LW aircraft speed specifications
 

http://lend-lease.airforce.ru/englis...ikov/part3.htm

The above is a link to an interesting article named

Conversations with N. G. Golodnikov

Part Three. P-39 Airacobra and Yaks

Towards the end of the conversation there is talk about the book specification speed of LW fighters, which I do not fully understand. I am no expert, but should we take the book speed of LW fighters with a pinch of salt as a result of this information?

A. S. Nikolay Gerasimovich, if you look at any reference book, the superiority in speed of German aircraft—the Bf-109G and FW-190—is indisputable. Minimum 20—25 kilometers at low altitudes and up to 80—100 kilometers at high altitudes. And you say ours did not lag behind?

N. G. No, some difference in speed always exists. At low altitudes we were a bit faster, at high altitudes they were. The difference was on the order of 10—20 km. But this difference was not so great that it ensured overwhelming superiority. In combat it was practically not discernible.

A. S. Nikolay Gerasimovich, sometime relatively long ago I was speaking with a pilot—a frontline veteran. Right after the war they flew in captured aircraft. And no matter how hard they tried, they were unable to attain the speeds the Germans had written in their specifications. The shortfall in speed was significant. In the end, they prevailed upon a German, a high-level specialist, and asked him, “Why this shortfall in speed? Are we using the engine’s capability incorrectly?” His response was that they would never achieve the target speed, because the German specifications showed the theoretical speed, and they were attempting to attain that speed on their instruments.

Nikolay Gerasimovich, in your view, is this possible?

N. G. Of course. We had a group of specialists with us from NII VVS. They were examining specifications and were looking at speed. “What speed is indicated at 7,000 meters? 780? Take away 100. And what about 3,000 meters? 700? Reduce it 70 km.” This is how they calculated the instrumented speed and, characteristically, almost always hit their target. Perhaps they knew something about our focus on speed.

Text © AndreySukhorukov
Translation © James F. Gebhardt

... the difference between true and indicated?

[Tongue-in-cheek] Don't worry. Soviet frontline pilots also never got the performance their aviation industry promised. [/Tongue-in-cheek]

Seriously: One interview done decades after the war is neither indicative of any trend or fact not an authority on anything but a veteran's personal recollections. It's just a tiny part of a very long and very complicated equation.

;)

Not supirsed at all

This is so unspecified that it is absolutely worthless besides the anecdotical value.

What german fighters in which version and what equipment? No Information.

Were they trying to reach the 190 A8 speeds with a F8 or so?

And then hearsay from a german specialist, who might say anything to please his new masters.

Worthless for any real value deductions, i'd say.

;)

S!

I wonder why AoA took it as a "truth" when certain criteria was met ;) For me that interview was nothing but an interesting study of viewsets, nothing more.

I think you need to prove that. :rolleyes:

Well TsaGi actually measured their Bf 109G-2 a bit faster than the German 'official' specs... ;)

;).....I dunno, just wanted to get on the winking bandwaggon.

And it's that which you decided to publish as actuals on your website.......

Yeah.....there's plenty of winkers on here:lol:

Problem? The first test published on the 109G the website were actually the worst ones (WNr. 14 026). You have there the worst and best tests, and everything between them.

Which ones do you believe?

Well, personally I believe the official specs (given with +/- 3% tolerance) are in good agreement with most tests, see Erla trials of 13 serial production airframes in avarage almost exactly macth the official figures; this is also true for the Soviet trials.

The rest are also well within this +/- 3% production tolerance, given variations in equipment etc.

zipper hit the nail on the head.

Yes, they are talking about the difference between indicated airspeed and true airspeed.

Here the Germans relate they will not see the performance on the Kennblatt curves (Vwck or TAS) on the airplanes airspeed indicator (Va or IAS).

Here TASGI or the manufacturer is attaining the airspeed calibration curves for instrument error.

No conspiracty theory required!!!

As for the state of German aerodynamics, I posted the following articles from the American Institute of Aeronautics and Astronautics library for you guys to enjoy!

I read inferiority complex.

I think YOU need to prove it. ;)



The TAS or IAS makes good sense to me.

So the claim is they were attempting to reach IAS's based on official figures which were actually TAS's, so what official sources were they using and did those sources not explain wether the speeds were IAS or TAS? or are we suggesting they were too stupid to realise they using the wrong speeds?

Pretty much...

Why don't you explain the German notations to us?

Vw

Vwck

I look forward to hearing it from a "real pilot", LMAO!!

Aww don't be jealous mate, you might be one one day.

p.s. you wouldn't happen to have a decent answer for the 'rest' of my question?

You two are one step away from a vacation, so cut it out.

So let us all not be so childish or hasty in our judgment of these men. One can be very intelligent and still lack knowledge.

http://img535.imageshack.us/img535/6...sydneycamm.png

But wait, Sir Sydney Camm is certainly not stupid. In fact he is an extremely intelligent and talented engineer who went on to design such swept wing aircraft as the Hawker Hunter.

http://www.rafmuseum.org.uk/london/c...unter-fga9.cfm

When you consider the fact, no other nation on earth had the depth of knowledge or experience in the transonic realm that the German aircraft industry possessed, you cannot fault the men of other nations for knowledge or understanding that is not in their possession.

Have you researched the Vw and Vwck notations, I would really like to hear your input on this matter!

Maybe if you cannot figure it out, these men were not "stupid" and do not deserve such a label?

But hold on a minute here, we aren't talking of entering the realms of transonic flight here, we are simply talking about misinterpreting between IAS and TAS......that doesn't sound credible that they wouldn't be aware there is a difference.

while on the subject of the P.1101.....wasn't it actually very 'useless'

Well, you are pilot.....right??

What do they have in common!!!

:grin:

Seriously?.....you are still in doubt?

Transonic flight and 'misinterpreting' IAS and TAS.......absolutely nothing.....why?

:rolleyes:

Of course, it was German, right??

http://img265.imageshack.us/img265/2876/p1101.png

So how many hours do you two have and what airplanes have you flown from take off to landing?

Nothing??

Really, think about it, every pilot has to account for it in their flight planning.

We will come back to it and here is a huge hint, if you recognize it.

Tell me, what is the difference between these too formula's?

Both formulat's express the same thing.

http://img855.imageshack.us/img855/3659/vw1o.jpg

http://img689.imageshack.us/img689/7158/vw2du.jpg

I am begining to think the men in the VVS were not so stupid, huh!

You certainly cannot explain it and you are pilot, right?

Yes it was obviously but that's not what I am getting at, I don't have agendas, it was primarily useless because it was incomplete, and any subsequent development inspired by the design were quite changed....almost like everyone who saw it knew there were improvements to be made.

How does Crumpp know that Camm was referring to the wing itself when he was shown it? And how does he know it was the sweep itself that he was referring to as useless? He doesn't, it's an assumption. There is no recording nor official transcript of the conversation to gather context therefore zero proof.

Crummp, i know he's a pilot for a fact, i know what he flies, you on the other hand i am doubtful.

you can whine all you like, them's the facts.

Yes...even PPL's, so how does it come a major research institution was unaware of the difference?

Yes I am, just like the copies of my commercial pilot's licence showed in the other thread, but I am not an amateur internet aerodynamicist so your graphs and walls of copy/pasted text etc etc hold no interest to me.

Osprey,

Sir Sydney Camm's reaction was typical in fact. Most of the aeronautical engineering community in the world had very little knowledge of swept wing theory, compressibility effects, and transonic flight.

An engineer in the United States had been doing some parallel work on swept wing theory and mach effects. His work was not considered mainstream or accepted by the majority of his colleagues until after the war when the German findings confirmed his....

No all of this related to the original poster's interesting anecdotes.

Really??

So, how was the United States able to produce the atom bomb?

They were aware of things nobody else was aware of!!!

Is it really a surprise that someone in advance of others in specific areas would develop things those without that specific knowledge could not explain????

I see you are avoiding answering the question. Please do your best!! It is ok and I expect you do not know the answer.

They express the same thing.

So you are sticking with the theory that the Russians were too stupid to understand the difference between IAS and TAS?

Go ahead and quote where I said this? It is a fact this is patently false.

You are just trying to get the thread locked, now.

Please answer the quesiton, you are pilot, right?

Have you found out the difference between the German notations for Vw and Vwck?

In order for your fantasy theory of "Russians were too stupid to understand" theory to be advanced...this answer to the difference between Vw and Vwck must be common knowledge that only an idiot would not see.

You are pilot, what is the answer to these two questions?

Just admit you don't know and I will explain it for you and everybody else. If you can't do that, I will explain it in a few days.

No......I don't want to answer your pointless question, it proves 'nothing'.

Presumably when you look it up...

OK so you didn't say the Russians were too stupid verbatim, but by implication that is exactly what you are saying.

@Uther....before you decide to give me a holiday I will just remind that I simply asked a question and Crumpp decided to come back with sarcasm and accusation, one of us is a real pilot and only one of us came up with proof, I hope people will realise an actual pilot's license kinda beats internet quotes in that department.

Forum rule 15:

15. Impersonation of other persons - Forum users are not allowed to impersonate another person (including celebrities), pretend to be 1C Company employees or representatives of 1C Company, or attempt to mislead users by indicating that you represent 1C Company or any of 1C's partners or affiliates.


Just sayin.

With all due respect, put up or shut up! Lol!
:-P
Please, these two just can't controll themselvs.

Both forumula's express Vw = V wahr = True Airspeed

This one represents the mathematical expression for True Airspeed recognized and used by the majority of the wartime world:

http://img689.imageshack.us/img689/7158/vw2du.jpg

This one represents the mathematical expression for True Airspeed including
adaptation of the Prandtl–Glauert compressibility correction:

http://img855.imageshack.us/img855/3659/vw1o.jpg

Such was the basis for the post war work on compressibility and compressible aerodynamics.

Since during the war, NII VVS did not have access to classified German research into compressible aerodynamics, their ability to correct Indicated Airspeed to True Airspeed to arrive at the same results as the Germans was limited.

Here we go, graphs and equations and name dropping German scientists.....all this fuss for what is simply compressibility error.

interestingly enough compressibility error makes an ASI 'over read' so not sure why compressibility error will have been a factor in the Russians tests not being able to reach speeds.

to this day the simple rule of thumb of 2% indicated airspeed per 1000' of altitude added gives a pretty accurate TAS result.

Surprised myself it took this long for a pilot to recognize it.

:grin:

whooosh....

Well if you just mentioned compressibility error in the first place it would have been simpler, but as usual you hide it behind the 'look at me and my clever internet aerodynamicist equations', another indication of someone who isn't a pilot, internet amateurs use gaphs and equations and pilots like to keep it simple with 'rules of thumb'
either way, now you have confirmed it you have also invalidated everything you contributed by failing to realise the error has the opposite effect to what the Russians were facing, apparently they couldn't reach the high speeds claimed despite their instruments over reading due to the error....

and to cap it all you put a smug 'whooosh' at the end

If the russian's calibrate their instruments based on the common expression for compressibility used at the time, they will always measure results which are slower than the German's.

Now, I don't know if that is the answer in this specific case. No details are passed along in the anecdote.

Robteks first post in this thread was spot on.

I just took the opportunity to demonstrate the following to the community.

It is a fact, the expression for compressibility effects was NOT the same. The implication of that is you cannot take performance data from different countries during WWII at face value.

The other damning fact is that all instruments, manifold pressure, rpm, airspeed indicators, altimeter, etc...require both periodic maintenance and calibration.

You claim to be a pilot but do not seem to understand these basic facts.

Instead you leap on the anecdotal bandwagon because it is something you think will advance your game shape agenda.

It is no different than the ridiculous "testing" of performance without first understanding the atmospheric conditions.

Both incident's are example of behavior that folks who understand aircraft performance would not undertake!! Like I did, they would think it is a very silly thing to do.

My suggestion is less whining from the community about specific aircraft performance to fit an agenda and more enjoyment of the game.

:)

:rolleyes:

If the russian's calibrate their instruments based on the common expression for compressibility used at the time, they will always measure results which are slower than the German's.

No claims, it's all been proven.

Actually I can agree, but I only decided to question the sudden conviction to the theory it was all about the difference between IAS and TAS, really it doesn't matter who calibrates how, like I mentioned a simple 'rule of thumb' calculation gives a pretty accurate result, I'm sure the Russians had thumbs too (even opposeable ones) the compressibility effects you talked about were really geared around transonic flight, given the anecdote was in all probability talking about more mainstream German aircraft i.e. the piston engined ones then theres not too much chance the data you provided was applicable.


Damming? how so? what makes you think the Russians were incapable of giving captured machines any maintenance, actually as a pilot i can tell you that instruments barely ever 'need' maintenance, sure they get checked for obvious reasons but seldom do they loose calibration.

you demonstrated something? appart from the usual internet trawled stuff and equations which I have to admit were barely readable I saw no demonstrations of anything relevant.

My 'gameshape agenda' as you put it is towards accuracy.

Which I did....youre welcome by the way.

Yeah, your specialty, sitting on the sidelines thinking evryone else is stupid.

From a guy who whinges about aircraft performance and barely plays the game....:grin:

just stick Crummp on ignore, he's not worth it.

If he told me it was raining outside, i'd still have to look outside to check.

Doesn't matter how the Russians calibrate their compressibility, I'm sure the 'captured' 'German' aircraft they were testing had 'German' instruments in them anyway.

:rolleyes:

Exactly.....whoosh!!!

Of course, the German instruments will always show up as slower compared to russian calibrated instruments.

Now aircraft performance is a percentage range over an median and that instrument error is not outside that range so you will find some agreement.

Baloney....

A considerable amount of maintenance is replacement of instruments. I have had to replace turn co-ordinators, manifold pressure gauges, oil pressure gauges, and re-calibrate rpm gauges.

On every airplane I have ever gotten IFR rated, it required maintenance to the pitot-static system.

All outside of the normal checks and required calibrations.

Acccuracy? You mean flight testing data without understanding atmospheric conditions???

Not very accurate IMHO!!

:grin:


http://forum.1cpublishing.eu/showthr...t=32523&page=4

I think blue pilots need a little more good sense, and less talking...

In Il2 1946 we had the same problem, blue pilots crying for improvements in their 109 and 190... now IL2 1946 = gameboy...

In Cliffs of dover we had the same, cry cry cry, Spitfire IIa ripped off Ia too, throtle problems, ridiculous curves of speed, ridiculous behavior over 14k and Sea Level...

Now you guys got over design speed like you always wanted!

great job Blue Pilots! :evil:

Make up your mind.....


Baloney

is this relevant? where has a lack understanding of atmospheric conditions come into this thread?

http://forum.1cpublishing.eu/showthr...t=32523&page=4

Ah the thread I was hoping you'd bring up, the one where you questioned this particular statement of mine...


I will point you to the attached checklist I used on the learjet, you probably don't know this but a checklist forms part of an operators 'Ops manual' and is a thoroughly audited document and 'must' be approved by the authorities, on the attachment you will notice the very 'abridged and tabular data' I mentioned....

It is funny that you suddenly now know what V1, V2 and balanced field length are....but know you don't just look at a genereic checklist or chart.


Yes, you are required to calculate them. No, you don't have to do it on a calculator and piece of paper....

There is a piece of gear that has been around for a while called an FMC but if you don't have one, then you still have to know the required take off profile.

We went through this already with both the FAR and JAR regulations!!

You know the ones you claimed you don't have to follow as a pilot in Europe??

There is no confusion except on your part.

They will always measure results which are slower than the German's.

Meaning the russian will always reach their measured TAS before the German TAS figures.

In otherwords, they will think the German data is always slower than actual TAS.

KJAC 242358Z 21009KT 10SM SKC 30/M04 A3010

Tell me your balanced field length based on your chart!!

Use a TO Weight of 9752kg's

Nothing generic about that checklist, it's the 'actual' one I used in the Learjet, with the actual data on it 'exactly' as I described it.

We don't have to follow FAR regulations in europe, JAR ones we do, you were the one that mentioned FAR 121.

Yes I am very confused at how you contradict yourself so massively with those statements I quoted, and am further stunned by your insistence that German instruments magically transform themselves into Russian ones when they cross the border.

Finally, no I don't need to do any of your silly little quizzes to prove anything, the only time I do that crap is for examinations, I'm not fighting an internet warrior face off here, I'm calling you out, pure and simple just show me a copy of your credit card sized FAA license or something tangeable.

Heres some more from me, this is 'ME' the same Craig Brierley from the scans of my license doing a job before I wen't on to fly Learjets, only viewable in the UK unless you do some fancy internet trickery I don't quite understand, now are you going to phone the BBC and the HM Coastguard up and tell them they are lying too, perhaps show them some little graphs to prove it? ask them some obscure little.

http://www.bbc.co.uk/britainfromabov...offcoast.shtml

HINT: Check the upper right corner of the forum labeled: "Private Messages" ;) Very, very useful.

No I prefer the public humiliation of Crumpp. Besides, the inboxes are way too small.

Are we really to believe that trained professional aviators and supporting aircraft technicians at the top of their game due to the intensity of war, with experience of constant life or death combat sorties, are getting IAS and TAS mixed up? I find such a thing very hard to believe.

No of course.. you're right! The winking face was sarcasm.

As Robtek states there are to many unknown variables.

What about the captured aircraft condition (crashed? was the propeller?)
Fuel quality used in those test?
Did they used the right boost settings? (IIRC they tested the Dora without MW50 and find it "slow" compared to their birds).
Was the German guy really honest or did he repeat what his master wanted to hear?

We can't ignore these ones, otherwise we could make a call to Luthier: please Luthier, tune down every german warbird's speed... those speed on the documents were only theorical. Listen to that interviewed guy!

I think you're smart enought to understand this... but still I wonder the reason of opening this thread... that was your target?

They could have used russian dials if the germans had smashed them up and or disabled/ruined the aircraft on those airfields which were over run. Crash damaged is another issue.

It is a tough concept I understand to grasp the fact compressibility corrections are calculated.

It is another tough one to grasp the fact that all instruments are calibrated by machines whose scale reflects that calculation.

It is also a tough one to grasp the fact the country leading the way on compressible aerodynamics, was Germany. Of course TASGI could determine TAS from IAS but not on the same scale.

Think of it like this. The russians are calibrating their dials with a yardstick and the Germans with a meter.

1 yard = .91 meters

When the Germans reaches 300kph, the Russian instrument will show 273kph.

Using the wrong calibration equipment will slip the scale the throw off the results.

I started the thread because, as I said in the first post, I did not understand the situation that was being reflected in the article; I was somewhat surprised. I also found it curious and had hoped that people in the community, especially those with knowledge and experience, may be able to shed some light on what appears to be a real world historic account. As a layman with an interest in aviation, I found it interesting given discussions about aircraft performance on the forum. I thought that others might find it interesting and intriguing too. Even though people have been interested and kind enough to respond to this thread, I still find the remarks in the article a bit of a mystery.

May I say that your post gives me an unsettled feeling, as you have made me feel that I need to justify what I believe to be a perfectly reasonable post; is that what you intended?

They would not have to change dials. It is calibrated by pressure differences.

The differences though are measured by the calibration equipment. If the calibration equipment uses a different yardstick, the results will reflect it.

You misunderstand, when retreating in Russia the Germans destryoed their equipment as best they could before it was captured. Obviously this depended on what resources and time they had left.

One way I read about was heap them all together and burn them. Smashing the dials with a hammer or submachine gun... Going to need more than calibrating after that... Crash landed aircraft may or may not be damaged. Did rounds enter the cockpit? Were the dials broken in the landing?

However I agree with you, different manufacturers use different tolerances and different methods.

Well you should have a better understanding of how airspeed is measured and that all nations did not have the same ability to express that speed.

Your post was a convenient opportunity to demonstrate that fact.

And they will remain a mystery. There is not enough information to make any concrete conclusions. We can only speculate.

Here are the facts:

1. Instruments require periodic maintenance and calibration. You will not see expected performance despite the fact the dials might show the correct reading if the instruments are off.

2. Not all nations expressed airspeed by the same measurements. There are different methods for determining the effects of compressibility. Some are more accurate than others and some are not very accurate depending on the realm of flight.

3. A pilots ability has a large effect on Vmax.

4. Aircraft require maintenance and will lose performance over time as engines and propellers wear.

5. Aircraft performance is a percentage range over a median. Some will be optimistic and other pessimistic. This is not only due to all the reason's listed above but manufacturing tolerances as well.

Absolutely. They did not want equipment to fall into Russian hands. It is highly unlikely that the Russians could fly any captured equipment without extensive repairs.

Even the jolt of hard landing can knock the instruments out of calibration.

If the Russian's calibrated German instruments, they would induce an error from the begining.

As Crumpp says: they will remain a mystery and IMO you should have achieve this conclusion on your own before posting here.

I mean, there's nothing wrong in asking these kind of questions in a serious message board frequented by real historians. BTW it's a good post and really interesting :-)

The problem is that in THIS room (FM/DM) it's only gas to feed the Red vs Blue battle, raising reactions like the one of our friend =AN=Felipe, since most guys here only care to nerf the other side. :-)

My opinion, of course. I got nothing against you personally ;-)

Nice to be told what I "should" have done. LOL, one needs a thick skin to post on this forum. 6.S.Manu questions the reason why I started the thread and then Crumpp talks down to me saying “I should have a better understanding of how airspeed is measured and that all nations did not have the same ability to express that speed” (thanks for the lesson; it would appear that I am not qualified to post on this forum and should go away then). I am beginning to feel that I am on the end of posts from people with a slightly superior attitude. I simply posted some surprising (to me) information that I had not seen before, that I thought would provide some anecdotal historical context as background to the aircraft performance debates on this forum. It would be nice if people exercised a little more common courtesy on this forum, or it will be dominated by less than polite postings.

I hope you understand the reason of my post. If my attitude (the perceived one) has annoyed you, then I politely ask to forgive me. ;-)

Thread cleaned up.

Any more off topic garbage personal attacks etc etc ...... infractions/bans will be applied.

This is a pretty interesting anecdote. Thanks for sharing.