to maintain airspeed and altitude in a 60 degree bank.

Not at the intersection of red boundry lines either. We have just enough power available to maintain a 60 degree bank. Since throttle, airspeed, bank angle, and altitude are constant we are in our maximum steady state turn. Our minimum radius maximum steady state turn is on the right hand boundry closest to the lift limit.

With more power available we could increase our bank angle in the dark grey zone. However this has some consequences.

All the best,

Crumpp

carguy_
08-29-2006, 12:42 PM
OMFG MATH RUN FOR SHELTER!!!! http://forums.ubi.com/images/smilies/compsmash.gif

Viper2005_
08-29-2006, 12:47 PM
http://forums.ubi.com/images/smilies/88.gif

faustnik
08-29-2006, 12:52 PM
At least Crumpp scetched in the "bad", "good", "bad" part in his diagram for us. http://forums.ubi.com/groupee_common/emoticons/icon_cool.gif

joeap
08-29-2006, 12:54 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by sudoku1941:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by joeap:
Guys what exactly does "hanging on the prop" refer too? The pilot's own plane or the opponents? Whatever, my limited experience in roller coasters, and as a passenger in commercial jets, (yes I know) leads me to say how often perception of events at such speeds can be different from what the words convey. Especially on this forum where it seems to mean helicopter like behaviour. I could see two planes climbing and having very little relative motion next to each other for example. </div></BLOCKQUOTE>

"Hanging on the prop" refers to being nose up very near to stall speed; you kind of "wallow" and "hang" there suspended; then, either you lower the nose, stall, spin, or if you can maintain enough control, hammerhead, jackknife or perhaps even tailslide some, because in the end gravity wins. I suppose the idea for the term comes from that feeling of "no visible means of support" and the inherent instability of the plane in that particular situation. </div></BLOCKQUOTE>

Thanks for the explanation. http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

WWMaxGunz
08-29-2006, 03:14 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">I'm saying that if you pull beyond (Cl^3/Cd^2)max that you're paying too much for your lift IMO because you are on the back side of the power curve.

If you only pull to (Cl^3/Cd^2)max then at constant altitude you'll bleed down to a maximum rate sustained turn.

Lift starts to get expensive as soon as you pull beyond (L/D)max. Beyond the minimum power requirement alpha, lift is very expensive. </div></BLOCKQUOTE>

I do believe that in more simmer-friendly terms there may be something of great importance to
the community in this... possibly.

Let's see if I've got this right;
---------------------------------------------------------
Cl is coefficient of lift which follows AOA steady till a bit short of the stall point where
the lift curve (AOA as the 'X' axis, Cl as the 'Y') goes from straight line up to curving over.

Cl_max is the highest point on the lift curve. At or just past(?) that we begin to stall?

Cd is coefficient of drag... total drag not just lift induced drag?

Just where does Cl cubed / Cd squared max out? Is it in that curving over but before Cl_max?

Back side of the power curve... that is level flight power curve where 'X' axis is speed and
'Y' axis is power required to maintain level flight?
With enough power you can fly stalled, correct?
---------------------------------------------------------

We can tell when stall occurs by the buffets or at least I can and many others can, helps to
pull up to it slowly.

But if the above works how I think I see it work then the best pull on turns is short of that
which does follow things I've seen in equations I can't reproduce and practices I can only
define as 'loosen up on the stick and see if the turn rate don't increase' or more generally
call 'the groove'. There was a LOT of discussion about that and IL2 back in the fall of 2002
that didn't really get anywhere with the sim itself. It was possible to slide around a very
small circle at low speed and make 360's faster than up at maneuver speed at least in some
planes. I wonder if the seeming 'semi-auto-rudder' had anything to do with it?

But anyway we could all use ---

1) A way or ways to know where to stop pulling stick if possible.

2) More understanding of these states and interaction with speed to understand more about
relative bleed in BnZ between the faster attacking plane and the slower target to gain better
expectation on who should lose what.

3) Perhaps also on BnZ exit after the guns pass especially wrt to climbing out.

But please if possible in terms that as many forum members as possible can use or barring
that at least label the terms! This is a HOBBY to me so I end up doing 3-4 web searches to
follow some posts. Like Vy being best climb speed.

NonWonderDog
08-29-2006, 03:16 PM
Kettenhunde's completely lost me. (I've never been able to understand the meaning behind Josf's disjointed posts to begin with.) I understand the theory he spouts and his occasional mangling of it, but I can no longer see the plot.

Kettenhunde, are you still arguing that a heavier plane, when the nose is below the horizon, will turn with less speed loss than a lighter plane? You still say this is somehow due to the "energy" of weight, right, and somehow has a greater percentage effect on the more massive plane? Does this somehow reduce the greater induced drag of the heavy plane or is it a separate effect?

Viper, I'd look at debating that tact instead of going back and forth on the meaning of graphs and this silly diversion on the definition of "the back side of the power curve." It should be pretty easy. Personally, I'm sick of this thread. Everything I have to say I've already said. I don't particularly care to pull out my notes and write out multiple mathematical proofs just to "win" an argument on some internet forum.

JG14_Josf
08-29-2006, 03:52 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Kettenhunde, are you still arguing that a heavier plane, when the nose is below the horizon, will turn with less speed loss than a lighter plane? You still say this is somehow due to the "energy" of weight, right, and somehow has a greater percentage effect on the more massive plane? Does this somehow reduce the greater induced drag of the heavy plane or is it a separate effect? </div></BLOCKQUOTE>

NonWonderDog,

If you can't understand what I am now going to write then that is OK by me.

If I'm not mistaken Crumpp, or Kettenhunde, has the lighter plane turning with less speed loss.

Of course that assumes a lot.

What I did ask is this:

Two planes exactly the same where one is heavier than the other side by side at max level speed and both planes turn at ClMax:

Both planes do not start out with the same energy.

The heavier plane starts out with more energy to burn since both planes are side by side at the same altitude and the same speed.

Both planes do not roll to the same bank angle to maintain level turn performance (no acceleration up or down subtracting or adding to gravity).

Both planes remain on the front side, at least, or at exactly CLMax (the angle of attack that generates the most lift) and both pilots manage to pilot the planes exactly the same i.e. the same error off CLMax and neither pilot 'sinks' the plane and both pilots have the same exact G tolerance, and both pilot maintain exactly the same G force during the turns.

NOW...which plane stalls first or, in other words, does the heavy plane with more energy "BLEED" more energy faster than the lighter plane or visa versa. The lighter plane starts out with less energy; of course.

Which plane stalls first?

If I can rewrite that question so as to avoid mangling or spouting disjointed theory then this may work:

Which plane stalls first?

Plane A: Heavy
Plane B: Light

Both planes are exactly the same except internal weight.

Both planes start turning at 700 kilometers per hour.

Both pilots hold exactly 6 times the force of gravity on a G meter installed in the cockpit.

Both pilots hold exactly a level turn without adding or subtracting altitude.

Which plane stalls first?

How did I do?

Is my question more mangled, disjointed, and beyond comprehension?

I can try again.

Is the question not relative to the topic?

What€s wrong about E-retention?

Viper2005_
08-29-2006, 04:19 PM
NoWonderDog, my intention is to get things right, not to win brownie points. I'm not in this to win a popularity contest. The nitpicking details are actually important, and if more people paid attention to them there would be a lot less whine on these forums.

WWMaxGunz,

Clmax is the point on the lift curve slope at which maximum lift is attained. Beyond it, lift decreases with increasing alpha. The definition of a stall varies depending upon who you talk to, but for practical purposes, once Cl starts decreasing you're onto a loser, even if the aeroplane hasn't departed (and some won't).

Cd is the drag coefficient. Generally it is the total drag of the thing you're talking about. So sometimes it means the Cd of the whole aeroplane, and sometimes it means the Cd of the wing section.

Generally speaking if you're going to talk about induced drag you'd use Cdi. Of course, if this were a scientific paper the "d" and the "i" would be subscripts.

(Cl^3/Cd^2)max (which looks much nicer when you can write it out properly!) is likely to be a bit after the end of the linear portion of the lift curve, but before Clmax. However, the only sure-fire way to work it out is to actually do the sums.

For the purposes of aircraft performance you're best advised to do your sums on the basis of data from the complete aircraft. Most aerofoil data is based upon the assumption of an infinite aspect ratio and therefore tends to give you a steeper lift curve slope than you'll see in reality.

The back side of the power curve is reached when you fly slower than the minimum power requirement speed (which happens to be the speed for maximum endurance in a piston engined aeroplane). Technically the back side of the power curve means that you're asking for a Cl&gt;(Cl^3/Cd^2)max.

The stall does not occur at the buffet. The buffet you feel is pre-stall buffet.

Most WWII fighters stall by dropping their nose and often a wing as well, leading to incipient spin.

Flight beyond the stall requires strong control authority; power isn't important. If you don't have power you'll just descend <span class="ev_code_red">very</span> fast...

Really what this all means is that you shouldn't pull to buffet if you can possibly help it. You get best "value for money" at a rather lower alpha.

Unfortunately there isn't a simple way to know when you've hit the optimum. But I can say that if you're in the pre-stall buffet the chances are that you've pulled too hard.

There are times when angles are more important than energy, and I'm not saying that you shouldn't pull hard.

I'm saying that you need to be gentle if you want to conserve e. But of course you knew that already.

If we were flying in X-Plane I could tell you to test for maximum sustained turn rate, note your stick position and simply hold that position (or less) for efficient turns. But we aren't and the stick controls force input rather than stick position.

As such, I guess it must all come down to experience, until such time as somebody comes up with a scientific method.

Glad you looked up Vy.

This is a hobby for me too, and surprising as it may seem, writing out definitions all day isn't a huge amount of fun. http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif

I'd be happy to contribute to a sticky of defintions (or a reading list), but frankly I can't be doing with giving defintions of everything everytime I post. If I did that I'd never get anything done!

Vx, Vy, Vyse, Vmca etc should be engraved upon the heart of every aviator. They matter. You can literally live and die by them.

Perhaps my biggest problem with the Mosquito in IL2 is that it doesn't care about Vmca. It was a killer IRL according to all the accounts I have read. In game it's a pussycat. As my only twin engined time is in a sim, all I can say is that trying to fly after an engine failure is quite diffiult. You'll see high footloads (&gt;100 lbf) and a high workload dealing with the dead engine. In this area IL2 is dumbed down. [/rant]

Kettenhunde
08-29-2006, 04:51 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Kettenhunde, are you still arguing that a heavier plane, when the nose is below the horizon, will turn with less speed loss than a lighter plane? </div></BLOCKQUOTE>


No and I never argued that. I said that weight contributes to thrust when the vector of lift is orientated below the horizon. Only then will it improve the aircrafts turn ability. That is a fact.

http://www.onpoi.net/ah/pics/users/503_1156778626_weighteffectonvertturn.jpg

http://www.onpoi.net/ah/pics/users/503_1156778272_orientationoflift.jpg

The effects of the weight vector in relation to the lift vector:

http://www.onpoi.net/ah/pics/users/503_1156889893_radialaccellerationsinaloop2.jpg

Each gains advantage in different portions of the loop based on the orientation of the lift vector.

Completely different concept from the heavy fighter points its nose down and can outturn the lighter aircraft......

The second part of the argument regarding induced drag and it effect:

What I said was that the power of induced drag to bleed energy is not critical unless the aircraft drops on the backside of lift curve.

Since then we have managed to confuse instantaneous turns with steady state turns, power curve with the lift curve, and produce calculations outside of the conditions of flight under discussion regarding induced drag.

We are making progress and viper knows what he talking about. Just having some trouble defining the conditions. A very common problem in this level of discussion on these gaming boards where people tend to speed read, make a snap judgment, and fire out €œthe answer€.

Notice in this aircraft that at no point is the plane unable to produce enough thrust to overcome drag production.

http://www.onpoi.net/ah/pics/users/503_1156889594_induceddragliftpower.jpg

Once it cannot produce enough thrust overcome drag to maintain that lift then it becomes critical.

It either trades Ps to maintain lift and overcome drag or it falls out of the sky....THAT is energy bleed.

Above a steady state turn the heavier aircraft will bleed more but keep in mind it has more Ps but it needs more Ps. It cannot maintain that state anyway. As long as it does not pull past CLmax then the penalty is not unmanageable.

Generally speaking, the lighter aircraft wins in the turns and the aircraft with less drag wins in the straight a ways. However you cannot draw conclusions about particular designs until you examined the aircraft as a system.

All the best,

Crumpp

WWMaxGunz
08-29-2006, 04:58 PM
Okay. For me the matter is to have useful info that most everyone here can use.
If charts or equations add to that then I'm glad they're there.
Whatever confuses... well that's difficult cause some people will always be confused.

I take it your alpha is AOA.

If I need more angle then I'd rather work the vertical than be greedy. Even just a bit of
nose down though may get me that target on the same pass.

I worked on systems trainers for a company and we flew an Aztec out to Witchita to go to Lear
school back in 87. The boss was the pilot/owner and went for extra sim time. So they threw
an engine out on takeoff at him and it took like 4 or 5 tries before he got it even as close
to the CL as the engines on the Lear 35 are. He related that on takeoff or landing with the
Aztec it would be sure death but that losing power on one in flight would mean stomping the
rudder and we'd probably be able to land. I haven't thought of trying one engine out on any
twin in the sim.... If you look on Zeno's they at least used to have single-engine ops film
for the P-38. IIRC only the left engine has a generator! Or is it the right engine? LOL!
BTW, the Lears at least up to 35 series don't control through hydraulics. They are a real
blast for response compared to the ones that do though. But if you ever get a chance to fly
one then make sure the owner can and does afford good maintenace since well that's the rep
that went there -- lower price by far tempts guys who can just afford one and then they can't
really keep em up. Other than that I don't call 3.5 to 5 mil in 1987 being exactly cheap
but then the guy who told me that owned an Aztec. Not shabby but way less than the Lear!

Viper2005_
08-29-2006, 05:22 PM
Most GA twins are deathtraps if you lose an engine.

If you ever fly a twin you should have Vmca engraved upon your heart.

I have flown aeroplanes with sub-standard maintenance. It's not a good idea. In fact, I intend to buy myself a parachute tomorrow. Literally.

The way I see it, if push comes to shove, you're not going to spend the money on anything else!

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">I take it your alpha is AOA.

If I need more angle then I'd rather work the vertical than be greedy. Even just a bit of
nose down though may get me that target on the same pass. </div></BLOCKQUOTE>

Yes, alpha = α = AOA

Other than that, please explain.

WWMaxGunz
08-29-2006, 05:38 PM
Explain? You mean about if I need more angle?

I can gain some alt to lose a bit of speed to where I can turn some of that extra without
bleeding so much then drop and roll into the rest of that extra angle while recovering
what I invested in the rise. Beats flat turns all to H. And if I can't get the shot that
way I am in good position to tactic out my next moves to try for another.

OTOH if I only need some extra then I can nose down a bit and turn more with gravity helping
and me being at slightly lowered G's in the drop then if need be roll and pull into it a bit
on the way back up to make my shot.

Being greedy for a quick kill is a good way to end up being the prey. If it takes an extra
few maneuvers then do it, is my line. Of course that does depend on the environment. Don't
want to be dancing around an have someone else dive through and whack me during the escapade.

Kettenhunde
08-29-2006, 06:21 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">By this I take it you really mean prop wash effects. </div></BLOCKQUOTE>

Hi Viper,

Sorry I missed this earlier.

No I mean thrust effects are different for propeller aircraft in comparision to jets.

Thrust for a jet is assumed to be constant over velocity.

Thus you can express Nzmax &lt;sus&gt; as:

Nzmax &lt;sus&gt; = T/W*(CL/CD)max

However for a propeller aircraft maximum thrust occurs at minimum power required so you cannot use the same formulation. I am sure your familiar with the effects of Tc.

Nzmax &lt;sus&gt; = THPavail/W * L/THPreq&lt;min&gt;

If we want to go into instantaneous turn performance we can do that. Might be interesting, especially on the whole "E bleed" conceptualization and its importance above the steady state envelope.

http://www.onpoi.net/ah/pics/users/503_1156897121_instantturndefinition.jpg

All the best,

Crumpp

p1ngu666
08-29-2006, 07:07 PM
ah thats qoute crumpp http://forums.ubi.com/images/smilies/16x16_smiley-happy.gif

once had a discussion over il2 vs 109 turning, and that proves me right http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif

viper, im not sure how well the sim models single engine safety speed, but above that the mossie could perform well on 1 engine. theres footage of one barrel rolling on 1 engine, and the camera is ground based http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif. it could climb on 1 engine too, something other twins could barely do.

the danger on single engine landings would be to dip below the safety speed then yaw/roll into the ground from the torque/offset power. below the safety speed the controls arent effective enuff to counter that.

at somepoint they did regular practise of single engine landings, but lost pilots http://forums.ubi.com/groupee_common/emoticons/icon_frown.gif, the pilot telling the story said he always flew 10mph~ faster than susposed to, to avoid the danger

p1ngu666
08-29-2006, 07:08 PM
oh and the safety speed was effected by weight. in *theory* we have the lightest FBVI possible, pretty much

Kettenhunde
08-29-2006, 09:12 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">ah thats qoute crumpp </div></BLOCKQUOTE>

Why does that make me nervous?

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">The way I see it, if push comes to shove, you're not going to spend the money on anything else! </div></BLOCKQUOTE>

Will it to us!

http://forums.ubi.com/images/smilies/16x16_smiley-tongue.gif

We can certainly use it and will put it to good use on more airplanes. We just bought the original "Scat VII" and are deciding if it or a Dora 9 will be our next restoration after "Black 3" and "White 1".

If we do "Scat VII" then we will have two original combat airframes flying side by side.

All the best,

Crumpp

GR142-Pipper
08-30-2006, 12:26 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by KraljMatjaz:
let me just repost what have I posted in the "why don't you like P-51" thread:

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by KraljMatjaz:
this thread may well be conneced with one of the big flaws of this 'sim': energy retention.

BnZ fighters are simply bleeding too much compared to TnB ones. that's why P51 NEVER (but in a single initial surprise dive from 1k alt advantage) can utilise it's better maneouverability at high speeds. ironically it is more maneouverable until it keeps flying straight. as soon as she tries to turn (let it be a gentle turn at 700 or 800kph) she'll bleed enormously and allow 109 to connect and do the job. many other examples are F6F vs A6M5, Fw190 vs Spit, P51 vs everything, P47 vs everything, F4U vs everything...

US fighters in this sim are mostly bnz that's why they are the ones that suffer most from this error. now throw in a bit of wobbling and a lacking DM (ammo boxes, hydrawlics, glycol coolant,.......) that lowers the efficiency of .50cals, and you have planes that require true masochists to pilot them. do u see how P40s and, a little bit sarcasticaly, P-39 are popular in this sim?

salute to all US planes pilots that do manage to do well in them by not always having 5k alt advantage (which I'm quite sure US pilots didn't always have, not on Pacific nor in ETO).

now all repeat after me:

"Oleg please in BOB do the energy retention right." </div></BLOCKQUOTE>

let's put the cards on the table now:

bnz fighters have no real options against tnb fighters but to run their *** out towards friendly aaa and screaming for help (assuming of course they met on a same alt - having 2k alt advantage was smart in ww2 and here, but presents a nice excuse for poor plane. u can do well in every plane with 2k advantage).

yes a group of 190As can be succsessful versus spitsIX only due to better armament which allows them to drag and bag all the spits before they manage to do the same, and in great numbers, 1v1 fw should immediately dive and run before it's too late.

tnb fighters simply retain E to well compared to bnz. how on earth am I about to use my better high speed manoeuvering in P51 versus 109 if I bleed all my speed in first 90 degrees of turning? i doubt p-51 was THAT bad at 1v1 same alt. same goes for f4u, f6f vs A6M5, fw190 etc etc etc.

all the historical reports claiming P51 could turn inside 109 are correct becuse they are reffering to turning at hihg speeds.


the trend of fighter developement toward the end of the war was tending towards bnz planes. f8f was greatly influenced by 190, as was La11.

another example (which I already mentioned in one of previous posts) is, ta..da.., the milion times heard Fw190A4 versus SpitV.

we may have a derated Fw and a 1942 spitV while we should actualy have a 9lb boost 41 one, but A4 still dominates the spit. however, the fw was known to have aproximately same optimal climbing speed but much steeper climbing angle and was getting away from spit in a steep sustained climb, and spit couldn't follow, because if he would pull up even further to get firing solution, he would stall.

in this sim they both climb at approximately same angle, but fw is faster and all you do is increase the distance between the planes (which is enough to get advantage over him though). </div></BLOCKQUOTE>Very good post and your characterizations are right on target.

GR142-Pipper

HellToupee
08-30-2006, 12:40 AM
um why should the 190 do anything other than dive and run when engaged in a co alt close in fight with a spitfire mk9? SPits climb and turn and far superior unless 190 has ufo traits in e retention its not going to win that kind of fight.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">
yes a group of 190As can be succsessful versus spitsIX only due to better armament which allows them to drag and bag all the spits before they manage to do the same, and in great numbers, 1v1 fw should immediately dive and run before it's too late. </div></BLOCKQUOTE>

Significant speed advantage not worth a mention? WHat does a p47 or even a spitfire do when faced with a zero or ki43, it must fight same as 190 fights a spitfire.

Xiolablu3
08-30-2006, 12:43 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by KraljMatjaz:

bnz fighters have no real options against tnb fighters but to run their *** out towards friendly aaa and screaming for help

</div></BLOCKQUOTE>

Just what are you expecting them to do?

WW1 Motto - Always above, Seldom same altitude - Never Below

And thats WW1 with its manouvrable bi-planes.

If you are in a plane which is faster than the enemy and are lower or co alt, you can get away, thats the beauty of them.

Dont complain that this is ALL you can do, it was very important in real war, dont complain just cos it doesnt get you a 10-1 KD ratio in game.

I repeat, what are you expecting to be able to do other than run away if you meet below in a faster, but worse climbing, less manouvrable plane?

EDIT: Hells Toupee beat me too it.

JG14_Josf
08-30-2006, 01:00 AM
Is this the forum where topics are irrelevant to what is on the table for discussion?

I'm just wondering. I read topics on Energy because energy is the name of the game.

Thanks for the charts.

NonWonderDog
08-30-2006, 02:00 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by JG14_Josf:
Both planes remain on the front side, at least, or at exactly CLMax (the angle of attack that generates the most lift) and both pilots manage to pilot the planes exactly the same i.e. the same error off CLMax and neither pilot 'sinks' the plane and both pilots have the same exact G tolerance, and both pilot maintain exactly the same G force during the turns.

NOW...which plane stalls first or, in other words, does the heavy plane with more energy "BLEED" more energy faster than the lighter plane or visa versa. The lighter plane starts out with less energy; of course.

Which plane stalls first?
</div></BLOCKQUOTE>

The math is too involved for me to work this one out at 4:00 AM, but assuming they both maintain the same coefficient of lift, I believe they should stall at nearly the same time. The heavier plane would stall at a higher speed, so overall, the lighter plane would bleed speed faster. Since both planes are at Cl_max, or at least the same angle of attack, both planes have the same initial drag. The same drag applied to both planes will cause the greatest speed loss to the lighter plane.

This is mostly irrelevant, however, because the lighter plane would be turning more sharply, at a higher load factor. They're both at Cl_max, so they both have the same lift, but the same lift applied to both planes causes greatest loading in the lighter plane. All the pilot of the lighter plane has to do is ease up on the stick, and he's won.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">
Both pilots hold exactly 6 times the force of gravity on a G meter installed in the cockpit.

Which plane stalls first?
</div></BLOCKQUOTE>

In this case, the heavy plane would undoubtedly stall first. If both planes are to maintain the same load factor, the heavy plane needs more lift. More lift, more drag.


These are two mutually exclusive cases. It's not possible for two otherwise identical planes with different weights both turning with the same coefficient of lift to have the same load factor.

WWMaxGunz
08-30-2006, 02:19 AM
I think I see true that esp at high speed I can get heavy bleed even before pre-stall buffets.
So just like always in sims for me, watching my speed is very important.

WWMaxGunz
08-30-2006, 02:35 AM
Well, THAT post went through (UBI forum reply box is POS coding!) so I'll try for another.

On BnZ I don't turn more than 45 degrees at one stretch and don't go for targets over
30 degrees from my path. If I need more then I need to pre-maneuver more.

On BnZ I hit from high delta-V or it ain't BnZ.

On BnZ I start shooting from long range to have time to correct if need be. I won't have
but 3 seconds or less to make my shot. I want to shoot from farther out also because if
the target turns hard then by the distance I am back I have less hard to turn to keep aim
ahead of the target. And I always want that.

Shooting from close only in BnZ gives me only a very short burst before I have to veer off.
When I'm feeling sharp then maybe I will but my reflexes and control have degraded for that.
I sure don't call following around in a 90+ degree turn shooting from 200m or less on a
turning target BnZ. If I have time for that then I don't have the delta-V for BnZ. As long
as I avoid that and hard bleeding pulls on exit then I don't have speed bleed problems!

I want at least 100kph more than the target in BnZ. Less and I am E-fighting at best.

If I try to E-fight against a plane with better powerloading than mine then I am stupid
for not knowing my target better and deserve to be shot down. Heavy or light does not
matter in E-fight, it is powerloading that does.

dieg777
08-30-2006, 04:58 AM
~S~ crumpp and viper and all, thanks for taking the time and effort to try to clarify this matter, however the maths has defeated me. I know that when I am in am online dogfight that none of this will help unless simplified.

I would appreciate it if one of you could therefore take the time to put all this theory into some general practical advice for myself , along the lines of what piper summerised and xiolablue added to on the last page.

In other words could you please fill in the gaps
below for me , in as plane english as possible please,without resorting to heavy maths theory.

The problem with E_ retention in this game is that x is not modeled correctly and so this causes planes of type y to fail to match the theoretical flight caracteristics in a,b,c,etc.

This means that pilots of planes of type y should be careful when performing manouvers a,b,c, and to ensure thay get the best performance should attempt to do e,f,g etc when carrying out these manouvers.

I would like to add in some of Robert shaws advice on the discussion of "running away"(when discussing the low vs high wing loading at similar T/W)

" the pilot of the high wing loaded aircraft has a serious problem, he has no performance advantage to exploit. he should chose E tactics , however recognise that the opponent has the superior dogfighter and should win a one-to-one fight, PILOT SKILL BEING EQUILL. the energy fighter should engage with the intention of eveluating the enemys technique quickly and disengaging if he proves to be the Red Baron"

so IMHO hit and run, or just run, is sometimes the only option if you wish to survive, I just wish I could remember this sometimes - the hardest part for me is picking my engagements or specifically when not to engage http://forums.ubi.com/groupee_common/emoticons/icon_rolleyes.gif

WWMaxGunz
08-30-2006, 08:55 AM
If you've got Shaw, go to the One on One tactics for dissimilar planes which is the case
between late 109's or FW's and Spitfire IX's which we all know is the 25 lb boost model.

What does it say about energy tactics? Well, the one who plans to use energy tactics is
supposed to have higher T/W. So find the speed at which that is true and don't blow it.
Somehow that don't translate to pulling a lot of circle in a FW going 600+kph trying to
circle with a Spit-25 tight circling at 400kph and able to keep it up indefinitely. Do
that and expect success and the problem is your expectations.

JG14_Josf
08-30-2006, 09:52 AM
NoWonderDog,

Thanks for taking the time and effort to decipher my question and provide your opinion on the answer.

Rather than argue over the language used to describe the questions that you find to be mutually exclusive, please, consider both to be the same question intended even though the words didn€t communicate that same exact question.

I can try to explain the question again to arrive more closely to the exact question and therefore show why the question must be free from opinion and be answered definitively one way or the other since the question answers this question:

What€s wrong with E-retention?

Back to the two identical planes (except weight) starting at 700 km/h straight and level side by side in line abreast formation:

The heavier plane at the same velocity and same altitude will posses a higher energy state. If the heavier plane at the same velocity and same altitude is much heavier then that same exact plane with much higher weight will posses a much higher energy state than the same plane that is the same plane only much lighter.

It may be a good idea, in my opinion, to keep that fact in mind as the planes begin to turn.

Next:

In order to simplify this part of the question: What€s wrong with E-retention? = for the sake of simplification I€m going to temporarily suggest ignoring the time and energy it takes to get from wings level to the 6 g turn for both planes. That moment in time is Instantaneous Turn performance if I€m not mistaken.

The idea, for simplification, is to picture the heavy plane and the light plane at the same altitude, the same speed, and at the pilot g limit of 6 times the force of gravity.

The question is then: Which plane stalls first?

The question is the same as: What is wrong with E-retention?

If the heavy plane stalls first, then, and perhaps, nothing is wrong with E-retention.

Please consider answering the question definitively before jumping to conclusions.

Back to both planes turning at 6 G while both planes (exactly the same plane except weight) are at the same altitude and the same speed.

Since both planes started the turn in line-abreast formation, now, one plane is ahead of the other plane. Let me propose that one plane is actually chasing the other plane on the same turn rate, the same turn radius, same speed, and same altitude €" at the start of the turn.

If the velocity and the G load are the same, then, and correct me if this is wrong, please, then the turn rate, and radius, are the same for both objects, any object, in time and space.

Now, and this is the part that I€m trying to communicate for discussion, if the heavy plane slows down faster, then, the heavy plane will turn a tighter radius and a higher turn rate. The plane that slows down less will, of course, BLEED less energy.

Remember, please, that the question being asked is this:

What€s wrong with E-retention?

If the people actually trying to answer the question can answer my question, then, I€ll be a long way toward answering the question myself and thanks for that.

Note: The heavy plane requires a steeper bank angle for the same G load in a level turn €" if I€m not mistaken.

Any errors or omissions are not intended by me. Any help refining the question and therefore the answer, definitively - is appreciated.

If, on the other hand, there is a desire to know how a double inferior plane (lower T/W and higher wing loading) can defeat a double superior plane with energy tactics then I€ve already posted that answer by Shaw in my earlier thread as an introduction to suggest that the game, depending upon the patch, and depending upon the planes compared, is wrong as far as E-retention is concerned.

Here it is again from page 6 on this wandering thread:

page 184
Double inferior conditions
------------------------------------------
Climbing extension/pitch-back tactics cannot be expected to work for the inferior fighter in this scenario, since the opponent has a Ps advantage. The other energy tactics discussed, which are intended to bleed the bogey's energy with a nose-to-tail turn...can still be effective against an inexperienced or careless opponent.
The following episode, found in Thunderbolt! by the World War II USAAF ace Robert S. Johnson, is one of the best examples available of the use of energy tactics (diving extension/pitch back) to defeat a double-superior opponent. The encounter described is a mock combat engagement over England between Johnson (P-47C) and an unidentified RAF pilot in a new Spitfire IX. The Spitfire had about a 25 percent better power loading and nearly a 25 percent lower wing loading. The Thunderbolt's only performance advantages were faster top speed, greater acceleration in a dive (because of the P-47s heavier weight and higher density), and better roll performance.) Johnson, undoubtedly one of the greatest natural fighter pilots of all time, used his roll performance defensively to allow himself the chance to build an energy advantage in a diving extension.

We flew together in formation, and then I decided to see just what this airplane had to its credit.
I opened the throttle full and the Thunderbolt forged ahead. A moment later exhaust smoke poured from the Spit as the pilot came after me. He couldn't make it; the Jug had a definite speed advantage. I grinned happily; I'd heard so much about this airplane that I really wanted to show off the Thunderbolt to her pilot. The Jug kept pulling away form the Spitfire; suddenly I hauled back on the stick and lifted the nose. The Thunderbolt zoomed upward; soaring into the cloud-flecked sky. I looked out and back: the Spit was straining to match me, and barely able to hold his position.
But my advantage was only the zoom-once in steady climb, he had me. I gaped as smoke poured from the exhausts and the Spitfire shot past me as if I were standing still. Could that plane climb! He tore upward in a climb I couldn't match in the Jug. Now it was his turn; the broad elliptical wings rolled, swung around, and the Spit screamed in, hell-bent on chewing me up.
This was going to be fun. I knew he could turn inside the heavy Thunderbolt; if I attempted to hold a tight turn the Spitfire would slip right inside me. First rule in this kind of fight: don't fight the way your opponent fights best. No sharp turns; don't climb: keep him at your own level.
We were at 5,000 feet, the Spitfire skidding around hard and coming in on my tial. No use turning: he'd whip right inside me as if I were a truck loaded with cement, and snap out in firing position. Well, I had a few tricks, too.
The P-47 was faster, and I threw the ship into a roll. Right here I had him. The jug could out roll any plane in the air, bar none. With my speed, roll was my only advantage, and I made full use of the manner in which the Thunderbolt could whirl. I kicked the Jug into a wicked left roll, horizon spinning crazily, once, twice, into a third. As he turned to the left to follow, I tramped down on the right rudder, banged the stick over to the right, around and around we went, left, right, left, right. I could whip through better than two rolls before the Spitfire even completed his first. And this killed his ability to turn inside me. I just refused to turn. Every time he tried to follow me in a roll, I flashed away to the opposite side, opening the gap between our two planes.
Then I played the trump. The Spitfire was clawing wildly through the air, trying to follow me in a roll, when I dropped the nose. The Thunderbolt howled and ran for the earth. Barely had the Spitfire started to follow-and I was a long way ahead of him by now - when I jerked back on the stick and threw the Jug into a zoom climb. In a straight or turning climb, the British ship had the advantage. But coming out of a dive, there's not a British or a German fighter that can come close to a Thunderbolt rushing upward in a zoom. Before the Spit pilot knew what had happened, I was high above him, the Thunderbolt hammering around. And that was it - for in the next few moments the Spitfire flier was amazed to see a less maneuverable, slower-climbing Thunderbolt rushing straight at him, eight guns pointed ominously at his cockpit.€ (Shaw quoting Johnson)

Note:
€œ The encounter described is a mock combat engagement over England between Johnson (P-47C) and an unidentified RAF pilot in a new Spitfire IX. The Spitfire had about a 25 percent better power loading and nearly a 25 percent lower wing loading.€

If the player of the game is inclined to desire another method described by Shaw, besides the one described by Shaw above, and one that does work in the game, then please consider looking up and figuring out Shaw€s Sustained Turn Technique.

Here is an example training track file of the Sustained Turn Technique:

http://people.ee.ethz.ch/~chapman/il2guide/tracks.htm (http://people.ee.ethz.ch/%7Echapman/il2guide/tracks.htm)

Download Energy Game

Or not

The question is:

What€s wrong with E-retention?

If the heavy plane slows down faster in the high speed turn, then, the heavy plane (if the power is kept on for both planes) turns a tighter level turn at a higher rate before stalling.

That is if both planes are exactly the same except for weight.

As Crumpp continuously notes:

€œHowever you cannot draw conclusions about particular designs until you examined the aircraft as a system.€

Physics on the other hand is definitive. Any object traveling at a given speed and a given G load (pilot or game limited g load) will turn at a known and fixed turn rate and radius.

It may help to picture the bank angles while the two identical planes (one heavier or much heavier than the other) turn at the same g load (6 G) starting from the same altitude and starting from the same velocity (the heavier plane starts with more energy) as both planes try to chase each other in a level turn.

I may be wrong, of course, but I think the plane with the steeper bank angle for that G load will turn a tighter turn at a higher rate. If I am not wrong: the heavier plane will have the steeper bank angle.

Of course, in reality, all the lighter plane has to do is chop the throttle and slow down €" or climb. The lighter plane (power off), not the heavier plane, would slow down quicker as the lighter, not the heavier plane, is accelerated by air mass quicker than the heavier plane and that ability for air mass to slow down lighter objects of the same size and shape remains a physical reality no matter which direction the object is traveling through air, no matter which game intends to model physics, and no matter who thinks what should do what.

I could be wrong: of course. That is why I am typing, asking, and trying to stay focused on the topic:

What€s wrong with E-retention?

A true WWII Combat Flight Simulator will inevitably be available as long as players actually want one €" and could recognize one if it existed.

WWMaxGunz
08-30-2006, 08:20 PM
Bank angle determines G's in coordinated turn.

GR142-Pipper
08-30-2006, 10:54 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by JG14_Josf:
The question is then: Which plane stalls first? </div></BLOCKQUOTE>If both planes are identically configured and are flying at the same altitude, both will stall at the same angle of attack however the heavier aircraft will be going faster when it stalls.

Here's an easily understood example. When aircraft make carrier landings, the object for the pilots, regardless of aircraft weight, is to maintain a constant angle of attack. The aircraft attitude is maintained as a constant and what varies is the approach airspeed. The heavier aircraft will be flying a faster approach than one similarly configured but at a lower weight. So we really don't care what our airspeed is...it's all about maintaining the proper angle of attack.

GR142-Pipper

Ratsack
08-31-2006, 03:10 AM
I see that a denizen of the Land of The Gibber has dropped by.

I suspect a short reading of Vogon poetry is in order:

'Groop, I implore thee, my foonting turlingdromes...'

Makes more sense than some the stuff above.

cheers,
Ratsack

Kettenhunde
08-31-2006, 06:37 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">So we really don't care what our airspeed is...it's all about maintaining the proper angle of attack. </div></BLOCKQUOTE>

Hi Gipper,

You have this backwards. You maintain airspeed as that is the critical portion. AoA is a limit however it can be "cheated" under certain circumstances by a skilled pilot. Airspeeds cannot be cheated however.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Yes, it is definitely possible to fly at an angle of attack higher than the critical angle of attack.

No, it is not possible to sustain flight at an airspeed below the stalling speed. </div></BLOCKQUOTE>

http://www.av8n.com/how/htm/vdamp.html#sec-beyond-stall

All other parameters being equal the heavier aircraft will stall first as it must maintain the higher velocity.

All the best,

Crumpp

NonWonderDog
08-31-2006, 07:50 AM
By "sustain flight" that means level flight. It's technically possible to fly below stall speed if you need less lift than the plane has weight. If you have enough engine power you can climb steeply (&gt;45 degrees) and if you have enough drag you can dive steeply at less than stall speed and be in a completely steady-state situation.

In the sim, planes with slats can fly straight ahead below stall speed at 0.8 G, losing altitude all the time. I believe that this should not really happen the way it does -- the plane should be much more unstable in pitch -- but it doesn't contradict the physics.

Kettenhunde
08-31-2006, 08:41 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">By "sustain flight" that means level flight. </div></BLOCKQUOTE>


No it means steady state flight.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">It's technically possible to fly below stall speed if you need less lift than the plane has weight. </div></BLOCKQUOTE>

It is not possible in steady state flight.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">In the sim, planes with slats can fly straight ahead below stall speed at 0.8 G, losing altitude all the time. </div></BLOCKQUOTE>

Because it is not steady state flight, notice your accelerations and think about what is happening with your forces of flight.

All the best,

Crumpp

Xiolablu3
08-31-2006, 08:53 AM
Sorry to lower the tone, but can a Jug really outroll a Spitfire? I thought the Spit had a pretty high rate of roll, even the non-clipped ones.

JtD
08-31-2006, 09:19 AM
Not at high speeds.

Xiolablu3
08-31-2006, 10:10 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by JtD:
Not at high speeds. </div></BLOCKQUOTE>

Rgr, thanks, just been reading up actually.

The Spitfire apparantly had a fantastic elevator at high speeds, but its ailerons became heavy. This would of course mean the roll rate was worse at high speed.

NonWonderDog
08-31-2006, 12:08 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Kettenhunde:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">By "sustain flight" that means level flight. </div></BLOCKQUOTE>


No it means steady state flight.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">It's technically possible to fly below stall speed if you need less lift than the plane has weight. </div></BLOCKQUOTE>

It is not possible in steady state flight.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">In the sim, planes with slats can fly straight ahead below stall speed at 0.8 G, losing altitude all the time. </div></BLOCKQUOTE>

Because it is not steady state flight, notice your accelerations and think about what is happening with your forces of flight.

All the best,

Crumpp </div></BLOCKQUOTE>

The funny thing about that 0.8 G situation is its steadiness. It's hard to explain how it works, mainly because I don't think it should happen, but I do believe the "overload" gauge in devicelink only tracks load directly up and down relative to your pilot. I think the 0.8G reading might mostly be due to error at high angles of attack. The plane actually obtains a steady descent after a couple seconds. What probably happens is that, since the nose is pointed so high, engine power makes up for some of the deficiency in lift. Since the plane is descending, there is a vertical component of drag that makes up the rest. In retrospect, I shouldn't have referred to this by its 0.8G devicelink reading, but it does mean that the wings are providing less than 100% of the lift needed to counteract weight.


Anyway, if you are pointed 90 degrees upwards and your maximum thrust is greater than your weight, you need no lift whatsoever. Level stall speed is completely irrelevant in this case, as the plane will fly at any speed. It might even hover, and you can't argue that a hover isn't a steady state.

That's just the limit case. Power will likewise decrease the lift needed in any climb. The engine thrust has a vertical component in a climb, after all. If you're climbing at a very steep angle it might even be the dominant vertical force.

The weasely way to get out of this one is just to say that the vertical component of engine thrust changes the speed at which the plane will stall in 1G flight, and thus changes the stall speed. That may be true, but the number given as "stall speed" is calculated for power-off level flight at maximum angle of attack. It's always found before the plane even makes a test flight. To say that steady flight is impossible below the stated stall speed in any situation is simply false.

People tend to put a lot more engineering importance on stall speed than it deserves. It's mainly useful in a practical sense: don't let the plane go below stall speed.

Remember, also, that "steady state" doesn't mean that the net accelleration is zero in an inertial frame. There are steady state turns in addition to steady level flight, steady climbs, and steady descents. It really just means that the calculations for one moment are valid in any other moment, even though the position or orientation of the object may have changed. The concept of steady climbs and descents, of course, assumes (unrealistically) that there are no variations in gravity or the atmosphere. So does level flight, for that matter.

WWMaxGunz
08-31-2006, 02:03 PM
There's more than one kind of stall speed and full power stall speed is one of them.
You have thrust component and also propwash over wings and on tail to deal with power-on.

GR142-Pipper
08-31-2006, 05:08 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Kettenhunde:
[QUOTE]So we really don't care what our airspeed is...it's all about maintaining the proper angle of attack. </div></BLOCKQUOTE>

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Hi Gipper,

You have this backwards. You maintain airspeed as that is the critical portion. AoA is a limit however it can be "cheated" under certain circumstances by a skilled pilot. Airspeeds cannot be cheated however. </div></BLOCKQUOTE>Respectfully, I have it correct. AoA can NOT be cheated as it automatically compensates for aircraft weight. If you fly a constant AoA, your flight attitude will be the same but your airspeed will vary according to weight. The heavier you are the faster your approach speed will be but your AoA will remain constant.

GR142-Pipper

p1ngu666
08-31-2006, 05:25 PM
pipper was a carrier pilot, presumeably this relates to carrier landings.

its quite possible that AOA ties in nicely with the right airspeed for landing, and the varying weight.

so he knows if he keeps AOA at say 5 degrees, then hes fine, from the start to finish of his flight.

WWMaxGunz
08-31-2006, 06:35 PM
If I fly straight with a constant AOA my speed may be higher or lower according to my weight
but my power controls whether or not my plane rises or drops. If I want to hold level flight
at some power then I need to vary my AOA.

The landing mantra; pitch to control speed and power to control altitude, which CAN get you in
trouble if you try to go too slow but otherwise is the best way I know of.

Perhaps the song (You are the) "Wind Under My Wings" should be "Wind Over My Wings"?

GR142-Pipper
08-31-2006, 06:59 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by p1ngu666:
pipper was a carrier pilot, presumeably this relates to carrier landings.

its quite possible that AOA ties in nicely with the right airspeed for landing, and the varying weight. </div></BLOCKQUOTE>Yes. This allows the pilot to only be concerned with maintaining a constant AoA during the approach.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">so he knows if he keeps AOA at say 5 degrees, then hes fine, from the start to finish of his flight. </div></BLOCKQUOTE>AoA will be higher on take off rotation/liftoff and during the landing approach when transitioning to landing configuration. Other than that it should be pretty low as you suggest.

GR142-Pipper

Kettenhunde
08-31-2006, 07:17 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">AoA can NOT be cheated as it automatically compensates for aircraft weight. </div></BLOCKQUOTE>

I think you should reread what I posted Gipper. Your statement of AoA is a hard limit is not correct. While AoA is very important it is speed that cannot be violated at the edge.

AoA can be cheated. It is possible to exceed critical AoA and still fly the plane. It takes considerable skill on the pilots part but it can be done. You are also not going to exceed it by much.

However you can maintain critical AoA and still fly the plane.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Just below the critical angle of attack, there is good vertical damping; just above the critical angle of attack there is strongly negative vertical damping. </div></BLOCKQUOTE>

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">We are now in a position to answer a question that used to cause a lot of confusion: can you fly €œbeyond€ the stall? Some people say yes, some people say no. The answer depends on whether you mean €œbeyond€ the stalling angle of attack, or €œbeyond€ the stalling airspeed.

That is,

* Yes, it is definitely possible to fly at an angle of attack higher than the critical angle of attack. (It may require super-human skill to overcome the pathological handling characteristics in this regime, but it is possible in principle to maintain a stalled angle of attack indefinitely.)
* No, it is not possible to sustain flight at an airspeed below the stalling speed. </div></BLOCKQUOTE>

http://www.av8n.com/how/htm/vdamp.html#sec-beyond-stall

However speed cannot be cheated. It is not possible to drop below stall speed and still fly the plane. The loss of dampening is a design limit.

I don't care if the pilot is Orville Wright that is true.

However, my comments only refer to the portion I quoted from your posting.

Your second portion, referring to landings, was not quoted because it is correct. However, the topic was not about maintaining critical AoA it was the possibility of exceeding it in controlled flight vs the possibility of flying below stall speed.

Your original statement places critical AoA as the "hard deck" for stall onset. It is important but not nearly as important as speed. Knowing your background I see why you thought this to be correct.

All the best,

Crumpp

WWMaxGunz
08-31-2006, 08:33 PM
I saw video of MiG-29's doing Cobra at the British airshow and if that wasn't beyond
critical AOA I wonder at those wings! They were not standing totally on the exhaust....

Finnish test pilot in 109G-6 at full power was able to maintain level flight at about 130kph,
the document has been shown here. Pitch was noted as 30 degrees.

Enough power and enough control with some speed is what it takes but how far that can be
pushed... tailplanes must also be not stalled? They have less angle of incidence than the
wings usually and with elevator you can change tailplane AOA so some of that impossible isn't.

GR142-Pipper
08-31-2006, 10:10 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Kettenhunde:
I think you should reread what I posted Gipper. Your statement of AoA is a hard limit is not correct. While AoA is very important it is speed that cannot be violated at the edge. </div></BLOCKQUOTE>Respectfully, I did read what you posted and it's not speed, it's AoA. The easiest and most basic example of this is that if you take two identically configured aircraft of the same type at the same altitude, one with full fuel and the other with 25% fuel, the two aircraft will stall at different airspeeds...but the SAME AoA. You're trying to make a case where none exists.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">AoA can be cheated. It is possible to exceed critical AoA and still fly the plane. It takes considerable skill on the pilots part but it can be done. You are also not going to exceed it by much. </div></BLOCKQUOTE>What you're describing is a controlled departure. This point is outside the fact that the aircraft has indeed departed (or stalled or built up a huge sink rate in the case of delta-winged aircraft) because it has exceeded its critical AoA...not because of it has reached a critical airspeed. The variable is weight. AoA automatically compensates for this. Airspeed does not.

GR142-Pipper

NonWonderDog
08-31-2006, 10:45 PM
Modern jet fighters have VERY interesting lift curves beyond the critical angle of attack. Lift drops off slowly, and there's usually a second or third (lower) peak at a very high angle of attack. Delta-winged aircraft never really stall like straight-winged aircraft do.

That's what lets MiG-29s, Su-27s, and F-22s do the cobra maneuver. You'd never pull it off in a Pitts Special. You'd spin out of the sky before you got halfway there, even if you had a vector-thrust jet engine strapped to the back.

I'm really not sure what caused me to go off on this tangent.

Kettenhunde
09-01-2006, 05:13 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">two aircraft will stall at different airspeeds...but the SAME AoA. </div></BLOCKQUOTE>

Your claim is speed does not account for weight??

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">The variable is weight. AoA automatically compensates for this. Airspeed does not. </div></BLOCKQUOTE>

It is right there infront of you in your own post. Your just not putting it together.

Come on Pipper, you know better than this, right?

Respectfully, think about what I am saying, read over the link a few times, and you will see it is correct.

All the best,

Crumpp

Kettenhunde
09-01-2006, 05:34 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">There is a whole range of angles of attack near the critical angle of attack that all produce about the same coefficient of lift (because the coefficient of lift versus angle of attack curve is quite flat on top). All the coefficient-of-lift values in this small range correspond to nearly the same airspeed --- namely VS, the stalling airspeed. </div></BLOCKQUOTE>

As a pilot on landing you are not looking at the airspeed indicator in most cases anyway. That does not mean Vs is not a hard limit.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">During the flare, the airspeed indicator doesn€t tell you anything you need to know. I once asked an airline captain to tell me at what airspeed his airliner touched down. He said €œI don€t know; I never looked. I€ve always had more important things to look at€. That was a good pilot€s honest answer. </div></BLOCKQUOTE>

http://www.av8n.com/how/htm/aoa.html#fig-ias-cl-aoa

All the best,

Crumpp

Xiolablu3
09-01-2006, 06:08 AM
I have to ask you knowledgable guys a question I have been wondering for a while.

Does a modern jet fighter have enough power to point straight up and keep climbing? Or will he eventually stall just like a W2 pilot?

JtD
09-01-2006, 06:48 AM
It stalls as soon as it runs out of fuel. http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

Many modern jets have a thrust/weight ratio above 1 (with certain altitude restrictions).

tigertalon
09-01-2006, 06:51 AM
If I may take MiG-29 as an example:

It's empty weight is approximately 8.200 kg, while fully loaded it's 18.000 kg. Its enines (R-33D) produce around 8,3 tonns of thrust with full afterburner, this sums up to 16 tonns of thrust.

So, the answer is yes they can. Most modern fighters have their trust/weight ratio larger than 1.

Viper2005_
09-01-2006, 07:33 AM
For once I agree with Pipper. The stall is a simple function of alpha, not airspeed.

Fly beyond the critical alpha and the flow over the wing will stall.

Speed only has an effect in as much as the stalling angle of attack varies as a function of Reynolds Number.

Vs is simply the speed (more accurately, dynamic pressure or "Q") at which Clmax produces a lifting force equal to the aircraft's weight, and as such is the minimum speed at which 1 g straight & level flight may be sustained at the particular weight and balance condition for which it has been calculated.

I have flown aeroplanes at speeds well below Vs without stalling; I just didn't ask for 1 g.

OTOH, pull beyond the critical alpha and the wing will stall, even if you're flying much faster than Vs. Pull 4 g and you'll stall at 2Vs. Pull 9 g and you'll stall at 3Vs.

This doesn't mean that you're bound to lose control (though in most cases, in most aircraft, you will). It just means that you've pulled beyond Clmax.

WWMaxGunz
09-01-2006, 08:40 AM
It's not like the lift goes to zero beyond critical angle.
Just that drag already high goes steeply higher.
If you've got the power to maintain lift and can still control the plane then you stay up.
Those two are very big IF's and my example is Cobra maneuver. HOW is important but also
beside the point.

Bf-190G-6 has power-off clean stall appx 155kph yet Finnish test pilot flew level full
power at appx 130kph and appx 30 degrees nose pitch. What is Cl_max for 109G-6? The
wing has angle of incidence above pitch and that was level flight.

A number of modern fighters have over 1G thrust available.
Most modern jets do not as most modern jets are subsonic transports AFAIK.

Kettenhunde
09-01-2006, 08:54 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">I have flown aeroplanes at speeds well below Vs without stalling; I just didn't ask for 1 g. </div></BLOCKQUOTE>

Then you were not violating the new Vs for that load factor.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Pull 4 g and you'll stall at 2Vs. Pull 9 g and you'll stall at 3Vs. </div></BLOCKQUOTE>

Your not flying at 2Vs or 3Vs. You are exceeding the new Vs for that load factor.

Vs increases at one over the square root of the cosine of a.

Since you don't believe me or this guy:

http://www.av8n.com/how/htm/author.html

Maybe you will believe this guy:

http://www.onpoi.net/ah/pics/users/503_1157121646_stallspeedinaturn.jpg

All the best,

Crumpp

Viper2005_
09-01-2006, 09:13 AM
The point being made is that you can either calculate Vs for your current weight, balance and load factor, or you can simply look at alpha.

Personally I think that the latter is a much more sensible approach because the stalling alpha is a constant under normal circumstances.

Kettenhunde
09-01-2006, 09:39 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Personally I think that the latter is a much more sensible approach because the stalling alpha is a constant under normal circumstances. </div></BLOCKQUOTE>

I agree and completely understand where your misconception arises. It comes from your practical experience as a pilot vs aeronautical sciences.

How many times have you stared at your airspeed indicator at touchdown? The answer should be never. You should be concentrating on your approach angles. Just remember that these are tied to your velocity. You are not a bad pilot because you don't realize Vs is the hard limit. In fact it is typical as watching a on approach puts your focus were it should be...outside the plane. While still allowing you to maintain awareness of where the plane is in the envelope. Staring at an airspeed indicator is not going to land the plane.

The whole point being that in science of flight stalling a can be cheated whereas Vs cannot be exceeded. That is a fact. Instructing pilots to concentrate on angles on approach does not violate anything and is a much safer way to land.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">We are now in a position to answer a question that used to cause a lot of confusion: can you fly €œbeyond€ the stall? Some people say yes, some people say no. The answer depends on whether you mean €œbeyond€ the stalling angle of attack, or €œbeyond€ the stalling airspeed. That is,

* Yes, it is definitely possible to fly at an angle of attack higher than the critical angle of attack. (It may require super-human skill to overcome the pathological handling characteristics in this regime, but it is possible in principle to maintain a stalled angle of attack indefinitely.)
* No, it is not possible to sustain flight at an airspeed below the stalling speed. </div></BLOCKQUOTE>

http://www.av8n.com/how/htm/vdamp.html#sec-beyond-stall

Vs is your hard limit.

All the best,

Crumpp

Viper2005_
09-01-2006, 11:37 AM
Now we're getting into a debate about terms and definitions more than anything else.

The only real limits are those imposed by thrust and control. Given enough thrust and enough control authority there are no limits. This has been effectively demonstrated by the MiG-29 OVT.

http://www.youtube.com/watch?v=oY3CyUDUe6c&mode=related&search=

http://www.youtube.com/watch?v=UZDVHFQTCfM&mode=related&search=

etc.

As for my flying habbits, I watch the ASI down to about 50 feet or perhaps a little lower depending upon the type of aircraft I'm flying. Then I forget about it because the chances are that having flown a stabilised approach at the correct speed, I've got sufficient energy to round out without worrying about the stall.

Of course, the ASI is pretty meaningless at high alpha anyway because of position error, and once you get into ground effect the stall speed can change quite considerably.

I only watch the ASI at all because the aeroplanes I fly don't have alpha vanes, so I can't watch my alpha.

The stalling alpha is a hard limit in that the wing will stall at the same alpha irrespective of aircraft weight & balance.

It is not always a hard limit from the point of view of stability and control. Some aeroplanes such as the Mig-29OVT can completely ignore the stall and continue to point their nose. At high pitch attitudes they can maintain height through the application of sheer brute thrust.

At a more humble level, I can knock a few knots off the stall speed of some aeroplanes by working hard on the rudders in order to prevent wing drop. Eventually of course I'll run out of elevator or my feet won't be fast enough, and down we'll come. But if you were to do the sums you'd probably find that large sections of the wing had been stalled for some time.

You can retain some measure of control beyond the stall, and you can keep flying. But you can't prevent the stall from taking place at the critical alpha.

Vs is a useful concept if you don't have a direct method of measuring alpha, but I'd rather fly an alpha schedule than have to constantly calculate and recalculate Vs as I change load factor, weight & balance during a flight.

Kettenhunde
09-01-2006, 12:27 PM
Hi Viper,

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">The only real limits are those imposed by thrust and control. Given enough thrust and enough control authority there are no limits. </div></BLOCKQUOTE>

Certainly but power available to power required is not the topic. The importance of Vs at the stall is the topic compared to the importance of a at the stall.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">But you can't prevent the stall from taking place at the critical alpha. </div></BLOCKQUOTE>

You most certainly can. You keep confusing the Vs listed in a POH with Vs(actual).

How many engineers do we need to consult on this?

Vs is the absolute limit. We are not debating "terms". It is an absolute hard fact as defined by the science. If stall is based on a it is because of behavior characteristics other than lift. It is a user defined Vs. It is not the absolute limit of the aircraft.

Let€s just consult the definition the US Navy uses since you were a Naval pilot:

http://www.onpoi.net/ah/pics/users/503_1157134752_vs.jpg

http://www.onpoi.net/ah/pics/users/503_1157134801_vs2.jpg


All the best,

Crumpp

p1ngu666
09-01-2006, 12:45 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Kettenhunde:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">I have flown aeroplanes at speeds well below Vs without stalling; I just didn't ask for 1 g. </div></BLOCKQUOTE>

Then you were not violating the new Vs for that load factor.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Pull 4 g and you'll stall at 2Vs. Pull 9 g and you'll stall at 3Vs. </div></BLOCKQUOTE>

Your not flying at 2Vs or 3Vs. You are exceeding the new Vs for that load factor.

Vs increases at one over the square root of the cosine of a.

Since you don't believe me or this guy:

http://www.av8n.com/how/htm/author.html

Maybe you will believe this guy:

http://www.onpoi.net/ah/pics/users/503_1157121646_stallspeedinaturn.jpg

All the best,

Crumpp </div></BLOCKQUOTE>

i wouldnt buy insurance off that chap http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif

ploughman
09-01-2006, 01:08 PM
Nice hat though.

p1ngu666
09-01-2006, 01:13 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Ploughman:
Nice hat though. </div></BLOCKQUOTE>

true, i need more hats alsho http://forums.ubi.com/images/smilies/shady.gif

WWMaxGunz
09-01-2006, 01:44 PM
If you're going to define stall speed as the speed for whatever the conditions are that it
doesn't fly however you want to define that then WTF, can't fly at less than "stall speed".

We could talk about wing AOA but since many wings have twist then some parts will stall while
other parts may not.

GR142-Pipper
09-01-2006, 02:36 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Kettenhunde:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Pipper: two aircraft will stall at different airspeeds...but the SAME AoA. </div></BLOCKQUOTE>
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Your claim is speed does not account for weight?? </div></BLOCKQUOTE>No, I'm claiming exactly the opposite. To be clear, stall speed IS influenced by weight and that stall speeds at a given altitude will vary depending on this variable (all else being held constant).

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">[QUOTE]Pipper: The variable is weight. AoA automatically compensates for this. Airspeed does not. </div></BLOCKQUOTE> </div></BLOCKQUOTE>

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">It is right there infront of you in your own post. Your just not putting it together.

Come on Pipper, you know better than this, right? </div></BLOCKQUOTE>Yes, I know exactly what I wrote. You keep trying to say that airspeed is the benchmark for determining a stall and it's not because this Vs CHANGES depending on aircraft weight. AoA provides a CONSTANT measure of an aircraft's position in the flight envelope. Heavier aircraft stall at higher airspeeds than the same aircraft at a lighter weight. AoA reflects this. Airspeed doesn't. It can't be any simpler. This is also why military and many commercial civilian aircraft have standardized on using AoA instead of indicated airspeed as the preferred way to manage airspeed during landing approach.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Respectfully, think about what I am saying, read over the link a few times, and you will see it is correct. </div></BLOCKQUOTE>Honestly, we'll just have to agree to disagree on this point.

GR142-Pipper

GR142-Pipper
09-01-2006, 02:45 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Viper2005_:
The point being made is that you can either calculate Vs for your current weight, balance and load factor, or you can simply look at alpha.

Personally I think that the latter is a much more sensible approach because the stalling alpha is a constant under normal circumstances. </div></BLOCKQUOTE>Exactly correct and simply stated.

GR142-Pipper

NonWonderDog
09-01-2006, 02:46 PM
Exactly, if you want to define a continuously changing stall speed and have it always equal to the speed at which the wing will stall no matter the circumstances, the number is absolutely meaningless. What use is a physical measure with indeterminate value? What use is a "hard limit" that changes continuously?

Each wing section will stall at a specific angle of attack. Average the lift over the wing, and you get a critical angle of attack of the aircraft. Command an angle of attack greater than this, and the the greater portion of the wing is stalled. The aircraft no longer exhibits postitive stability. The plane has stalled. It may be possible to control the aircraft anyway (see MiG-29, Su-27, or F-22 -- although delta wings ARE a special case), but any increase in angle of attack will create much more drag and less lift. This can happen at any speed, depending on control authority.

Vs is just the speed at which the wing at critical angle of attack will create lift exactly equal to weight. There's even a forumula:

Vs = sqrt( W / (C_Lmax * 1/2 * rho * S) )

At speeds less than this, the plane will not fly at 1G without some vertical force other than lift. It will still fly if the lift requested is less than W. This won't happen in level flight without a vertical thrust, and thus the speed is labeled "stall speed."

Are Harrier Jump Jets "stalled" when they take off? Do they remain "stalled" until they reach stall speed? No, because the wings are kept at a low angle of attack and the jets are used to provide the vertical force the wings are incapable of providing at low speed. It doesn't matter if the thing's flying backwards, the wings won't be stalled unless the angle of attack of the wings is greater than the critical angle.



Goddammit, I'm studying to be an aerospace engineer and I've spent most of my life around pilots. I may be young, but don't tell me I know nothing. Stall speed is an effective lower limit on turn speed because level turns of any bank angle are impossible at a load factor of one or less. Professor Rogers in that article is obviously not speaking of 0.5G turns in near-vertical climbs in an aircraft with a thrust to weight ratio greater than one, for instance. Such pointless turns COULD take place well below Vs. (Assuming you use a sane definition of Vs, of course.)

Kettenhunde
09-01-2006, 04:26 PM
Thanks for the discussion guys. Enjoyed it at times. Good luck on figuring out your E-rentention game problems!

All the best,

Crumpp

ploughman
09-01-2006, 04:29 PM
See ya'.

sudoku1941
09-01-2006, 08:19 PM
They can throw around all the trig functions they want, and bandy about the definitions of particular flight characteristics all they want.

What they probably can't do, is say that IL-2 follows earth physics and aerodynamics properly. It's pretty clear, even to those of us without a scientific calculator and a thick textbook full of equations, that it doesn't.

Kettenhunde
09-01-2006, 08:29 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Pipper says:
AoA provides a CONSTANT measure of an aircraft's position in the flight envelope. </div></BLOCKQUOTE>

Critical a changes as well.

The shape of the lift polars varies with several factors, AR being one of them. When you get a low AR, the polar tends to be very flat on top. Offering a wide variety of a with little change in lift.

http://www.onpoi.net/ah/pics/users/503_1157164762_lift.gif

Here we can see that a does in fact vary even on the same aircraft:

http://www.onpoi.net/ah/pics/users/503_1157151013_stallaoa.jpg

http://www.onpoi.net/ah/pics/users/503_1157134752_vs.jpg

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">NWD says:
Vs is just the speed at which the wing at critical angle of attack will create lift exactly equal to weight. </div></BLOCKQUOTE>


The forces have to be in balance at all times. That is a basic principle of flight. If your condition of flight is level then lift always equals weight.

All the best,

Crumpp

WWMaxGunz
09-01-2006, 08:48 PM
The best E-retention info I got was from Viper about the pre-stall condition where there does
become a very real problem in drag.

Although I could deal with just a bit more on Cl^3/Cd^2 perhaps as graphs. I've seen the Cl
graphs where you get coefficient of lift with respect to AOA as a slanted line that curves
over and down; angle of slant, shape of curve, where the top is all depend on the wing. And
I've seen formula for induced drag but that's not total drag or coefficient of drag.....

Coefficient of drag is a constant in'nit?

And we want the AOA that is close to level flight at best climb speed, but still level flight
as the AOA of best turn while more than that and it's bleedin-time.

If I've got that right then maybe something sim-useful can be salvaged from this after all.

I look back at Vipers post on page... SEVEN that since has been tracked off on grounds of
a single term, the meaning of stall speed as opposed to reference single condition stall
speed like the EAA and FAA would have into a substitute for whenever you stall how fast
you are going yup that's it.... sorry Crumpp but varying terms, it's best explained that
you're not using them in the standard way -before- we go in circles for five pages. What
you can add is cool but hey it's like driving in parts of New Jersey, the traffic circles
when you're not a local.

I still forget "the meaning of Q" and isn't S from the lift and drag equations a different
S for each? Like wing surface and flat-plate surface?

And then there's the power you pay for lift and work over distance with velocity in there
somewhere... how does our speed play in this or does that play directly or is it that at
some lesser speed if you have this mass your AOA will exceed the optimum and screw yourself?

Oh joy. I hope the answer will be easier than SETI cryptography.

Kettenhunde
09-01-2006, 09:23 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Coefficient of drag is a constant in'nit? </div></BLOCKQUOTE>


No it changes over the envelope. Think of these coefficients as CL required and Cd required. They are required in that condition of flight.

It is very easy to get general SWAG of Cd or total drag if you know the TAS or True Airspeed, altitude that speed was attained, and power produced at that speed. You need a standard atmospheric table as well.

In level flight thrust opposes drag.

Thrust = 375 * Prop efficiency * Engine HP / TAS

By calculating thrust you know the force of drag. Plug that into the formula and you have the Cd:

Cd = D / (A * .5 * r * V^2)

D = Drag Force
A = reference area - usually the wing area but it is more correct to use the wetted area.

r = density in slugs/ft3 - found on your standard atmospheric table for the altitude the speed was attained

V = velocity, or your True Airspeed in feet per second.

Now you have your Cd. If you can calculate Cdithen you can figure out Cdo or the parasitic drag coefficient.

CL required of course is your lift coefficient which you get from rearranging the lift formula:

Cl = L / (A * .5 * r * V^2)

L = weight of the aircraft if your in level flight
r = density at altitude in slugs/ft3

V = velocity in ft/sec

You can see from the basic lift formula that lift depends on velocity.

Now that you have your CL your ready to calculate Cdi.

Cdi = (Cl^2) / (pi * AR * e)

AR = Aspect Ratio or span^2/Area of the wing.
e = efficiency factor of the wing. You can calculate this or get in the ballpark with the NACA wing profiles. Most wings on WWII designs have an efficiency of around .85

Now you can calculate thrust, drag, and lift coefficients. Of course there are other formulas and factors. The more correct data and more factors you account for the more accurate your results. This will give you a good SWAG though...Scientific Wild AZZ Guess.

All the best,

Crumpp

Kettenhunde
09-01-2006, 09:43 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">I still forget "the meaning of Q" and isn't S from the lift and drag equations a different
S for each? Like wing surface and flat-plate surface? </div></BLOCKQUOTE>


q is an expression for dynamic pressure. It forms part of the lift and drag equations.

q=1/2 x p x V2 (p = atmospheric density, V@ is velocity squared)

Wing surface? I think your refering to wing area.

Flat plate surface is not correct. Most likely you mean flat plate area. This is a method of comparing the relative drag.

Flat plate Area = A*Cd or Reference area x Cd. The aircraft with more flat plate area has more drag. You can have a higher Cd but less drag when compared with other designs based on the wetted area.

Wetted area is the area that is producing forces. For lift it is the wing and depending of the design and conditions of flight, portions of the fuselage and tail. For drag it is generally the lift surfaces and frontal area. However it can the whole surface area of the plane.

All the best,

Crumpp

NonWonderDog
09-01-2006, 11:07 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Kettenhunde:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">NWD says:
Vs is just the speed at which the wing at critical angle of attack will create lift exactly equal to weight. </div></BLOCKQUOTE>


The forces have to be in balance at all times. That is a basic principle of flight. If your condition of flight is level then lift always equals weight.
</div></BLOCKQUOTE>

Re-read what I wrote. I wrote that stall speed is when the wing at critical angle of attack creates lift equal to weight. If you keep the wing at critical angle of attack, the speed at which L=W will be stall speed. At stall speed, the only way to get lift equal to weight is to position the wing at the critical angle of attack.

In some cases, this may not be possible due to controllability issues. The minimum controllable speed is then reported in the POH as stall speed. Most of the time, however, it's just the speed at which critical angle of attack is necessary to produce lift equal to weight.


In that excerpt you quoted it even says that "the stall speed measurement [must be] consistent and repeatable." This is only true if there is one predefined stall speed. It can't change constantly depending on pitch angle, load factor, and power. Because of that, there are always odd situations in which it is possible to fly the plane controllably below stall speed.

Xiolablu3
09-02-2006, 03:32 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by sudoku1941:
They can throw around all the trig functions they want, and bandy about the definitions of particular flight characteristics all they want.

What they probably can't do, is say that IL-2 follows earth physics and aerodynamics properly. It's pretty clear, even to those of us without a scientific calculator and a thick textbook full of equations, that it doesn't. </div></BLOCKQUOTE>

Hurray! Stigler is here again to p*ss on the bonfire.

Ratsack
09-02-2006, 04:44 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by sudoku1941:
They can throw around all the trig functions they want, and bandy about the definitions of particular flight characteristics all they want.

What they probably can't do, is say that IL-2 follows earth physics and aerodynamics properly. It's pretty clear, even to those of us without a scientific calculator and a thick textbook full of equations, that it doesn't. </div></BLOCKQUOTE>

Did somebody come and trip-trap over your bridge, Stig?

cheers,
Ratsack

Viper2005_
09-02-2006, 05:54 AM
Ok gunz, let's take this a step at a time.

(Cl^3/Cd^2)max will give you the minimum power requirement for a given quantity of lift.

For a glider, this gives you minimum sink rate.

For a powered aeroplane, if constant thrust horsepower is available across the speed range, flying at the angle of attack (alpha) which gives (Cl^3/Cd^2)max minimises the power required for 1 g flight, and therefore maximises the quantity of excess power available. Since rate of climb is dependent upon excess power, flying at (Cl^3/Cd^2)max should put you at Vy.

Of course in reality, the quantity of thrust horsepower available is not constant across the speed range, and of course engine thrust acts to reduce the quantity of lift which the wing must produce.

Therefore, IRL Vy isn't quite the same as the speed at which (Cl^3/Cd^2) is maximised in level flight.

However, for most piston engined aeroplanes with reasonable performance (as opposed to hot-rods) you'll find that the difference is quite small.

Anyway...

Really it all comes down to a simple question:

"What do you want?"

In order of decreasing Cl:

If you want maximum lift, aim for Clmax
If you want minimum power requirement, aim for (Cl^3/Cd^2)max
If you want minimum drag, aim for (Cl/Cd)max.

The difficult problem is making the correct choice for your circumstances.

In general, the faster you're flying, the further down that list you should look.

In this context, Cd is a variable, not a constant. The more Cl you're asking for, the higher the Cd you'll have to put up with.

By convention, if you're talking about wings, S is the wing area in both the lift and drag equations. If you're talking about bodies such as the fuselage, S is usually the frontal area.

In this context, I'd tend to index both lift and drag against wing area. Then we can cancel out S (since for most aircraft it's a constant anyway) and make life a little simpler.

WWMaxGunz
09-02-2006, 07:43 AM
No litmus for game use then. But knowledge that there is a region of AOA with some penalty
even before the buffets and with speed and with weight the cost in E goes up, if I have even
that right.

I can see that in climbing nose up that AOA is reduced since the plane is rising, thrust from
the prop does have a vertical component and propwash does increase airspeed over some of the
wings beyond airspeed of the rest of the wings. Flying nose-high you get the latter two yet
I read that power-on stall speed should be LESS than power-off stall speed and that does NOT
jive with the Finnish 109G-6 test results.

I wonder how Stiglr gets his results? The models not matching historic data? Does that
disprove the physics model or the modelling of the planes? Or is it the "it doesn't do what
I expect" test? Oh yeah, he has Targetware to show what is completely real. I wonder what
you can adjust with TW?

Kettenhunde
09-02-2006, 08:52 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Flying nose-high you get the latter two yet
I read that power-on stall speed should be LESS than power-off stall speed and that does NOT
jive with the Finnish 109G-6 test results. </div></BLOCKQUOTE>


Actually that depends on the aircraft. Reduced power is generally better than full power due to asymmetrical lift production of the vortex.

It depends on the design as well. The propeller tends to induce some rolling moments &lt;movement&gt; at the edge of the stall. The magnitude of the moments is unique to the design.

There are also a number of devices which can be used to reduce or eliminate these moments.

We can see the effects of a leading edge device in these polars:

http://www.onpoi.net/ah/pics/users/503_1157208340_corsairrollingmomentatthestall.jpg

http://www.onpoi.net/ah/pics/users/503_1157208377_leadingedgedevice.jpg

Keep in mind too that test flight data is only as good as the pilot flying the plane and the engineers rigging/interpreting the instruments.

All the best,

Crumpp

Kettenhunde
09-02-2006, 11:19 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">By convention, if you're talking about wings, S is the wing area in both the lift and drag equations. If you're talking about bodies such as the fuselage, S is usually the frontal area. </div></BLOCKQUOTE>


Yes for SWAG's. However engineer's use the wetted area in an analysis as it provides a much more accurate picture.

http://www.onpoi.net/ah/pics/users/503_1157217467_p51fw190drag.jpg

http://www.onpoi.net/ah/pics/users/503_1157217519_fw190a.jpg

All the best,

Crumpp

Viper2005_
09-02-2006, 12:02 PM
Wetted area is mainly used for calculating skin friction drag. If you want to use it for other things, fair enough. It doesn't actually make any difference since

D = Q*Cd*S

Using your table of data, for the Fw-190A8, Cdswet = 0.0071, and Swet = 735 ft^2.

So, multiply them together and we get 5.22 ft^2 of equivalent flat plate area.

Wonderful. But we could equally divide that number by the frontal area of the Fw-190 to calculate its Cd with respect to frontal area.

Or we could divide that 5.22 ft^2 by the wing area.

It doesn't really matter as long as you make certain to compare apples with apples.

However, it's actually very challenging to accurately calculate the wetted area of any practical aeroplane because of all those pesky rivets, panel lines and fastners.

So you end up with an approximation.

It's quite easy to calculate the frontal area because it's just a projection.

It's quite easy to calculate the wing area because it too is just a projection.

Wetted area is really useful for carrying out accountancy tasks. Lots of wetted area means lots of skin friction drag. Little wetted area means low skin friction drag.

If you wanted to study the effects of fitting various aeroplanes with laminar flow wings, perhaps the first step would be to calculate what percentage of the wetted area was wing.

If most of the wetted area is wing surface then laminar flow is worthwhile (as is the case in a glider for example). If not much of the wetted area is "spent" on wing surface then going to a laminar flow wing makes less sense because you'll see less benefit...

Consider Dora vs Anton. The dora has more wetted area but less drag in the conditions for which data was collected (what were those condition btw?).

What does this really tell you?

Well, it seems that despite the great efforts made to reduce the drag of the BMW801 installation, there was a reasonably large amount of pressure drag associated with it, such that the reduction in frontal area made possible by the jumo213 installation produced a drag benefit despite the increased skin friction drag caused by that extra wetted area.

Nice CFD image, but it isn't very useful since it appears to model neither the prop, engine exhaust nor indeed the flow through the engine cowling.

And of course it doesn't feature any guns.

In otherwords, it's what you would call SWAG...

Kettenhunde
09-02-2006, 03:04 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Wetted area is mainly used for calculating skin friction drag. </div></BLOCKQUOTE>

And is this not important??

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">By convention, if you're talking about wings, S is the wing area in both the lift and drag equations. If you're talking about bodies such as the fuselage, S is usually the frontal area. </div></BLOCKQUOTE>

Frontal area is usually used to calculate form drag, another subcomponent of parasitic drag.

Being that skin friction drag is also a part of parasitic drag, and a subcomponent of total drag, it gives a more accurate prediction to use CDswet.

http://selair.selkirk.bc.ca/aerodynamics1/Drag/Page1.html#Total%20Drag

CDswet is used for more than skin friction drag predictions as well. It is good indication of an airframes freedom from flow seperation.

Referring to total drag required and lift required coefficients:

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> Crumpp says:
A = reference area - usually the wing area but it is more correct to use the wetted area. </div></BLOCKQUOTE>

Absolutely correct. You repeat the same thing in fact. Only difference is instead of acknowledging the fact wetted area is more useful you decide to rebuff it as if engineers do not like to use it!

Just try googling it:

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Results 1 - 10 of about 28,100 for "wetted area" drag </div></BLOCKQUOTE>

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Viper says:
For a powered aeroplane, if constant thrust horsepower is available across the speed range, </div></BLOCKQUOTE>

And this statement is just flat out wrong for propeller powered aircraft. Your IF will never occur because propeller aircraft never have constant thrust across the speed range. I already explained that 3 pages back! It applies to jets but has no application to propeller powered aircraft.

Start calculating Tc!

Tc = T/pV^2D^2

Basic math will tell that dividing by velocity will lower the Tc as velocity goes up!

Thrust is not constant in propeller aircraft and the thrust effects formulas are completely different. I posted them earlier in this thread.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">
However, it's actually very challenging to accurately calculate the wetted area of any practical aeroplane because of all those pesky rivets, panel lines and fastners. </div></BLOCKQUOTE>

It is geometry is all. Not really all that hard.

http://adg.stanford.edu/aa241/drag/wettedarea.html

It is very easy to take some measurements in a tunnel and apply it to the structure of the aircraft. Engineers have been doing it for quite a while now in the aerospace industry.

Everything I posted is absolutely correct. I simply clarified because to a layman reading your post it seemed you contradicted the statement I made about wetted area. I did not want guys like Gunz to get the wrong impression.

In fact if you read my earlier post I explain that using wing area is just fine for SWAG's.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> Crumpp said:

Now you can calculate thrust, drag, and lift coefficients. Of course there are other formulas and factors. The more correct data and more factors you account for the more accurate your results. This will give you a good SWAG though...Scientific Wild AZZ Guess. </div></BLOCKQUOTE>

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Nice CFD image, but it isn't very useful since it appears to model neither the prop, engine exhaust nor indeed the flow through the engine cowling. </div></BLOCKQUOTE>

Thank you. Although it was in fact very useful for it's purpose.

All the best,

Crumpp

WWMaxGunz
09-02-2006, 05:00 PM
I see flat plate area, wetted area and... Cdswet --- a coefficient

I see that flat plate is for form drag part of total drag and... the wetted area is for parasitic
to add to that?

Really to me the back of a shape can be more important in reducing drag at least at low speeds
to cut vortexes. Teardrop shaped bicycle tube has the circular leading edge with trailing edge
like a rain drop that works well enough to see it produced and used. It doesn't have a sharp
or elliptic front edge. But I guess that's part of the flat-plate because if I just look at the
projection of a FW straight-on it is way bigger than 5.22 sq ft.

So anyway we have our IL2 plane making a highpeed dive on another one and we want to know if
the BnZ plane is bleeding way too much while the turn fighter is not which hey I don't think
it's the case but it's nice to have something to back EITHER VIEW up with.

So far I get that IRL if you aren't careful with the stick then even before stall buffets you
can get past the most efficient pullout or turn and while it's not as bad as stall, it's going
to cost extra in terms of energy for angle. Pass that into stalling even slightly and you're
really going to pay. Also there is that the more G's you pull, the higher your stall speed
will be which would make at least a G-meter if not a G-stall-indicator very, very handy.

Hmmmmmmm --- we DO have devicelink data that can give speed and changes in heading.

How many G's is the target pulling and how many is the attacker pulling case to case matters.
There is that the target can just ride his best maneuver turn and know that the exit speed
will not be less no matter how many turns he makes and in fact he will accelerate when he
lets up while the attacker may not because his speed on entry is high from diving and well
beyond ordinary level speed --- unless he has bled so badly that he CAN accelerate just by
flying near-level in which case he has blown the BnZ into B-n-drag-race then guess who wins?

BnZ speed being so high, it's maybe the G's of transition and correction that can getcha.
Target is pulling maybe 3 G's so the Boomer wants to keep his G's down to 3 or less, which
is why I say shoot from farther out and use deflection. Someone turns tight 300-400m in
front of me, I can angle ahead of that with less than 2 G's for a short time. And if I
shoot crossing his path then I can exit away from his turn. He has to roll and then turn
to follow me and that takes time. I also note that Hartmann did his exits with diving away
from what I read he wrote, he did not try to fly to the moon right after a guns pass.

And I add a last note from looking at those flat-plate equivalent areas. They are all less
than 9 sq ft! In high speed dives which is another area that IL2 is said to be wrong we
have IRL that the prop disk at near top speed is equivalent to a solid flat disk of the same
area as a circle the diameter of the prop which is way more than those flat-plate areas.
Since FB I do know that what you do with prop pitch does affect how fast your plane can dive.
It does leave to wonder that just maybe the sim engine physics are not a crock of feces even
in the face of expectations based on un-quantified story reading.

Viper2005_
09-02-2006, 05:08 PM
#1 Wetted area is great for calculating skin friction drag, but it is not the be all and end all. Frontal area is of greater importance because in general skin friction is less important than pressure drag.

#2 I did not say "constant thrust" I said "constant thrust horsepower". Please read more carefully.

1 hp = 550 ftlb/s

So, 1 thp will give you 1 lbf at 550 fps, which is about 375 mph if memory serves.

Halve the speed and you'll get double the thrust from the same number of thrust horsepower. Thrust horsepower is a very useful concept in piston engined aircraft design. It is usually defined as

thp = bhp*prop efficiency

In fact you'll find that it is often also used when designing turboprops, in which case one generally works with ehp rather than bhp.

In the case of the Merlin, exhaust thrust was very significant, and the ehp was much greater than the bhp, especially in the case of the Mustang. Since prop efficiency falls off at high Mach number, the exhaust thrust was especially important, and provided a substantial proportion of the thp at the top right hand corner of the flight envelope.

#3 Why are you so bothered by skin friction? It's certainly not unimportant, but pressure drag is far more important, as indeed is demonstrated by the relative Cdwets of the Anton and Dora.

Certainly it's easy to apply simple geometry to calculate the surface area of simple shapes. But real aeroplanes are not simple shapes due to the presence of panel lines, rivets and fastners.

Accurate wetted area calculation is almost impossible because at a microscopic level there is no such thing as a smooth surface. You can approximate, but the error associated with that approximation is inherently larger than that associated with a measurement of projected frontal area or projected wing area.

Furthermore, at the design stage one doesn't know the wetted area of one's aeroplane. In general you start out with a mass estimate based upon existing structural data and some performance requirements.

This allows you to calculate the required wing area. Then you can start working out how to arrange the various "off the shelf" components. This will generally give you a reasonable idea of the frontal area. Often you can fix this long before the wetted area is known.

A classic example of this was the Spitfire.

K5054 was built with flush rivets throughout. Split peas(!) were then applied to simulate domed rivets so that a trade study could be conducted. The production aeroplane used a combination of dome and flush rivets based upon these tests. Obviously the wetted area of the production machine was higher than that of the prototype due to the incorporation of said domed rivets.

#4 What did you use the CFD for? What code did you use?

Without prop wash effects it's unlikely to have provided an accurate stall prediction.

Drag estimation is unlikely to be accurate because it doesn't model flow through the cowling (look how high the Cp is inside the cowling where the fan should be), nor does it model scrubbing drag from the prop wash.

It might give a good indication of transonic behaviour since prop wash is likely to be unimportant. But the lack of cowling flow could reduce its accuracy considerably since the devil is in the details with this sort of thing.

(AFAIK the Anton had a maximum tactically useful Mach number of 0.75, whilst Dora was good to 0.77, presumably due to its superior fineness ratio.)

BTW, getting off topic, why is the V-1710 so popular for Dora restorations?

Kettenhunde
09-02-2006, 07:21 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">I see that flat plate is for form drag part of total drag and... the wetted area is for parasitic
to add to that? </div></BLOCKQUOTE>

Wetted area is just a more exact reference area. It is the area in contact with the air stream and producing forces.

It is defined as the area which gets wet when water mist is added to the air stream. Simple stuff huh?

You can have wetted area for lift and wetted area for drag. For example, in some conditions of flight, the fuselage produces lift. This is true uncoordinated turns. Now I am not saying make uncoordinated turns in your game. Remember it also produces much more drag than it does lift! However it just illustrates that wetted area is a more exact reference area to use if you have it.

Wing area is fine for your home computer based game comparisons. If you have data on the other reference areas then by all means use it. While wetted area is more accurate, only in rare cases will it change outcome.

Flat plate is used to make quick comparisons of drag force between designs and is an expression of how much drag it produces. It is most commonly used for parasitic drag comparison.

Depends on which coefficient of drag you apply to it however. It can be used to compare total drag in a specific condition of flight, a subcomponent of drag, or drag of a specific part of the aircraft.

Flat plate area is defined as the area of a flat plat placed normal to the air stream.

So in the case of our CDswet, we are comparing the parasitic drag component of total drag.

http://www.onpoi.net/ah/pics/users/503_1157217467_p51fw190drag.jpg

In this case we see that although the Spitfire Mk IX has a lower CDswet, it produces more parasitic drag than the FW190A8. It produces the equivalent of a flat plate with an area of .18 ft^2 or 25.92 in^2.

As for prop effects in IL2 I am not an expert on the game. IRL, as a prop driven aircraft increases Mach number propeller efficiency drops dramatically.

http://naca.larc.nasa.gov/reports/1949/naca-tn-1784/index.cgi?page0031.gif

The transonic realm presented many challenges to WWII designers and its exploration was in its infancy. Instrumentation just was not accurate in the 1940's in this region of flight.

Drag rises dramatically in the transonic realm:

http://www.centennialofflight.gov/essay/Theories_of_Fli...onic_Flow/TH19G5.htm (http://www.centennialofflight.gov/essay/Theories_of_Flight/Transonic_Flow/TH19G5.htm)

As your propeller efficiency drops your drag increases and at some point it does act as brake. Since instruments were not that accurate. I would be suspicious of any mach numbers exceeding mach .8 by very much in any WWII fighter. IIRC the mach .86 PR Spitfire modified for high speed trials lost its propeller during that dive to achieve that speed!

Remember for instantaneous performance, energy is treated differently than in the sustained envelope.


All the best,

Crumpp

cawimmer430
09-02-2006, 07:26 PM
Yeah, I was wondering why some propeller planes in the sim can match the Me-163B's climb rate. What BS... http://forums.ubi.com/groupee_common/emoticons/icon_mad.gif

Also, since when can slow Zero's keep up with a Mustang on a level flight? http://forums.ubi.com/groupee_common/emoticons/icon_frown.gif

Kettenhunde
09-02-2006, 08:34 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Viper says:
#1 Wetted area is great for calculating skin friction drag, but it is not the be all and end all. Frontal area is of greater importance because in general skin friction is less important than pressure drag. </div></BLOCKQUOTE>

You have misread me again. Please find were I make any claims about the importance of friction over pressure drag. I simply state the fact using wetted area gives a more accurate prediction.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">#2 I did not say "constant thrust" I said "constant thrust horsepower". Please read more carefully. </div></BLOCKQUOTE>

Your correct I did misread you on this one.

It would be nice if followed your own advice as you have misread me more than once and simply ignored it. Or worse yet defended it so we have these multiple page banters.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Viper says:
In the case of the Merlin, exhaust thrust was very significant, </div></BLOCKQUOTE>

Exhaust thrust is important in many WWII designs. Most designers were aware of the benefits. IMHO the British were rather late in realizing it but made up for lost time. There is very little to choose between WWII designs regarding technology.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Viper says:
Accurate wetted area calculation is almost impossible because at a microscopic level there is no such thing as a smooth surface. </div></BLOCKQUOTE>

That is why we have wind tunnels and test flights. It is very easy to figure out the wetted area, measure the force, and make the calculations.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Viper says:
Furthermore, at the design stage one doesn't know the wetted area of one's aeroplane. </div></BLOCKQUOTE>

I just thought Gunz wished to learn how to compare existing designs, not build new ones. At some point in the design process you have absolute nothing. Just as idea for an airplane.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">The zero-lift drag coefficient, although useful as a measure of comparative aerodynamic refinement, has a basic limitation because the coefficient is based on wing area, and, for a given wing area, many different fuselage and tail sizes may be employed. Thus, differences in zerolift drag coefficients may be interpreted as a difference in aerodynamic refinement when the difference may result from a significant difference in the ratio of wetted area to wing area.

In order to remove the effect of variations in the ratio of wetted area to wing area, a zero-lift drag coefficient based on total wetted area rather than wing area was estimated in reference 90 for most of the aircraft for which drag data are given in figure 7.7. </div></BLOCKQUOTE>

http://www.hq.nasa.gov/pao/History/SP-468/ch7-5.htm

All the best,

Crumpp

WWMaxGunz
09-02-2006, 09:33 PM
Actually I'm trying to get useful tools regarding E-retention and avoiding excess bleed.

It may be possible that some parts of the sim physics can be validated or disproved.
Wouldn't THAT be a gas, to have answer to one of the main questions and sources of so much
controversy?

Would either Crumpp or Viper like to take a swipe at this kind of thing? There is data
from devicelink apps that can be logged per fraction of a second which I do during playback
of tracks so yes even online tracks can be used. We don't get positional data though which
would be a blast but we do get much other data like IAS, alt, attitude data and even change
in attitude data. Not perfect but maybe enough data.

Also what you guys know about speeds where props become brakes? About the compare of the
area of prop disk to the effective flat-plate are of the planes which factors down a LOT
smaller than I had thought. With the formula for thrust decreasing with speed does that
pretty much mean the line extends below zero into negative thrust at least? If a plane
has positive thrust enough to fly level at 500kph IAS then could the efficiency hit zero
by 900 or less?

I have Star Office for spreadsheet among other apps. It is a free download and compatible
with Excel. Is this a project worth doing? We still have people here who would I think
also help. Perhaps those who want and have expertise might collaborate in private topics
if not just pursue it on their own. Easier I think as cooperation IF the you-said-I-said's
wouldn't make solo pursuits more efficient or even possible.

Viper2005_
09-02-2006, 09:39 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by cawimmer430:
Yeah, I was wondering why some propeller planes in the sim can match the Me-163B's climb rate. What BS... http://forums.ubi.com/groupee_common/emoticons/icon_mad.gif </div></BLOCKQUOTE>

Most likely you aren't flying the 163 correctly.

It likes to fly fast. You'll do better at 400-500 km/h than at the 250 km/h or so favoured by so many piston engined fighters.

Used properly, the 163 has an almost unbeatable ROC.

Kettenhunde, I'll deal with your post tomorrow, since it's now far too late at night for technical discussion.

However, I am sorry if I have misread any of your posts.

Kettenhunde
09-03-2006, 08:46 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Also what you guys know about speeds where props become brakes? </div></BLOCKQUOTE>


IMHO, I would be suspicious of any WWII fighter making claims of going much beyond Mach .80.

Here we can see a drag polar of NACA 2315 over mach. This is just the airfoil and not an aircraft:

http://www.onpoi.net/ah/pics/users/503_1157293501_drag.jpg

The transonic realm and supersonic realm of flight just were not understood very well in comparison to today. The investigations were hampered by cumbersome formulation that did not really become useful until the advent of computers and an inability to experiment other than very dangerous flight testing.

A series of simple corrections was developed for transonic flight which worked well until the higher mach numbers near critical mach.

Advances were made however and by the end of the war the basic formula for a transonic/supersonic aircraft was in place. All the pieces were there just not put together yet.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Propellers usually encounter the adverse effects of compressibility at flight Mach numbers below that at which the aircraft configuration itself penetrates the critical region because portions of the blades of the propeller, particularly near the tip, are traveling at a higher speed relative to the air than the aircraft itself. Compressibility problems on aircraft propellers were first encountered during the 1930's, and research studies were made in those years in an effort to improve propeller design. This work continued on through World War II. One major investigation that gives an indication of the type of research undertaken in the development of improved propellers is described in reference 108. New planform shapes, new twist distributions, and new airfoil sections designed especially for propellers all combined to result in significant increases in the stream Mach number at which the propeller showed serious losses in efficiency. It seemed clear, however, that the propeller was likely to constitute the ultimate limitation on the speeds that could be reached with aircraft employing this means of propulsion. </div></BLOCKQUOTE>

http://www.hq.nasa.gov/pao/History/SP-468/ch5-2.htm

All the best,

Crumpp

Kettenhunde
09-03-2006, 09:41 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">However, I am sorry if I have misread any of your posts. </div></BLOCKQUOTE>

No problem. I guess...

Seriously don't apologize if you don't think you misread me.

I entered the discussion talking about energy and weight effects. Energy and weight is treated differently depending on where you€re at in envelope and depending on the condition of flight. My comments have generally been from the POV of the envelope at or below the power curve as this is the realm were energy is most important.

It is not a brownie point contest and has been nice distraction over my days off. Satisfies my short attention span and breaks up the monotony of sitting at this computer writing a magazine article.

All the best,

Crumpp

JG14_Josf
09-04-2006, 10:52 AM
What's wrong with E-retention?

Two identical planes starting out at 700 km/h in a level 6 G turn:

Question A:

Which plane stalls first if one plane is twice the internal weight as the other plane (all else being equal)?

A. The Heavy plane
B. The light plane

Which plane in the 6 G level turn has the steeper bank angle:

A. The heavy plane
B. The light plane
C. Both planes in a 6 g turn are flying at the same bank angle.

If the answer is A - then:

Which plane in a level turn starting at 700 km/h in a 6 G (pilot limit) level turn will have the smaller turn radius and the higher turn rate?

A. The Plane slowing down sooner
B. The plane slowing down later
C. The plane with the higher bank angle
D. The answer to what is wrong with E-retention for anyone who actually want's to answer the question.