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View Full Version : Dive accelaeration, engine limitation and stuf..



OldMan____
08-12-2004, 07:50 PM
Decide to make some weird tests on diving from 10 k.. and discoveredd .. it can NOT be an engine limitationondive speed!!

Most fighters dive the same.. but a few planes contradict this rule... biplanes, stuka.. and TB3!! TB3 can go down from 10 km to 0m at 360 km/h .. 90degree dive.. and will take 2 km to each that speed!!! A fighter reaches 360 in 300 meters dive! So if ONE plane can dive slower tha others.. why hell all fighters dive same?

If brute force does not solve your problem... you are not using enough!

OldMan____
08-12-2004, 07:50 PM
Decide to make some weird tests on diving from 10 k.. and discoveredd .. it can NOT be an engine limitationondive speed!!

Most fighters dive the same.. but a few planes contradict this rule... biplanes, stuka.. and TB3!! TB3 can go down from 10 km to 0m at 360 km/h .. 90degree dive.. and will take 2 km to each that speed!!! A fighter reaches 360 in 300 meters dive! So if ONE plane can dive slower tha others.. why hell all fighters dive same?

If brute force does not solve your problem... you are not using enough!

papote10
08-12-2004, 10:16 PM
this sim would be complete if they added correct dive speeds and energy bleeding when manouvering.......

then i would quit my job and play all day and all night

WUAF_Badsight
08-12-2004, 10:41 PM
that one plane you mentioned is a HELL of a lot different to any fighter in FB

sure looks like planes accelleration in a dive is linked to its accelleration ability in the horizontal in FB dont it

.
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Fennec_P
08-13-2004, 01:24 AM
All fighters don't dive same. If you try them out and compare the results, there are clear acceleration differences.

But they are generally close to each other, so you might not notice this in combat. A difference of 100m/min will show up nice on a chart, but won't help you one bit in combat.

Long story short, the planes that combine low drag with high T/W ratio accelerate best in level flight, and in a dive. La-7 and Me-262, very good. I-16 and P-11, not so good.

Heavy planes (P-47, FW-190) accelerate better at the top end, in the 500-800km/h range. Light planes accelerate better in the low speed range, and usually break apart shortly after.

Try it yourself, but this time with a stopwatch.

[This message was edited by Fennec_P on Fri August 13 2004 at 12:34 AM.]

robban75
08-13-2004, 03:19 AM
All the powered diveacceleration tests I've done has left me with one conclusion. The Yak-3, La-7, D-9, Spitfire, P-51, P-47 basically all dive at the same accelerated rate. Fighters with a lower terminal dive speed cannot keep up in the acceleration once the "shaking" begins. So, in order to escape in a good diving fighter, one has to reach almost terminal velocity. The terminal velocity is individual indeed. The D-9 has a terminal dive speed of 900km/h IAS, whereas the light and nimble Yak-3 can manage 830km/h(IIRC). So, the D-9 will only outdive the Yak-3 once he ha passed 800-830km/h. And reaching terminal velocity in a D-9 was hardly neccessary in order to escape any VVS fighter in RL.

http://members.chello.se/unni/D-9.JPG

Oberleutnant Oskar-Walter Romm thoughts on his aircraft.

"I found the Fw 190D-9 to be greatly superior to those of my opponents. During dogfights at altitudes of between about 10,000 and 24,000ft, usual when meeting the Russians, I found that I could pull the D-9 into a tight turn and still retain my speed advantage. In the descent the Dora-9 picked up speed much more rapidly than the A type; in the dive it could leave the Russian Yak-3 and Yak-9 fighters standing."

[This message was edited by robban75 on Fri August 13 2004 at 05:06 AM.]

OldMan____
08-13-2004, 04:51 AM
It is not a point of TB3 being completely different. IT works in game, it does not accelerate like a fighter.. so the engine supports ways of limiting the dive acceleration of each fighter.


Ad all main fighters.. from YAK 1 to Me262 dive EXACTLY the same (measured in replay tracks at /14 speed) up to the point the shaking starts.


I wonder if this will be solved in PF.. since without superior dive.. american planes will be doomed againts Japs. So this time the force (of market) will be with us.

Maybe just adding the same shaking effect that makes acceleration slower a little bit earlier (and softer) would solve partially the problem.

And a 100km/h speed dive difference would do a HELLL of a difference in combat!!! Even a 50km/h would.

If brute force does not solve your problem... you are not using enough!

OldMan____
08-13-2004, 04:54 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by OldMan____:
It is not a point of TB3 being completely different. IT works in game, it does not accelerate like a fighter.. so the engine supports ways of limiting the dive acceleration of each fighter.


Ad all main fighters.. from YAK 1 to Me262 dive EXACTLY the same (measured in replay tracks at /14 speed) up to the point the shaking starts.


I wonder if this will be solved in PF.. since without superior dive.. american planes will be doomed againts Japs. So this time the force (of market) will be with us.

Maybe just adding the same shaking effect that makes acceleration slower a little bit earlier (and softer) would solve partially the problem.

And any difference would help me. The poitn is not meters per second.. it KM/H!!! 20 or 30 km/h would make me cry of happines in my 190 or all p47 pilots as well.

If brute force does not solve your problem... you are not using enough!<HR></BLOCKQUOTE>

If brute force does not solve your problem... you are not using enough!

OldMan____
08-13-2004, 04:55 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by OldMan____:
It is not a point of TB3 being completely different. IT works in game, it does not accelerate like a fighter.. so the engine supports ways of limiting the dive acceleration of each fighter.


Ad all main fighters.. from YAK 1 to Me262 dive EXACTLY the same (measured in replay tracks at /14 speed) up to the point the shaking starts.


I wonder if this will be solved in PF.. since without superior dive.. american planes will be doomed againts Japs. So this time the force (of market) will be with us.

Maybe just adding the same shaking effect that makes acceleration slower a little bit earlier (and softer) would solve partially the problem.

If brute force does not solve your problem... you are not using enough!<HR></BLOCKQUOTE>

If brute force does not solve your problem... you are not using enough!

OldMan____
08-13-2004, 04:55 AM
srry

If brute force does not solve your problem... you are not using enough!

robban75
08-13-2004, 06:05 AM
Edit:

hop2002
08-13-2004, 06:13 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>And reaching terminal velocity in a D-9 was hardly neccessary in order to escape any VVS fighter in RL.<HR></BLOCKQUOTE>

How do you define escape?

Somebody posted the TAIC report on the Zero on the AH board recently. What's suprising is how little difference there was between the planes in dive and zoom climb.

The P-51 vs Zero:

Dive began at 200 ias at 10k ft. After 27 seconds, when the Zero had reached it's pre set speed limit (set for safety reasons, presumably) , the P-51 was 200 yards ahead.

Same conditions, P-38J, again 200 yards ahead after 30 secs.

At 25k ft, same ias, the P-38j was 75 yards ahead after 30 secs.

P-47 at 10k ft, 100 yards ahead after 30 secs.
P-47 at 25k ft, 300 yards ahead after 30 secs.

Same sort of story for zooms. Zooms were begun after a dive to 310 ias, and held until 130 ias.

The P-38J was 300 feet above the Zero. The P-51 500 feet. The P-47 was 600 feet above.

These figures were obtained using amongst the best divers of the war, against the Zero, which was one of the worst.

I think people are expecting too much from short dives and zooms.

wojtek_m
08-13-2004, 08:01 AM
Exactly hop2002! I dont get the whole discussion about dive accelerations and the "physics model limitations" FB supposedly has... it's really basic physics so I cannot imagine it isnt done. If there was no atmosphere every mass (a feather or a steel ball) would dive the same, because of the gravity. With atmosphere we should include individual drag and power to weight ratios of the particular fighter, but the differences should be small! They should be less and less the higher you start your dive, because there is significantly less air up there.
Example: FW190 D9 against La7
Power to weight ratios: La7 0.57 HP/kg, Fw190D9 0.39 HP/kg =&gt; La7 significantly outperforms the FW here
Drag: no figures here but the FW generates less drag for sure
So we have the two effects working agains each other. But even if the FW would generate significantly less drag it would dive better only at high speeds, because drag~speed^2. And again these are small effects and the gravity is EQUAL for the two. Some FW190 fans are expecting to outdive an La7 which is on their tail, but that wasnt that easy and happened that fast... it should work at very high speeds though. I was diving often after Fw190s and they accelerate good in a dive... Generally the individual drag figures for the aircraft need perhaps a refinement, but they arent that far off.

-Logos-

robban75
08-13-2004, 10:13 AM
"How do you define escape?"

Escape by having alot better dive acceleration.
"Diving away, Oscar Romm easily outdistanced the Russian fighters attempting to follow him." He flew a D-9 by the way.

Performance wise the La-7 and D-9 are quite similar in climb and speed.

La-7 1850hp, 3265kg, vs D-9 2100hp 4350kg. Difference in max climbrate 24m/sec vs 22.5 m/sec. No stellar differences here.

The La-7 needed 5.1 minutes to reach 5000m(in game 3.9), whereas the D-9 needed 4 minutes(in game the same). Forsazh could only be used up to 2000m, and this is why the D-9 pulles ahead to 5000m. In FB/AEP, the La-7 can outclimb the D-9 between 6000m and 9000m. Funny aint it?

Topspeeds at SL 612km/h vs 612km/h. As close as it gets.

I do believe that the D-9 could outdive the La-7 in RL without any difficulty just like it could outdive the Yak-3 and Yak-9, and just like the Fw 190A-3 could outdive and outzoom the Spitfire MkIX without difficulty, (if we are to believe Mr. Eric Brown.)

A light airframe with large wings and low wingloading can work wonders in sustained climbs and turnfights offering alot of lift, but at the same time a fighter with a high wingloading and a relatively heavy weight has lower drag, and this is beneficial in dives and zoomclimbs, as the the Fw 190 and Spitfire matchup clearly shows. In FB, this simply wont happen.

http://members.chello.se/unni/D-9.JPG

Oberleutnant Oskar-Walter Romm thoughts on his aircraft.

"I found the Fw 190D-9 to be greatly superior to those of my opponents. During dogfights at altitudes of between about 10,000 and 24,000ft, usual when meeting the Russians, I found that I could pull the D-9 into a tight turn and still retain my speed advantage. In the descent the Dora-9 picked up speed much more rapidly than the A type; in the dive it could leave the Russian Yak-3 and Yak-9 fighters standing."

OldMan____
08-13-2004, 10:50 AM
The problem is I don t get even 100 meters from a zero behind me when diving with a dora (until the point where zero start loosing parts)

If brute force does not solve your problem... you are not using enough!

hop2002
08-13-2004, 11:08 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Escape by having alot better dive acceleration.
"Diving away, Oscar Romm easily outdistanced the Russian fighters attempting to follow him." He flew a D-9 by the way.<HR></BLOCKQUOTE>

What were the realtive energy states? If one plane already has a speed advantage when entering the dive, it will make a big difference.

It's important to remember that such things are hard to gauge. In tests, they tried to ensure equal conditions. In combat, you had planes with different fuel states, meeting at different speeds, at different engine settings. And not forgetting different skill levels of the pilots.

The pilot who enters the dive first will have a definite advantage, because he'll have started accelerating first, and will have opened a gap before the other pilots realise what's happening.

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>I do believe that the D-9 could outdive the La-7 in RL without any difficulty just like it could outdive the Yak-3 and Yak-9<HR></BLOCKQUOTE>

I have a hard time believing the D9 and LA7 were as different as the P-51 and Zero, and the difference between them, under equal conditions, was around 200 yards after a fairly sustained dive.

As wojtek said, gravity affects both planes equally.

To illustrate just how small the differences would be, gravity produces an acceleration of just under 10 m/s.

If you take two planes in a dive, both with the same maximum speed, and apply the acceleration to gravity to only one of them, and assume that it suffers no rise in drag, after 5 seconds it will have opened a gap of only 125m.

And that's assuming gravity doesn't apply to the trailing plane, and the drag increase doesn't apply to the leading plane. ie conditions which it's impossible to get in real life.

If you assume one accelerates under gravity at twice the speed of the other, the gap after 5 seconds will be just over 60m.

And even that's more than you could expect under equal conditions.

And in the meantime, you have to be diving at maximum speeds to get these differences, and in vertical dives, and in 5 seconds you will dave descended 3,000 ft or more.

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>d just like the Fw 190A-3 could outdive and outzoom the Spitfire MkIX without difficulty, (if we are to believe Mr. Eric Brown.)<HR></BLOCKQUOTE>

Brown never flew them head to head, afaik.

The Spitfire pilot during the tests against Faber's 190 was Hugh Godefroy. According to him:

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>If Jamie followed the favourite German technique of flicking over on his back and going straight down, he would pull away from me in the first two or three thousnd feet. After that the Spitfire IX could gradually catch him. <HR></BLOCKQUOTE>

And some of that advantage is going to be the roll rate of the 190, which allowed it to flick over much quicker than the Spit.

Don't forget that's a Spit IX at 15 lbs, with much worse acceleration than the Spit IX we have in game (climb rate was about 800 ft/min worse)

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>A light airframe with large wings and low wingloading can work wonders in sustained climbs and turnfights offering alot of lift, but at the same time a fighter with a high wingloading and a relatively heavy weight has lower drag, and this is beneficial in dives and zoomclimbs, as the the Fw 190 and Spitfire matchup clearly shows. In FB, this simply wont happen.<HR></BLOCKQUOTE>

I'd also note that every fighter took great pains to keep the weight down. I don't know of any that carried ballast to make them dive and zoom better, which should tell you something about the importance of weight/dive/zoom.

Any fighter could have done with more armour, which would add weight and make dive and zoom better, and improve resistance to damage, but even with the benefits of increased armour, it wasn't often fitted, apart from the bare minimum for the pilot.

faustnik
08-13-2004, 11:12 AM
So Hop are you saying that you don't believe that the 190 had a significant dive and zoom climb advantage over the Spit? You pick one quote where one test pilot says the difference was not so great. There are many others which state the difference was significant.

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CHDT
08-13-2004, 11:18 AM
I'm coming back always with the same story, but, remember, with the first patch for FB, the energy fighters had this little edge in dive and zoomclimbs which permit them to dictate the fight, if they were correctly flown.

So what happened? Hard whining of the t&b babies, then second patch, back to the status-quo http://ubbxforums.ubi.com/infopop/emoticons/icon_rolleyes.gif


P.S: Some docs here about the 190:

http://www.pbase.com/chrisdnt

robban75
08-13-2004, 11:23 AM
Diving away from British and VVS fighters were common practice for a good reason(see below). The LW pilots learned the hard way that this tactic didn't work against the better diving U.S fighters.

Wings of Luftwaffe
- By Capt. Eric Brown former RAF test pilot

From high-speed cruise, a pull up into a climb gave the Fw 190 an initial advantage owing to its superior acceleration and the superiority of the German fighter was even more noticeable when both aircraft were pulled up into a zoom climb from a dive.In the dive, the Fw 190 could leave the Spitfire Mk IX without difficulty and there was no gainsaying that in so far as manoeuvrability was concerned, the German fighter was markedly the superior of the two in all save the tight turn - the Spitfire could not follow in aileron turns and reversals at high speeds and the worst heights for its pilot to engane the Fw 190 in combat were between 18.000 ft and 22.000 ft(5.485 and 6705 m), and at altitudes below 3.000 ft (915 m). "

http://members.chello.se/unni/D-9.JPG

Oberleutnant Oskar-Walter Romm thoughts on his aircraft.

"I found the Fw 190D-9 to be greatly superior to those of my opponents. During dogfights at altitudes of between about 10,000 and 24,000ft, usual when meeting the Russians, I found that I could pull the D-9 into a tight turn and still retain my speed advantage. In the descent the Dora-9 picked up speed much more rapidly than the A type; in the dive it could leave the Russian Yak-3 and Yak-9 fighters standing."

JG14_Josf
08-13-2004, 12:27 PM
There is much confusion concerning the physics of WWII fighter performance.

If the idea is to be scientific then the only real evidence that can support any claim of actual relative performance is at best a guess.

The next best evidence, in the words of Robert Shaw is:

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Comparison testing, in which enemy aircraft are flown against friendly fighters, is undeniably the best method of gathering this crucial information. <HR></BLOCKQUOTE>

The idea that WWII combat plane relative performance capabilities can be proven with a computer program of any kind requires that the information being put into the program is accurate.
This is not realistic. True values for Thrust, Drag, and Mass are not available. The best that can be done is an average guestimate.

Even if the 'most' true values for every physical property a plane has that effects relative performance is found then a program is required to accurately crunch the numbers.

This is not something that can be done on a desk top computer.

Back to Shaw's 'comparative testing' that is 'undeniably' the best method.

People have done comparative testing both 'in game' and 'in the real war' and the re****s have illuminated an obvious contradiction.

To the extent that the contradiction exists the simulation fails to simulate. This is a best guess evaluation based upon the undeniable best method i.e. comparison testing.

As to the question of weight on performance.

Higher output engines tend to weigh more and higher output engines add to dive acceleration.

Weight adds to dive acceleration because air is less capable of dragging down higher mass.

During the initial acceleration from zero velocity the force of gravity is greater than WWII combat plane thrust. Drag is not much of a factor. The higher mass plane will be accelerated at the same rate as the lighter plane by the force of gravity, however, if the heavier plane is heavier because it has more thrust then what is the effect of this greater thrust on dive acceleration? Remember gravity is a greater force than thrust on all WWII combat planes (unless there are some that accelerated straight up from 0 velocity).

OldMan____
08-13-2004, 02:14 PM
Never tried... but think will make a clean FB install.. no ACE. For what everyone says.. it was a more acurate FS, with less external pressures.

It is a pitty I wont find people to fly with.

Don't understand me wrong. I dont like to flame and know how hard is to keep a game working. Know how hard is to implement each new feature. But I get very disapointed, since I do not want to fly Turn And Burn planes. And in current situation there is no Turn and burn plane.. there are planes and other things that are exactly the same but dont turn... not a single difference over the worse turn. If This was the true during war.. germans would for sure have copied captured spitfires in the first month of war againt england.

I do not want to have the best plane ( becaus ethat I dont fly the Spit and P51), but I want a plane I can use ONE TATIC that works.. other than turning like a dog chasing its own tail.

If brute force does not solve your problem... you are not using enough!

[This message was edited by OldMan____ on Fri August 13 2004 at 01:24 PM.]

hop2002
08-13-2004, 04:57 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>So Hop are you saying that you don't believe that the 190 had a significant dive and zoom climb advantage over the Spit? <HR></BLOCKQUOTE>

What's significant?

It's not a trick or flippant question.

Is what a pilot in test report calls significant what a pilot in FB would call little difference?

The only dive reports I've seen that quantify the differences are the TAIC ones. I expected them to show much larger differences, quite honestly.

I only came across the info from Hugh Godefroy a few months ago, and again I expected the 190 to have shown a greater advantage.

I think, in games, we shoot from futher out, we think a difference of 400 yards is small, when during the war they would think it large. Thus a 200 yeard difference to them would be "significant", and to someone in the game might seem like almost nothing.

We tend to play wih icons in game. Range is usually how far you can shoot at maximum.

In real life, if you could get a short distance away, and break below the line of sight, you could literally lose your opponent, very easily.

Those TAIC tests quantify the seperations achieved. They are not as large as I thought.

Is there anyone who thinks that the Spitfire IX would not outdive the Zero?

If the Spit IX would outdive the Zero (and we know that even the Spit V did), then the differnce between the Spit IX and P-51 would be less than the distance between the Zero and the P-51. So what sort of difference between the Spit IX and P-51? 100 yards? Is that significant?

Look at the zoom climb figures again:

Zooms were begun after a dive to 310 ias, and held until 130 ias.

The P-38J was 300 feet above the Zero. The P-51 500 feet. The P-47 was 600 feet above.

I get the impreession people flying FB want to be safely out of guns range above their opponent after a zoom. If it doesn't happen for the P-51 or P-47 against the Zero, how is it going to happen for the 190 against a Spit or La7?

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>You pick one quote where one test pilot says the difference was not so great. There are many others which state the difference was significant.<HR></BLOCKQUOTE>

Most quotes are from combat pilots, and cannot be seperated from the situation.

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>From high-speed cruise, a pull up into a climb gave the Fw 190 an initial advantage owing to its superior acceleration and the superiority of the German fighter was even more noticeable when both aircraft were pulled up into a zoom climb from a dive.<HR></BLOCKQUOTE>

And from the test of Faber's 190:

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>When both aircraft were flying at high cruising speed and pulled up into the climb from level flight, the Fw 190 had a slight advantage in the initial stages due to it's better acceleration. This superiority was slightly increased when both aircraft were pulled up into a climb from a dive<HR></BLOCKQUOTE>

Slight advantage, slightly increase to the advantage. That's the original report, the report Brown is quoting from (paraphrasing)

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>During the initial acceleration from zero velocity the force of gravity is greater than WWII combat plane thrust. Drag is not much of a factor. The higher mass plane will be accelerated at the same rate as the lighter plane by the force of gravity, <HR></BLOCKQUOTE>

Correct. Acceleration due to gravity, excluding drag, is not dependent on mass. A light weight will accelerate due to gravity at the same rate as a heavy one.

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>however, if the heavier plane is heavier because it has more thrust then what is the effect of this greater thrust on dive acceleration? <HR></BLOCKQUOTE>

You can ignore the acceleration due to gravity, because it wil be the same for both aircraft.

Excluding drag, that leaves only the thrust of each aircraft, and it's mass.

exact thrust is hard to find because you have to know prop efficiency, but if you assume the same for both aircraft, then it's a simple case that the higher power to weight ratio aircraft will accelerate faster in a dive, excluding drag.

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Remember gravity is a greater force than thrust on all WWII combat planes (unless there are some that accelerated straight up from 0 velocity).<HR></BLOCKQUOTE>

It certainly is on all prop fighters.

Typically, a WW2 fighter would be putting out 1 - 2,000 lbs of thrust from it's prop, depending on speed, and would have, in a vertical dive, the same thrust as it's weight in lbs from gravity, ie about 7,400 lbs for a Spit IX.

Drag is the only really difficult issue involved, approximate thrust is fairly easy to work out.

OldMan____
08-13-2004, 05:18 PM
just to leave no questions.. 100 meters advantage would be a DREAM !!!!! I would advertise this as a very good advantage. But we dont get 1 meter advantage (ok ok.. maybe 1 m we do get).

maybe the hole point on diving seem bugged due to the slightly altered climb os most planes (a 190 can only outclimb a TB3... http://ubbxforums.ubi.com/infopop/emoticons/icon_frown.gif )

If brute force does not solve your problem... you are not using enough!

faustnik
08-13-2004, 05:24 PM
From the RAF Farnborough report comparing captured Fw1903 vs. Spit V:

DIVE: "the Fw 190 can leave the Spitfire with ease"

CLIMB: When both aircraft are pulled into a climb from a dive, the Fw190 draws away very rapidly and the pilot of the Spitfire has no hope of catching it."

These indicate a substantial energy fighting advantage.

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wojtek_m
08-13-2004, 06:16 PM
@hop2002: Bravo! It's nice to see a guy who knows what he is talking about on this board.

@faustnik: Please provide DATA if you want to prove anything. Pilot quotes are mostly VERY subjektive even if I highly respect WW2 pilots.

Look at this from robban's sig:
Oberleutnant Oskar-Walter Romm thoughts on his aircraft.

"I found the Fw 190D-9 to be greatly superior to those of my opponents. ... in the dive it could leave the Russian Yak-3 and Yak-9 fighters standing."

My question: how often did Mr. Romm see a yak3 in combat 1,2,.. 5 times? How could he tell what the relative energy states were? What was the distance between the fighters? Possibly he was lets say 20km/h faster going into the dive and he entered it 1 sec before his opponent and it makes a BIG BIG difference...

Another quote from the other side:
Kozhedub: In combat potential, the Yak-3, La-7 and La-9 fighters were indisputably superior to the Bf-109s and Fw-190s.

Now, which aircraft is superior??? Kozhedub was an ace, so should we believe him? Or should we believe Romm??? I believe Mr. Maddox only believed Mr. DATA and thats why the sim is pretty good, even at dive accelerations...

JG14_Josf
08-13-2004, 06:21 PM
Hop,

I've heard this argument before where a persons says first:

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>You can ignore the acceleration due to gravity, because it wil be the same for both aircraft <HR></BLOCKQUOTE>

and then says:

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>the higher power to weight ratio aircraft will accelerate faster in a dive <HR></BLOCKQUOTE>

I am having a hard time with this only because fighter combat is my interest and fighter pilots don't know these facts so they report things that contradict these facts. Therefore I have a problem with these facts.

If gravity is a greater force than thrust then how does power to weight effect acceleration? Gravity is already accelerating the plane faster than the engine thrust can accelerate the plane. Gravity is already moving the mass of the plane faster than the engine thrust can move the mass of the plane. The mass of the plane is already moving the plane faster than the engine can because the force of gravity insists upon moving that mass.

Then the argument moves on to this quote:

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>excluding drag.
<HR></BLOCKQUOTE>

Here is where the higher mass, assuming everything else is equal, allows the plane to accelerate against the air molecules faster.

Although there are many of those who insist that phsyics confirm the games lack of historically accurate relative dive performance. I remain sceptical and my tendency is to put more value in the opinions of the pilots who actually flew these planes during the war and had their lives on the line.

OldMan____
08-13-2004, 07:21 PM
Disconsidering drag would be ok.. for tie foghters http://ubbxforums.ubi.com/infopop/emoticons/icon_wink.gif But is not the case!! So.. everyone does know gravity is same for any weight.. bug what matters is DENSITY!! (looking deeper that is only a single facet of being aerodinamic) that is why a brick falls faster than a box of same size made of paper. So it is IMPOSSIBLE that all planes dive same speed.. i am not taking into acount any individual aircaft like 190 or p47, that is for ALL... all have different drag.. so each one will dive at different acceleration.


Even Me262 that have much LESS drag than ANY propeler plane.. do dive at same speed in game.

If someone with REALLy good knowledge comes here and explain why I would be wrong. I would appreciate. But for know I reall y think there should be SOME sort of difference.. even 10 km/h after 1000m

If brute force does not solve your problem... you are not using enough!

hop2002
08-13-2004, 07:40 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>nd then says:

quote:the higher power to weight ratio aircraft will accelerate faster in a dive



I am having a hard time with this only because fighter combat is my interest and fighter pilots don't know these facts so they report things that contradict these facts. Therefore I have a problem with these facts.
<HR></BLOCKQUOTE>

I did say ignoring drag. I was discussing the basic physics involved. Note I finished with:

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Drag is the only really difficult issue involved, approximate thrust is fairly easy to work out.<HR></BLOCKQUOTE>

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>If gravity is a greater force than thrust then how does power to weight effect acceleration? Gravity is already accelerating the plane faster than the engine thrust can accelerate the plane. Gravity is already moving the mass of the plane faster than the engine thrust can move the mass of the plane. The mass of the plane is already moving the plane faster than the engine can because the force of gravity insists upon moving that mass. <HR></BLOCKQUOTE>

Acceleration is a force. You add all forces together, not just take the largest one.

The forces are cumalative. A Spitfire weighing 7400 lbs in a vertical dive has a thrust due to gravity of 7400 lbs. To that you must add the thrust of the prop. If the pilot fires a handgun at a plane behind him, you must also add the force opposed to the bullet. It all has to be added, no matter how small it is.

Of course, we can ignore really minor forces because they aren't going to make a large difference, but in the example above the Spitfire ha a total effective drag of 7400 lbs, plus say 1200 lbs from the prop, for 8600 lbs total.

As speed increases, the prop produces less thrust, but it still has to be added. IIRC, in the trials where the Spit reached just over 600 mph, they gave the total thrust from the prop and exhausts combined as only 200 lbs or so.

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Here is where the higher mass, assuming everything else is equal, allows the plane to accelerate against the air molecules faster.<HR></BLOCKQUOTE>

Yes. Acceleration = net force (thrust - drag)/mass

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Although there are many of those who insist that phsyics confirm the games lack of historically accurate relative dive performance. I remain sceptical and my tendency is to put more value in the opinions of the pilots who actually flew these planes during the war and had their lives on the line.<HR></BLOCKQUOTE>

I haven't seen any satisfactory dive figures based on calculating thrust, drag and mass. Mass and thrust are farily easy, drag is very difficult. You quoted some basic physics facts, I was replying to those, not suggesting I was calculating acceleration fully.

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>From the RAF Farnborough report comparing captured Fw1903 vs. Spit V:

DIVE: "the Fw 190 can leave the Spitfire with ease"<HR></BLOCKQUOTE>

Even with this we have a problem, because it's not clear what Spitfire V is modelled in game.

Against Faber's 190, the RAF tested a Spit V at 12 lbs boost.

The in game Spit V has the speed of a Spit V at 9 lbs, the climb rate of a Spit V at 16 lbs (16 lbs was approved just after Faber's 190 was tested).

Whatever, the 190 should accelerate faster in a dive than the Spit V though.

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>My question: how often did Mr. Romm see a yak3 in combat 1,2,.. 5 times? How could he tell what the relative energy states were? What was the distance between the fighters? Possibly he was lets say 20km/h faster going into the dive and he entered it 1 sec before his opponent and it makes a BIG BIG difference...
<HR></BLOCKQUOTE>

That's what I always worry about pilot accounts. And is he even identifying his enemy correctly?

The Germans claimed Curtiss fighters and Moranes and Dewotines during the BoB, despite the fact none were flying. They claimed to have destroyed twice as many Spits as Hurricanes, despite the fact half as many Spits as Hurris were destroyed. The vast majority of their losses were put down to Spits, iirc, rather than Hurricanes which scored many of them. Does that mean pilots were suprised by the speed of a "Hurri" that was actually a Spit?

Not just the Germans either. The RAF pilots claimed many He 112s, despite the fact none were involved.

OldMan____
08-13-2004, 08:02 PM
Well at least you agreesomething is not perfect right now.

I think most prejudiced planes are FW190, P47 and maybe P51 and p38.


It is very frustrating now.. since lets say spit vs 190.. both gain same speed.. but just as dive finished.. 190 looses all speed much faster than spit. So Dive was benefical to SPIT.. not 190 as it should.

Not trying to make anything againt SPIT.. understand that.. just fact is most comparisson informations were made by RAF

If brute force does not solve your problem... you are not using enough!

LEXX_Luthor
08-13-2004, 08:22 PM
robban75:: <BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>"Diving away, Oscar Romm easily outdistanced the Russian fighters attempting to follow him." He flew a D-9 by the way.<HR></BLOCKQUOTE>Romm may have been doing long time duration dives (of varying dive angles), much more than the immediate dive accel we are hoping to see. We also don't know the Russian fighters' initial speeds and altitudes relative to Romm--an experienced (real life http://ubbxforums.ubi.com/infopop/emoticons/icon_smile.gif ) Fw~190 ace can be considered has knowing how to keep high speed at all times and doing it, at all times.

The pilot story does not have the information we need. Our basic problem is that popular pilot stories are made to entertain the public, not to educate hard core flight simmers on flight performance data.

robban:: <BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>La-7 1850hp, 3265kg, vs D-9 2100hp 4350kg.<HR></BLOCKQUOTE>
-----&gt; La~7 .57 hp/kg
------&gt; D~9 .48 hp/kg

robban we talked long ago about how drag changes astronomically with small changes in speed. Drag is far greater at high speeds where the D9 may have a drag advantage over La~7. At low speeds with much lower drag, the La~7's greater hp/mass could give it an acceleration advantage over the D9.

robban, your old level acceleration tests showed La~7 having accel advantage over D9 until high level speeds, where D9 accel began to take over the La~7 accel in your published data.

Fw~190 was never known as a great accelerator. Great range, great firepower, and great dive. But not acceleration by itself. (and great roll too http://ubbxforums.ubi.com/infopop/emoticons/icon_smile.gif ) So its still a Great plane. http://ubbxforums.ubi.com/images/smiley/11.gif I like the Great range thing the best of course.



I am very intrigued by hop's ideas on seperation rates. This could be a huge Pink Elephant for the FB dogfighter community.


__________________
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"I had actually pre ordered CFS3 and I couldnt wait..." ~Bearcat99
"Gladiator and Falco, elegant weapons of a more civilized age" ~ElAurens
:
"Damn.....Where you did read about Spitfire made from a wood?
Close this book forever and don't open anymore!" ~Oleg_Maddox http://ubbxforums.ubi.com/images/smiley/16x16_smiley-surprised.gif

SkyChimp
08-13-2004, 08:26 PM
I believe the Spit should retain the speed it gained in a dive longer than the Fw. The Fw-190As and Spit IX had somewhat comparable top speeds, but the Sptifire was cleaner and once the planes leveled out the Fw would have lost what initially gave it the advantage. IMO, the advantage then would shift back to the Spitfire which had less drag and thus, would have bled off excess speed less quickly.

Dive advantages are difficult to quantify. Different planes had different advantages at different altitudes at different stages of a dive. That's one of the reasons contradictions to what we've come to expect abound.

Regards,
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LEXX_Luthor
08-13-2004, 08:31 PM
http://www.boardy.de/images/smilies/kopfpatsch.gif

Fw~190 Great bombload too....worthless for dogfight simmers.

OldMan____
08-13-2004, 08:44 PM
spit did not had best aerodinamics than 190 9at least not much).. otherwise it would dive faster than 190. Indeed.. the same wing that gave hin less bleeding in turns increases drag so the spit should regain advantage only after maneuvering begins again.

Anyway.. the discussion here was not if plane A is better than B.. is planes should have different dive acc? It seems so.


One important thing remembered is tha shallow dive is different from step dive. I will test it too.

If brute force does not solve your problem... you are not using enough!

LEXX_Luthor
08-13-2004, 08:57 PM
How are you testing? http://ubbxforums.ubi.com/images/smiley/11.gif

__________________
http://ubbxforums.ubi.com/images/smiley/10.gif Flyable Swedish "Gladiator" listed as J8A ...in Aces Expansion Pack

"You will still have FB , you will lose nothing" ~WUAF_Badsight
"I had actually pre ordered CFS3 and I couldnt wait..." ~Bearcat99
"Gladiator and Falco, elegant weapons of a more civilized age" ~ElAurens
:
"Damn.....Where you did read about Spitfire made from a wood?
Close this book forever and don't open anymore!" ~Oleg_Maddox http://ubbxforums.ubi.com/images/smiley/16x16_smiley-surprised.gif

faustnik
08-13-2004, 09:03 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by wojtek_m:


@faustnik: Please provide DATA if you want to prove anything. Pilot quotes are mostly VERY subjektive even if I highly respect WW2 pilots.



<HR></BLOCKQUOTE>

Wojtek,

I was quoting a test report not pilot opinion. The Fw190 pulled away from the Spit V in side by side controlled test conditions.

This is different then one pilot claiming that his aircraft was superior.

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LEXX_Luthor
08-13-2004, 09:35 PM
Self Contradiction Alert

LOIS_Lane:: <BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>
(1) Drag is far greater at high speeds where the D9 may have a drag advantage over La~7.

(2) Fw~190 was never known as a great accelerator.<HR></BLOCKQUOTE>
I may be contradicting myself. http://www.boardy.de/images/smilies/kopfpatsch.gif


Apologies robban http://ubbxforums.ubi.com/images/smiley/11.gif http://ubbxforums.ubi.com/images/smiley/11.gif http://ubbxforums.ubi.com/images/smiley/11.gif



__________________
http://ubbxforums.ubi.com/images/smiley/10.gif Flyable Swedish "Gladiator" listed as J8A ...in Aces Expansion Pack

"You will still have FB , you will lose nothing" ~WUAF_Badsight
"I had actually pre ordered CFS3 and I couldnt wait..." ~Bearcat99
"Gladiator and Falco, elegant weapons of a more civilized age" ~ElAurens
:
"Damn.....Where you did read about Spitfire made from a wood?
Close this book forever and don't open anymore!" ~Oleg_Maddox http://ubbxforums.ubi.com/images/smiley/16x16_smiley-surprised.gif

Bull_dog_
08-13-2004, 10:17 PM
The original point of engine limitations is well taken...I had begun to think this to be true...and I'm thinking the torque thing on the lightning might be hogwash too... The TB-3 is an extreme example, but it illustrates that there are significant differences between aircraft...I suspect in drag. I know Jets aren't prop planes, but they don't exhibit torque so, although I don't understand the code, there are engines that are torqueless.

Now back to the debate...lots of subjective terms being tossed around..."significant"..I would likely define that as something that would give a pilot a decisive edge. So does the Spitfire have a decisive edge in the dive against a Zeke? It should...but only Oleg can determine that. I don't know that I've seen much objective data on the subject.

This I do know...at least on aircraft I'm most familiar with...lightning, jug, mustang, spits...ailerons, rudders and elevators didn't fall off in high speed dives except where compressibility occurs...compressibility did not occur at low altitudes unless the speed was acheived at a higher altitude first...air induced drag would and did slow the aircraft down...this is where mass comes into play...kinetic energy, mass and drag had a "significant" impact on accelaration, retained energy, and zoom.

Now how much? If only I knew, but I don't. I am convinced the energy modelling isn't right because I don't have a "signicant" advantage when I dive in my P-47 away from a 109 for example...so relatively speaking I don't feel like energy is modelled right and definitely not in zoom... in real life if a spit and a jug dove from 20k at the same dive angle to 5000 ft and pulled up at the same angle the jug would pull up first because he reached 5000 ft faster and when they reached their original speed the jug would be higher due to zoom...how much? A significant amount!! If only we knew.

In real life, the Jug was safe from nearly all enemies as long as he had a good 10 or 15 K to dive and that is against Fw's too who had a good dive and superior low altitude speed....the Jug would just leave them behind.

This game would play much different...MUCH different if Fw's, 109's, Jugs, Lightnings, Mustangs could outdive their lightweight adversaries... Yaks', La's, Ki's, Spits and P-39's!

We'd probably see far fewer cries of Uberplane etc if a P-47 had an La-7 chasing him at 20K and the P-47 dove..the La follows...the P-47 pulls out and hammerheads back on the tail of the La due to poor zoom climb in the La and the Jug proceeds to kill him...wouldn't that be neat http://ubbxforums.ubi.com/infopop/emoticons/icon_smile.gif

JG14_Josf
08-13-2004, 11:15 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>We'd probably see far fewer cries of Uberplane etc if a P-47 had an La-7 chasing him at 20K and the P-47 dove..the La follows...the P-47 pulls out and hammerheads back on the tail of the La due to poor zoom climb in the La and the Jug proceeds to kill him...wouldn't that be neat <HR></BLOCKQUOTE>

I quoted the above only to add to this line of thinking.

Energy fighting like the above imaginary example requires that the two planes fly in a manner where one plane gains energy over another. If for example the LA7 simply refused to follow the P-47 and instead waited for the P-47 to zoom up then it goes to follow that the LA7 would not have lost any relative energy.

However if the Spitfire VB (specific evidence is available for thie SpitVB and FW190A3 plane matchup so I use that instead of the LA7 vs P-47 example) anyway... if the Spitfire VB follows the FW190A3 in a dive it will be playing into the hands of the FW pilot. The FW190 will be gaining relative energy with faster dive acceleration; more speed equals more energy, but only if the Spitfire pilot follows.
The energy fight requires that the target plays the game.

What is also obvious, to me at least, is that if a pilot of an inferior diving plane knows this condition he would be less likely to follow. What this means is that planes with dive acceleration advantages would have an escape. An escape that is much less viable when no such advantage exists untill the slower plane reaches Vmax.
Planes with greater climb rates have an escape/energy gaining advantage. Planes with faster level speeds have an escape/energy gaining advantage. Planes with higher top dive speeds (before breaking up) have an escape/eenrgy gaining advantage. However the game does not model a dive acceleration escape/energy gaining advantage for the planes that historically had these advantages.
This is a glaring ommision to me.
To say a little dive acceleration is no big deal is like saying a small turn rate advantage is no big deal, a small climb advantage is no big deal, or a small top speed advantage is no big deal.
I fight a game called energy fighting. If I can gain energy I use that advantage. It is much better to have a little climb advantage, for example, than be a little less able to climb. One is a combat advantage and the other is a combat dissadvantage. One allows one plane to gain relative energy the other causes one to lose relative energy.
If all the planes flew the same, as they do in dive acceleration now, then the game would be what?

OldMan____
08-14-2004, 04:58 AM
Very good post. Summarized the whole thread.

Anyway.. someone said thtat FB prior to ACE had this modeled.. so can anyone confirm this?

If brute force does not solve your problem... you are not using enough!

Diablo310th
08-14-2004, 08:24 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by JG14_Josf:
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>We'd probably see far fewer cries of Uberplane etc if a P-47 had an La-7 chasing him at 20K and the P-47 dove..the La follows...the P-47 pulls out and hammerheads back on the tail of the La due to poor zoom climb in the La and the Jug proceeds to kill him...wouldn't that be neat <HR></BLOCKQUOTE>

I quoted the above only to add to this line of thinking.

Energy fighting like the above imaginary example requires that the two planes fly in a manner where one plane gains energy over another. If for example the LA7 simply refused to follow the P-47 and instead waited for the P-47 to zoom up then it goes to follow that the LA7 would not have lost any relative energy.

However if the Spitfire VB (specific evidence is available for thie SpitVB and FW190A3 plane matchup so I use that instead of the LA7 vs P-47 example) anyway... if the Spitfire VB follows the FW190A3 in a dive it will be playing into the hands of the FW pilot. The FW190 will be gaining relative energy with faster dive acceleration; more speed equals more energy, but only if the Spitfire pilot follows.
The energy fight requires that the target plays the game.

What is also obvious, to me at least, is that if a pilot of an inferior diving plane knows this condition he would be less likely to follow. What this means is that planes with dive acceleration advantages would have an escape. An escape that is much less viable when no such advantage exists untill the slower plane reaches Vmax.
Planes with greater climb rates have an escape/energy gaining advantage. Planes with faster level speeds have an escape/energy gaining advantage. Planes with higher top dive speeds (before breaking up) have an escape/eenrgy gaining advantage. However the game does not model a dive acceleration escape/energy gaining advantage for the planes that historically had these advantages.
This is a glaring ommision to me.
To say a little dive acceleration is no big deal is like saying a small turn rate advantage is no big deal, a small climb advantage is no big deal, or a small top speed advantage is no big deal.
I fight a game called energy fighting. If I can gain energy I use that advantage. It is much better to have a little climb advantage, for example, than be a little less able to climb. One is a combat advantage and the other is a combat dissadvantage. One allows one plane to gain relative energy the other causes one to lose relative energy.
If all the planes flew the same, as they do in dive acceleration now, then the game would be what?<HR></BLOCKQUOTE>

I have been following this thread but not posted before. JG14_Josf....I think you have hit the nail on the head. I could not agree more with what you have said. I'm no physisis(hmm spelling) nor am I good at testing...but from reading the results of tests run by those who do..and from reading all accounts I have to agree. The question now becomes....with all this info. and to some extent proof.....How do we convince Oleg to model it? (if it can be modeled in this game engine) or do we ahve to wait till PF ids available. I fly the Jug 99% of the time and know all too well the problems with dive acceleration and zoom climb limitations. I have to admit tho...with the latest patch both of those did improve for teh Jug. But...it would be better if all planes reflected differences in dive and zoom capabilities. Realism is waht we all are looking for...not for our particular plane to be better or uber than anyone elses. Just give me a Jug that performs realisticly compared to others I fly against and with.

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OldMan____
08-14-2004, 10:38 AM
Lets just gather information. Any documetn you can find.. post here. When we have enough data we open a thread at ORR.

If brute force does not solve your problem... you are not using enough!