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Gaston444
01-10-2010, 03:51 PM
I have several times now posted this Soviet evaluation of months of early encounters with the FW-190A. This evaluation of course shows a FW-190A that is I am told completely at odds with the general accepted view of the FW-190A. To cite just 3 quick quotes: "FW-190 has better horizontal maneuverability than Bf-109"-"The FW-190A will inevitably offer turning combat at a minimum speed"-"The FW-190A does not like vertical maneuvers";

http://www.ww2f.com/russia-war...iences-fw-190-a.html (http://www.ww2f.com/russia-war/21828-russian-combat-experiences-fw-190-a.html)



Since this condensed ACTUAL combat evaluation of the Anton against light fighters apparently shows Il-2's (and most other computer games) FW-190As to be mostly fictional constructs (unless the words and language here are both totally meaningless, of course...), some have tried to discredit it by pointing out that this same document contains an evaluation of the truly fictional He-100 service fighter, a German propaganda ploy.

I countered at the time that the original document contains the equivalent of text of over 100 lines for the FW-190A, while fewer than 8 are devoted to the He-100 evaluation... Now I just learned in the November 2009 "Replic" issue #219, something that, if true, would at least bolsters somewhat my defense of this document: The USSR purchased THREE He-100 for evaluation prior to hostilities...

I realize the two US Navy tests and a few RAE conclusions do not support my viewpoint on the FW-190A, but even the RAE maintains that the FW-190A vastly out-turns the Me-109G...

So if you want to discredit this Soviet evaluation of the FW-190A, the most detailed and extensive actual combat evaluation of the FW-190A I am aware of so far, you are likely going to have to do better than to point out that it mentions the He-100...

Gaston

BillSwagger
01-10-2010, 07:53 PM
Originally posted by Gaston444:
"FW-190 has better horizontal maneuverability than Bf-109"


The FW190 has better roll performance and probably better high speed elevator deflection but i don't think there is any indication that the Fw190 could make a tighter turn than a 109. Also, this document comes from the perspective of when engaging in a Lavochkin.



"The FW-190A does not like vertical maneuvers";

Simply put, the Lavochkin is a lighter plane, and will have the advantage in the vertical against the 190s. The lighter 109s had a better chance in the vertical.




FW-190A vastly out-turns the Me-109G...

Gaston

This depends on speed and altitude, even in game, but to use the word "vastly" is an over statement.

Physics tells me the lighter of the two planes usually has the better radius, dont you agree?
Usually the lighter plane has lower stall characteristics that allow for tighter turns at lower speeds.

I should also point out that the FW190 has higher wing loading which is not a typical characteristic of a superior turning plane.

I still have a hard time seeing your view of the Fw190A because of these reasons.


Bill

ImpStarDuece
01-10-2010, 08:24 PM
even the RAE maintains that the FW-190A vastly out-turns the Me-109G

Cite please

http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

JtD
01-10-2010, 10:16 PM
Still to be provided by Gaston444 with name of the source (5th enquiry):
Clean power off stall speed for 109G:
Clean power off stall speed for 190A:

Daiichidoku
01-10-2010, 11:21 PM
oh no!

you guys actually responded to this thread http://forums.ubi.com/images/smilies/34.gif

TheGrunch
01-11-2010, 12:53 AM
I've already discussed with you my many objections to using this report as an archetype for the FW-190's usage. As usual you've just decided to ignore everything I said without arguing my points and post it again somewhere else with no alteration of your conclusions. Boooooring. Almost as bad as Owl, asks a question and then ignores all the answers.

K_Freddie
01-11-2010, 09:38 AM
I stand here on my 'pulpit' and say to yee.. "Every LA and Yak pilot that encountered a FW190 felt confident that they were going to win this battle"... As it is written in the report and we shall believe.
http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif

M_Gunz
01-11-2010, 10:02 AM
What FW190-A and What Bf109G? IMO the OP does not care since he refers to the 190 as "the Anton".

I just hope that those who know better quit feeding the troll.

M_Gunz
01-11-2010, 10:05 AM
Originally posted by BillSwagger:
Physics tells me the lighter of the two planes usually has the better radius,

Your physics needs work, even with the word usually in there.

BillSwagger
01-11-2010, 10:32 AM
if you could help me understand how a heavier plane could have a better turn radius than a lighter plane, im all ears.

I dont disagree that in some situations this might hold true. I just know that typically a lighter plane turns better at slower speeds than the heavier one.
Wing design also comes into play, but i'm just a simmer, i was trying to keep the discussion in the context of the 109 and 190, not the exceptions.


There is a loaded weight difference of nearly 3000lbs. At max takeoff weight, the 109 is as much as an empty fw190.



Bill

JtD
01-11-2010, 10:51 AM
Hey Bill, wing loading is more important to that than pure weight. For instance, the F6F Hellcat can turn tighter than a 190. It is heavier, but has a much larger wing area.

Eventually, this all comes down to the stall speed, the plane with the lower stall speed can do the tighter turn.

BillSwagger
01-11-2010, 10:55 AM
thanks for clarifying.

Actually the 109 and 190 have a similar wing load, favoring the 109 by 4-10 pounds/squ.ft. depending on models.

Then we look at stall speeds, which historically the Fw-190 was known to have an above average stall speed. (127mph)
The 109G was closer to 90 mph, but don't quote me, i just did a brief google search for the info.

JtD
01-11-2010, 11:06 AM
The 109 has leading edge slats, which help to reduce the stall speed. The Fw has not. This is where you need to get into the details of the construction (there are many) to find more exact relations, but as a first guess wing loading works fairly well.

But, providing the stall speeds for clean 109 and 190 is what Gaston444 is asked to do.

JG52Karaya-X
01-11-2010, 11:13 AM
Originally posted by BillSwagger:
Actually the 109 and 190 have a similar wing load, favoring the 109 by 4-10 pounds/squ.ft. depending on models.

They do not, even remotely...

Let's compare the heaviest serial production Bf109 versus one of the lightest FW190s

Bf109K-4

takeoff weight: ~3350kg
wing area: 16.04m^2
wing loading: around 209kg/m^2

FW190A-3

takeoff weight: ~3950kg
wing area: 18.5m^2
wing loading: around 214kg/m^2

Even in this comparison of extremes its obvious that the FW190 comes in second. And we're not even taking the leading edge slats of the Bf109 into account! So you see the Bf109 should and did enjoy a rather distinct turning advantage over the FW190 at slow speeds.

For a contemporary FW190 to the Bf109K-4

FW190A-8

takeoff weight: ~4300kg
wing area: 18.5m^2
wing loading: around 232kg/m^2

BillSwagger
01-11-2010, 11:39 AM
more interesting stuffs:

refers to a USAAF test in 1943: Fw190G and P-47D-4 (no paddle prop)


on the topic of turn:

"At speeds in excess of 250 mph IAS, the two aircraft were turned on each other's tail as tight as possible and alternating the turns left and right. The P-47 easily out-turned the Fw 190 at 10,000 ft and had to throttle back to keep from overshooting, a level of superiority that increased with altitude. It was found that the Fw 190 was very heavy in terms of fore and aft control, and vibrated excessively. Below 250 mph IAS however, the ability of the Fw 190 to hang on its propeller and turn inside the P-47 was very evident. The Fw 190 was also able to accelerate suddenly and change to a more favourable position."

acceleration/ climb / dive:

"During acceleration tests the Fw 190 initially held an advantage at all heights and speeds, quickly gaining about 200 yards, but at 330 mph IAS (Indicated Air Speed) the P-47 began to overtake rapidly and quickly drew away. The story was very much the same in the climb with the Fw 190 being superior over the first 1,500 ft, but thereafter the P-47 achieved dominance and out-performed the Fw 190 by 500 ft/min. Dives of 65 degrees were carried out from 10,000 ft to 3,000 ft, starting at 250 mph IAS. Once again the Fw 190 held an initial advantage but was passed by the P-47 at 3,000 ft at a much greater speed."

See
Peter Caygill, Focke Wulf 190, Airlife Publishing, 2002.

K_Freddie
01-11-2010, 12:37 PM
You forgot the part about (AFAIR) the FW190 not being in peak condition - The US technicians were not up to scratch with servicing the FW190, There was also the question about the fuel used.

This is if we're talking about the same report.. that is.
http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif

Frankthetank36
01-11-2010, 12:47 PM
The 190 isn't as good in the vertical? Ha ha ha. HA. Vertical is where the 190 shines, the roll rate makes it very easy to change direction when going straight up or down. If I dogfight in a 190 instead of zooming away after a pass, it is almost always in the vertical. The 109 is better in the horizontal and that was why the Soviet pilots generally feared it more, since most of the combat took place near the ground.

Waldo.Pepper
01-11-2010, 12:52 PM
Can't you guys spot a troll yet? One post, to stir up a mess, then he slinks off and watches the fun. Why do you persist in feeding these people?

Bremspropeller
01-11-2010, 01:19 PM
Turning-capabilities derived from wing-loading...clearly deerves a http://forums.ubi.com/images/smilies/partyhat.gif

There's a bit more to it than comparing wingloading.
I thought it's been repeated often enough to even make the most learnng-resistant people understand that.

Seems like I'm wrong http://forums.ubi.com/images/smilies/compsmash.gif

JtD
01-11-2010, 01:44 PM
Oh, feel free to bring up a number of examples where the aircraft with the considerably higher wing loading can do the tighter turn - power off, clean config. I'll answer with five times the number of examples where it doesn't, just so you understand that the trend in fact exists.

BillSwagger
01-11-2010, 02:27 PM
Originally posted by K_Freddie:
You forgot the part about (AFAIR) the FW190 not being in peak condition - The US technicians were not up to scratch with servicing the FW190, There was also the question about the fuel used.

This is if we're talking about the same report.. that is.
http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif

Refers to a test done in Italy in Dec 1943. There were two captured 190Gs, this was one of them. The author also mentions that the report indicated the plane was in remarkably good condition for a captured plane. This is a different plane than the one tested in the UK, but probably underwent similar rigging.
I can say, however there are other charts and graphs that back this information using different models. I will try to locate the graph, but if memory servers me, it was a P-47C and a 190A-3, and a handful of other warbirds of the same era including the spitfire and 109.


To make a point about turn performance, which i think is relevant to the thread, is that the P-47D-4 was able to out turn the FW190 "easily" in speeds above 250IAS, where the tables turn under such speeds.

I think in reading articles and pilots accounts that make mention of "turning inside" or "turning with" a plane, that a context of what speed the encounter occurs at is very important.

I might not need base every planes characteristic on wing loading and weight, but that seems to be the more substantial indicators of turn radius particularly in low speed dogfights.
and if not, what else is another factor for shorter turn radius?



Bill

Bremspropeller
01-11-2010, 02:27 PM
...if you can tell me what a power-off turn has in common with combat-flying http://forums.ubi.com/images/smilies/sleepzzz.gif

BillSwagger
01-11-2010, 02:43 PM
ahhh yes, is this the one?

http://www.wwiiaircraftperform...g/fw190/fw190a5.html (http://www.wwiiaircraftperformance.org/fw190/fw190a5.html)


http://www.wwiiaircraftperformance.org/fw190/fw190a5-climb-43.jpg


From the looks of this, you can see various plots of different configurations of the climb rate of the 190 and its looks to have its best RoC under 4000ft. Otherwise its in line with the climb rate of a P-47D-10 and in some configurations worse above 4,000 ft.
Anyone still think the early FW190A was good in the vertical at 15,000ft?

Bremspropeller
01-11-2010, 02:50 PM
1.32 ata

BillSwagger
01-11-2010, 03:22 PM
you mean the one with the red line on the graph?

The 190G-3 looks to be a bit better than that, and still about the same as P-47D-10 at 56" no paddle blade.


Bill

Bremspropeller
01-11-2010, 03:50 PM
There is no mention of the G-3's power-setting and state of installed equipment.

tomtheyak
01-11-2010, 04:23 PM
Just to throw another bit of complication in...

A good power loading can offset a higher wingloading.

Why?

So we all know that we create drag creating lift, right, and to over simplify, that drag burns energy.

If that energy loss is so great (as in a tight turn) that eventually we slow down so much we reach the stall speed for what ever G loading we are at in the turn, then the a/c will stall.

With excess power we very much reduce the time it takes to reach this state - if at all.

A good example of this is the yak-3 which has a wingloading of 181 kg/m² compared to a spitfire MkVb at 119.91 kg/m², you'd expect the Spit to walk all over the Yak if wing loading was all we needed - but they have near identical power loadings (0.36 kW/kg).

(figures from Wiki - I know, I know but you got any official date stamped authentic documents, you get em and correct me, as far as I am concerned they'l do as an example.)

This means for the same power loading the yak will accelerate quicker, and might lose less energy to lift-drag in the turn, but this depends on....

...The aerofoil profile, which will change the rate of energy loss, not to mention the effect it's coefficient of lift will have - wing area means little if the shape of the wing is inefficient at producing lift.

So not a simple thing any more is it?

Despite this I still think the original poster is chasing some fanboi agenda, but then I have a Spit in my sig so I got to be biased, right?

BillSwagger
01-11-2010, 06:07 PM
Originally posted by Bremspropeller:
There is no mention of the G-3's power-setting and state of installed equipment.


http://www.wwiiaircraftperform...rg/fw190/eb-104.html (http://www.wwiiaircraftperformance.org/fw190/eb-104.html)

power settings are in section VII figure 4.

fuel grade is in section N.



I also might mention from the same report:

" H. Maneuverability and Aerobatics

The outstanding maneuverability feature of this airplane is it extremely high rate of roll. The radius of turn, however, is poor and it is only slightly improved by using the maneuvering flap position of 15 degrees. If pulled fast, the airplane tends to stall out abruptly with little warning. Elevator control forces are very heavy in a tight turn, requiring constant use of the elevator trim control. "

JtD
01-11-2010, 10:37 PM
Originally posted by Bremspropeller:
...if you can tell me what a power-off turn has in common with combat-flying http://forums.ubi.com/images/smilies/sleepzzz.gif

Well, that was just for simplicities sake. So that I can save myself from more smart butt comments like vector thrusted VTOL aircraft. But, if you feel you can't do without that, please bring up a number of examples where the aircraft with the considerably higher wing loading can do the tighter turn - power on, clean config. I'll answer with five times the number of examples where it doesn't, just so you understand that the trend in fact exists.

And since I'm a good sport, I'll give you five simple examples to start with, and there are as many more as one could desire.
1. 109G @ 2800 kg can turn tighter than the same 109G @ 2900 kg (lower wing loading).
2. 109G @ 2900 kg can turn tighter than the same 109G @ 3000 kg (lower wing loading).
3. 109G @ 3000 kg can turn tighter than the same 109G @ 3100 kg (lower wing loading).
4. 109G @ 3100 kg can turn tighter than the same 109G @ 3200 kg (lower wing loading).
5. 109G @ 3200 kg can turn tighter than the same 109G @ 3300 kg (lower wing loading).

Yes, it is that simple. Considering wing loading irrelevant for estimating a minimum turn radius quite obviously is stupid.
Feel free to add a number of other relevant aspects in well thought out, long post. This might be of value to others, but just hopping in, not even bothering to read and process what exactly had been written and putting a http://forums.ubi.com/images/smilies/partyhat.gif label on it, is clearly a very poor contribution.

JtD
01-11-2010, 10:57 PM
Originally posted by BillSwagger:

From the looks of this, you can see various plots of different configurations of the climb rate of the 190 and its looks to have its best RoC under 4000ft. Otherwise its in line with the climb rate of a P-47D-10 and in some configurations worse above 4,000 ft.
Anyone still think the early FW190A was good in the vertical at 15,000ft?

EB 104 was also tested at 1.42 ata and 2700 rpm. It achieved a maximum climb rate of 4000 ft/min in low gear and 3000 ft/min in high gear. These numbers appear very high when compared to what you usually see in Fw documents, but they still exist.
However, a good climb rate is not all you need to be good in the vertical, as you may know the P-47, in particular the early models, also were quite good in vertical maneuvers but, as you can see, they too lacked climb rate.


what else is another factor for shorter turn radius

If you really are just looking for the minimum turn radius, I, again, have to recommend looking for the stall speed. The plane with the lower stall speed will almost always be able to do the tighter turn.

BillSwagger
01-12-2010, 12:42 AM
Originally posted by JtD:
EB 104 was also tested at 1.42 ata and 2700 rpm. It achieved a maximum climb rate of 4000 ft/min in low gear and 3000 ft/min in high gear. These numbers appear very high when compared to what you usually see in Fw documents, but they still exist.
However, a good climb rate is not all you need to be good in the vertical, as you may know the P-47, in particular the early models, also were quite good in vertical maneuvers but, as you can see, they too lacked climb rate.


what variant of the FW190 would that be?

So looking at the climb rate of an Fw190 eb104 at 2700rpm at 42", how does that other test compare? Also climb rate and zoom climb is very different, and i have to wonder if what you are referring to is not an example of the FW190 zoom performance instead.

For example, the P-47D at 1500ft (220IAS starting speed) at 64" WEP could achieve 10,000ft in 2 minutes, over 5000ft of that climb was achieved in about 20 seconds. So yeah, climb rate is not an indicator of a vertical maneuver but i wouldn't dare say the P-47Ds best climb was 5000ft/min. Makes me wonder what the 47d achieved in zoom at 70"...=)

That's why i pay particular attention to the manifold and rpm settings on some of these comparisons.
If the Fw190 is run at a lower HG setting than what was typical then i could see the discrepancy.

Bill

M_Gunz
01-12-2010, 07:29 AM
Originally posted by BillSwagger:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by JtD:
EB 104 was also tested at 1.42 ata and 2700 rpm. It achieved a maximum climb rate of 4000 ft/min in low gear and 3000 ft/min in high gear. These numbers appear very high when compared to what you usually see in Fw documents, but they still exist.
However, a good climb rate is not all you need to be good in the vertical, as you may know the P-47, in particular the early models, also were quite good in vertical maneuvers but, as you can see, they too lacked climb rate.


what variant of the FW190 would that be?

So looking at the climb rate of an Fw190 eb104 at 2700rpm at 42", how does that other test compare? Also climb rate and zoom climb is very different, and i have to wonder if what you are referring to is not an example of the FW190 zoom performance instead. </div></BLOCKQUOTE>

Of course he is. He just pointed out that zoom is also a form of vertical performance.


For example, the P-47D at 1500ft (220IAS starting speed) at 64" WEP could achieve 10,000ft in 2 minutes, over 5000ft of that climb was achieved in about 20 seconds. So yeah, climb rate is not an indicator of a vertical maneuver but i wouldn't dare say the P-47Ds best climb was 5000ft/min. Makes me wonder what the 47d achieved in zoom at 70"...=)

Not a huge lot more. The majority of a zoom has to do with the speed you start. Prop thrust is a fraction of gravity
and you want to compare a small fraction of a fraction to get something much bigger? Some yes but only some.

JtD
01-12-2010, 08:46 AM
Originally posted by BillSwagger:
what variant of the FW190 would that be?

That would be the same G-3 you have in the chart already, second from the bottom of the list. To my knowledge EB-104 is the US designation number for that plane. The 4000 fpm and 3000 fpm are figures for best sustained climb, just like the 3390 and 2630 you have in the chart already for 1.32ata/2400rpm. Which, too, are high when compared to other data, but are also seen in documents of other tests. Eventually 4000/3000 are on the high side, but not unreasonable. They were also achieved by later, heavier 190's with higher boost and some extra hp.

And, yes, zoom climb and diving/dive acceleration are very important aspects of vertical combat, the best sustained climb does not tell the whole story.

Bremspropeller
01-12-2010, 09:40 AM
Considering wing loading irrelevant for estimating a minimum turn radius quite obviously is stupid.


Stupid ferkin overpaid engineers http://forums.ubi.com/images/smilies/compsmash.gif


And tell me how your chart of similar 109s with different wingloadings has any signifigance on comparing different aircraft with different Ca/ Alpha curves.

Yes you can and will take wingloading into consideration when comparing x to x; it's actually the only value that changes here - you can't tell different performance apart by only looking onto that single factor, when comparing x to y.
There's a bit more to it then just wingload.

If you won't compensate for different Ca/ AoA curves and diferent excess-power, you're merely guessing, nothing else.

I actually wonder what is so hard to understand about that issue.

It's as simle as that:

X and X: wingload will work.
X and Y: more factors are needed.

BillSwagger
01-12-2010, 10:10 AM
Originally posted by Bremspropeller:

X and Y: more factors are needed.

Which other factors?

stall speed?

what else.


Bill

JtD
01-12-2010, 10:34 AM
Originally posted by Bremspropeller:

And tell me how your chart of similar 109s with different wingloadings has any signifigance on comparing different aircraft with different Ca/ Alpha curves.

There is no significance to that. What the point in asking silly rhetorical questions? Do you think your remarks look better that way?


you can't tell different performance apart by only looking onto that single factor, when comparing x to y.

No, it's all about an estimate. If you don't know the meaning of an estimate, go look it up. Wing loading is a very significant parameter and very easily available. I'd probably need less than an hour to look it up for the 100 most important types used in WW2. If I based a minimum turn radius chart on that, I'd be 80+ % right. In the meantime, you won't be able to finish even ONE airfoil based calculation that allows to exactly determine the minimum turning circles.


If you won't compensate for different Ca/ AoA curves and diferent excess-power, you're merely guessing, nothing else.

Feel free, go do it, 100 planes, you've got an hour. To save you some trouble, excess power has nothing to do with the minimum turn radius.

As for guessing, no, I'm still estimating. You really should look that up. http://forums.ubi.com/groupee_common/emoticons/icon_rolleyes.gif

JtD
01-12-2010, 10:48 AM
Originally posted by BillSwagger:
Which other factors?

stall speed?

what else.

Stall speed would eventually be a result of the factors he's thinking of.
Wings produce lift, and if you want to scientifically calculate the lift it produces, you'll need to start with the profiles of the airfoils used in the wing, determine the max lift factor they have based one fluid dynamics. Multiply the max lift factors with the corresponding wing areas, and you'll get a first guess on the wings lifting capability. Leaving aside some special low speed lift devices like leading edge slats or flaps, you'd still have to deal with lots of actual aircraft construction details to eventually get the lift right, say wing twist, disturbed airflow due to guns, coolers and what not else, there's a **** load of that.

You'll then get a certain lift factor, which you can use to calculate the actual lift by multiplying it with v². The speed at which the lift equals the weight of the plane is the stall speed.
In other words, instead of spending lots of money on good software or lots of time into calculating your lift factor, you can simply measure the stall speed and determine the max lift factor from that.

As a minor factor, there's also the planes load limit, because the minimum turn radius of a plane happens at the max g stall speed when pulling max g. Though the increase towards slower speeds is marginal.

Bremspropeller
01-12-2010, 10:58 AM
excess power has nothing to do with the minimum turn radius.


Right, and minimum turn-radius is important for fighting in the first place. http://forums.ubi.com/groupee_common/emoticons/icon_rolleyes.gif


No, it's all about an estimate.

Well, if you're interested in estimates - I'm not.
Go on with your guesstimates, but don't pretend you can tell "a/c performance" with that.

na85
01-12-2010, 11:05 AM
Originally posted by Bremspropeller:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">excess power has nothing to do with the minimum turn radius.


Right, and minimum turn-radius is important for fighting in the first place. http://forums.ubi.com/groupee_common/emoticons/icon_rolleyes.gif


No, it's all about an estimate.

Well, if you're interested in estimates - I'm not.
Go on with your guesstimates, but don't pretend you can tell "a/c performance" with that. </div></BLOCKQUOTE>

You've been pwned pretty hard man, you might want to sit down. You complain about "overpaid engineers" but clearly you don't understand what engineers do.

The scientist asks: "How does it work?"

The engineer asks: "Does it work well enough to suit our purposes?"

JtD
01-12-2010, 11:06 AM
Originally posted by Bremspropeller:

Right, and minimum turn-radius is important for fighting in the first place. http://forums.ubi.com/groupee_common/emoticons/icon_rolleyes.gif

Yeah, like I said, you don't even bother to read and process what others write but think you need to tell them they are wrong.


Well, if you're interested in estimates - I'm not.
Go on with your guesstimates, but don't pretend you can tell "a/c performance" with that.

Yeah, there's another two points you missed.

DuckyFluff
01-12-2010, 12:39 PM
What is a FW 190 G3 please??

I may have missed something but I don't recall a version of the 190 Anton G3.

JtD
01-12-2010, 01:09 PM
The Fw 190G was a long range fighter bomber variant of the Fw 190. The G-1 and G-2 were conversions from the A-4 and A-5 respectively, while the G-3 was technically related to the A-6 but built as G-3 right away.
The main differences between the G and A series are the removal of guns, the G did neither have the outer wing guns nor the cowling machine guns, the addition of bomb racks and the usage of drop tanks.
In game we have the A-4/U-8 and A-5/U-8 which are basically early designations for G-1 and G-2.

Bremspropeller
01-12-2010, 01:40 PM
You complain about "overpaid engineers" but clearly you don't understand what engineers do.

The scientist asks: "How does it work?"

The engineer asks: "Does it work well enough to suit our purposes?"

I know how engineers design airplnes.
They don't estimate http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

Squeezing 5% more efficiency out of an airframe or engine IS going back to "how does it work".
Others may do the research for you, but in the long run, new technology isn't made by assuming stuff - you have to integrate it and make it work.
That requires you to understand how it works.



Yeah, like I said, you don't even bother to read and process what others write but think you need to tell them they are wrong.

No, I just approach the problem differently.
You're putting up estimates and you think that a 80% hit-rate of your estimate is good.
Well, if you think that four out of five is a good ratio for "betting your life onto", fine.

I think a 20% ratio of being surprised because my initial guess was only a rough estimation ain't that good.

BTW: thanks at Tom for the example Yak vs Spit.


Accepting a "20%" error-margin for the sake of quickness over correctness...
Somebody's gonna cry a tear or two over that.



BTW: The 190G-3 has additional armor over the A.

JtD
01-12-2010, 01:58 PM
Originally posted by Bremspropeller:

You're putting up estimates and you think that a 80% hit-rate of your estimate is good.

No, I don't think this is particularly good, but I think it is a lot better than what you have provided so far. Which is ... nothing. So your chances are 50/50, I'd therefore go for my 80+ % and be a lot better off. That's how estimates work. If you don't get it, I can't help it.

na85
01-12-2010, 02:21 PM
Originally posted by Bremspropeller:

I know how engineers design airplnes.
They don't estimate http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

Nor do they push for ten significant digits when two will do.

If you catch my drift.

DuckyFluff
01-12-2010, 02:22 PM
Originally posted by JtD:
The Fw 190G was a long range fighter bomber variant of the Fw 190. The G-1 and G-2 were conversions from the A-4 and A-5 respectively, while the G-3 was technically related to the A-6 but built as G-3 right away.
The main differences between the G and A series are the removal of guns, the G did neither have the outer wing guns nor the cowling machine guns, the addition of bomb racks and the usage of drop tanks.
In game we have the A-4/U-8 and A-5/U-8 which are basically early designations for G-1 and G-2.

So these figures are for a captured low level Jabo ground attack aircraft which was not really expected to go air -to-air?? (most guns removed)and for which getting the engine to run properly was a problem.?

So a captured low-level ground attack aircraft with a dodgy engine, which was de-tuned for Jabo duties, was tested against hi alt pure fighters.........that works.

Ever hear the phrase apples and oranges?

So all this BS that has proceeded is POINTLESS?

M_Gunz
01-12-2010, 02:30 PM
Even the shape of the wings makes a very real difference. Stick with the stall speed, it is at least
the result of many factors.

Excess power may not reduce your minimum turn radius but it sure helps with sustainable turn rate!
Few if any of these planes can sustain 4G's and some not much over 3G's, that's just the fighters
and more power can get the same airframe able to hold higher G's at a wider radius while still
bringing the nose around faster. I can skid around a very small circle at less than 2G's but it
takes a lot longer than I can turn clean at 3G's.

Being able to pull more AOA with higher wingloading and enough power can give a tighter circle but
the power requirement becomes extremely steep. Compare wingloading between a Spitfire and Bf109
from the BoB and you know that wingloading alone would have the 109 in much worse position than
it really was, than a comparison of stall speeds will show. That alone should tell that Brems is
not talking out of his butt even if you don't take his points.

na85
01-12-2010, 02:34 PM
Originally posted by M_Gunz:
Even the shape of the wings makes a very real difference. Stick with the stall speed, it is at least
the result of many factors.

Excess power may not reduce your minimum turn radius but it sure helps with sustainable turn rate!
Few if any of these planes can sustain 4G's and some not much over 3G's, that's just the fighters
and more power can get the same airframe able to hold higher G's at a wider radius while still
bringing the nose around faster. I can skid around a very small circle at less than 2G's but it
takes a lot longer than I can turn clean at 3G's.

Being able to pull more AOA with higher wingloading and enough power can give a tighter circle but
the power requirement becomes extremely steep. Compare wingloading between a Spitfire and Bf109
from the BoB and you know that wingloading alone would have the 109 in much worse position than
it really was, than a comparison of stall speeds will show. That alone should tell that Brems is
not talking out of his butt even if you don't take his points.

Depends on what you're trying to compare. I was under the impression we were comparing turn radii.

BillSwagger
01-12-2010, 03:08 PM
Originally posted by DuckyFluff:
So a captured low-level ground attack aircraft with a dodgy engine, which was de-tuned for Jabo duties, was tested against hi alt pure fighters

The performance of the G-3 seems to be better than that of the A-5, probably because it was trimmed for weight to allow for bombs and to give it better range, but the engine was tuned for better low altitude performance. That does it make it a dodgy engine.

The test i was referring to was that of a G-3 that was reported to be in great condition. The other one tested in the UK involved rigging it with ballast to indicate the same approximate weight of an A-5. (by the way "Anton" refers to the A. You don't call it an Anton G-3.) I'm not sure where this presumption of a "dodgy engine" comes from. That's news to me, and not in the article i posted. Did you read the article posted?

The test in late '43 im referring to was done in Italy, and compared it to that of P-47D-4.

When people say the engine was tuned down in these tests its because the USAAF admits to not pushing the aircraft too hard to help preserve the captured plane and its parts. What i would like to know is what the proper settings are for the G-3.
The test indicated it was run at 2700rpm and 42" hg. was it capable of more and how much?
So far i haven't been able to find much on the G-3, but pay particular attention to the hg and rpms and it should tell you if the plane was run at max power or not.



Bill

K_Freddie
01-12-2010, 03:20 PM
As a side note,
Somewhere during WW2 there is mention of a 'friendly' DF match between a ME109 and a FW190 - the FW190 won !! Both pilots were considered experten.
http://forums.ubi.com/groupee_common/emoticons/icon_cool.gif

M_Gunz
01-12-2010, 03:26 PM
Originally posted by na85:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by M_Gunz:
Even the shape of the wings makes a very real difference. Stick with the stall speed, it is at least
the result of many factors.

Excess power may not reduce your minimum turn radius but it sure helps with sustainable turn rate!
Few if any of these planes can sustain 4G's and some not much over 3G's, that's just the fighters
and more power can get the same airframe able to hold higher G's at a wider radius while still
bringing the nose around faster. I can skid around a very small circle at less than 2G's but it
takes a lot longer than I can turn clean at 3G's.

Being able to pull more AOA with higher wingloading and enough power can give a tighter circle but
the power requirement becomes extremely steep. Compare wingloading between a Spitfire and Bf109
from the BoB and you know that wingloading alone would have the 109 in much worse position than
it really was, than a comparison of stall speeds will show. That alone should tell that Brems is
not talking out of his butt even if you don't take his points.

Depends on what you're trying to compare. I was under the impression we were comparing turn radii. </div></BLOCKQUOTE>

Thought I did address that, see the part in bold-text above. I was under the impression we were discussing
combat conditions as well in which sacrificing turn rate and your speed for radius is a poor bargain at best.

yuuppers
01-12-2010, 04:42 PM
42" Hg is just slightly more than 1.45, so the engine was over boosted, unless the engine was cleared for 1.65.

2700rpm is the top speed for the BMW801.

Bremspropeller
01-12-2010, 05:40 PM
No, I don't think this is particularly good, but I think it is a lot better than what you have provided so far.

I'm not here to "provide" anything.

JtD
01-12-2010, 11:10 PM
Just a little reminder to all:

An unsustained, horizontal minimum radius turn is also the peak turn rate turn. You're flying at your load limit stall speed, doesn't get better than this.

Sustained turn is different.
---
The Fw 190A and G were both driven by the same BMW801D-2 engine.

Gaston444
01-13-2010, 12:53 AM
Funny that the US test continually referred to is never linked:

http://img105.imageshack.us/img105/3950/pag20pl.jpg

I never include the other page since it is of less interest to our issues.

This test absolutely backs-up the Soviet evaluation of the FW-190A as low-speed turn fighter with very poor high-speed handling. Note also the "tendency to black-out the pilot", which is an obvious reference to the same Soviet observation in different words: "will "hang" on pull-out, and fall an EXTRA 220 m AFTER pulling out... That is obviously a "tendency to black-out the pilot" by nose-up deceleration, since the BETTER P-47 pull-out did NOT warrant the same accolade...

Now, stop everything, and try to explain this to me ANY other way: How can a MUCH BETTER pull-out by a P-47 be contrasted to a MUCH worse pull-out by a FW-190A, and the FW-190A STILL getting panned for "a tendency to black out the pilot" ?????????????????????????????????????????????????? ????????????????????????????????????????????


As for the RAE saying the Me-109G is drastically out-turned by a FW-190A, P.102 of "Le Fana de l'aviation, Hors-serie #38. Avions de chasses, Quel etait le meilleur?". They add the P-51 vastly out-turns the Me-109G with two full underwing tanks installed! But NOT the FW-190A, even if the P-51B is without tanks!

This is of course test pilot garbage: I do however buy that the P-51B is little affected in turns by the full drop tanks, but severely affected in the climb: I have long recognized prop-tracted performance in turns or in climbs as having little relationship, unlike in computer games... But more on this later...

The Me-109G was roughly equal or better in sustained turns to a downthrottled P-51D flaps up, and may have been slightly inferior only if the P-51's flaps were down, at a high prop pitch, and FURTHER downthrottling made by the P-51 in a level turn... (Downward/upward spirals of course throw a wrench in sustained turn performance comparisons)

People wonder how a 120 MPH stall FW-190A can out-turn a 100 MPH stall Me-109G: The reason is simple but counter-intuitive: Fighting in a prop fighter required consecutive 360° turns because gun firepower was often too weak for a short firing pass, so you had to pepper the target at least a little while to get an effect. 360° turns will quickly get you into lower speeds, which is why "out-turn" is so maddeningly referred to in those days without speed, because maximum-rate 360°s would get you fast to sustained low-speed turns anyway, unless coming out of a really huge dive...

Enter dowthrottling: Fighter pilots found out that sustaining turns at full power, was in many TRACTED prop aircrafts, a good way to get out-turned and shot down by a downthrottled slowpoke, and not just above 250-300 MPH...

This is because, at low speeds, the straight nose of a fighter tends to immediately pull you OUT of the turn if you add power, much faster than any resulting increase in speed. The same thing works the other way: Downthrottling immediately TIGHTENS the turn, much better than any drop in speed would justify... When you think about it, the nose always points OUT of the turn, and so, depending on type/speed, adding power there is BAD for turn radius AND rate...

I know this is a rather paradigm-changing consideration, but it explains why jet-age based theories correlate so poorly with WWII reality... Traction vs propulsion: Emphatically NOT the same thing in flight...

I think features of the center of gravity, wing shape, nose angle and especially THE SHORTER NOSE would allow the FW-190A to out-turn the Me-109G by letting the Anton lay down more power without being "pulled out" by the power...

Note that according to Karhila, the best sustained turn speed for the Me-109G-6 was.... 250 km/h! That's 160-170 MPH folks... Not quite kosher with the 260 MPH+ doghouse graphs now is it?:

http://www.virtualpilots.fi/fe...icles/109myths/#g6r6 (http://www.virtualpilots.fi/feature/articles/109myths/#g6r6)

And this revealing P-51 account, which pretty much says a lot...:

http://www.spitfireperformance...hanseman-24may44.jpg (http://www.spitfireperformance.com/mustang/combat-reports/339-hanseman-24may44.jpg)

It should be noted test pilots seemed not to have been aware of this, and may have always made turns at FULL power, which is why so much of actual test data seems like so much garbage. I mean, a flaps up Merlin P-51 massively out-turning a clean P-47D? Really? A P-51B with FULL drop tanks MASSIVELY out-turning a clean Me-109G-6? Really?

Note on the other hand, how beautiful is the agreement between Russian fighter pilot recommendations and the US test made in Italy by FRONT-LINE US fighter pilots... I'm happy to hear this particular FW-190G was "in unusually good condition for a captured aircraft"...

The FW-190A's short nose may have been a lot more tolerant of this full power in turns nonsense than the Me-109G, but it also benefitted from downthrottling, as an ace described doing in an A-8 PRIOR to the merge with P-51Ds... He gained on the deck from a TAILING P-51D and shot it down at very low speeds after 2-3 360°s...

EVERY modification or tactic this Western ace used on his 190A-8 was geared exclusively towards low speed turn performance: long chord ailerons, extended futher by field-made hinge spacers, all of which worsened the high-speed roll rate, broad wood prop, downthrottling etc...

And then add to the picture that out of the ENTIRE War only one quote has surfaced that the Me-109G out-turns the Anton, a Rechlin test pilot quote from a La-5 test, AND the Me-109G had MW-50, a boon perhaps to test pilot methods... Plus some dubious Russian turn times not correlated to a test date or airframe, or that may have been at full power...

Feel free to believe what you want, but I'll go with the people whose accounts agree rather beautifully with each other, and that's the fighter pilots, not the test pilots...

Gaston

TheGrunch
01-13-2010, 03:18 AM
Originally posted by Gaston444:
This is because, at low speeds, the straight nose of a fighter tends to immediately pull you OUT of the turn if you add power, much faster than any resulting increase in speed. The same thing works the other way: Downthrottling immediately TIGHTENS the turn, much better than any drop in speed would justify... When you think about it, the nose always points OUT of the turn, and so, depending on type/speed, adding power there is BAD for turn radius AND rate...
We've been through AAALL this before, Gaston. Yaaawnn. You don't read anything that people reply with anyway. Or at least you don't take it in. But this particular speck of ignorance requires an answer. How is it that a jet engine in the rear of an aircraft doesn't PUSH it out of a turn? All that matters in terms of thrust is the magnitude and the direction. A jet engine pushes the aircraft forward, a TRACTOR prop pulls the aircraft forward, although obviously the prop aircraft is affected by torque and p-factor. The difference in terms of calculating engine thrust vs. sustained turn performance for a jet compared with a prop aircraft comes from those factors, not some magical semantic difference you've invented in your mind.
I still don't understand what you're trying to say in terms of the aircraft being "pulled out of the turn" that doesn't affect jets equally. Because guess what, if you're talking about the angle of the nose relative to the aircraft's flightpath, it DOESN'T point out of the turn. It points into the turn. This is called Angle of Attack, genius.

myrrhcedar
01-13-2010, 03:40 AM
the 190 would be my favorite plane to fly in 1946, especially the d-9...

...if i could see anything, that engine just makes visibility too bad. the 109 is half the plane but the fact that I can see where I'm going means I get twice as many kills with it.

Gaston444
01-13-2010, 04:34 AM
But this particular speck of ignorance requires an answer. How is it that a jet engine in the rear of an aircraft doesn't PUSH it out of a turn?


Because the wing's center of lift is AHEAD of the thrust point on a jet, while on the single-engine prop-tracted fighter aircraft it is BEHIND by a considerable distance: The wing's center of lift has to fight the entire lenght of the nose to lift the propeller-driven nose that wants to go straight from the thrust: Jet thrust does push on the wing's center of lift, but that wing's center of lift this time has the leverage by being ahead of the thrust and closer to the (much lighter, in both in relative weight and thrust) nose you want to lift... The leverage on the nose is positive for the wing lift in the case of a jet.

On the prop aircraft it is the thrust that is closer to the nose, so it has more say on where that nose wants to go... It has a lever AGAINST the wing's center of lift...

Pick up a hammer by the head it will feel lighter: It's easier to to tell a mass where you want it to go by grabbing it directly than to pick it up by the end of a long arm...

Then there is the additional difference that the propeller disc has a broader surface of contact to resist being twisted out of its path.

Gaston

JtD
01-13-2010, 08:44 AM
Still to be provided by Gaston444 with name of the source (6th enquiry):
Clean power off stall speed for 109G:
Clean power off stall speed for 190A:

You prop pull theories really made me laugh again, thanks for posting! I'll explain what's so funny as soon as you answer the above enquiry.

M_Gunz
01-13-2010, 10:01 AM
Oooooooh, look at -all- the fishies! But only... suckers!

TheGrunch
01-13-2010, 10:20 AM
Originally posted by Gaston444:
Pick up a hammer by the head it will feel lighter: It's easier to to tell a mass where you want it to go by grabbing it directly than to pick it up by the end of a long arm...

Wow, so the fact that the thrust originates from behind instead of in front of the centre of gravity and centre of lift makes all the difference, eh?
I bet no scientists ever thought of that when they weren't making all those pusher prop aircraft that they never made.

Gaston444
01-13-2010, 12:25 PM
-The advantage of a heavy nose producing power is stability. Hence the instability of many tail-heavy pusher prop designs.

The stall/spin characteristics were a critical issue, and pusher prop fighters were likely problematic to spin and recover...

Also, with the technology of the times, high power pushing engines, with a fuselage shielding them from the windstream, overheated. On the Do-335 the problem was never solved.

Note pilots were apparently stunned by the Do-335's handling...

They tried hard...

Gaston

Gaston444
01-13-2010, 12:33 PM
Quote, JTD: "Still to be provided by Gaston444 with name of the source (6th enquiry):
Clean power off stall speed for 109G:
Clean power off stall speed for 190A:

You prop pull theories really made me laugh again, thanks for posting! I'll explain what's so funny as soon as you answer the above enquiry."

-I just did three posts ago, but obviously this is far beyond your reading skills. You just proved you don't read my posts, so I would invite you to stop cluttering my thread... Thank you.

Gaston

JtD
01-13-2010, 12:36 PM
No, you just wrote down two numbers. No source. So for all I know, you could have rolled that on a dice.

I admit you got the trend right, compliments for that. You could start thinking about how well a Fw 190 and Bf 190 would turn at 120mph, if your numbers were right. But that would be pushing it.

AndyJWest
01-13-2010, 12:53 PM
-The advantage of a heavy nose producing power is stability. Hence the instability of many tail-heavy pusher prop designs.

Can you provide any source to back up your assertion that 'producing power' in the nose improves stability, as opposed to getting the CG correct, which is essential in any aircraft?

BillSwagger
01-13-2010, 01:14 PM
Gaston,
I think you need to realize that different turn advantages occur at different speeds depending on the planes.

Much of what you describe about throttle down turning makes some sense to me, and it is something i've questioned before.
You also have to recognize that "hanging on the prop" in such turns involves the use of more power/throttle, so perhaps it is the degree of the turn, and timing at which throttle use is important to effective turning.

I might also point out the tests i've referred to both say that the 190 didn't respond well in lower radius, lower speed turns.


http://www.wwiiaircraftperform...rg/fw190/eb-104.html (http://www.wwiiaircraftperformance.org/fw190/eb-104.html)

"H. Maneuverability and Aerobatics

The outstanding maneuverability feature of this airplane is it extremely high rate of roll. The radius of turn, however, is poor and it is only slightly improved by using the maneuvering flap position of 15 degrees. If pulled fast, the airplane tends to stall out abruptly with little warning. Elevator control forces are very heavy in a tight turn, requiring constant use of the elevator trim control."

http://www.wwiiaircraftperform...g/fw190/ptr-1107.pdf (http://www.wwiiaircraftperformance.org/fw190/ptr-1107.pdf)
In the other test, its reported the FW190 could not match the maneuvers of the F4U with out dropping a wing.
I wouldn't consider the F4U a low speed turn fighter.

I still don't agree with your view about the 190 being a better low speed turn fighter than a 109. Your pilots accounts need a reference to speed, because i'm certain that at different speeds, the 190 might be better in a turn, however the 109 is still going to be better in turn radius. You made a reference to the 109s best turn speed, and that no doubt is going to be a tighter sustained turn than what the FW190 could match.


Bill

Gaston444
01-13-2010, 01:25 PM
Ever heard of the advantages of front-wheel drive versus rear-wheel drive? Yes there is "torque steer" in some car models, but basically it helps stability to be pulled rather than pushed...

It's the same thing here. Also, front-wheel drive cars tend to "understeer" versus rear wheel-drive cars tending to "oversteer". In this case however, the power on the front taxes the available traction, but the result has some resemblance even if the mechanism is very different.

Basically, in flight, the lenght of the rear leverage, from the elevators forward to the center of lift, is fighting the lenght of the leverage of the pull of the powered nose back to the same center of lift.

Hence reducing the nose power tilts the balance of the two leverages towards the elevator action...

It goes without saying that this patently obvious issue does not exist for jet propelled aircrafts, and is thus totally ignored in post-war formulas...

This explains some of the radical disparities WWII combat pilot accounts have with test pilot accounts and much of the theorizng since...

Gaston

Gaston444
01-13-2010, 01:41 PM
Sorry Bill, I missed your post as we posted at the same time.

The Navy test you mention has a phrase in it that is retrospectively illuminating as to the differences between test pilot and combat pilot procedures: Rough quote: "Throttle action in the Navy aircrafts required more steps to change throttle settings, but this has little effect in combat as all the controls are kept at full power during combat"

So this could illustrate some of the test procedural problems...

Note I agree with you the Me-109G probably has a tighter turning radius when dowthrottled as low as 250 KM/H, but it is likely the FW-190A has a similar or better turn RATE by maintaining a higher speed, say 300 km/h, in a wider radius.

It would be a "cold lag" chase, but in general pilots found the FW-190A superior in the general area below 400 km/h, or 250 MPH. What goes on precisely within that with both pilots downthrottling is hard to say...

Note "hard elevators" seem to indicate higher speeds...

Gaston

AndyJWest
01-13-2010, 02:04 PM
Gaston, I asked for <span class="ev_code_RED">a source</span> to back your assertions, not irrelevant waffle about front-wheel drive.

Have you actually studied physics?

BillSwagger
01-13-2010, 02:49 PM
Originally posted by Gaston444:
FW-190A has a similar or better turn RATE by maintaining a higher speed, say 300 km/h, in a wider radius.



This is in line more with my thinking, which is where radius and rate are much different in terms of speed.

I think as the war the advanced the ability for a plane to maintain speed through turn maneuvers was better than making the tightest turn. Making tighter turns presumes the loss of speed, or lower speed handling characteristics which are more indicative of the 109 airframe. There aren't any ww2 fighters that can make a sustained 6 g turn with out bleeding speed, save a change in altitude ie diving as they turn. Its the bleeding of speed that enables the tighter turn, until load factors become an issue and the wing can no longer turn at those Gs and the speed in the turn.

For this reason, throttling down will enable to the plane to bleed speed faster than having the throttle forward through the turn. I don't need to find a reference as i think most of us would agree to this. However, in a sustained turn, the lack of throttle may cause the plane to bleed too much speed, in which case the plane can no longer sustain the airspeed nessecary to hold a stable turn.

I don't think its an on and off tactic, but an experienced pilot will know when to throttle down, and when to push forward to gain the most out of the planes turning ability.
The kicker is, no matter how much of expert or which tactics are used, a 109 is the lighter of the two planes and offers lighter wing load. I just don't think the 190 would be able to sustain any tighter turn radius with a 109 no matter how much engine on or off the pilot does.



Bill

Viper2005_
01-13-2010, 03:14 PM
Originally posted by yuuppers:
42" Hg is just slightly more than 1.45, so the engine was over boosted, unless the engine was cleared for 1.65.

2700rpm is the top speed for the BMW801.

taking 1 ata = 29.92"Hg, 1.42 ata = 42.4864"Hg.

You seem to have assumed that 1 ata = 1 bar. I don't think that this is correct, because if the Germans had wanted to measure their manifold pressure in Bar, they could have done so easily, as the Bar predates WWII considerably. It's not as though it would have taken up more space on the instrument...

Xiolablu3
01-13-2010, 03:18 PM
Wing loading is a good general pointer for a planes sustained turn performance.

of course you have to factor in if the plane has high lift devices or not which help it maintain control near the stall.

Stall speed is also a good indicator of low pspeed turn performance. The airplane wich remains responsive at the lower speed will generally have an advantage in low speed turning circles.

This is why JTD is asking Gaston for the stall speed of each aircraft, as these figures speak volumes.

Gaston, I assume you are Josf registered? If so, hi there.

na85
01-13-2010, 04:17 PM
Gaston doesn't seem like Josf to me. For one, Josf knew how to use the quote functionality, a skill that seems to elude Gaston.

yuuppers
01-13-2010, 04:34 PM
Originally posted by Viper2005_:
taking 1 ata = 29.92"Hg, 1.42 ata = 42.4864"Hg.

You seem to have assumed that 1 ata = 1 bar. I don't think that this is correct, because if the Germans had wanted to measure their manifold pressure in Bar, they could have done so easily, as the Bar predates WWII considerably. It's not as though it would have taken up more space on the instrument...

http://img.villagephotos.com/p/2005-12/1114844/Boost.jpg

BillSwagger
01-13-2010, 05:01 PM
this table looks off, Yuppers.


I will say that 1.00 ata is suppose to be equal to one pressure of atmosphere, and on the US chart that looks to be under 29". Under 29" barometric pressure is usually indicates a rainy day, or even a storm.

Its quite possible this chart is off as much as 1" if on a clear day, the barometric pressure is closer to 30 inches. You might notice that the Japanese and British both call this measurement "0".

I've checked other converters and 42 inches HG = 1.404 ata, but maybe the Germans compensated for some other factor.

yuuppers
01-13-2010, 05:16 PM
1 at<span class="ev_code_RED">m</span> = 29.92" HG

1 at<span class="ev_code_RED">a</span> = 28.96" HG

BillSwagger
01-13-2010, 05:27 PM
Originally posted by yuuppers:
1 at<span class="ev_code_RED">m</span> = 29.92" HG

1 at<span class="ev_code_RED">a</span> = 28.96" HG

that explains it, so what does "ata" stand for?

yuuppers
01-13-2010, 05:40 PM
Originally posted by BillSwagger:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by yuuppers:
1 at<span class="ev_code_RED">m</span> = 29.92" HG

1 at<span class="ev_code_RED">a</span> = 28.96" HG

that explains it, so what does "ata" stand for? </div></BLOCKQUOTE>
ata = atmosphere absolute

BillSwagger
01-13-2010, 06:15 PM
how is that different than Barometric absolute = 29.92"

I actually think that the ata as the Germans used it, factors in altitude or a pressure reading other than at sea level. For example it might be a pressure reading on the ground somewhere in Germany, as oppose to sea level.

For all tense and purposes, ATA, from what i've read is used in scuba gear to factor in additional weight of the air on top of the pressure of the depth of water.

Viper2005_
01-13-2010, 07:30 PM
I just found this:

http://de.wikipedia.org/wiki/T...sche_Atmosph%C3%A4re (http://de.wikipedia.org/wiki/Technische_Atmosph%C3%A4re)

It's certainly not the first time I've been wrong, and it probably shan't be the last...

*edit* It seems quite possible that the guys testing at 42" Hg made the same mistake as me (this assumes that they fitted an American manifold pressure gauge).

Thanks yuuppers. I learned something today. http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

M_Gunz
01-13-2010, 08:53 PM
From a completely different forum:

for further identification [at] can be extended as [ata] Technische Absolut Atmosphäre or [atü] Technische Überdruck Atmosphäre.

Perhaps a German-speaker can add something to this?

Gaston444
01-13-2010, 09:00 PM
Quote, BillSwagger: "You also have to recognize that "hanging on the prop" in such turns involves the use of more power/throttle, so perhaps it is the degree of the turn, and timing at which throttle use is important to effective turning."

-This is exactly what I used to think, but now I think the downthrottling is a more "stable" tactic, as only the FW-190A had a simple enough "brainbox" to throttle up and down continuously during a turn.

Most WWII fighters were not so flexible, and "hanging on the prop" refers to the adjustment to not LOSE speed rather than any action to increase it. Once all the actions were done to downthrottle to the best sustained turn rate speed (around or below 190-200 MPH for a flaps-down Merlin P-51), it was better to optimize for the maintaining of that lower speed despite the tightest possible sustained turn, rather than try for any speed increase while turning.

What "hanging on the prop" looked like, from the ground, was a prop that went from being invisible to more visible as the pilot downthrottled, and his aircraft slowed down. Then, to retain this lower speed, despite the increased tightening of his turn, he increased the prop pitch to get more "bite" per revolution, and this loaded the downthrottled engine further, slowing down the prop even more while THE AIRCRAFT MAINTAINED SPEED, giving the visual impression that the now slowly-revolving prop took on the "weight" of the tightened turn, which actually occurred through the action of increasing the prop pitch. This is what "Hanging on the prop" was like: An impression of "weight" slowing a prop...

If you look at this sustained level turning combat in detail, you will see that downthrottling was NOT followed by occasionally throttling up, but was instead followed by FURTHER downthrottling to gain in turn rate, after he noted that his initial, more timid, downthrottling had succeeded in getting the Me-109G-6 to "stop cutting me off". It is likely that if the Me-109G-6 had himself downthrottled to his best sustained turn rate of 160-170 MPH, as Finnish ace Karhila claims, then the P-51D would likely have had to remain at 190-200 MPH, perhaps with a stalemate occurring, with the P-51D cutting a wider circle at higher speed but not with a faster turn rate. (15 minutes single turn contests were frequent!)


http://www.spitfireperformance...hanseman-24may44.jpg (http://www.spitfireperformance.com/mustang/combat-reports/339-hanseman-24may44.jpg)

They were very close, but at these low power levels the P-51D seems here better than the Me-109G-6, which likely did not downthrottle. Compare with this other combat account, which in a more complete version explains that the P-51 did not go under 300 km/h(200 MPH)while sustaining the level turn. "I had trouble getting deflection, despite my smaller turn radius, because he was going at 300 km/h (probably to his 250-260 km/h peak). Then he made a mistake and his airplane warned, forcing him to loosen his turn and giving me the deflection I needed":

http://www.virtualpilots.fi/fe...icles/109myths/#g6r6 (http://www.virtualpilots.fi/feature/articles/109myths/#g6r6)

The FW-190A was unique in that the "brainbox" could "dip" power rapidly and then add it, and its powerful ailerons could mitigate the stall. I think from reading hundreds of combat encounters that the FW-190A's peak sustained turning rate had a turning radius smaller than a Merlin P-51D but larger than a Me-109G-6 going at 170 MPH, but that the speed it could sustain in that radius was sufficiently higher that it significantly out-turned either, albeit from the outside position on the Me-109G ("cold lag").

Note that, unlike the P-51D, the FW-190A remained competitive in sustained turns all the way to 250 MPH, but after that the P-51D was far superior in unsustained high-speed turns, forcing aileron reversals on the lumbering Anton, as did the P-47D. I'm pretty sure the Me-109G remained slightly better in turns than the Merling Mustang a bit further out than the FW-190A, about 300 MPH without gondolas, and even regained some slight superiority with a tail-heavy trim in dives past 400 MPH.

The idea that the FW-190A had great high-speed handling, aside roll rate, is just bizarre... It is true the earlier short-nosed FW-190A-3/4s were said by Rechlin to "out-turn the Me-109 at ANY speed": See Video... It is very possible the 6" shorter-nosed Antons were better turning at high speeds than the 109, but I doubt the later ones were...

In any case, the linked "Hanseman" combat shows the downthrottling was not a "short-term" temporary tactic, but was indeed aiming towards the peak available sustained turn rate...

The "always full power in combat" comments from the Navy FW-190A test speaks volumes as to the irreconciliable disparities between tests and combat accounts...

Gaston

P.S. No I am not Josf.

G.

AndyJWest
01-13-2010, 09:12 PM
What "hanging on the prop" looked like, from the ground, was a prop that went from being invisible to more visible as the pilot downthrottled, and his aircraft slowed down. Then, to retain this lower speed, despite the increased tightening of his turn, he increased the prop pitch to get more "bite" per revolution, and this loaded the downthrottled engine further, slowing down the prop even more while THE AIRCRAFT MAINTAINED SPEED, giving the visual impression that the now slowly-revolving prop took on the "weight" of the tightened turn, which actually occurred through the action of increasing the prop pitch. This is what "Hanging on the prop" was like: An impression of "weight" slowing a prop...

If you increase the prop pitch as you slow down, you risk stalling the prop. Like an aircraft wing, there is an optimum angle of attack for a prop blade. Not that this matters in the slightest, as I don't suppose you will offer any more evidence to back this statement up than you have for your previous ones.

Have you ever studied physics?

yuuppers
01-13-2010, 09:34 PM
Originally posted by Viper2005_:
Thanks yuuppers. I learned something today. http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif
Your welcome.

What the chart shows quite well is how low the boost was for German engines, but then they did run them at a higher CR.

R_Target
01-13-2010, 10:34 PM
Originally posted by Gaston444:
The Navy test you mention has a phrase in it that is retrospectively illuminating as to the differences between test pilot and combat pilot procedures

The lead project pilot on this test, Fitzhugh Palmer, was a veteran combat pilot before moving to USN TacTest.


Rough quote: "Throttle action in the Navy aircrafts required more steps to change throttle settings, but this has little effect in combat as all the controls are kept at full power during combat"

Which page and paragraph would that be on?

JtD
01-13-2010, 10:55 PM
Originally posted by M_Gunz:
From a completely different forum:

for further identification [at] can be extended as [ata] Technische Absolut Atmosphäre or [atü] Technische Überdruck Atmosphäre.

Perhaps a German-speaker can add something to this?

ata = absolute pressure
atü = overpressure = ata - 1

BillSwagger
01-13-2010, 11:05 PM
After reading about absolute pressure, it is considered to be 29.92", however ata on the chart appears to be 28.96" hg. I'm wondering why the difference here.

Wurkeri
01-14-2010, 04:08 AM
Originally posted by BillSwagger:
After reading about absolute pressure, it is considered to be 29.92", however ata on the chart appears to be 28.96" hg. I'm wondering why the difference here.

Easy, the tehcnical atmosphere is agreed to be:

1 kg/cm^2 = 9,80665 N/cm^2 => 1 ata = 28,96" Hg (32 F)

This is simply because 1 kg/cm^2 makes calculations simple.

While the standard atmosphere is agreed to be at sealevel:

1 atm = 10,1325 N/cm^2 = 1,0332 ata => 29,92" Hg (32 F)

And hence the difference:

1 atm = 29,92" Hg
1 ata = 28,96" Hg

Gaston444
01-14-2010, 11:28 AM
Quote, R_Target: "Which page and paragraph would that be on?"

-This is related to a Navy vs FW-190A test comment that stated that the FW-190A "brainbox" throttle was convenient but had modest effects on combat, since full power settings were usually kept "full forward" all the time during combat.

There are TWO Navy tests of the FW-190A: one of a Navy F6F-5 and F4U-1D against a FW-190A-5 equivalent, the other of the F6F-3 and the earlier F4U-1 against a FW-190A-4 (with almost identical conclusions). "Widewing" on Aces High knows where the earlier FW-190A-4 Navy test can be found.

This "rough" quote is from a US Navy test quote relating to the FW-190. I didn't make it up out of thin air you know...

Note it was also standard for Soviet doctrine to keep all settings "full forward" during combat...

Gaston

K_Freddie
01-14-2010, 12:01 PM
Originally posted by Gaston444:
This is related to a Navy vs FW-190A test comment that stated that the FW-190A "brainbox" throttle was convenient but had modest effects on combat, since full power settings were usually kept "full forward" all the time during combat.
I would imagine that this would speficially apply to the PTO (Navy F6F-5 and F4U-1D) as the allied a/c were mostly faster than the Japanese a/c, and this is the way they flew.

Further than that it doesn't make much sense to be limit oneself to this idea, as one can see.. little flaws in a/c analysis start appearing. http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

Gaston444
01-14-2010, 11:05 PM
True, but at the time I read it it did make sense to me: The only control that might have been mentioned as being touched would be the prop pitch during combat.

The Russian throttle doctrine was also supposedly of an "all forward all the time" type during combat, but the prop pitch control might also have been exempted from that. (It was from a British pilot quote to that effect, noting that their Hurricanes had trouble following Russian crews when trying to simulate escorting the Pe-2: "We later learned that it was SOP for the Russians to run all combat aircrafts exclusively at full power throughout the combat zone, from take-off to landing!"...)

Note Karhila does mention some Russians did sometimes cut their throttle in turns, but that he would cut his Me-109G throttle even further to gain gradually the advantage at around 250 km/h...

German tests of a captured La-5 noted that it required no less than 8 separate actions by the pilot to effect a throttle change, and yet they felt that this was only one disadvantage among others, and spent more time on the issue of aileron low-speed reversal in turns...

They did note the complicated La-5 throttle as a disadvantage, but not a show-stopper, and they still rated the La-5's acceleration as excellent below 10.000 ft., but rapidly worsening above...

The US Navy comment about "all forward all the time" being the US(Navy?)norm in combat was made in the context of evaluating the FW-190A's "brainbox" throttle, not in the context of Japanese aircrafts...

They also noted the lack of fine adjustments on the FW-190A's throttle made formation flying more difficult.

Since in most WWII fighter types there are several steps to change the throttle, I always assumed the US Navy's comment meant "full forward" was common practice in combat, and this was reinforced by the British pilot comments about the Russian combat doctrine.

These apparent disparities in procedure would go a long way to resolve test vs combat disparities in comparative sustained turn rates...

Gaston

ImpStarDuece
01-14-2010, 11:11 PM
Originally posted by Gaston444:

The Russian throttle doctrine was also supposedly of an "all forward all the time" type during combat, but the prop pitch control might also have been exempted from that. (It was from a British pilot quote to that effect, noting that their Hurricanes had trouble following Russian crews when trying to simulate escorting the Pe-2: "We later learned that it was SOP for the Russians to run all combat aircrafts exclusively at full power throughout the combat zone, from take-off to landing!"...)

Note Karhila does mention some Russians did sometimes cut their throttle in turns, but that he would cut his Me-109G throttle even further to gain gradually the advantage at around 250 km/h...



Cites please.

Website or book & page number will do.

ImpStarDuece
01-15-2010, 12:04 AM
I’ve collated the commentary from the BuAer test of an F4U-1 and F6F-3 against a FW 190A5/U5 (mislabelled in the test as a “FW 190 A/4”), with specific attention paid to manoeuvrability and engine operation:

Draw your own conclusions…





HORIZONTAL ACCELERATIONS:

“It should be noted that the application of full power in the FW-190 was much easier than in the either airplanes due to the fact that it was necessary to use only the throttle control”

TURNING CIRCLES:

Results of comparative tests of turning characteristics showed the F4U-1 and the F6F-3 to be far superior to the FW-190. Both the F6F and the F4U could follow the FW-190 in turn with ease at any speed, but the FW-190 could not follow either of the other two airplanes. The FW-190, when in a tight turn to the left and near the stalling sped, exhibits a tendency to reverse aileron control and stall without warning. Similarly, when turning to the right it tends to drop the right wing and nose, diving as a result.

From a head-on meeting with the FW-190 both the F4U-1 and the F6F-4 could be directly behind the FW-190 in one turn. From a position directly behind it was possible to turn inside the FW-190 and be directly behind it again in about three turns.

MANUVERABILITY:

The F4U-1 and the F6F-3 were found to be more manoeuvrable than the FW-190. No maneuvers could be done in the FW-190 which could not be followed by the F4U-1 and F6F-3.

It was found hat the FW-190 requires a much greater radius in which to loop than do either the F4U-1 or F6F-2, and tens to stall sharply when trying to follow the F4U-1 or F6F-2 in a loop.

Formation flying was extremely difficult with the FW-190 because of the lack of powerplant control.

GENERAL CHARACTERISTICS IN MOCK COMBAT

The FW-190 is a very simple aircraft to fly in combat and seems to be designed for pilot convenience. It has a no-warning stall which tends to reduce its efficiency in combat against aircraft which can fly at near the stalling speed. In general it is considered to be an excellent interceptor-type aircraft which is at a disadvantage against aircraft designed for the purposes of “in fighting”.

One throttle level controls propeller pitch, manifold pressure, mixture, magneto timing, and throttle setting, making operation comparatively simple.


GENERAL OPINION OF PILOTS AS TO RELATIVE MERITS…

…it is felt that although more automatic features are provided in the FW-190, less direct control over variable settings is provided and the pilots has, as a result, less actual control over the engine performance.

SUGGESTED TACTICS TO BE USED AGAINST THE FW-190…

If attacked by the FW-190, the F4U-1 and F6F-3 can evade by the use of tight turns. When followed by the FW-190 the F4U and F6F can evade by the use of tight loops. If the FW-190 attempts to follow the other airports in tight loops it stalls out.

In general, whenever the hit-and-run technique cannot be employed, the F4U and F6F should make every effort to close with the FW-190, in both offence and defence.



I’ve also added selected commentary on performance and handling characteristics from the AAF memorandum on the FW-190G-3 (the US captured 6 190G-3s, intact, in Italy in 1944):






Summary:

It [the FW-190] compares favorably with standard AAF fighter types in maneuverability, speed and climb at low and medium altitudes, but is definitely weaker in performance at altitudes over 28,000 ft. Stability was satisfactory at the weight and c.g. at which the airplane was tested and the controls are excellent at all speeds up to 400 MPH indicated airspeed where the elevator tends to become quite heavy and noticeable buffeting and vibration of the airplane occurs.


Flight Characteristics

A. Cockpit Layout


The engine control which automatically selects the correct propeller pitch and fuel mixture for any power setting is a desirable feature since the pilot need concern himself only with the throttle setting.

G. Stalls and Stall Warning

The airplane has a gentle stall and controls remain effective up to the stall. Adequate warning of the stall is given by shaking of the airplane and controls.


H. Maneuverability and Aerobatics

The outstanding maneuverability feature of this airplane is it extremely high rate of roll. The radius of turn, however, is poor and it is only slightly improved by using the maneuvering flap position of 15 degrees. If pulled fast, the airplane tends to stall out abruptly with little warning. Elevator control forces are very heavy in a tight turn, requiring constant use of the elevator trim control.

The airplane responds to the controls satisfactory in performing rolls, loops, Immelmanns and other aerobatics.

Conclusions

The FW-190, AAF No. EB-104, is a well armored fighter airplane with provisions for carrying heavy armament and it compares favorably with standard AAF types of the same date in maneuverability, speed, and climb at low and medium altitudes.

R_Target
01-15-2010, 12:52 AM
Originally posted by Gaston444:
Since in most WWII fighter types there are several steps to change the throttle, I always assumed the US Navy's comment meant "full forward" was common practice in combat

If there was a "USN common practice", it would be to use whatever throttle settings are necessary for what the pilot is trying to do. Lt. Buck Dungan was in a scrap over Orote, Guam, June 19, 1944:


"I pulled up into an extremely tight vertical turn and chopped my throttle to kill speed so I could get around quickly..."

If you could post or cite the actual document you're referring to, it might clear up some confusion.

AndyJWest
01-15-2010, 01:06 AM
If you could post or cite the actual document you're referring to...
He won't. Or if he does, it actually says something else entirely.

I don't think Gaston is the slightest bit interested in actual aircraft performance during WWII. He's just interested in 'proving' everyone else wrong.

He still hasn't told us how much physics he has actually studied. He seems to have some interesting theories, but I wouldn't want to attempt to fly in an aeroplane designed according to them.

Gaston444
01-16-2010, 04:13 AM
Of the citations asked, I can only post this one relating to the peak sustained turn rate of the Me-109G-6 being at around 160-170 MPH (250 km/h), and this with the necessity of the engine downthrottled (which proves in itself that the peak sustained turn rate CANNOT occur at full power...):

http://www.virtualpilots.fi/fe...icles/109myths/#g6r6 (http://www.virtualpilots.fi/feature/articles/109myths/#g6r6)

As to the British/Russian comments on the Russian throttle use being "full forward" in combat, this was far too long ago for me to remember, but the quote is very accurate...

Note that the comment in the US navy case was just that the FW-190A's "brainbox" throttle was not an overwhelming advantage in combat, and here in the test it was judged by US Navy pilots that they would prefer the "direct control over variable settings" rather than the "convenience" of automatic controls:
"…it is felt that although more automatic features are provided in the FW-190, less direct control over variable settings is provided and the pilot has, as a result, less actual control over the engine performance."

To me this could be read as: The convenience of being able to easily change the throttle in the heat of battle is less important than having fuel consumption/range/speed enhancing control during cruising, or for more consistent and tighter formation flying. These were the common big advantages of these clumsy manual controls over the FW190A "brainbox", advantages that were also attributed to the Me-109.

Remember that the FW-190A's "brainbox" changed prop pitch, fuel/air mixture and rpm all in one move, all of which was likely good enough for combat "performance" over a short time in a hectic battle... So the "performance" and "control" advantage here could very well be non-combat in nature where finer control was more important...

Note that absolutely nowhere in almost all these tests, from any nation, is there any mention of using lowered throttle settings to enhance turn performance: The only thing that ever gets mentioned in all these tests is the use of flaps...

In looking this up I came up on the Mike Williams site on this gem of a test: 23 August 1943:


http://www.wwiiaircraftperform.../f4u/f4u-1-02296.pdf (http://www.wwiiaircraftperformance.org/f4u/f4u-1-02296.pdf)

In it, finally(!) some sustained turn evaluations that make sense, unfortunately for the P-47C variant only:

F4U-1 vs p-51B: F4U has a better (sustained?)radius of level turn than the P-51B with or without flaps.

F4U-1 vs P-47C: F4U has a better (sustained?) radius of level turn than the P-47C AT BEST FLAP SETTINGS (for the F4U-1)...

F4U-1 vs P-38G: F4U and P-38G are similar in (sustained?)radius of level turn, with/without flaps. Slight edge to F4U-1...

Finally something that looks exactly like what I thought was the actual hierarchy from combat accounts...

Note ALL other US tests, and some UK ones as well, have the P-47D as INFERIOR to the P-51B in level turns...

It is true they are not defined here as "sustained"...


Quote, AndyJWest: "I don't think Gaston is the slightest bit interested in actual aircraft performance during WWII. He's just interested in 'proving' everyone else wrong."


-Here is the link to the thread I started here showing one Data Card from the boardgame variant I created (note what I can E-mail to you is much better than the irregularities seen here in the reds):


http://forums.ubi.com/eve/foru...011036708#9011036708 (http://forums.ubi.com/eve/forums/a/tpc/f/23110283/m/9011036708?r=9011036708#9011036708)



There are 8 color Data Cards in total plus two black-and-white ones, and all those 1/144 scale profile drawings in the upper right corner of the color Data Cards are made entirely by me(except the P-47) owing to the inaccuracy of suitable GA drawings...

There are 3 pages of rules, plus 3 pages of the rules "summarized" in plain-speak.

The data was gathered, and the files constantly changed, over the 14 year course of making this boardgame... Though the data of the cards is crude for speed and acceleration, what matters is the performance hierarchy relationship between aircrafts.

To achieve some resemblance to reality, among other things, all the 1200 P-51/P-47 combat reports on the Mike Williams "WWII Aircraft Performance" site were carefully read... There were evidently thousands of others sources, plus all the widely known and available WWII tests, of course.

There are still many guesses, but doing many more aircrafts types is to me unthinkable because the available maneuverability "picture" is far too poor on too many of them, even for the simplistic data on these cards...

To play the my game variant, you do need the original "Air Force" rules booklet, but I can photocopy mine and send it to your address for free. The counters, plain hexagon "map" and logsheets can all be downloaded from online sites related to Avalon hill's "Air Force" system. You don't really need to find an original "Air Force" game.

My game variant, "Advanced Air Force", has 8 color cards: Me-109G-6(1.42 ATA), FW-190A-8, P-47D(72" MAP included), P-51B/C/D(72"-80" MAP included), Spitfire Mk XIV(+18 lbs), Me-163B, P-38L (64" MAP), A6M5 Zero, plus the B-24J and B-29 in black-and white text Data Cards with formation flight and handling info.

You can get this E-mailed to you in PDF files for free if you contact me at: gaston1_01@hotmail.com

Each Data Card represents hundreds of hours of work and research, and the advantage here is that the data could and was easily changed thousands of times for each card over 14 years: You still doubt my interest in this?

Gaston

M_Gunz
01-16-2010, 09:30 AM
Based on combat reports written by the survivors, hand-picked ones too? Any no-contact missions there?

na85
01-16-2010, 10:01 AM
this was far too long ago for me to remember, but the quote is very accurate...

Sure, it's too long ago for you to remember but the quote we should just accept?

JtD
01-16-2010, 10:25 AM
Originally posted by Gaston444:
F4U-1 vs p-51B

Please note: The B after the P-51 is your invention.

For someone who's done the insane amount of research you describe, the following should be easy:

Still to be provided by Gaston444 with name of the source (7th enquiry):
Clean power off stall speed for 109G:
Clean power off stall speed for 190A:

M_Gunz
01-16-2010, 12:28 PM
But JtD, which variants? G models vary, they tended to get heavier. 109G-2 or 109G-6Late or 109G-6A/S?
FW's... just got meaner.

The same airframe with one prop gets better climb while another gets better speed. Which prop is used
is part of the IL2 model. We found that one out from Oleg back when he posted.

Does one or both get lumbered with gunpods or any externals? The weight during test, IL2 equivalent is
fuel %, ammo load and arming. I don't think that gunpods help to run a slower stall.

JtD
01-16-2010, 01:31 PM
I don't care which one he picks. Variants, conditions etc. should all be in the source. We can then make up our mind on how good the numbers are.

BillSwagger
01-16-2010, 02:40 PM
We can all pick apart the exceptions, where maybe a pilot managed to gain that 2 percent better performance that made all the difference in a dogfight, but i think we should be focusing on the commonalities not the exceptions.

A few posts back, Gaston admitted that the 109 has the better radius, and that the FW190 had a better turn rate at higher speeds.
This is something i tend to agree with at most altitudes. I think the 109 would be better in higher altitude turns (25K +) where having a lighter wing load, airframe, would be advantageous in turning in the thinner air.

I could be wrong, but it was my inclination that 109s could out turn Mustangs at higher altitudes, however the mustang was faster, as was the P-47. Speed adds to rate of turn, but does not mean better radius. So in a 109, it would be in the interest of the pilot to make tighter turns, and the Mustang to make wider turns.

In these situations, i don't see throttling down being of any help to Mustang or P-47 pilots, but possibly better for a 109 pilot that needs to make a tighter turn than what his current speed allows. Speed leads to G load, where Mustangs and P-47s were better designed in this area.


Bill

M_Gunz
01-17-2010, 07:18 AM
At high altitudes the one who has most engine power left usually turns better. The BoB Hurricane could out-turn
the BoB 109's from 4000 ft down and was at a disadvantage from 8000 ft up, the 109's turned better there. It was
due to the Hurricane engine running out of breath while the 109 had not.

Kettenhunde
01-17-2010, 12:30 PM
Ailerons reversing before the stall point is a serious stability and control problem that sets the aircraft up for an incipient spin.

This is not a characteristic of a properly rigged aircraft. This is reflected in the aircraft's rigging instructions and I think this has been discussed before on these forums.

http://www.pprune.org/archive/index.php//t-75116.html

All the best,

Crumpp

ImpStarDuece
01-17-2010, 02:34 PM
As to the British/Russian comments on the Russian throttle use being "full forward" in combat, this was far too long ago for me to remember, but the quote is very accurate...


Comedy gold.

So, you can't remember the source but the quote is "very accurate"...

BillSwagger
01-17-2010, 04:00 PM
Originally posted by M_Gunz:
At high altitudes the one who has most engine power left usually turns better. The BoB Hurricane could out-turn
the BoB 109's from 4000 ft down and was at a disadvantage from 8000 ft up, the 109's turned better there. It was
due to the Hurricane engine running out of breath while the 109 had not.

But being out turned in rate is different than being out turned in radius, which is where most of the thread has left people in disagreement.


Bill

Gaston444
01-17-2010, 04:29 PM
Quote, ImpStarDuece: "Comedy gold.

So, you can't remember the source but the quote is "very accurate"..."


-By the way, aren't you the guy who told me I was "out of my depth" on roll rates by showing a bunch of roll rates to prove your point, but somehow "omitted" to mention that the 180° set of roll rates was at 3G and the 360° set was at 1G?

Besides, who cares what a British pilot said about the operation of a bunch of Pe-2s? It doesn't entail that individual fighter pilots followed these procedures slavishly, as Karholi points out in the link I provided... The Pe-2s are merely an indication that running the throttles "full forward" as a matter of course is not an inconceivable procedure in combat...

If the La-5 had 8 steps to change the throttle, that's another indication that downthrottling was a convenience that was optional or infrequent in combat in the minds of engineers...


Quote, BillSwagger: "A few posts back, Gaston admitted that the 109 has the better radius, and that the FW190 had a better turn rate at higher speeds.
This is something i tend to agree with at most altitudes. I think the 109 would be better in higher altitude turns (25K +) where having a lighter wing load, airframe, would be advantageous in turning in the thinner air.

-Absolutely true for high altitudes: The power/weight ratio and the wingloading do seem to matter more up high. The FW-190A's poor high altitude performance is why the Me-109G was kept on.

As for the FW-190A being better at "high speeds", I meant ONLY up to 400 km/h(250 MPH)... Above that, the earlier short-nose FW-190A-3/4s seem to hold on to some sort of advantage, since Rechlin testing clearly says the early 190s "out-turn and out-roll the Me-109 at ANY speed":

http://www.youtube.com/watch?v=R0YLLBvIBFk

However, I think that even then the margin was slim above 400 km/h, or that it is a slight overstatement given the preponderance of sustained turns in those days, and that a tail-heavy trim Me-109G was certainly superior in pull-outs above 420 MPH, given the FW-190A's very poor pull-out performance. Longer-nosed FW-190A-5s and later variants were likely noticeably worse than a Me-109G above 400 km/h(250 MPH), and even much more so far above that... Hence Rall's "Sabre vs Floret" analogy, which is so clear it really requires no explanation (and was intended that way...).

The fact that it is not widely known that the Me-109G-6's peak sustained turn rate COULD NOT be achieved at full power at lower altitudes, and was achieved at around 250 km/h (160 MPH), shows just how LITTLE we know about these old aircrafts...

That the FW-190A had a better turn rate in a wider radius at 300-400 km/h does not make it a high-speed boom-and-zoomer...

Gaston

P.S. JTD, I have answered your question: Please read my posts and stop trolling this thread...

G.

M_Gunz
01-17-2010, 06:27 PM
Originally posted by ImpStarDuece:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">As to the British/Russian comments on the Russian throttle use being "full forward" in combat, this was far too long ago for me to remember, but the quote is very accurate...


Comedy gold.

So, you can't remember the source but the quote is "very accurate"... </div></BLOCKQUOTE>

It oughtta be his sig.

M_Gunz
01-17-2010, 06:37 PM
This is THE SOURCE? (http://www.youtube.com/watch?v=R0YLLBvIBFk)

We're discussing over a clip from a stupid History/Discover Channel blanket statement show?
What's next? If it was printed in a newspaper it MUST be true in all ways?
Let's just have the Jehova's Witnesses in to judge flight models at 7AM after the Bible talk!
My friend's grand-daughter is 6, almost 7. Pretty soon she'll be ready to post here too.

na85
01-17-2010, 07:57 PM
This thread is an ubizoo classic! http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif

Kurfurst__
01-18-2010, 05:21 AM
Originally posted by ImpStarDuece:
Comedy gold.

Indeed, and with you on board, it just got better. http://forums.ubi.com/images/smilies/34.gif

K_Freddie
01-18-2010, 11:55 AM
To continue... http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif

With regard to the FW's poor high alt performance.. It was bad for continous high alt DFs, but the tactics they used was to get up there, get the speed up and if there are no enemy fighters, stay there - otherwise they'd dive down to altitudes where the FW could 'fly again'.

This by no means makes the one fighter better than the other - but for the tactics used in a particular situation.
http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif

JtD
01-18-2010, 12:04 PM
Originally posted by Gaston444:
JTD, I have answered your question: Please read my posts and stop trolling this thread...

You did not name your source. You just invented two numbers. Not good enough.

ImpStarDuece
01-18-2010, 03:19 PM
Originally posted by Kurfurst__:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by ImpStarDuece:
Comedy gold.

Indeed, and with you on board, it just got better. http://forums.ubi.com/images/smilies/34.gif </div></BLOCKQUOTE>

Glass, stones and houses...

M_Gunz
01-18-2010, 03:47 PM
There's two ways to deal with vague sources.
1) That's not telling enough to get anything useful out of.
2) Oh BOY! I can read all kinds of BS into that!

Please Kurfurst could we have German clean stall data on examples of 109G and FW190A?

K_Freddie
01-18-2010, 04:15 PM
Originally posted by M_Gunz:
Please Kurfurst could we have German clean stall data on examples of 109G and FW190A?
And.. if possible, make it for different altitudes as well.

- The Wheels on the bus go round and round... -

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

AndyJWest
01-18-2010, 04:22 PM
Originally posted by K_Freddie:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by M_Gunz:
Please Kurfurst could we have German clean stall data on examples of 109G and FW190A?
And.. if possible, make it for different altitudes as well.

- The Wheels on the bus go round and round... -

http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif </div></BLOCKQUOTE>

Shouldn't unaccelerated stall speeds be at pretty well constant IAS regardless of altitude?

BillSwagger
01-18-2010, 04:56 PM
Whats indicated at 1000ft is not the same as whats indicated at 30,000ft even if your instruments read the same number, in part because of pressure changes in the instrumentation.
But technically, i think EAS might be more of what you are talking about, where 100 EAS at 100ft is suppose to act on the plane the same way as 100 EAS at 30,000ft, if i'm not mistaken.

K_Freddie
01-18-2010, 05:03 PM
Ideally, yes...
But, NO... as 'unaccelerated' never really occurs because as you go higher at the same speed, to keep the same Altitude you have to increase your AoA as the air gets thinner providing less 'winglift'. Also the AoA of your sensors (Pitot) change giving you different values.

As your AoA increases.. you are 'accelerating' towards a stall condition. This is the same as pulling higher G's at lower altitudes.
http://forums.ubi.com/groupee_common/emoticons/icon_cool.gif

AndyJWest
01-18-2010, 05:10 PM
Originally posted by BillSwagger:
Whats indicated at 1000ft is not the same as whats indicated at 30,000ft even if your instruments read the same number, in part because of pressure changes in the instrumentation.
But technically, i think EAS might be more of what you are talking about, where 100 EAS at 100ft is suppose to act on the plane the same way as 100 EAS at 30,000ft, if i'm not mistaken.
If we are talking about unaccelerated stall speeds, the difference between IAS (or at least calibrated IAS/CAS) and EAS will be insignificant, I'd have thought - from what I understand they only differ because of compressability. I did say 'pretty well constant'.

K_Freddie:
'Unaccelerated' as in a stall in level flight. Clearly the stall speed TAS will increase.

K_Freddie
01-18-2010, 05:18 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">
Assuming fixed GW, CG, and AOA...

At higher density altitude:

1) The true airspeed necessary to generate sufficient lift increases. This means that you have to fly FASTER to maintain your stall margin.

2) The reduced air density causes the AS indicator to read lower than true.
As the pilot flys faster (to keep indicated airspeed at normal values), the TAS will then be higher than at sea level.

Convienently, the amount of reduction in IAS at higher density altitudes approximately matches the required increase in TAS to maintain normal stall margins...so we just fly the same numbers regardless.


Note: your groundspeed will be higher on landing, so the distance remaining markers will go by more quickly.



No, indicated stall speed should remain the same.

If you have a multi engine rating refer to your Vmc vs Stall speed diagram, should answer the question in graphical terms.



Good info! Thanks Rick

Folks, I hate to disagree with all you guys, but this issue is pretty important so I think we need to correct this before MORE people get incorrect information.

Stall speed INCREASES with altitude. Whether you look at IAS, CAS, EAS or TAS, they ALL increase with altitude.

Since PFDs display CAS (not IAS), and TAS has no importance whatsoever in the stall margin, we should only really talk about CAS and EAS.

EAS is really the airspeed that we need to be concerned about when relating airspeed to stall margin, and the stall speed in EAS increases with altitude.
A good rule of thumb is the 2kts/5000ft rule, but at cruise altitudes the increase is even greater than this approximation and varies depending on aircraft type.
The CAS stall speed will increase by an even greater degree due to compressibility effects... and since this is what we see on the PFD, we should keep and even greater "buffer".


I urge everyone to review some good aerodynamics or performance books because IMHO there should be no confusion whosoever over such a basic and fundamental aerodynamic principle. High altitude aerodynamics must be one of the most poorly understood areas of flight training and unfortunately it is not taught enough (FAA requires it for a commercial but applicants are seldom quizzed on it....and my experience is that regional airlines do a very poor job at teaching it).
Unfortunately, there are WAY to many books that contain incorrect or in some cases outdated information, so be careful about what you trust.

Long story short -> if you ever find yourself having to deviate from company profile at high altitudes, remember stall speed will be higher than what you would otherwise encounter at sea level.
</div></BLOCKQUOTE>

K_Freddie
01-18-2010, 05:47 PM
From an instrument POV..
- IAS relies on differential pressure with regard to incoming airflow to static airflow. the WW2 pitot type tubes

If you're at sea level you'll get the greatest pressure differential.. hence higher IAS.

If you're in outer space.. you'll get 'zippo' IAS

So as you can see there is a 'lowering' of the IAS the higher you go.

Instruments are calibrated, but in reality (RL) they're NOT. Thus the post above about IAS inceasing with Altitutde.

In Game I have no clue as I've never flown RL WW2 a/c
http://forums.ubi.com/groupee_common/emoticons/icon_cool.gif

M_Gunz
01-18-2010, 05:56 PM
Originally posted by K_Freddie:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by M_Gunz:
Please Kurfurst could we have German clean stall data on examples of 109G and FW190A?
And.. if possible, make it for different altitudes as well.

- The Wheels on the bus go round and round... -

http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif </div></BLOCKQUOTE>

IAS... please don't be a dweeb.

EDIT:ADD: Oh well, too late!

Hey Freddy, as you increase alt you only go faster TAS to meet stall speed. The thinner air has the same effect
on the pitot as it does on the wings, stall IAS stays close enough to constant to call it that. Please get it
straight. And remember that in IL2 the atmosphere is not correct above 10 km.

Here is a CLUE for you: FAA Reference Stall Speeds do NOT include ALTITUDE information.
But if you think different then SHOW IT.

I hate to disagree with all you guys, but this issue is pretty important so I think we need to correct this before MORE people get incorrect information.

And even the FAA is "in on it". (http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgNPRM.nsf/0/5f857d0b67ba060086256c870067f137!OpenDocument)

Kettenhunde
01-18-2010, 06:25 PM
the stall speed in EAS increases with altitude.

This is not a correct concept.

Below is the correct concept.


As altitude increases, the density ratio (Greek letter sigma) decreases. The higher the altitude, the higher the true air speed of the stall. The indicated stalling air speed remains the same (as does the calibrated and equivalent air speed) with increasing altitude, but the actual speed through the air mass (TAS) increases.

http://www.erau.edu/er/newsmedia/articles/wp3.html

M_Gunz
01-18-2010, 08:11 PM
BTW Freddy, I find you to be a veritable font of incorrect information.
But you just keep those flaps down, "Ace".

BillSwagger
01-18-2010, 09:55 PM
i know i could glance at wiki for five minutes and be a ubi expert on aerodynamics. http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

I know IAS will fluctuate with altitude, and TAS will need to be higher in order to stay above stall speeds as you climb, but i thought EAS factored in the changes in pressure so that you could derive the "equivalent" performance of the aircraft which would include stall characteristics. Since its calculated from IAS, i know that EAS changes with altitude as well but my thinking is that 70EAS at sea level is the same (same in as how the aircraft would respond, not the same speed) as 70EAS at 30,000ft because its factored in pressure changes, CAC, or what ever other instrument errors. Its a more useful and consistent number.
I think i might be missing some parts, but is that not what EAS is for?

Anyway,

yeah, the Fw190 can't turn a tight radius with out dropping a wing.

Bill

AndyJWest
01-18-2010, 10:06 PM
Um, I think BillSwagger has a point. We were discussing relative turning abilities of different aircraft in combat, which implicitly means 'at the same altitude', so corrections for EAS vs CAS or whatever are largely irrelevant.

Actually, I suspect that most of us know more about aerodynamics than the Wright brothers ever did, but there is a heck of a difference between having knowledge, and being able to apply it. Real WWII aircraft were more likely designed on the 'that's better than we had before' principal than by anything more abstract.

Kettenhunde
01-19-2010, 02:31 AM
i know that EAS changes with altitude

EAS does not change with altitude. Some folks who did not understand the mechanics made the mistake of recalculating the density ratio over altitude. They covered this mistake up inside layers of computer code so that it was readily apparent to someone who is not familiar with the computer code.

That is not correct. By definition EAS is TAS at sea level and the density ratio used throughout the altitude range when calculating EAS is the density ratio at sea level.

We use a ratio of 1 for standard conditions. Density ratios other than one represent non-standard conditions.

I think you guys are confusing power and thrust effects with speed measurements.

For example, Vx and Vy do converge at ceiling but this is due to changing power and thrust NOT the AoA or the airspeed measurement.

M_Gunz
01-19-2010, 02:41 AM
5 minutes with Wiki and you too can confuse your own BS with reality is more like it.
Quick answers to complex questions or things you never really knew only make quick mistakes.
5 minutes is not even beginning to be long enough to look for mistakes let alone check on them.

For example 5 minutes is enough to read up on wing loading and decide it's important. Good!
You already had! This is all you need to prove that's all there is to it! Ding! 5 Minutes!

Read the sig, maybe it will begin to make sense.. and maybe not. But take your time about it.

Kettenhunde
01-19-2010, 02:51 AM
Real WWII aircraft were more likely designed on the 'that's better than we had before' principal than by anything more abstract.


They had more knowledge of 2000 hp power producer design in 1940 than we do today. We just don't work with that kind of thing much.

There is not much a designer in 1940 could learn today about subsonic power producer aerodynamics. What they could learn about is high speed compressible flow aerodynamics as well as Stability & Control design.

CUJO_1970
01-19-2010, 06:11 AM
Originally posted by Kettenhunde:

They had more knowledge of 2000 hp power producer design in 1940 than we do today. We just don't work with that kind of thing much.

There is not much a designer in 1940 could learn today about subsonic power producer aerodynamics.


This is a great point!

It makes me think of the whole "standing on the shoulders of giants" thing.

Kurfurst__
01-19-2010, 06:43 AM
Originally posted by M_Gunz:
Please Kurfurst could we have German clean stall data on examples of 109G and FW190A?

I only have data for landing configuration from datasheets, but you can try the British tests on my site for the Bf 109G-2 in the desert, they did such test, though I guess that would only open another old can of worms about how we define stall speed...

M_Gunz
01-19-2010, 11:59 AM
Reference Stall Speed;
It used to be the speed at which you started to drop and was later changed to the lowest 1G flight speed
to better control the certification process, AFAIK from FAA documents. Just how far back the first case
goes I do not know.

K_Freddie
01-19-2010, 12:24 PM
Originally posted by M_Gunz:
BTW Freddy, I find you to be a veritable font of incorrect information.
Of course.. http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif
A little technical stuff on Pitot Heads (http://www.allstar.fiu.edu/aero/PSSI.htm).. a lot of misinfo there.
http://forums.ubi.com/groupee_common/emoticons/icon_cool.gif

JtD
01-19-2010, 12:35 PM
Originally posted by Kurfurst__:

I only have data for landing configuration from datasheets, but you can try the British tests on my site for the Bf 109G-2 in the desert, they did such test, though I guess that would only open another old can of worms about how we define stall speed...

Is there nothing in the pilot handbooks?

And I don't think there's much to debate about the British procedure. They were kind of mixing stall and gliding, but the info is still separate.

M_Gunz
01-19-2010, 02:20 PM
Originally posted by K_Freddie:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by M_Gunz:
BTW Freddy, I find you to be a veritable font of incorrect information.
Of course.. http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif
A little technical stuff on Pitot Heads (http://www.allstar.fiu.edu/aero/PSSI.htm).. a lot of misinfo there.
http://forums.ubi.com/groupee_common/emoticons/icon_cool.gif </div></BLOCKQUOTE>

Sure, CYA. Straighten us all out like you were right from go.
Nothing like higher stall speed (IAS... duh) with increasing alt there, as you stated.
Nothing that makes F-A of a real difference.

At least you didn't bring in black holes and relativistic conditions.

BillSwagger
01-20-2010, 07:50 AM
Originally posted by M_Gunz:
5 minutes with Wiki and you too can confuse your own BS with reality is more like it.
Quick answers to complex questions or things you never really knew only make quick mistakes.
5 minutes is not even beginning to be long enough to look for mistakes let alone check on them.

For example 5 minutes is enough to read up on wing loading and decide it's important. Good!
You already had! This is all you need to prove that's all there is to it! Ding! 5 Minutes!

Read the sig, maybe it will begin to make sense.. and maybe not. But take your time about it.


I get a lot from these forums, both you and crump seem to carry a lot of knowledge on the subject. point is, i get the feeling sometimes people flip over wiki and regurgitate the info posted there with out really understand what the heck they are saying.

I'm still trying to understand EAS, and how it is used. I know how its calculated.

Crump says EAS doesnt change with altitude, which sort of make sense. Am i wrong in saying that EAS is used as a way to gauge how a plane will respond?

For example, a plane flies at 25,000ft, doing 120IAS, however it responds to control inputs like its flying at 100IAS at sea level. The EAS would actually be somewhere close to 100, right?



Bill

JtD
01-20-2010, 08:22 AM
If EAS is the same, the aircraft behaves the same, simply speaking, so yes. Major systematic differences between IAS and EAS only show at high altitudes and high speeds, so for most purposes of WW2 aircraft you can use both IAS and EAS without much difference.

Mind you, when discussing general aircraft behaviour on this board we generally use IAS = CAS, technically speaking CAS would be more correct.

M_Gunz
01-20-2010, 09:09 AM
Extreme alt you get error, with emphasis on extreme as in WTF up there beyond any 25000 ft.
High speed as in around .6 Mach and +up+ the guage reads HIGH not low and gets worse with
increased Mach. Get really high up and .6 Mach starts closing on your stall speed. 6G's
takes less than 2.5x 1G stall so somewhere wayyy up high you might just run into trouble
judging a hard turn. How high and how fast, hmmmmm? Because at 10 km alt TAS is about 171%
CAS and .6 Mach is where the difference begins to become real.

In IL2 there is no difference I can find between IAS and CAS, our pitots read true.

Usefully accurate IAS/TAS chart for the non-anal-retentives. (http://www.maw-superaereo.it/utility/IAS-TAS-CHART.pdf)

Speed of Sound by Altitude Tables (http://www.aerospaceweb.org/question/atmosphere/q0112.shtml)

I read Mach 1 at 10 km to be 1078 kph TAS, 630 kph CAS. 60% of that is 378 kph. Looks to ME as if over 300 kph
CAS at 10 km alt you get a very small error that builds up to something real by 360-380 kph IAS. Damn, that's
going to make really hard maneuvers a bit difficult to judge wayyyy up there after the kind of dive it will
take to go that fast wayyyy up there. Should I worry about 1 G stall? No but I should take care when trying
HARD TURNS and not just blindly pull while watching my instruments or speedbar and taking little or no note
of how the plane is actually flying.
Cause to worry? Not for me. I can tell when I'm approaching stall unlike those who figure it out only after
they have started into the vicious spin they've pulled themselves into. Considering that the same players
should stick to 3 km alt or (usually) less on a noob server it shouldn't be a problem for them either.

Kettenhunde
01-20-2010, 09:17 AM
Am i wrong in saying that EAS is used as a way to gauge how a plane will respond?

It does not change with altitude. That is what makes it so useful. If we apply the correct compressibility correct it remains constant. That is why we work in ratios as well. It is simpler to figure and get the correct concept.


EAS is the most commonly used speed measurement in calculating an aircraft's performance envelope. It is easy to convert to TAS and greatly simplifies things. Even better, it is the correct way to do things.

EAS is just CAS corrected for compressibility error.

It works not matter what altitude or speed realm and does not change at a constant thrust.

M_Gunz
01-20-2010, 09:28 AM
Originally posted by BillSwagger:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by M_Gunz:
5 minutes with Wiki and you too can confuse your own BS with reality is more like it.
Quick answers to complex questions or things you never really knew only make quick mistakes.
5 minutes is not even beginning to be long enough to look for mistakes let alone check on them.

For example 5 minutes is enough to read up on wing loading and decide it's important. Good!
You already had! This is all you need to prove that's all there is to it! Ding! 5 Minutes!

Read the sig, maybe it will begin to make sense.. and maybe not. But take your time about it.


I get a lot from these forums, both you and crump seem to carry a lot of knowledge on the subject. point is, i get the feeling sometimes people flip over wiki and regurgitate the info posted there with out really understand what the heck they are saying. </div></BLOCKQUOTE>

And there's others who have been down that road over and over and just look for a link to serve as a road sign.
That can take 5 mins to post on a good day, over an hour on a bad one.

Nobody I know of is perfect and there are few if any blanket answers to any question so there's almost always
room to say the word error in all but the most carefully worded reply. You just have to ask yourself what kind
of emphasis you want to place on the revelation of such error and how far into DOH you want to take it.

Here's an example I had to read twice just to believe it was posted:

Folks, I hate to disagree with all you guys, but this issue is pretty important so I think we need to correct this before MORE people get incorrect information.
Stall speed INCREASES with altitude. Whether you look at IAS, CAS, EAS or TAS, they ALL increase with altitude.

Technically correct, practically worthless. Yeah, let's get all upset and quit using IAS to fly by. Someone
call the FAA and force them to include altitude info in all the V-speed regulations!

Here's a clue: the speedbar goes by 10 kph increments.

K_Freddie
01-20-2010, 09:54 AM
That whole quote is from a aviation website (Not me), and that piece is from someone, I guess, has many hours flying experience at altitude
You can argue all you want with him.. http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

Kettenhunde
01-20-2010, 10:04 AM
Whether you look at IAS, CAS, EAS or TAS, they ALL increase with altitude.

It is not even technically correct. Only TAS increases with altitude.....

Some people are confusing power and thrust effects with speed measurements.

Because they do not grasp this, it leads to further confusion when they read a pilot comment or anecdote.

It is a fact that EAS, IAS, and CAS do not change with altitude. It is not a feeling, a guess, or conjecture.

M_Gunz
01-20-2010, 10:25 AM
Originally posted by K_Freddie:
That whole quote is from a aviation website (Not me), and that piece is from someone, I guess, has many hours flying experience at altitude
You can argue all you want with him.. http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

Or your interpretation which is what I did.

M_Gunz
01-20-2010, 10:27 AM
Originally posted by Kettenhunde:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> Whether you look at IAS, CAS, EAS or TAS, they ALL increase with altitude.

It is not even technically correct. Only TAS increases with altitude.....

Some people are confusing power and thrust effects with speed measurements.

Because they do not grasp this, it leads to further confusion when they read a pilot comment or anecdote.

It is a fact that EAS, IAS, and CAS do not change with altitude. It is not a feeling, a guess, or conjecture. </div></BLOCKQUOTE>

Couldn't I say that IAS decreases with alt *compared* to TAS?

Kurfurst__
01-20-2010, 04:23 PM
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 Kurfurst__:

I only have data for landing configuration from datasheets, but you can try the British tests on my site for the Bf 109G-2 in the desert, they did such test, though I guess that would only open another old can of worms about how we define stall speed...

Is there nothing in the pilot handbooks? </div></BLOCKQUOTE>

Not in the ones I've seen, though of course there could be more, but generally you only find speeds suggested for approach, speeds where you can lower the landing gear etc, much unlike the typical British Pilot manuals which usually note both power on and power off stall speeds... though I guess thats sufficient for a combat pilot, as after all stall speed is defined for 1 g, and increases rapidly with the g-load, or more precisly, angle of attack sustainable by the wing at a given airspeed. OTOH I've seen a memorandum for pilots reminding them of this effect and the concept of high-speed stall...

I would risk saying that the typical WW2 pilot actually know very little of his own plane's performance envelope and general aerodynamics. The signs of this are everywhere when you read them, and the instructions from higher places... After all, this was all just theory, and of limited use to a practical person like a fighter pilot; it would suffice if he knew what signs the aircraft would show before stalling, and when to ease up on the stick...


And I don't think there's much to debate about the British procedure. They were kind of mixing stall and gliding, but the info is still separate.

Oh, I've seen those discussions where people would go after each other's throat on these... http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

Kettenhunde
01-20-2010, 04:27 PM
I would risk saying that the typical WW2 pilot actually know very little of his own plane's performance envelope and general aerodynamics.


You are correct. They were very much practical pilots. They did not know and were not taught much theory at all.

The fighter pilots of WWII were nothing like today's fighters in requirements for academic knowledge of aerodynamics.

na85
01-20-2010, 04:36 PM
I would imagine German pilots in particular knew less and less about their aircraft as the war progressed, what with such a drain on pilot reserves and decreases in training time/quality.

Kettenhunde
01-20-2010, 04:44 PM
Couldn't I say that IAS decreases with alt *compared* to TAS?

Only if your setting a flight director to maintain a specific mach number.....


No, IAS is constant while TAS is a function of density.

People are confusing such facts as Vx increases with altitude and Vy decreases. This is because of power and thrust not the airspeed measurement.

Some early Jets can also see a change in stall speed as they are thrust limited and not aerodynamically limited.

Once again, all of this is power and thrust effects and not the result of airspeed measurement changes.

Bremspropeller
01-20-2010, 05:32 PM
Well, aircraft were considered "throw away stuff" back then.
They weren't supposed to last long.
It was war, after all.

Then, you might consier that airplanes were much less sophisticated an complicated back then.
They didn't have two or even thre hydraulic-cycles, a couple of radar-modes or autopilot-modes.
They didn't have complicated avionics in the first place.

Thus, there were only few things in comparison, pilots had to know.

Power-settings, take-off and approach-speeds, blower-settings and range/ max endurance figures , on top of a few troubleshooting issues (hydraulic or electric gear/ flaps?; why does the engine sound that way and where does the smell come from?)...

Transonic aerodynamics hadn't been completely figured-out, so there was basicly nothing to teach the pilots about in terms of high-speed flight.

It's pretty ineresting to compare pilots of those ages to pilots of today:
some things got a lot easier and others got a lot harder.

Kettenhunde
01-20-2010, 05:39 PM
It's pretty ineresting to compare pilots of those ages to pilots of today:


I agree. It is almost a reversal from today's pilotage.

Back then, the plane was hard to fly, the avionics were simple, and the weapons easy to operate.

Today the planes are very easy to fly, the avionics very complicated, and the weapons take more training than the aircraft. Sometimes the weapons are so time consuming to operate, they need a dedicated crewman to do nothing but run radars and operate weapons.

Gaston444
01-20-2010, 07:18 PM
There was quite a steep learning curve from newly trained pilots compared to those with front-line experience.

This could explain the huge gap between WWII theory and tests and actual combat reality (where the FW-190A was widely accepted as a specialized medium-low-speed turn fighter: Find me ONE US or British WWII combat pilot that actually says the Me-109G out-turns the FW-190A... Hundreds say the exact opposite, as does the Russian summary...)

I know of a well-known anecdote that was discussed here long ago: An experienced US squadron leader in the UK was lecturing his newly-arrived Merlin P-51 pilots fresh from training in the USA: To show them how much they still knew nothing, he took them on in mock combat at low altitude in a P-40 vs their P-51s, and proceeded to kick their asses all over the place in individual combat...

I always wondered how was that possible, since his pupils-adversaries would all have hundreds of hours in various aircrafts, and would be very familiar with their new P-51s by the time they got even near front-line combat in 1944...

Yet these fairly experienced pilots could not cope at all with a P-40, in their P-51Ds, having PASSED all requirements for active service...

I think it was likely that the commander knew how to use downthrottling in turns...

Maybe unrelated to downthrottling, but in a similar vein, Japanese pilots found the faster Ki-84 could not cope at all with the Ki-100 in mock combat, to the point one Ki-100 could still win against 3 Ki-84s, and repeat this when pilots were exchanged...

In theory there is no reason for such a radical advantage to a much slower aircraft, but even in late 1945, and taking in most combat accounts I have read of the 44-45 period, it appears clearly that high speed was not as much life as dogma would have us believe... The ability to maintain a slower speed at the highest possible rate of turn seems to be as or even more critical...

It seems there was quite a gap between 1944 combat theory and 1944 practical combat knowledge... Especially in Western Europe, low-speed sustained turn maneuverability over multiple 360s was still considered important, even in 1944-45.

Gaston

M_Gunz
01-20-2010, 07:23 PM
Originally posted by Kurfurst__:
as after all stall speed is defined for 1 g, and increases rapidly with the g-load,

Yet slower than the increase in g-load itself. The speed increases with the square root of the G's.
At 4 G's it is twice the 1 G stall, at 6 G's it is still less than 2.5 times -- 45% for 2 G's more.
That should be good to know!


<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">And I don't think there's much to debate about the British procedure. They were kind of mixing stall and gliding, but the info is still separate.

Oh, I've seen those discussions where people would go after each other's throat on these... http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif </div></BLOCKQUOTE>

Do you remember when the 109G-6 was "proved" to have too much lift because it could be glided down to 135 kph
before a wing would drop, all on the basis of faulty interpretation of Dave Southwood's article on Black Six?
When one member goes after the modeling on such a screwy basis and attacks counters to his method as "only
theory" (yah, the FAA regs are not about reality http://forums.ubi.com/images/smilies/53.gif) then what is left?

Now they make mods to "fix" what they don't like. Plane A should be better at Performance X than Plane B, so....

BillSwagger
01-20-2010, 10:49 PM
Originally posted by Gaston444:
This could explain the huge gap between WWII theory and tests and actual combat reality (where the FW-190A was widely accepted as a specialized medium-low-speed turn fighter: Find me ONE US or British WWII combat pilot that actually says the Me-109G out-turns the FW-190A... Hundreds say the exact opposite, as does the Russian summary...)

As was mentioned before, i think it depends on the speed of the engagement. I know you see a tv show that says the FW190 out turned the 109 at any speed, but there is considerable data to go against that. One, the 109G has lower stall characteristics, two, US/British tests concluded that the 190 has a horrible turning radius.



Yet these fairly experienced pilots could not cope at all with a P-40, in their P-51Ds, having PASSED all requirements for active service.........................

............it appears clearly that high speed was not as much life as dogma would have us believe... The ability to maintain a slower speed at the highest possible rate of turn seems to be as or even more critical...



The conclusion you are making here could easily be explained another way. I think it has more to do with fighting the fight your plane was designed for.
High speed was essential to a late war dogfight, turning was part of it, but more an issue of corner velocity. In a turn fight, planes lose speed, making them easier targets for the faster moving planes. The idea behind 44/45 planes was to design them in such a way that they could change direction with as least loss of energy as possible. This entails not making the tightest turn.

In contrast, take a P-40 and have it attempt to follow a P-51 in a flat turn at its best CV. The P-40 would need to stay in a dive just to keep up. What you sited is only an example how unfamiliar pilots were to new aircraft, but you can't site it as an error in perception of combat tactics/designs.

Gadje
01-21-2010, 03:36 AM
Originally posted by Gaston444:
........the Earth is flat.........
Gaston

I hold you responsible for the death of several thousand of my much needed brain-cells.

M_Gunz
01-21-2010, 05:19 AM
Originally posted by Gaston444:
I know of a well-known anecdote that was discussed here long ago: An experienced US squadron leader in the UK was lecturing his newly-arrived Merlin P-51 pilots fresh from training in the USA: To show them how much they still knew nothing, he took them on in mock combat at low altitude in a P-40 vs their P-51s, and proceeded to kick their asses all over the place in individual combat...

I always wondered how was that possible, since his pupils-adversaries would all have hundreds of hours in various aircrafts, and would be very familiar with their new P-51s by the time they got even near front-line combat in 1944...

It is simply because the P-40 is much better at low to mid speed flat turning than the P-51. Much better.
He SUCKERED them into slowing down and they lost. AVG pilots would do the same for bet money with the noobs.

There's no need to invent anything to explain, it's the pilot not the plane.

Gaston444
01-22-2010, 03:29 AM
Quote, Billswagger: "In contrast, take a P-40 and have it attempt to follow a P-51 in a flat turn at its best CV. The P-40 would need to stay in a dive just to keep up."

If it evolved into SUSTAINED turns, probably...

I agree with the assesment that the Merlin P-51 can keep its speed better in turns because it has more power-to-weight, broader prop blades and likely much less drag in turns. But the Merlin P-51's "peak sustained turn rate", the one that matters more because it is sustained beyond a 180°/360° jerk, is around 200 MPH (flaps-down etc)... With much reduced power...

Since the P-40 has good high speed controls that are similar acting to those of the P-51 (as far as I know), it could very well be that it is the P-40 that should keep speeds high, refusing turn-fighting against a downthrottling P-51, because the disparities between them might NARROW with higher speed... They both burn speed in high-speed unsustained turns anyway...

In my anecdote, I think it is only because the P-40 pilot KNEW his trainees would NOT downthrottle, and would accept turn-fighting, that he could afford to do it: Despite a likely P-51D superiority at reduced throttle flaps-down/coarse pitch etc, dowthrottling an inferior prop fighter against a superior one that will NOT downthrottle gives the edge in turn rate to the downthrottler. At least in the world of nose-driven aircrafts that ACCEPT turn-fighting... That's probably what he was counting on them not knowing...

In real-life, unless you are chasing, you do not really get to choose a wide range of speeds for your sustained turns, if you accept turn-fighting, because the sustained turns must be at a higher rate than whatever the chaser is doing; you are "locked-in" the turn, in effect... So if the chaser is counting on his high-speed handling control quality, and thus keeping the power up, you can keep the power up too, and maybe benefit from better high-speed controls and response in the process, if he is wrong about the relative value of yours and his...

Or take this: You are (on the deck) equal in turn rate, faster and wider, to a chaser that is slower and narrower; If he cuts throttle to get narrower and slower still, and this STILL increases his turn rate, then you have to do something: Roll out of the turn, add power and make a run for it, refusing to turn-fight, OR you have to downthrottle yourself...

You CANNOT add power AND stay in the turn, and you likely cannot even KEEP power and stay in the turn...

If he could afford to downthrottle and this STILL increased his turn rate, and you cannot duplicate that, the turn fight will be lost.

Ie:

A Merlin P-51 can probably sustain an equal rate of turn to a Me-109G by going at 300-320 km/h, dowthrottled, coarse prop and flaps down, and sustaining enough speed to cut a wider circle faster, but any increase of power will pull it OUT of its turn, instantly slowing the turn rate drastically for a disproportionately small gain in speed (compared to the instant loss in turn rate).

This means adding throttle at 300 km/h for the turning Merlin P-51, while the turning Me-109G does not, will result instantly in the Me-109G gaining angles on the P-51, despite the German aircraft staying "behind" at 300 km/h...

If the Merlin P-51 pulls off power from 300 km/h, and the Me-109G does not, the reverse will happen, and the P-51 will gain. However if the Me-109G also pulls off power, it is likely the 250 km/h (160 MPH) peak sustained turn rate of the Me-109G (according to Ace Karholi) is lower than that of the P-51, giving the Me-109G some sort of edge, assuming everything else is equal, which it may not be. (They are likely closer in rate than radius)




http://www.virtualpilots.fi/fe...icles/109myths/#g6r6 (http://www.virtualpilots.fi/feature/articles/109myths/#g6r6)

Less speed at the peak sustained turn rate means less power, less power for a given nose lenght, turn aerodynamic quality and wingloading means a tighter radius, a tighter radius means a HIGHER turn rate.

The FW-190A was unique in that it had to lay off LESS power for a given radius (a virtue of the short nose, probably, but maybe also of a lot of other things, aileron stall supression etc...), meaning that even in a marginally wider radius it had MUCH more speed.

In other words, adding power to a longer nose DECREASES available wing lift... This is MUCH less acute on jets because the wing lift is ahead, and is free to rise up on its own, instead of being pulled down from the front...

I realy hope this is obvious, and why post-war theorists ignored it is just a measure of how little they cared about has-been prop fighters...

The "Corner Speed" of the P-51D is widely accepted in simulation games as being around 270 MPH, or a whopping 430 km/h. Modern test pilots in 1989 have it pegged at 550-600 km/h, or "very close to the maximum level speed" to quote their exact words...

This discrepancy is because the 1989 test pilots actually TESTED the real thing at Military Power, while games only CALCULATED it: Close enough to maximum power to be significant...

At high speed, the authority of the controls is what really matters for the peak unsustained turn rate: It has three distinct levels: Pilot-stick, stick-attitude, attitude-trajectory. When they actually TESTED the darn things, they found the P-51D's Pilot-stick poor (heavy), but the other two were probably very good, so in effect as long as you don't beat the pilot's muscles, the instantaneous turn rate kept increasing until say, 550-570 km/h or so, at the test altitude of 10 000 ft.... (Or whatever they meant by "very close to the maximum level speed"...)

The high-speed quality of the P-51D's controls (and the pilot's strenght)used the high-density windspeed to OVERCOME the strong straightening, and wing-lift reducing, tendencies of Military Power....

Wing-lift is reduced by nose-applied higher power, but eventually high speed overcomes this reduction by adding more lift to the wing... And this keeps going on way past 270 MPH...

At these speeds, the FW-190A has great pilot-stick(if trimmed right), great stick-attitude, but terrible attitude-trajectory, hence: "tendency to kill speed by sinking"-"diving from a 45° angle, after pull-out will fall an extra 220 M."-"Tendency to black-out the pilot(with a "much inferior angle of pull-out": Doesn't THAT ring a bell?)" ETC... Add nauseam...

So in effect, the 1989 "Corner Speed" was a test of the quality of the P-51D's high-speed controls DESPITE their fighting against near full power... It has nothing to do with the P-51D's peak rate of sustained turns, which is somewhere under or at 200 MPH (with flaps down etc)...

So what if BOTH the P-40 and the P-51D downthrottled? I don't claim to know at either at low or high speeds, but it could very well be the P-40, to be at its RELATIVE best to the Merlin P-51, MIGHT need to keep the speed UP and thus refuse turn-fighting...

It would be nice if one could say WWII simulation games simply make the mistake of displaying WWII fighter aircrafts that are pushed by a jet tailpipe at the bottom of the rudder, but the 1989 test shows how inapplicable even that is to reality: The prop's straight pull, and the nose lenght's leverage AGAINST being lifted, has such a strong depressing effect on the available winglift that the theoretical 270 MPH Corner Speed of the P-51D is in fact closer to 350 MPH or more at Military Power. As tested in 1989 folks... So at War Emergency Power, "Corner Speed" could be even higher...

Yes, at these 350 MPH+, it does mean a higher rate of turn can be achieved than when sustaining turns at 200 MPH, but by the time a 360° has been done, you are likely down to lesser rates of turn if you keep the power up.

As was noted by the 1989 testers: "This very high Corner Speed entails a very rapid loss of energy when turning at the structural limit"

Which is why, given the time it takes to put the 2% of fired bullets the average pilot puts ON target(Luftwaffe stats), LOW speed turning matters...

Gaston

P.S. I would think it is pretty clear that when Rall chose his "floret" metaphor, he did not intend to mean that the floret was more useable in a CURVE than a SABRE, for Pete's sake...

Those British tests supposedly complaining about the "enormous" (probably higher speed) turn radius of the FW-190A (1450 ft. vs 1000 ft. for the Spitfire V could very well be from above 250 MPH) also conclude "the FW-190A equals the P-51B in turn rate, and they thus both vastly out-turn the Me-109G, and so does the P-51B even with full drop tanks(RAE)".

But you don't want to dwell on that, do you? (Rightly so, as it wrong for both German aircrafts, though not for their hierarchy amongst themselves...)

The total lack of Allied fighter pilot claims that the heavier Me-109G (900 lbs/420 Kg heavier than the barely turn-winning F, according to Rall) out-turns the FW-190A should also give anyone a clue... (Especially with numerous quotes to the contrary, and given how turning performance as a whole was in those days completely dissociated from high speed unsustained turn radius, which is exactly what the 1000 ft. vs 1450 ft. quote is!)

G.

M_Gunz
01-22-2010, 04:35 AM
P-40E stall is lower than P-51D stall for both clean or both flaps down. P-40 turns better than P-51.
P-40 can turn at speed where all the P-51 can do is maintain height. There is no mystery to explain.
Ask the folks with the POH's.

Xiolablu3
01-22-2010, 05:21 AM
Originally posted by M_Gunz:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Gaston444:
I know of a well-known anecdote that was discussed here long ago: An experienced US squadron leader in the UK was lecturing his newly-arrived Merlin P-51 pilots fresh from training in the USA: To show them how much they still knew nothing, he took them on in mock combat at low altitude in a P-40 vs their P-51s, and proceeded to kick their asses all over the place in individual combat...

I always wondered how was that possible, since his pupils-adversaries would all have hundreds of hours in various aircrafts, and would be very familiar with their new P-51s by the time they got even near front-line combat in 1944...

It is simply because the P-40 is much better at low to mid speed flat turning than the P-51. Much better.
He SUCKERED them into slowing down and they lost. AVG pilots would do the same for bet money with the noobs.

There's no need to invent anything to explain, it's the pilot not the plane. </div></BLOCKQUOTE>

Exactly.

Xiolablu3
01-22-2010, 05:29 AM
[QUOTE]Originally posted by Gaston444:


P.S. I would think it is pretty clear that when Rall chose his "floret" metaphor, he did not intend to mean that the floret was more useable in a CURVE than a SABRE, for Pete's sake...

QUOTE]

IMO its pretty obvious what he meant :-
He meant that the FW190 was a aircraft with a heavy blow which you could bring down once and hit very hard.
The Bf109 is a lighter aircraft which is easier to whip around, but has a lighter punch.

But of course you can interpret it how you want... http://forums.ubi.com/images/smilies/53.gif

Bremspropeller
01-22-2010, 11:15 AM
You can whip the 190 around just as well - you just need a higher speed to start with.

M_Gunz
01-22-2010, 11:30 AM
Originally posted by Bremspropeller:
You can whip the 190 around just as well - you just need a higher speed to start with.

How many times before you're not fast at all? Once? A full 360 even?

Bremspropeller
01-22-2010, 11:37 AM
That applies to any aircaft.

BillSwagger
01-22-2010, 04:03 PM
Originally posted by Gaston444:

A lot of what you say makes perfect sense to me Gaston, but where you lose me is the idea that down throttling allows for a better sustained turn radius. In my mind, down throttling allows the pilot to decrease the radius faster than bleeding speed through turning alone. In order to sustain any radius the plane will need to throw the throttle forward again. I'm sure an F-16 could turn with a P-51 if it was down throttled, but that's not really the idea behind flying such a bird. I liken that analogy to flying the P-51 with its flaps down to hold its best sustained radius.


I think i already mentioned that its not an on/off effect and has more to do with the speeds at which the pilot is entering a turn, whether he is in lead or pursuit, and of course how the plane was designed.

For example, typically, planes in pursuit throttle down to avoid an over shoot in the first place and if you are throttled down its easier to bleed off the speed that would otherwise inhibit the pilot from gaining a lead pursuit.

A P-51 pilot uses a lag pursuit instead, only because the P-51 will hold more energy on the outside of the turn, than trying to cut inside, meanwhile the lead plane bleeds off more speed attempting the tighter turn.

The P-40 is more capable in the turn radius where its best suited by its power mass.

You don't fly to make the tightest turn, you fly to hold speed while changing direction. If two pilots pass each other head on at the same speed, 400mph, and then make a turn, which plane has the advantage? The one that turns a tight radius and gets his nose pointed back the other way the fastest? or the one that gets his nose pointed back the other way still doing 400mph?
The P-51 is going to make a better circle at that speed, than the P-40 might do if it keeps a straight line.


Heres a little blurp about the P-40 and pay careful attention to the description of how the plane is used against a Zero.
http://staff.jccc.net/droberts/p40/avgtact.html


Bill

Gaston444
01-22-2010, 05:33 PM
Quote, Billswagger: "In my mind, down throttling allows the pilot to decrease the radius faster than bleeding speed through turning alone. In order to sustain any radius the plane will need to throw the throttle forward again."

This is exactly what I used to think, but it became clearer to me, in the light of SEVERAL P-51 and other downthrottling accounts, that lower turn speed, and especially lower power, had greater and more durable virtues than I previously assumed. Note in this account how initial downthrottling procures gains on a CHASER, and, far from being followed by upthrottling, it is found that FURTHER downthrottling produced MORE gains...

http://www.spitfireperformance...hanseman-24may44.jpg (http://www.spitfireperformance.com/mustang/combat-reports/339-hanseman-24may44.jpg)

Then add to this Karliha's quote: "If the enemy cut his throttle, I would then cut my throttle even more. The optimal speed for the Me-109G-6 seemed to be around 250 km/h (160 MPH)..."

All this clearly indicates to me that, contrary to our jet combat assumptions, slow speed had durable virtues of its own with SOME front-pulling propeller fighters, which meant that, contrary to jets, something poisonous often happens, on many prop types, to the sustained turn rate when power is added to the nose and not the rear...

In theory more power is always better, but with prop aircrafts, it seems the very high power sometimes imposed an unreasonably high speed to have enough slipstream to overcome the wing-lift robbing inertia of the increased power...

Going slow had its own inherent, and DURABLE, virtues. Also, unlike jets, prop aircrafts have, proportionately to their maximum level speed, much more acceleration from low speed, so the penalty of going slow is less serious if speed is suddenly needed...

A few prop fighters, like the P-47, seem more speed-oriented. Though they may occasionally fight from a low speed, it is usually from a climbing spiral after multiple 360°s, with no downthrottling mentioned... I think the short nose and good high-speed handling may be a factor here, making downthrottling much less of a benefit.

How far you should downthrottle probably varies greatly from type to type, and it can also be used for short-term cutting off. However, short-term cutting off of an enemy in FRONT is not the same thing as the long-term gaining on one BEHIND... On some types, downthrottling is a great advantage to SUSTAIN higher rates of turns...

Downthrottling to effect a cutting off from behind, or to avoid an overshoot, is a case of the tree that should not hide the forest.

Gaston

Kettenhunde
01-22-2010, 05:54 PM
How many times before you're not fast at all? Once? A full 360 even?


As long as the engine is running you can do it until you run out of gas.

M_Gunz
01-22-2010, 07:53 PM
I was replying to "whip it around" with a FW. In that context.. till you run out of alt.

Kettenhunde
01-23-2010, 04:10 AM
I was replying to "whip it around" with a FW. In that context.. till you run out of alt

In what context? There is no context in the term "whip it around". It is nonsensical and describes nothing in terms of any condition of flight.


Are you talking about aileron turns? A Spitfire wing design cannot match the torsional load of the Focke Wulfs.

Are you talking about instantaneous turn? All aircraft at the same angle of bank and velocity make exactly the same turn in the instantaneous portion of the flight envelope.

Are you talking about the sustained turning ability? In any airplane, as long as the pilot bothers to look at his airspeed indicator he can fly any precise speed in this sustained envelope until he runs out of gas. It is a simple matter of relaxing pressure on the stick when you reach that speed.

I think we have covered the mechanics of turning flight several times. The participants in this thread excluding Gaston should be well versed on the effect of load factor, rate, and radius. I also think they should be well versed on the fact a "sustained turning advantage" is very much dependent on the condition of flight.

A P47 has a sustained turning advantage over a Spitfire under some conditions of flight.

All the best,

Crumpp

M_Gunz
01-23-2010, 05:29 AM
Which is why...


Originally posted by M_Gunz:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Bremspropeller:
You can whip the 190 around just as well - you just need a higher speed to start with.

How many times before you're not fast at all? Once? A full 360 even? </div></BLOCKQUOTE>

Kettenhunde
01-23-2010, 12:15 PM
I don't get it M_Gunz.


How many times before you're not fast at all? Once? A full 360 even?

Which aircraft are you saying is "forced to go slow"?

Any aircraft that can sustain a higher load factor at a higher speed can force its opponent to go slower. Once again, this is sustained performance. As long as the aircraft's engine is running it can do this without changing the condition of flight.


From the USN FTM:

Specifically, a higher limit load factor is a significant advantage, producing a higher turn
rate and forcing an opponent to slow down to match your turn.

M_Gunz
01-23-2010, 12:40 PM
I'm saying that if you go yanking the nose around -hard-, you will lose energy.
Some planes can get away with this better than others. All have a maximum sustained
turn, for sure, with their own minimum radius. Again some are better at this, some
you can keep pulling hard for more angle to lower speeds than others.

Some planes trade energy for angles better than others, longer than others is a fact.
That's why some planes are better in a turn fight and against those others should
not continue playing that tactic. FW pays a higher price near stall than most others.
I thought this would be obvious.

Add:

quote:
From the USN FTM:

Specifically, a higher limit load factor is a significant advantage, producing a higher turn
rate and forcing an opponent to slow down to match your turn.

That to me reflects a state of mind for the opponent that IMO you can only hope for.
A better opponent will start in to flying yoyos and keep the ability to zoom above on short notice
while you bleed yourself down and become less able to dodge let alone zoom. You end up the sucker
instead of your opponent.

Kettenhunde
01-23-2010, 01:30 PM
FW pays a higher price near stall than most others.

That is not correct. The only difference it the velocity at which the stall point occurs.

It pays the "same price" as any other aircraft at that point in its envelope.


Some planes trade energy for angles better than others, longer than others is a fac

Once again, this does not make any sense unless you put it in context of a speed.

If aircraft performance is sustained performance then the airplane can maintain it as long as the engine is running. The speed determines what is sustainable performance.

It is easy to maintain a specific speed in an aircraft.

Bremspropeller
01-23-2010, 01:30 PM
You have to consider excessive thrust at given speed.

A 190 has more at high speed, than say, a 109.

M_Gunz
01-23-2010, 02:41 PM
Sure. A faster plane can turn at speeds where the slower either can't keep up or can't turn at all
while maintaining that speed. Near that end of the speed range the faster plane turns better. If
both pull unsustainable turns then, I would expect the faster plane to hold the edge for a while.

In terms of "whipping around" I would also consider the maneuver speed of both, the one that can
pull full authority at higher speed without breaking (usually the faster plane) will have an edge
for as long as that lasts, IMO for less than 90 degrees of flat turn. In planes like FW's, P-51
and P-47 I don't like to flat turn more than 30 degrees to catch a target if that once I've got my
speed up. In such a case I immediately look to other options such as going into the vertical,
setting up a series of moves to put me in a firing solution, extending or leaving him behind.
Pulling hard turns for long takes the fast heavy out of his advantage, usually rather quickly.

How far will you turn? How much speed or alt will you spend? The fast heavies, I don't find the
"exchange rate" favorable perhaps because they are not so great at lower speed combat as my target.
In a Spitfire I worry less since it's less of a pig below 400 kph. If the guy in the FW wants to
slow down to match then he has made the poor decision unless he can make a quick kill in the process.

Kettenhunde
01-23-2010, 06:23 PM
How far will you turn? How much speed or alt will you spend?

I am still confused. I thought we where discussing sustained performance.

Only if the topic is instantaneous performance will the aircraft will have to expend speed or altitude.


I would also consider the maneuver speed of both,

Absolutely Va is a factor and very much a consideration for real pilots. Exceeding Va can damage or break the airframe even without maneuvering. In any rough air, the first thing a pilot does is slow to Va.

Can you think of what a faster velocity Va does for you?

Which airplane will have a faster Va, one that stalls at 50KEAS or one that stalls at 100KEAS?

M_Gunz
01-23-2010, 08:59 PM
If I have the higher maneuver speed then I can pull half-stick at higher speed too.

Can you really tell about Va from Vs or is that also an in-general-with-exceptions thing?

Kettenhunde
01-23-2010, 09:19 PM
I can pull half-stick at higher speed too.

The aircraft with the higher Va can pull more violent maneuvers at a higher speed.


Can you really tell about Va from Vs or is that also an in-general-with-exceptions thing?

Yes, you can really tell about Va from Vs.

Gaston444
01-24-2010, 03:05 AM
Quote, Kenttenhunde: "Are you talking about instantaneous turn? All aircraft at the same angle of bank and velocity make exactly the same turn in the instantaneous portion of the flight envelope."


-I wish this would not blind you to the fact that, depending on pilot handling, they do not all build Gs in the same way up to the maximum available G, and that this results in the maximum available G being not as clear-cut as you may think, because at some point up the scale, the pitch can increase beyond a pilot's initial input... This is what they mention in the P-47 comparison as a "tendency to black-out the pilot", and it can only mean that increased-drag deceleration Gs (through the uncontrolled presentation of a much increased frontal area) are mixed-in with a brief and abnormal "pivoting" increase in the turn rate... This means real Gs with no real turn or pull-out value:


http://img105.imageshack.us/img105/3950/pag20pl.jpg



In other words, the FW-190A can "stall", with near-full three-axis control, obliquely "inside" its own turn instead of stalling towards the outside... With full 3 axis control, I don't call it a "stall", and it is usually called "mushing".

Stalling towards the "inside" of the turn, through a sudden "pitch up", can seem as desirable, and may confuse a chaser momentarily with the deceleration, but the gain is fleeting as it often results in an instant wing drop (a "real" stall), or the turning is changed into a diagonal deceleration that elongates the curve... Or, if vertically pulling-out, in a massive loss of altitude, with a VERY slow exit speed (and usually with a blacked-out pilot)...

This airliner-oriented chart shown on this issue is probably what makes you unable to see that the FW-190A had a very undesirable trajectory response to pitch changes above 250 MPH, especially in vertical pull-outs... This abrupt high-speed response made inexperienced FW-190A pilots correctly timid in abrupt stick pulls at higher speeds, but it also seems to occasionally have made them wrongly timid in their handling at low speed...

In addition, the evidence for the FW-190A's pathetic dive pull-out performance is coming in from virtually all sources (except Kurt Tank's misleading Kg of pull per G figure, see oblique "inside" deceleration explanation above...), and I defy anyone to find ANY anecdotal evidence that the Anton turned well COMPARATIVELY to any US fighter above 250 MPH, up to 400 MPH or more, and especially to the right at ANY of the above 250 MPH speeds...

This willful ignorance of the FW-190A's obvious reality comes, I guess, from considering that an aircraft is either in a stall or not. I think if you still have three-axis control, or near-full 3 axis control, it is not a stall, and pilots, knowing this full well, will inevitably pull hard enough to reach these less than mathematically "perfect" conditions... AND some aircraft are more prone to reach them than others... Maybe tailplane partial stalling or blanketing is the issue here.

http://www.ww2f.com/russia-war...iences-fw-190-a.html (http://www.ww2f.com/russia-war/21828-russian-combat-experiences-fw-190-a.html)

Direct quote: "However, the FW-190 is never able to come out of a dive below 300 or 250 meters (930 ft or 795 ft). COMING OUT of a dive, made from 1,500 meters (4,650 ft) and at an angle of 40 to 45 degrees, the FW-190 falls an extra 200 meters (620 ft)."

COMING OUT are the critical words here: The aircraft falls 620 ft(!), still with full 3 axis control, WITH THE NOSE LEVEL OR UP. Rest assured it can do the same, to a lesser extent because of the sometimes abrupt assymetrical wing drop, if the whole thing is tilted on its side...

So the TRAJECTORY doesn't even match the direction the nose is pointing! Are you really saying ALL aircrafts behave like this if the speed is the same? Why did the Russians bother pointing it out then?

Besides, what does anyone else have to say about Karhila's claim that the Me-109G-6's PEAK sustained turn rate is at around 250 km/h (160 MPH)?

Isn't that a clue that the Me-109G cannot maintain its peak sustained turn rate at full power? Or, let me guess, this Finnish ace doesn't know what he is talking about? But many of you, of course, have already decided you know better...

I know it is a fetching game, but don't let it prevent reality from intruding...

I have explained this as best as I could: If you want to persist in your total ignorance, be my guest...

Gaston

Gaston444
01-24-2010, 03:12 AM
Exclude the P-38G from US fighters, as it is quoted as inferior-turning above 150 MPH to the early short-nosed FW-190A-3/4s in a UK test...

Early short-nose FW-190As may have had somewhat better high-speed handling than the later ones I was thinking of when writing the above: Rechlin is even quoted as saying "The FW-190 out-turns and out-rolls the Me-109 at ANY speeds..."

Gaston

Kurfurst__
01-24-2010, 04:15 AM
Originally posted by Gaston444:

Early short-nose FW-190As may have had somewhat better high-speed handling than the later ones I was thinking of when writing the above: Rechlin is even quoted as saying "The FW-190 out-turns and out-rolls the Me-109 at ANY speeds..."

Gaston

I'd love to see that Rechlin paper. Which one is it and when was the testing done?

M_Gunz
01-24-2010, 05:31 AM
Kurfurst, AFAICT the link below is "THE SOURCE":


Originally posted by M_Gunz:
This is THE SOURCE? (http://www.youtube.com/watch?v=R0YLLBvIBFk)

We're discussing over a clip from a stupid History/Discover Channel blanket statement show?
What's next? If it was printed in a newspaper it MUST be true in all ways?
Let's just have the Jehova's Witnesses in to judge flight models at 7AM after the Bible talk!
My friend's grand-daughter is 6, almost 7. Pretty soon she'll be ready to post here too.

Kettenhunde
01-24-2010, 05:33 AM
Oh, feel free to bring up a number of examples where the aircraft with the considerably higher wing loading can do the tighter turn - power off, clean config.

Power off is not sustainable performance. All aircraft at the same angle of bank and velocity make exactly the same turn power off.

Power on, they can sustain a turn based off the aircraft power available.

For example take the most common Spitfire Mk IX variant, the Merlin 66 @ +18 at 20,000ft:

http://img196.imageshack.us/img196/6510/spitfiremerlin6618fl20.jpg (http://img196.imageshack.us/i/spitfiremerlin6618fl20.jpg/)

And compare it to the P-47D-22 at 20,000 feet:

http://img194.imageshack.us/img194/1655/p47d22toweight56inhg.jpg (http://img194.imageshack.us/i/p47d22toweight56inhg.jpg/)

The Spitfire is woefully inadequate when matched in a sustained turning contest with the P-47 under these conditions.

All the best,

Crumpp

BillSwagger
01-24-2010, 05:45 AM
i see the differences in numbers, but i'm trying to understand the charts posted, Crump.

What does thrust limit and lift limit have to do with these two planes turning under these conditions?

Are we to assume a similar radius, or is that something based on the numbers indicated by load factor, and the speed?

Are you able to decipher when the wing stalls, by looking at these charts?

Just trying to understand this a little better,


thanks

Bill

M_Gunz
01-24-2010, 05:59 AM
Lift limit is the edge of stall. Thrust limit is the most the plane can sustain at full power.
Where the pink curve meets the blue curve is the hardest turn the plane can sustain. You have
the EAS-knots and the G's from there but not the turn radius though that can be determined from
speed and G's.
If you follow the pink curve above the blue then you have unsustainable performance, the plane
will slow down which quickly lowers the G's it can pull. It falls back down along the pink curve
if piloted right until it is again below the blue curve. How fast this happens is not knowable
with the chart information.

Although the P-47 can sustain higher G's it does that at a much higher speed than the Spitfire.
Higher radius, more circumference to fly around and a big enough difference does not equal less
time to turn 360 degrees. If the Spitfire is turning inside at equal or better rate then the
P-47 is not going to win the turn contest, it is going to end up in front of the Spitfire guns.

BillSwagger
01-24-2010, 06:31 AM
thanks Gunz

So am i to understand this correctly?

Where the P-47D turns at 3.5Gs at approx 175k(EAS) it is not making a tighter turn than the Spitfire?
It doesn't look like the Spitfire matches that turn, so what does that mean?
The Spitfire either makes a lower G turn (wider turn) or slows down.


Bill

K_Freddie
01-24-2010, 06:34 AM
Gamewise.. the ability of the FW to 'mush it' (as gaston444 says)with lots of instantaneous applied stick, is usually all you need to get a bead on your target.

It's not important to follow through a complete turn.
http://forums.ubi.com/groupee_common/emoticons/icon_cool.gif

Kettenhunde
01-24-2010, 07:27 AM
The Spitfire either makes a lower G turn (wider turn) or slows down.

That is correct. It is not hard to figure both the rate and radius either. It is a simple formula to hand jam off the chart or I also have as part of the spreadsheet.

Being that most of the WWII fighters were similar in performance, ie within 10%, their rate of turn is also very similar. You can expect ~21 degrees/sec for most of them. The maximum rate of turn of course occurs at different speeds for different aircraft.

The P47D22 is a very rough customer in terms of sustained turning performance for a Spitfire Mk IX Merlin 66 +18 at 20,000 feet.

Kettenhunde
01-24-2010, 09:08 AM
There still seems to be some confusion on how all this comes together and works.

All fighter aircraft designers regard sustained maneuverability as an important characteristic for any fighter aircraft. Maneuverability being comprised of sustained turning ability and agility.

This fact seems to be confused with the ability to sustain high load factors at low velocity.

Speed and sustained turning performance are linked by the physics. The faster an aircraft can travel, the larger its sustainable turn performance envelope. The designer has considerable influence on where he wants that performance to peak within the performance envelope.

Spitfire Mk IX +18 Rate of Turn:

http://img202.imageshack.us/img202/9046/spitfiremkixmerlin6618r.jpg (http://img202.imageshack.us/i/spitfiremkixmerlin6618r.jpg/)

Spitfire Mk IX +18 Radius of Turn:

http://img63.imageshack.us/img63/2204/spitfiremerlin6618radiu.jpg (http://img63.imageshack.us/i/spitfiremerlin6618radiu.jpg/)


P47 Rate of Turn:

http://img684.imageshack.us/img684/8393/p47d22rateofturn.jpg (http://img684.imageshack.us/i/p47d22rateofturn.jpg/)

P47 Radius of Turn:

http://img684.imageshack.us/img684/8073/p47d22radiusofturn.jpg (http://img684.imageshack.us/i/p47d22radiusofturn.jpg/)

Notice that in its best turn velocity of 137KEAS, the Spitfire holds a rate and radius advantage.

However if it tries to match the P47's sustained turn performance at 180 KEAS, it cannot achieve the rate of turn, the P47 will bring guns to bear first, and the Spitfire will lose the sustained turn fight.

BillSwagger
01-24-2010, 09:36 AM
Thanks for the explanation Crump. I knew what i was looking at, but it was hard for me to grasp that the P-47 could actually out turn a spitfire under the right conditions.

It just seems that if the P-47 were to dive and turn, then it gives the opportunity for the Spitfire to have the speed to hold a tighter turn. The P-47 is faster in the dive so turning wouldn't be the thing to do anyway.


Originally posted by K_Freddie:
Gamewise.. the ability of the FW to 'mush it' (as gaston444 says)with lots of instantaneous applied stick, is usually all you need to get a bead on your target.

It's not important to follow through a complete turn.
http://forums.ubi.com/groupee_common/emoticons/icon_cool.gif

yes but a mush in a turn would put the plane in a spin, considering that the air doesn't act evenly over the inside wing, as the outside wing, correct?

Kettenhunde
01-24-2010, 10:37 AM
Thanks for the explanation Crump. I knew what i was looking at, but it was hard for me to grasp that the P-47 could actually out turn a spitfire under the right conditions.


You are welcome.



It just seems that if the P-47 were to dive and turn, then it gives the opportunity for the Spitfire to have the speed to hold a tighter turn. The P-47 is faster in the dive so turning wouldn't be the thing to do anyway.

I am speaking of a co-energy engagement at 20,000 feet. The P47's sustained turning ability dictates the fight.


I don't understand what you mean by dive and turn. Remember, there is only two types of aircraft performance, sustained and instantaneous. All aircraft's instantaneous turn performance is exactly the same.

Now the ability to change speed is not the same!

In instantaneous turn performance, the aircraft that slows down the fastest wins the turn fight. We don't worry about bank angle because none of this is sustainable and the pilot can choose from any bank angle he wishes.

So it all goes back to which aircraft slows down the fastest. That is easy to figure by summing the forces and determining your deceleration rate.

Once the sustained performance line is reached, the airplane no longer decelerates.

Also, examine the lift line performance. Nothing regarding turn performance improves as you go down the lift line. Your lift limited turn performance peaks where the thrust limit and lift limit intersect.

There is nothing regarding a fighter aircraft turn performance that will improve by going slower than that intersection velocity.

So when folks point to performance that is down that lift line, it is pretty much a fantasy assumption the airplane will ever be intentionally operated at that point in a turning dogfight.

Xiolablu3
01-24-2010, 11:12 AM
Originally posted by Kettenhunde:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Oh, feel free to bring up a number of examples where the aircraft with the considerably higher wing loading can do the tighter turn - power off, clean config.

Power off is not sustainable performance. All aircraft at the same angle of bank and velocity make exactly the same turn power off.

Power on, they can sustain a turn based off the aircraft power available.

For example take the most common Spitfire Mk IX variant, the Merlin 66 @ +18 at 20,000ft:

http://img196.imageshack.us/img196/6510/spitfiremerlin6618fl20.jpg (http://img196.imageshack.us/i/spitfiremerlin6618fl20.jpg/)

And compare it to the P-47D-22 at 20,000 feet:

http://img194.imageshack.us/img194/1655/p47d22toweight56inhg.jpg (http://img194.imageshack.us/i/p47d22toweight56inhg.jpg/)

The Spitfire is woefully inadequate when matched in a sustained turning contest with the P-47 under these conditions.

All the best,

Crumpp </div></BLOCKQUOTE>

Official Test:-


http://www.wwiiaircraftperform...p-47/p-47c-afdu.html (http://www.wwiiaircraftperformance.org/p-47/p-47c-afdu.html)

25. Manoeuvrability – The good aileron control gives the P-47 an
excellent rate of roll even at high speeds, and during mock combats
it was considered to roll as well as, if not better than the
Spitfire at about 30,000 feet. At lower altitudes there is nothing
to choose between them. The rate of turn of the Spitfire is
naturally superior to the heavier P-47 and in turning circles it was
found that after four turns the Spitfire could get on the P-47’s
tail and remain there with a chance of shooting with correct
deflection. When 'bounced'; if a climbing turn towards the attack
were made, either aircraft was able to evade the other, but if the
climbs were continued, the Spitfire was able to draw away above for
another attack. On the level the speeds were so much alike that if a
big interval occurred between the aircraft it was difficult to
re-engage decisively. When bounced, if the Spitfire used a diving
turn to evade it would be caught in the dive, though the P-47 was
given difficult shooting at high speed; if the P-47 dived steeply it
was unable to climb back to re-engage.

Unofficial thoughts from an Eagle Squadron pilot who flew both :-

"One day in January 1943 General Hunter, the Commander of the 8th Fighter Command, came to visit us at Debden. He said he had a surprise for us. We were soon to re-equip with the very latest American fighter, the P-47 Thunderbolt. As he spoke we heard an unusual engine noise outside and one of the new fighters landed and taxied up beside one of our Spitfires. We went outside to look it over. It was huge—the wing tip of the P-47 came higher than the cockpit of the Spitfire. When we strapped into a Spitfire we felt snug and part of the aircraft—the Thunderbolt cockpit, on the other hand, was so large that we felt if we slipped off the *******ed seat we would break a leg! We were horrified at the thought of going to war in such a machine: we had enough trouble with the Focke-Wulf 190's in our nimble Spitfire Vs—now this lumbering seven-ton monster seemed infinitely worse, a true air inferiority fighter. ***Initial mock dog-fights between Thunderbolts and Spitfires seemed to confirm these feelings—we lost four Thunderbolt pilots in rapid succession, spinning in from low level, while trying to match Spitfires in turns. In the end our headquarters issued an order banning mock dog fighting in Thunderbolts below 8,000 feet.****

Gradually, we learned how to fight in the Thunderbolt. At high altitude, she was a hot ship and very fast in the dive; the technique was not to mix it with the enemy, but to pounce on him from above, make one quick pass and get back up to altitude; if anyone tried to escape from a Thunderbolt by diving, we had him cold. Even more important, at last we had a fighter with the range to penetrate deeply into enemy territory—where the action was. So, reluctantly, we had to give up our beautiful little Spitfires and convert to the new juggernauts. The war was moving on, and we had to move with it.

The change to the Thunderbolt might have been necessary militarily, but my heart remained with the Spitfire. Even now, thirty years after I flew them on operations, the mere sound or sight of a Spitfire brings me a deep feeling of nostalgia, and many pleasant memories. She was such a gentle little airplane, without a trace of viciousness. She was a dream to handle in the air. I feel genuinely sorry for the modern fighter pilot, who has never had the chance to get his hands on a Spitfire—he will never know what real flying was like."

Bremspropeller
01-24-2010, 11:24 AM
P-47C @ undisclosed speed and altitude vs. P-47D-22 at given speed and altitude figures http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

Read what Robert Johnson has to say about mixing it up with Spitfires.
It's all about knowing your aircraft's capabilities and avoiding it's weaknesses.

Kettenhunde
01-24-2010, 11:29 AM
P-47C @ undisclosed speed and altitude vs. P-47D-22 at given speed and altitude figures

LOL... http://forums.ubi.com/images/smilies/25.gif

That covers it nicely.

K_Freddie
01-24-2010, 11:31 AM
Originally posted by BillSwagger:
yes but a mush in a turn would put the plane in a spin, considering that the air doesn't act evenly over the inside wing, as the outside wing, correct?
If it's unbalanced over both wings and not anticipated by the pilot .. it can start a spin, Yes.

http://forums.ubi.com/groupee_common/emoticons/icon_cool.gif

hop2002
01-24-2010, 12:26 PM
Originally posted by Kettenhunde:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Oh, feel free to bring up a number of examples where the aircraft with the considerably higher wing loading can do the tighter turn - power off, clean config.

Power off is not sustainable performance. All aircraft at the same angle of bank and velocity make exactly the same turn power off.

Power on, they can sustain a turn based off the aircraft power available.

For example take the most common Spitfire Mk IX variant, the Merlin 66 @ +18 at 20,000ft:

http://img196.imageshack.us/img196/6510/spitfiremerlin6618fl20.jpg (http://img196.imageshack.us/i/spitfiremerlin6618fl20.jpg/)

And compare it to the P-47D-22 at 20,000 feet:

http://img194.imageshack.us/img194/1655/p47d22toweight56inhg.jpg (http://img194.imageshack.us/i/p47d22toweight56inhg.jpg/)

The Spitfire is woefully inadequate when matched in a sustained turning contest with the P-47 under these conditions.

All the best,

Crumpp </div></BLOCKQUOTE>

What odd figures.

According to these the P-47 at 56" is about 40 knots faster in level flight at 20,000ft than the Spitfire IX at 18 lbs.

You can see the Spitfire IX and P-47 performance figures at www.wwiiaircraftperformance.org (http://www.wwiiaircraftperformance.org)

Actual difference was about 10 mph.

BillSwagger
01-24-2010, 12:30 PM
Originally posted by Kettenhunde:


I don't understand what you mean by dive and turn. Remember, there is only two types of aircraft performance, sustained and instantaneous. All aircraft's instantaneous turn performance is exactly the same.


What i meant, through looking at the chart it appears the sustained turn is dictated by the power/thrust of the engine, right?

So in a dive you are going to see higher speeds out of both planes, but the spitfire appears to pull higher Gs at lower speeds. Doesn't this, in effect, mean that although its turn may slow it down, it would still cut inside the P-47 in a dive?

I guess what remains to be measured or demonstrated is how much it would slow down by cutting inside.

i've also read the pilot account mentioned above, and i think it speaks volumes about the need for a big lumbering plane with range. I think most pilots that crashed in those mock fights were caught trying to pull out of dive. I read that in a 5G pull out, the controls were heavy enough to require both hands.

Actually, i wonder if control forces were heavy for all planes above 5 Gs. It just seems the airspeed, compiled with the elevators acting against the (weight of the plane X 5) would equate to quite a bit of elevator stick force. But i just got done reading how P-40s could pull 9 Gs for brief moments, and the P-40 was said to have heavier stick forces. Maybe it didn't.


I would like to see a chart like the ones above for the 190, since thats what this thread is about.
Do you have that Crump?


Bill

hop2002
01-24-2010, 12:35 PM
P-47C @ undisclosed speed and altitude vs. P-47D-22 at given speed and altitude figures

Ah, but look at the speed and altitude figures given. Convert those in to true air speed in mph and see if anything jumps out at you http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

Kettenhunde
01-24-2010, 03:37 PM
Ah, but look at the speed and altitude figures given.

397mph TAS / 1.37 = 289mph * .869 = 252KEAS

That is going off JL165 here:

http://www.spitfireperformance.com/jl165rr.html

The Spitfire performance actually comes from a spreadsheet using data you provided Hop....

Yes it is 6.3% optimistic over published data on the type.

The P47D22 speed is 296KEAS not 304KEAS. I left the speed from a P-47M analysis. It does not change a thing about the outcome or even the speeds it occurs.

The prediction gives very good agreement.

hop2002
01-24-2010, 04:04 PM
I didn't say the Spitfire figures were odd.

In fact it looks more like 262 keas on your graph. But the problem is the P-47. As I said you show it as about 40 knots faster, at 20,000ft.

Mike Williams has P-47 figures on his page. He even has 2 entries for the P-47 @ 56" in his graph. 407 mph and 410 mph at 20,000ft.

410 /1.37 = 299 mph * .869 = 260KEAS

So where does the 305 KEAS on your chart come from?

480 / 1.37 = 350 mph * .869 = 304 KEAS.

You are using figures for a P-47 doing over 480 mph at 20,000ft. The P-47M managed 440 mph at 20,000ft at 70"

So as far as I can see, the "P-47D at 56" you claimed is actually a P-47M at 70" with an extra 40 mph added on.

Kettenhunde
01-24-2010, 04:25 PM
What i meant, through looking at the chart it appears the sustained turn is dictated by the power/thrust of the engine, right?

That is correct.


Doesn't this, in effect, mean that although its turn may slow it down, it would still cut inside the P-47 in a dive?

The whole thing with a dive confuses me. What condition of flight are you talking about? It looks like this would be instantaneous performance as we are in a dive and engine power is not a factor and all turn performance is the same.

The amount of load factor an airplane can sustain for a given speed only applies to that speed. It does not translate into any other condition.


I think most pilots that crashed in those mock fights were caught trying to pull out of dive.

I read it and sound to me like pilots goofing around trying to match performance at speeds their airplane was not capable of performing. It can easily take ~10,000 feet to recover an aircraft from a spin entry. If it is inverted, it may never recover.

That is assuming the pilot was capable of giving proper control inputs.

Spinning an aircraft can be extremely dangerous. You can do everything correctly and the aircraft not recover.

The Spitfire Mk IX is expressly prohibited from spinning below 10,000 feet as it will not recover. The P47 list's a fairly responsive spin recover and normal control input. The aircraft requires firm but smooth control input for recovery. It cautions that recovery can take up to 3 complete turns at 1000ft loss per turn so hold your input at least that long before reattempting control inputs. It also says to try 1/2 throttle if it does not recover.

In theory, at 10,000 feet that gives you three chances to smoothly and firmly input the correct control response at the right throttle setting before you die.


It just seems the airspeed, compiled with the elevators acting against the (weight of the plane X 5) would equate to quite a bit of elevator stick force.

It is called gradient and is measured in units called "stick force per G". The trick on longitudinal stability and control is make your stick force per G high enough the pilot does not kill himself without making it so high he has difficulty attaining the force required. About 85lbs of pull force was considered ideal for high speed recovery.

Kettenhunde
01-24-2010, 04:33 PM
hop says:
But the problem is the P-47

Re-read my first post please and understand what it is telling you. If I have to consistently repeat myself to you, I will ignore you as trolling.


The P47D22 speed is 296KEAS not 304KEAS. I left the speed from a P-47M analysis. It does not change a thing about the outcome or even the speeds it occurs.

The prediction gives very good agreement.



The P47 is fast and should be at 296KEAS:

http://img33.imageshack.us/img33/1655/p47d22toweight56inhg.jpg (http://img33.imageshack.us/i/p47d22toweight56inhg.jpg/)

As I said, it does not change the outcome of the prediction in the least.

All the best,

Crumpp

hop2002
01-24-2010, 04:43 PM
Crumpp, using your own calculation:

(TAS mph /1.37)*.869 = KEAS

(467 mph / 1.37) * .869 = 296 KEAS

So you are using figures for a P-47 doing 467 mph TAS at 20,000 ft. In fact, running at 70" HG, the P-47M did 440 mph at 20,000ft.

You are comparing a Spitfire against a fantasy P-47 with far more power than they had historically. Not content with that, you claimed the figures were actually for a P-47D running at 56".

M_Gunz
01-24-2010, 04:56 PM
Originally posted by Kettenhunde:
There still seems to be some confusion on how all this comes together and works.

All fighter aircraft designers regard sustained maneuverability as an important characteristic for any fighter aircraft. Maneuverability being comprised of sustained turning ability and agility.

This fact seems to be confused with the ability to sustain high load factors at low velocity.

Speed and sustained turning performance are linked by the physics. The faster an aircraft can travel, the larger its sustainable turn performance envelope. The designer has considerable influence on where he wants that performance to peak within the performance envelope.

Spitfire Mk IX +18 Rate of Turn:

http://img202.imageshack.us/img202/9046/spitfiremkixmerlin6618r.jpg (http://img202.imageshack.us/i/spitfiremkixmerlin6618r.jpg/)

Spitfire Mk IX +18 Radius of Turn:

http://img63.imageshack.us/img63/2204/spitfiremerlin6618radiu.jpg (http://img63.imageshack.us/i/spitfiremerlin6618radiu.jpg/)


P47 Rate of Turn:

http://img684.imageshack.us/img684/8393/p47d22rateofturn.jpg (http://img684.imageshack.us/i/p47d22rateofturn.jpg/)

P47 Radius of Turn:

http://img684.imageshack.us/img684/8073/p47d22radiusofturn.jpg (http://img684.imageshack.us/i/p47d22radiusofturn.jpg/)

Notice that in its best turn velocity of 137KEAS, the Spitfire holds a rate and radius advantage.

However if it tries to match the P47's sustained turn performance at 180 KEAS, it cannot achieve the rate of turn, the P47 will bring guns to bear first, and the Spitfire will lose the sustained turn fight.

And if it doesn't while the P-47 continues to flat turn then the P-47 becomes the target. Lesson is that the P-47
pilot should not play the Spitfire pilot's game. He should use his greater speed to achieve fast vertical separation
and perform a reversal from above. Spitfire may have a better best sustained climb but it won't beat P-47 high speed
zoom.

In the same way that the AVG used P-40's to beat the Japanese fighters, that is how P-47 should fight Spitfires.

Kettenhunde
01-24-2010, 04:56 PM
You are comparing a Spitfire against a fantasy P-47 with far more power than they had historically.


Hop,

For your piece of mind, even putting the P47D-22 at 262KEAS does not change the outcome of the turn prediction. Turn performance is about excess power and the P47 just has way more power than the Spitfire Mk IX Merlin 66 at that velocity.

What is the sea level speed for a P47D-22?

~340mph TAS sound reasonable?

What is the power output at sea level and 20,000 feet?

~2300 hp for both?? That is what the data I have shows.

This is going somewhere so please answer the questions and I will make it clear to you. Maybe some folks will learn something along the way.

It goes back to the thread I started a few weeks ago and need to finish up.

Bremspropeller
01-24-2010, 05:04 PM
And if it doesn't while the P-47 continues to flat turn then the P-47 becomes the target. Lesson is that the P-47
pilot should not play the Spitfire pilot's game.

You're forgetting that the Spit bleeds off energy while the P-47 turns at it's max sustained-turn, which means, if it unloads, it will accelerate.

So, while the Spit tries to win the angles-fight by going to a lower E-level, the P-47 still has the chance to unload and run, or convert speed into altitude or both.

M_Gunz
01-24-2010, 05:16 PM
That's why I prefer the P-47! To my view he has more high energy options.

ADD: It is also why I wrote the next sentence after the part you quoted:
He should use his greater speed to achieve fast vertical separation

I can't figure out why you dropped that part of what I wrote and point out what I've been posting anyway.

hop2002
01-24-2010, 05:18 PM
Posted 24-01-10, 23:56 Hide Post

quote:
You are comparing a Spitfire against a fantasy P-47 with far more power than they had historically.



Hop,

What is the sea level speed for a P47D-22?

~340mph TAS sound reasonable?

What is the power output at sea level and 20,000 feet?

~2300 hp for both?? That is what the data I have shows.

This is going somewhere so please answer the questions and I will make it clear to you. Maybe some folks will learn something along the way.


Both assumptions sound about right. But Crumpp, can you answer 1 simple question?

Does the chart you just posted show the P-47D doing about 467 mph at 20,000 ft?

M_Gunz
01-24-2010, 05:23 PM
467/440 = 1.061, ie 6.1% more.

hop2002
01-24-2010, 05:33 PM
467/440 = 1.061, ie 6.1% more.

6.1% more speed = how much more power?

And 440 was the speed for the P-47M with 2,800 hp.

M_Gunz
01-24-2010, 05:37 PM
He made an example only. It's not like he is pushing some kind of agenda. Would a SLOWER P-47 turn faster?

Kettenhunde
01-24-2010, 06:04 PM
Does the chart you just posted show the P-47D doing about 467 mph at 20,000 ft?


No it does not hop. It shows a predicted trend for sustained turn performance over the aircraft envelope and is compared to the Spitfire under the SAME conditions of flight.


Both assumptions sound about right.

Good I thought they were valid but do not proclaim to be an expert on the P-47 series.

Now we know that power does not change and our True Airspeed at sea level equals our EAS.

Therefore the airplane will offset the same drag forces at 20,000 feet that it does at sea level with the same amount of power.

So...

340mph EAS * .869 = 295KEAS

Our P-47 should be capable of achieving 295KEAS at 20,000 feet if our power is the same.

295KEAS * 1.37 = 404 KTAS or 467mph TAS.

Do the same with the Spitfire...we now have a very good prediction of the relative forces acting on our airplanes! The value of equivalent airspeed should be glaring and obvious at this point in predicting aircraft performance trends. That is why we use it and it is easier to use as well.

We know what the Spitfire achieves at sea level and the power. It is ~100hp lower at 20,000ft which drops our EAS speed from sea level.

Why does that not line up with some 70 year old report??

Most of that speed reduction is the environmental effect of density on propeller efficiency. That is an environmental effect linked to velocity that effects both aircraft's performance equally.

Lastly some of this is also compressibility modeling....the technique I used just eliminates most of that error by putting all the airplanes under the same compressibility correction rules.

Does any of this matter or effect our turning performance trend prediction??

Not in the least.....We know the trends of the aerodynamic forces acting on the aircraft. Everything else is environment or our ability to express the effects of that environment. Lets just eliminate all that guess work because in order for anything to be valid, we have to apply it to both aircraft. Our relative performance trend stays the same but the speeds shift.

Nothing to do with how much relative power or thrust these aircraft can devote to a turn.

We just care about the relative amount of excess power the P-47 and the Spitfire can devote to turn performance so we can get a valid prediction of performance trends.

What you can say is that at 20,000 feet, the P47 can turn at its best turn speed and it can sustain a higher load factor at a higher speed than the Spitfire Mk IX Merlin 66 +18 is capable of sustaining.

That forces the Spitfire to slow down in order to realize its sustained level turn performance advantage which occurs at a lower speed.

Terrenceflynn
01-24-2010, 07:28 PM
The Oscar and Zero are completely modeled wromg too.

ALL Oscars KI31ABC had 8MM rubber self sealing tanks.

Oscars KI43II - III had 13mm rubber around fuel tanks, and had engines that could be run at full throttle for 30 minutes.

The 12.7mm machines are woefully lacking their explosive ammo, and explosive tracer ammo, as well as hitting power. IT IS IMPOSSIBLE TO GET KILLS WITHH THE KI43II and III in game.

Kettenhunde
01-24-2010, 07:47 PM
And if it doesn't while the P-47 continues to flat turn then the P-47 becomes the target. Lesson is that the P-47 pilot should not play the Spitfire pilot's game. He should use his greater speed to achieve fast vertical separation and perform a reversal from above. Spitfire may have a better best sustained climb but it won't beat P-47 high speed zoom.

Where do you guys get this idea that if you turn, your speed will spiral down to nothing?

It is very easy accelerate in a turn with an airplane much less not loose airspeed or hold a precise airspeed.

Gaston444
01-24-2010, 09:36 PM
Quote, Kurfust: "I'd love to see that Rechlin paper. Which one is it and when was the testing done?"


-It is a History Channel quote, described as direct from Rechlin, for early FW-190As vs Me-109Fs most likely... Do you think they made it up?:

http://www.youtube.com/watch?v=R0YLLBvIBFk

Gunther Rall said: "They (Rechlin) told us this new FW-190A could out-turn our Me-109F (900 lbs lighter than G), HOWEVER, I could out-turn it"

So Gunther Rall concurs that Rechlin DID say something along the lines of what the History Channel says...

I do have one Rechlin quote to the contrary: In the La-5's 1944 evaluation, they mention that the la-5 turns, at low altitudes, worse than a Me-109G with MW-50 boost, while also turning better than a FW-190A of unspecified model.

The speed is not mentioned, which could make all the difference, as may do the Me-109's MW-50 power at higher speeds.

Above 250 MPH, I am fairly sure a clean Me-109G will out-turn any FW-190As of the A-5 model and later, and maybe more so with MW-50 if speeds get even higher.

This Rechlin La-5 quote is the ONLY WWII quote of the Me-109G out-turning the FW-190A I have read out of ALL of WWII... The ONLY one people... All Wartime FW-190A opponents disagree with this if they have experienced both in combat: Russian, American, British pilot accounts all say the opposite, including British tests that have some other problems of their own.

Yes, I do know about those Russian turn times: Dates and airframes #s would be nice for the German stuff... But even then, these figures might only reflect the use of full power if no speeds are attached...

The Rechlin's La-5 comment is itself likely to be a turn rate comparison done at full power.

At 160-250 MPH, I hold that the FW-190A's turn radius is larger, but the turn rate higher, than that of a Me-109G. This may hold true even with the Me-109G down to its peak sustained turn rate speed of 160 MPH, as long as the FW-190A is allowed some extra speed in a wider radius. The turn rate might be close or equal then...

That ONE Rechlin La-5 test sentence is rather very little to hang on to for the computer game simulation edifice...

As for late Anton models past the A-5 having competitive comparative turn, or pull-out, performance above 250 MPH, the evidence is even clearer: Absolute Zero...

If you have a test, or any other non-calculated account, that actually says the Me-109G out-turns the FW-190A below 250 MPH, I would be VERY interested to see it...


Gaston

AndyJWest
01-24-2010, 09:49 PM
http://forums.ubi.com/groupee_common/emoticons/icon_rolleyes.gif

BillSwagger
01-24-2010, 10:55 PM
Originally posted by hop2002:
Crumpp, using your own calculation:

(TAS mph /1.37)*.869 = KEAS

(467 mph / 1.37) * .869 = 296 KEAS

So you are using figures for a P-47 doing 467 mph TAS at 20,000 ft. In fact, running at 70" HG, the P-47M did 440 mph at 20,000ft.

You are comparing a Spitfire against a fantasy P-47 with far more power than they had historically. Not content with that, you claimed the figures were actually for a P-47D running at 56".


A lot published data on the P-47 are posted as guaranteed performance, and in those tests it states a degree of error of as much as 5% for speed. Its likely the P-47 was plotted at several different speeds well above whats posted in those reports, particularly whats used in the data with M and the N.

Here is a Speed test of the P-47D, it goes 444mph at 23000ft.
http://www.wwiiaircraftperform.../p47d-44-1-level.jpg (http://www.wwiiaircraftperformance.org/p-47/p47d-44-1-level.jpg)

Probably a bubble top judging from the serial number, but it should drive the point home regarding the P-47 and published speed.


I dont think top speed was the point of the discussion anyway.

As for the dive, Crump, if i'm reading the charts correctly, it looks like if the plane attempts a turn that places figures on the left side of the pink plot lines the plane will have problems with the turn.

A dive allows the plane to go faster than its sustained speed, staying above the blue plot lines. And is the case with the spitfire and P-47, those pink dots are further to the right on the P-47 plot. So that tells me the planes won't match the same Gs at the same speed. The Spitfire can pull more Gs at slower speeds even if its not sustained, allowing it to cut inside the P-47 in a dive.

For example, the P-47 can only pull 2.5Gs at 150IAS, where the spitfire pulls 4Gs. Actually that would be slow even in level flight, but I'm trying to illustrate the point more so.


Bill

M_Gunz
01-24-2010, 11:51 PM
Originally posted by Kettenhunde:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">And if it doesn't while the P-47 continues to flat turn then the P-47 becomes the target. Lesson is that the P-47 pilot should not play the Spitfire pilot's game. He should use his greater speed to achieve fast vertical separation and perform a reversal from above. Spitfire may have a better best sustained climb but it won't beat P-47 high speed zoom.

Where do you guys get this idea that if you turn, your speed will spiral down to nothing?

It is very easy accelerate in a turn with an airplane much less not loose airspeed or hold a precise airspeed. </div></BLOCKQUOTE>

That is with each making his best sustained horizontal turn. Nothing there about speed going below best sustained.
Simple fact is that the Spitfire pilot is not constrained to keeping speed with the turning P-47 nor would a following
P-47 be constrained to slowing down to stay on the Spit's six.. in my world at least.

hop2002
01-25-2010, 02:10 AM
No it does not hop. It shows a predicted trend for sustained turn performance over the aircraft envelope

And the predicted trend is 467 mph at 20,000 ft.


Now we know that power does not change and our True Airspeed at sea level equals our EAS.

Therefore the airplane will offset the same drag forces at 20,000 feet that it does at sea level with the same amount of power.

So...

340mph EAS * .869 = 295KEAS

Our P-47 should be capable of achieving 295KEAS at 20,000 feet if our power is the same.

295KEAS * 1.37 = 404 KTAS or 467mph TAS.

Do the same with the Spitfire...we now have a very good prediction of the relative forces acting on our airplanes!

OK, the Spitfire had about 1650 hp at sea level, speed 335. It had about 1600 hp at 20,000 ft. There's very little power difference between the Spit at sea level and 20,000ft. There's very little speed difference between the Spit and P-47D @ 56", at either sea level or 20,000ft. In your charts there is an enormous speed difference.



We know what the Spitfire achieves at sea level and the power. It is ~100hp lower at 20,000ft which drops our EAS speed from sea level.

No, power difference is at most 50hp.

But Crumpp, we have the actual aircraft test results. We know the speed of the Spitfire at 20,000ft: 390 - 400 mph. We know the speed of the P-47 at 56" at 20,000ft: 395 - 410 mph. Yet your graphs show the Spitfire at 413 mph, the P-47 at 467 or 481 mph.


Does any of this matter or effect our turning performance trend prediction??

Not in the least.

Your model says the P-47 is capable of 467 mph at 20,000 ft with 2300 hp. It was actually capable of about 405 mph under those conditions. And you think that doesn't change your results?

Your model shows a P-47 with something over 3300 hp.


He made an example only. It's not like he is pushing some kind of agenda. Would a SLOWER P-47 turn faster?

Not like he's pushing an agenda? He has a graph that's labelled P-47 at 56". The P-47 had about 2300 hp at 56". To get the performance Crumpp is showing you need over 3300 hp, far more than even the P-47M or N had.


A lot published data on the P-47 are posted as guaranteed performance, and in those tests it states a degree of error of as much as 5% for speed. Its likely the P-47 was plotted at several different speeds well above whats posted in those reports, particularly whats used in the data with M and the N.

Here is a Speed test of the P-47D, it goes 444mph at 23000ft.
http://www.wwiiaircraftperform.../p47d-44-1-level.jpg (http://www.wwiiaircraftperformance.org/p-47/p47d-44-1-level.jpg)

Flight test reports show speeds achieved, not guaranteed performance. Look at the chart you linked to, speed for the P-47 at 56" at 20,000 ft was 395 mph.

Even at 70", speed was 427 mph. Crumpp is showing it at 467 mph for 56".


I dont think top speed was the point of the discussion anyway.

Look at Crumpp's chart. It shows sustained level speed of 296 KEAS. It should actually be about 257 KEAS. Look how the graph would change.

And a P-47 sustaining over 3.5G at 20,000 ft? Maybe with the 3300 hp Crumpp's chart assumes, but not in real life.

deepo_HP
01-25-2010, 04:12 AM
Originally posted by hop2002:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">I dont think top speed was the point of the discussion anyway.
Look at Crumpp's chart. It shows sustained level speed of 296 KEAS. </div></BLOCKQUOTE>
then just replace the label 'p-47 xx' with some other plane. even if the data don't exist in 'real life', the plot makes sense in terms of turn-performances.
i agree with billswagger, it is not about top-speeds. i find the plots explain well, how sustainable performance relates to speed, and how this matters when comparing planes with different characteristica.

quite more interesting than the opener's conclusions on crosslinking pilot-tales and sabre-metaphores and referencing test-results with tv-shows about 'meshersmitts'.

Kettenhunde
01-25-2010, 04:29 AM
It shows sustained level speed of 296 KEAS. It should actually be about 257 KEAS. Look how the graph would change.

Maybe with the 3300 hp Crumpp's chart assumes

Don't make up your own Bull****. My chart assumes 2300 hp shaft horsepower which you agreed was a valid assumption.


Hop says:
Both assumptions sound about right.

http://forums.ubi.com/eve/foru...851013728#6851013728 (http://forums.ubi.com/eve/forums/a/tpc/f/23110283/m/2221055328?r=6851013728#6851013728)

I explained how it is done. I understand none of that is taught on the internet. Sorry but you have to go to a classroom to learn such techniques.


Look at Crumpp's chart. It shows sustained level speed of 296 KEAS. It should actually be about 257 KEAS. Look how the graph would change.


You don't understand how lift, thrust, and drag are linked. Load factor is a directly affected by thrust. We are comparing 2300 hp to 1525 hp.....

Lift and drag are also connected. If you increase one, then the other MUST increase as well. This is why your assumption the outcome changes is baloney, Hop. That is why I keep saying to look at aircraft as a system and not just one characteristic.

The P47 at 20,000 feet simply has better sustained turn performance a certain speeds than the Spitfire. Why this is so surprising to you is beyond me. It is just simply physics.

Here we have the P47D22 assuming propeller losses at altitude....

Our propeller efficiency has gone from 85% to 73%....

http://img715.imageshack.us/img715/8417/p47d22forhop.jpg (http://img715.imageshack.us/i/p47d22forhop.jpg/)

Even compared to an optimistic Spitfire Mk IX Merlin 66 +18 the P47 still has better sustained turn performance at 20,000 feet. If we adjust the Spitfire Mk IX to more average data and account for density effects on the propeller, the gulf widens considerably....

Ahh It widens back to exactly what the relative line up BEFORE we started assuming environmental effects!

Lets not even worry about the optimistic data but lets just account for density effects...

http://img715.imageshack.us/img715/8098/spitfiremkixmerlin6618d.jpg (http://img715.imageshack.us/i/spitfiremkixmerlin6618d.jpg/)

Even if we use all the optimistic data for the Spitfire and assume it is flying in a complete different environment from the P47....

http://img254.imageshack.us/img254/6510/spitfiremerlin6618fl20.jpg (http://img254.imageshack.us/i/spitfiremerlin6618fl20.jpg/)

Hey check it out... the relative line up is exactly the same! At ~180KEAS, the P47 can sustain a higher load factor than the Spitfire Mk IX Merlin 66 +18.

What else you want me to do Hop? How else can give the Spitfire an advantage for you?

http://forums.ubi.com/images/smilies/25.gif

Kettenhunde
01-25-2010, 04:55 AM
Simple fact is that the Spitfire pilot is not constrained to keeping speed with the turning P-47 nor would a following P-47 be constrained to slowing down to stay on the Spit's six.. in my world at lea

That is correct.

I see I misunderstood your conditions.

Kettenhunde
01-25-2010, 05:06 AM
A dive allows the plane to go faster than its sustained speed, staying above the blue plot lines.


Yes it does bill...You are trading altitude for airspeed.

That is why turn fights tend to spiral down to the treetops.

Keep in mind the P47 in our example can convert airspeed to altitude. A zoom climb to Vx from 180KEAS takes ~3.4 seconds to gain 970 feet in altitude. The Spitfire moves his nose 80 degrees during that time.

If the P47 shallows out his turn and zooms then you can see how the yo-yo fights develop. The P47 can sustain a series of yo-yo's in the turning circle. When he rolls the vector of lift below the horizon he makes large load factor gains.

It is two steps forward and one step back around the circle but the end result is the P47D22 has the sustained maneuvering performance to give a Spitfire Mk IX Merlin 66 +18 a run for its money in a dogfight.

That is if it wants to stay in the turn circle and fight angles.

The P47D22 at 20,000 feet can sustain a higher load factor than the Spitfire so it can always force the Spitfire to go slower, give up altitude, or lose the fight.

*edited for clarity

Kettenhunde
01-25-2010, 06:41 AM
OK, the Spitfire had about 1650 hp at sea level, speed 335. It had about 1600 hp at 20,000 ft.

No it didn't...

Do you have Merlin 66 chart at +18?

http://www.spitfireperformance.../merlin66hpchart.jpg (http://www.spitfireperformance.com/merlin66hpchart.jpg)

Gaston444
01-25-2010, 04:27 PM
Notice how there is still not one quote, or test, on how the Gustav out-turns the Anton at low altitudes in sustained turns below 250 MPH...

I think for people that have less invested in computer simulations, that alone would be a powerful clue...

Be widely advised I am not holding my breath...

Gaston

M_Gunz
01-25-2010, 06:25 PM
The only truth is in quotes and anecdotes generally short on conditions and specifics?
Data and charts don't count?

Gunther Rall "they told us this but I did the opposite" doesn't tell you that what
"they told" was wrong then you should get your reasoning-box checked perhaps. It is
funny how you use the first part to back your phony point up while ignoring the
negation of that very point from the very source you give. Rall flew both planes.

You don't do the science or the math so you're stuck misinterpreting quotes and now
you demand that quotes be presented to disprove you? Even The Joke misused charts,
he had more tricks that you do!

You're just Trolling, Gaston. And frankly it got pathetic before you started this thread.

Gaston444
01-25-2010, 10:37 PM
It's all in the maths guys... Who cares what ace pilots actually said...

But you contrarians don't even know WHY Karhila claimed, very specifically, that the Me-109G-6 had to be downthrottled all the way down to 160 MPH to reach its peak sustained turn rate... Not to mention that you didn't even previously KNOW that the Gustav's peak sustained turn rate was found this low... Neither did the pushed-from-the-rear math by the way...

And THAT, folks, is skating dangerously close to saying you don't know nothing.

But you don't say that, because as Socrates observed, most people don't even know they know nothing...

Gaston

AndyJWest
01-25-2010, 10:40 PM
pushed-from-the-rear math
As opposed to where yours comes from?

Erkki_M
01-25-2010, 11:13 PM
Originally posted by Gaston444:
It's all in the maths guys... Who cares what ace pilots actually said...

But you contrarians don't even know WHY Karhila claimed, very specifically, that the Me-109G-6 had to be downthrottled all the way down to 160 MPH to reach its peak sustained turn rate... Not to mention that you didn't even previously KNOW that the Gustav's peak sustained turn rate was found this low... Neither did the pushed-from-the-rear math by the way...

And THAT, folks, is skating dangerously close to saying you don't know nothing.

But you don't say that, because as Socrates observed, most people don't even know they know nothing...

Gaston

Where exactly does Kyösti Karhila mention the 109G's best sustained turn was 160mph? He does mention a dogfight with P-51s in a gondola armed 109, but does not mention the 250kmph or 160mph to be any kind of optimal turning speed(which it is not). He also doesnt mention he ever purposefully slowed down to that speed, but that he kept his turning easy enough to maintain that speed and to not get any slower. Note that the article you read is a translation, not original. Also note that the P51s were later found to be either Yaks or P40s that were, apparently, painted gray and not green or brown that they usually were. Both P40 and Yak have higher optimal speed for sustained turn than the 109.

M_Gunz
01-26-2010, 03:45 AM
Originally posted by Gaston444:
It's all in the maths guys...

SHOW IT.

M_Gunz
01-26-2010, 03:59 AM
Originally posted by Erkki_M:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Gaston444:
It's all in the maths guys... Who cares what ace pilots actually said...

But you contrarians don't even know WHY Karhila claimed, very specifically, that the Me-109G-6 had to be downthrottled all the way down to 160 MPH to reach its peak sustained turn rate... Not to mention that you didn't even previously KNOW that the Gustav's peak sustained turn rate was found this low... Neither did the pushed-from-the-rear math by the way...

And THAT, folks, is skating dangerously close to saying you don't know nothing.

But you don't say that, because as Socrates observed, most people don't even know they know nothing...

Gaston

Where exactly does Kyösti Karhila mention the 109G's best sustained turn was 160mph? </div></BLOCKQUOTE>

Or anything about sustaining such a turn under less than full power?

*IF* you are going faster than best turn IAS *THEN* you get a wider radius *BUT* there is a big difference
between slowing down to best turn speed and how much power you need to use to sustain such a turn.

And then in lost in the words of quote-land just what did he mean by the words he used and how well do
they translate to now?

Grabbing for Socrates now? LOL, what a joke! If you understood what that is about then you'd not use it
for the purposes you do, Gaston! Your second-hand interpretation of first-hand accounts is beyond it!

Erkki_M
01-26-2010, 07:48 AM
M_gunz, very easy to find out.

The interviewer of this article http://www.virtualpilots.fi/hi...tiKarhilaCoffee.html (http://www.virtualpilots.fi/hist/WW2History-KyostiKarhilaCoffee.html) Jukka O. Kauppinen is at the very moment online @ #warbirds in ircnet.

The original, Finnish version:

http://www.virtualpilots.fi/hi...iKarhilaKahvila.html (http://www.virtualpilots.fi/hist/WW2History-KyostiKarhilaKahvila.html)

He mentions nothing about the best sustained speed there either. Translation to English is not direct, but pretty good.

M_Gunz
01-26-2010, 08:54 AM
I think they are the ones who did interview Gunther Rall and some others?
If so they are VERY GOOD and I like them VERY MUCH!

In the 70's I had seen assessment of the Finnish military around WWII.
They were judged to be highly elite, even the Regulars were crack troops.
Maybe I have come to expect high standards from Finland, that is what I see.

Erkki_M
01-26-2010, 09:13 AM
http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

There were certain advantages in being mostly an agricultural country back then... ...and having 1 year compulsory arms service for men(and which was made even longer after the winter war). Everyone knew how to handle guns, hunt, navigate and generally to survive and live in the woods even during winter... You couldnt say the same about most of the Soviet soldiers they sent here from the Ukraine area for example.

More good articles here:
http://www.virtualpilots.fi/hist/

JtD
01-26-2010, 10:12 AM
You guys will be amazed how well everything works once you figure out that at a constant 2300 hp power, thrust is not the same at 340 and 467 mph TAS. How silly is that. http://forums.ubi.com/groupee_common/emoticons/icon_rolleyes.gif

A simple and optimistic estimate puts it at 420 mph.

Daiichidoku
01-26-2010, 11:08 AM
i did NOT make this

i just happened to come across it surfing just the other day

http://img.photobucket.com/albums/v479/Daiichidoku/finland.jpg

BillSwagger
01-26-2010, 11:11 AM
"Technicians at the Republic Aircraft Corporation ran the engine at extreme boost pressures at 3,600 hp for 250 hours without any failure using common 100 octane avgas, but in general, the R-2800 was a rather fully developed powerplant right from the beginning."

and then i read something like this and think...hmmm, it could've gone faster,maybe, slightly, a little, tad bit more. http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif


http://www.aviation-history.com/engines/pr-2800.htm



Bill

K_Freddie
01-26-2010, 11:58 AM
Didn't they run WW2 planes on higher octane?
Which would probably shorten the lifespan considerably at full boost.
http://forums.ubi.com/groupee_common/emoticons/icon_cool.gif

JtD
01-26-2010, 12:10 PM
Originally posted by BillSwagger:
"Technicians at the Republic Aircraft Corporation ran the engine at extreme boost pressures at 3,600 hp for 250 hours without any failure using common 100 octane avgas, but in general, the R-2800 was a rather fully developed powerplant right from the beginning."

I'll believe the 3600 as soon as I see the test document for that. In the meantime, I'll consider it a typo and will go with 2600.

Wiki has the same paragraph, but dropped the 3600 hp line. I'd guess they did it for a reason.

So does anyone have that test report?

Kettenhunde
01-26-2010, 12:41 PM
Jtd wrote:

blah blah blah.....TAS.

It is in EAS, Jtd. Your favorite....

JtD
01-26-2010, 01:42 PM
Originally posted by Kettenhunde:
It is in EAS, Jtd. Your favorite....

Originally posted by Kettenhunde:
295KEAS * 1.37 = 404 KTAS or 467mph TAS

Roughly 3150 hp for that, with your numbers. Or about 420mph TAS for 2300 hp.

It's funny how it is hop2002 who "doesn't understand", when your are telling fairy tales, again.

You're back on ignore, so no need to reply.

hop2002
01-26-2010, 02:03 PM
No it didn't...

Do you have Merlin 66 chart at +18?

Yes, my fault, I took the hp from a static chart.

But the chart you linked shows the same, about 50 hp lost between sea level and 20,000 ft.


Don't make up your own Bull****. My chart assumes 2300 hp shaft horsepower which you agreed was a valid assumption.

Crumpp, a P-47 can't do 467 mph at 20,000 ft on 2300 hp. It's just not possible.

We've seen from the tests that 2300 hp for a P-47 = 410 mph, at most.



Even compared to an optimistic Spitfire Mk IX Merlin 66 +18 the P47 still has better sustained turn performance at 20,000 feet

So thrust has dropped so much that speed falls from 467 mph to about 410, but sustained G barely falls?

Can we see the figures, rather than just the output? It doesn't look right, anymore than it did when the speed was up over 480 mph.

Because if your model shows that a P-47D with 2300 hp does 467mph at 20,000ft, when US tests showed it actually did 395 - 410mph, then there's something wrong with your model.


What else you want me to do Hop?

Let's see the spreadsheet. Because the first results from it were, frankly, silly.

BillSwagger
01-26-2010, 02:04 PM
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 BillSwagger:
"Technicians at the Republic Aircraft Corporation ran the engine at extreme boost pressures at 3,600 hp for 250 hours without any failure using common 100 octane avgas, but in general, the R-2800 was a rather fully developed powerplant right from the beginning."

I'll believe the 3600 as soon as I see the test document for that. In the meantime, I'll consider it a typo and will go with 2600.

Wiki has the same paragraph, but dropped the 3600 hp line. I'd guess they did it for a reason.

So does anyone have that test report? </div></BLOCKQUOTE>

I don't see it as being that far fetched.


mentioned again, here...

http://enginehistory.org/Frank%20WalkerWeb1.pdf look at page 9, starts on page 8.

"Ultimately, the maximum power achieved on the "B" series was 2800HP at 2700rpm. Maximum power on the "C" series was 3800HP at 2800RPM. The maximum manifold pressure ever recorded was a staggering 150 inches of mercury (in/hg)!"


You can probably find more information on it if you read into Frank Walker, who introduced water injection to PW engines in the 1940s.



Bill

M_Gunz
01-26-2010, 03:17 PM
Originally posted by K_Freddie:
Didn't they run WW2 planes on higher octane?
Which would probably shorten the lifespan considerably at full boost.
http://forums.ubi.com/groupee_common/emoticons/icon_cool.gif

How so? Lower octane makes the engine knock at full boost.

TheGrunch
01-26-2010, 10:58 PM
Originally posted by M_Gunz:
How so? Lower octane makes the engine knock at full boost.
I hear quicker lead fouling of spark plugs was a big problem, but I am by no means an expert. Nothing to do with engine service life, of course, but still a big problem for a fighter pilot.

JtD
01-26-2010, 11:08 PM
Originally posted by BillSwagger:
I don't see it as being that far fetched.

mentioned again, here...

http://enginehistory.org/Frank%20WalkerWeb1.pdf look at page 9, starts on page 8.

"Ultimately, the maximum power achieved on the "B" series was 2800HP at 2700rpm. Maximum power on the "C" series was 3800HP at 2800RPM. The maximum manifold pressure ever recorded was a staggering 150 inches of mercury (in/hg)!"

There's a difference between achieving 3600/3800hp and maintaining it for 250 hours, using standard WW2 aviation fuel.
It is not impossible, just unlikely. So I'd like to see the original document. I'm also curious about the differences between the B and C series of the R-2800, another thing I didn't read into yet.

R_Target
01-27-2010, 12:08 AM
From R-2800:Pratt & Whitney's Dependable Masterpiece:


As an interesting footnote in the development of the R-2800, during WWII Frank Walker was charged with the task of testing the ADI system developed for the R-2800. During the
same time period, Pratt & Whitney was testing early development versions of the R-4360. Frank regarded the R-2800 as his baby and consequently wanted to prove to the world
that there was still life left in it. He made it a personal goal to keep up with the power output of the R-4360 with "his" R-2800. When reports came through that 3000hp had
been achieved with the R-4360 he met that challenge by boosting the R-2800 to ever higher manifold pressures and feeding it additional ADI fluid. With these changes, Frank met
the 3000hp challenge. Then the R-4360 reached 3500hp. No problem. Frank ran his R-2800 to an amazing 140" Hg manifold pressure and fed as much ADI fluid as the engine could
tolerate. Again he matched the R-4360's 3500hp. When the 3800hp threshold was achieved by the R-4360, Frank ran his R-2800 to a stratospheric 150" Hg to match the 3800hp
benchmark. However, Frank had to call it quits at 3800hp; it would have been a difficult explanation to make to his superiors if he had blown up his R-2800 in the test cell.
What makes this story more remarkable is the fact that Frank's R-2800 was a lowly "B" engine. And as Frank found out, not unnaturally, there is no replacement for
displacement. Even so, for a while he gave the R-4360 and it's development team a good run for it's money. As a further endorsement of the R-2800's sound and rugged design,
Frank made regular test runs of 3000hp for one hundred hours.

R_Target
01-27-2010, 12:13 AM
Originally posted by JtD:
I'm also curious about the differences between the B and C series of the R-2800, another thing I didn't read into yet.

IIRC, one of the big changes was a finer cut on the cooling fins and improved baffling, which enabled the higher hp of later Double Wasps. I can probably dig up some more.

M_Gunz
01-27-2010, 12:33 AM
Originally posted by TheGrunch:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by M_Gunz:
How so? Lower octane makes the engine knock at full boost.
I hear quicker lead fouling of spark plugs was a big problem, but I am by no means an expert. Nothing to do with engine service life, of course, but still a big problem for a fighter pilot. </div></BLOCKQUOTE>

I remember a big block (450 IIRC) car we used when I was a guard at a pharmaceutical plant in 76. Every week or so it
had to be taken out and run hard to "clean the plugs" as crud built up just cruising the parking lot and idling.
That leaves me wondering if the buildups happen because the same fuel that allows huge power is not suited for much
less than huge power. I thought that hard running burned plugs up and how can you do that and deposit coatings at the
same time? LOL! But I'm not a motorhead so I can only wonder and laugh, perhaps only at my own silly ideas.

TheGrunch
01-27-2010, 12:44 AM
Originally posted by M_Gunz:
But I'm not a motorhead so I can only wonder and laugh, perhaps only at my own silly ideas.
Neither am I. I think you're right, though. I presume that those P-51 pilots that had lead fouling troubles with higher octane fuels had those troubles because they were flying at their best economical cruising speeds for huge periods of time. It frequently comes up in Bud Fortier's book, for example. Mind, was there not some discussion recently about how 150 octane fuels were officially if not completely withdrawn from service some time in 1945 due to the same problem?

M_Gunz
01-27-2010, 12:59 AM
Posts on what happened and a lot of discussion on high-boost running and knock but I don't remember
anything about how or why crud built up on the plugs. It doesn't mean there wasn't, I just don't
remember.