La-7 vs ??? (attn Franek)
 

Now you have a chance to present the facts according to the test reports you mentioned in your response in the favorite book thread! I am not doubting it, I just would like to see more comprehensive quotations from those reports, not just one liners!

Jukka
Where is the thesis for discussion and should we limit to La-7 only?
The other thing is a definition of a good fighter, I think we should discuss such parameters like speed vs height, range, armament, manouverability, etc. What else?

Although I'll probably stay clear of this thread I'd like to add that an a/c is much more than just a sum of its primary statistics. Where are ease of handling, ease of maintenance, ease of manufacture, reliability, ability operate from unprepared fields, if its handling conforms to the relative fighter doctrine, ability to absorb damage, ability to carry significant ordenance, combat range, ability as a weapons platform.

Many if not most of these variables are missing in the average a/c stat...

Carl-Fredrik Geust hit the mark when he quoted Soviet reports on respectively the 109 and 190, which according to their doctrine were of an exact opposite opinion to those of the Western Allies, the Bf 109 was the "soldier's" a/c, its relevant sub-type always superior to the Fw 190. So who are we to say that the Soviets were wrong in their judgement?

Perhaps this only proofs that I don't understand the subject?

Bounding the subject
 

You ask about "....ease of maintenance, ease of manufacture, reliability, ability operate from unprepared fields, if its handling conforms to the relative fighter doctrine, ability to absorb damage, ability to carry significant ordnance...."

One answer is "a long way down the list" IF the aircraft concerned is so outclassed it is shot down in disproportionate numbers to its successes. After all, the Lancaster was pretty easy to maintain, could absorb a lot of damage, and carry vast ordnance. OK, that's an extreme example, but just what are you asking about?

If the role of the fighter is to be judged on its ability to shoot down opposing aircraft - and that, I believe, is the bottom line - then most of the parameters above are of minor importance.

If you wish a much wider discussion, perhaps to compare other aspects of military aircraft operations, and perhaps explain some otherwise slightly odd decisions, then some of these parameters were valuable sometimes.

Yes, it would be nice to have more information readily available on other aspects than pure performance. On the other hand, how many people would understand a complete set of stability and control derivatives?

Graham
I think you nailed the problem though I think I would add such thing like automatics that was often decisive in achieving best performance in combat conditions. I would discuss handling qualities and damage absorbtion ability only in extreme cases.
Also, I think we must discuss some basic equations, otherwise how to expain weight is a very significant parameter?
Now, the most important question. What should we comapre? We have La-7 and Yak-3 on one side but what on the other? Both aircraft were introduced during the second half of 1944 - at the time following aircraft entered service: Spitfire XIV, Tempest V, P-51D, Fw 190D, Me 109K.
Everyone agrees?

If a/c are close in performance in terms of speed, climb and generally the "basic stats list", then secondary variables gain in importance.

There are plenty of types that had good performance, but were deemed failures because of poor reliability. The Lancaster was based on the less succesfull Manchester.

Ease of handling certainly is an important factor next to the basic stats.

You might not rate ease of maintenance, or reliability high, but if your in service rate drops quickly, you won't get the benefit of increased performance translated to tactical or possibly strategic advantage.

Yes, it depends on the discussion.

If you want a basic "measurement contest", you'll do fine without secondary considerations, if you want a significant answer, you'll try to go beyond and perhaps come up with different answers.

Otherwise just open Jane's and look for the fastest fighter packing a good punch and you'll have your winner.

Yes, we can also discuss Yak-3 as well. Parameters to be discussed should include not only straight performance data but also rate of turn, rate of roll, how easy a particular plane was to fly to and beyond limits (e.g. was there adequate stall warning) and so on. Emphasis should be on average aircraft in service, i.e. not aircraft in special trim for tests etc.

Ruy is also right. For example, is it better to have a fighter with 10 mph more speed if the slower fighter has 50% greater in service rate (assuming equally qualified ground staff in both cases)?

But, let us compare parameters that were within aircraft designer´s sphere, i.e. cockpit layout is in, but quality of individual instruments is out.

And Franek, I got the impression that you have data from evaluation reports, not just one graph here and another there.

Sorry guys, but what is the point at these discussion?
To say which fighter was the best?

I have in mind, that combat heights at eastern front were much lower as over the Reich. So soviet planes were designed to perform at lower heights. According to russian sources most combat heights were below 4200m.
This was reasoned in low heights for Il-2 and Il-10, which seldom climbed over 1500m.

Mostly forgotten are perfomances with normal combat powers and not WEP, which was often used to run away.

Jens
The question is were Soviet aircraft designed to fit into their doctrine or was their doctrine created on what they were able to build?
Since Roland Garros standard tactcis was to get higher and to attack from the sun. This basic rule applies to both Western and Eastern Fronts, unless you believe there are different rules of physics here.
Finally concerning WEP, I recomend to read an interview with Soviet ace Golodnikov on Lend lease site. A very interesting comments!

Ruy
We are discussing aircraft that were built in thousands, so I do not think they had any major design flaws that were making them unacceptable.
Some flying characteristics can be deducated from available data, it is simple aerodynamics and mechanics of flight. I hope Graham will use some of his experience here!
And one last note - do not laugh of Jane's. It is a very valuable publication recommended for use by aviation engineers!

Jukka
Unfortunatelly I do not have evaluation reports of Soviet aircraft. Nonetheless some information appeared here and there and conclusions are often quite surprising.
For example Robert Bock in his Yak-7/9 monograph by Aj Press (p.30-31 in Polish edition) notes that when Yak-9P s/n 01-04 was tested (23.03-23.07.1947), it did include comparative trials with P-63C-1. It turned out that Kingcobra was better in horizontaldog-fight, getting on tail in 5 turns. Yak-9P had better performance only to 3000m but interestingly was a better diver, outclassing American fighter.
Another comparison was done in Yugoslavia - Spitfajer, Belgrade 1997.
Aircraft tested were Yak-3 and Spitfire VC trop. It turned out that both aircraft were entirely comparable, Spitfire being better in horizontal and Yak in vertical. It must be noted however, that tropical Spit was rather a lazy cow comparing to filterless one.
Also, very interesting are comments from a Soviet report prepared after the incident over Nis. It was noted that P-38 was better in horizontal turns rather than Yak-9, the latter being superior in vertical manouvers.
I think those samples show how much mythicised Soviet technics is.
I have to digitise my collection of vrious data and graphs, so I would rather prefer to answer some questions rather than to write a big article on the subject. There are some documents that I still have to get like opinions of Skalski concerning Yak-9.

Well, that is interesting info. BTW, somehow the Yak-3 inferiority in turning doesn´t surprise me. One Finnish site (virtualpilots) has a translation of Yak-3 Pilot´s Notes. These Notes give the impression of quite bad accelerated stalling characteristics.

Yak-9´s inferiority in turns is a bit surprising for it has much lower wing loading and better power loading than the P-38. But, I don´t mind, I am a P-38 fan!

Jukka
Judging by shape of the wing, I expect Yaks to be very prone for aileron stall, this may be very dangerous during take offs, landings and dog-fights. There was a similar problem with Fw 190.
Please note that all the comparisons were with slightly outdated Western aircraft!

VVS fighter properties
 

Hi guys.

I am sorry Franek, but some of your statments are not true! I have looked into this a little bit and sought expert help.

A few points:

Your statement "For example Robert Bock in his Yak-7/9 monograph by Aj Press (p.30-31 in Polish edition) notes that when Yak-9P s/n 01-04 was tested (23.03-23.07.1947), it did include comparative trials with P-63C-1. It turned out that Kingcobra was better in horizontaldog-fight, getting on tail in 5 turns. Yak-9P had better performance only to 3000m but interestingly was a better diver, outclassing American fighter"

is not true. You should know that Bock is a self-appointed anti-Soviet historian, which should be evident from his writings. You cannot take such important claims as above to be true without looking into it if you suspect the author to be unfairly biased! I have asked Mr. Pilawskii about NII VVS reports about the comparative trials to which you refer and there are none! As a matter of fact prototype 01-04 was never used for comparative purposes, only for testing of various equipment and fuel cells arrangements. Besides, it had a wooden fuselage and was not, therefore, fully representative the Yak-9P.

According to Mr. Pilawskii there was another comparative test done (reference: TsAMO fond NII VVS opis 645266, list 385-390) using the first all-metal Yak-9P against P-63C-1 s/n 311626 and this is the test Bock is referring to. At normal weight (3220 kg) that Yak-9P was superior to the P-63 in all respects. However, when tested in overload condition (3588 kg) the Yak-9P was still superior up to 2000 meters, above which the P-63 was a better turner, getting on the tail of the Yak in about 5 turns. But the important point is that the Yak-9P was overloaded, in normal condition the Yak would get on the P-63's tail in 3-4 turns, depending on altitude.

So the claim that the Yak-9P was outclassed by the P-63C stands unsubstantiated. At best, Bock's claim is a misrepresentation of facts.

Furthermore, your statement:

"Also, very interesting are comments from a Soviet report prepared after the incident over Nis. It was noted that P-38 was better in horizontal turns rather than Yak-9, the latter being superior in vertical manouvers."

is also dubious at best!

There are simply no such tests in existence! A P-38L s/n 44-2421 was
extensively tested at NII VVS and the LII and two reports on this testing can be found in TsAMO fond NII VVS opis 639331, list 90, and TsAMO fond 29 opis 1165, del 8232, list 5-6, according to Mr. Pilawskii. I suggest we find them and read them before we take the above quote to be true! Simply put, there is nothing in them to suggest that the P-38 in any way could compete with the Yak.

Also, the comment:

"Judging by shape of the wing, I expect Yaks to be very prone for aileron stall, this may be very dangerous during take offs, landings and dog-fights. There was a similar problem with Fw 190."

is, well, interesting. While it may be true that you expect Yaks to be prone to aileron stalls, the fact is that they were not! If there is one aspect of the Yaks that were tested and tested again is was the wing configuration! In fact, the Yaks had no aileron stall problem and were superior to their western counterparts (including Luftwaffe fighetrs in this respect.

Finally, your coment:

"The question is were Soviet aircraft designed to fit into their doctrine or was their doctrine created on what they were able to build?"

suggests to me that you are biased against Soviet fighters! There can in my view be no doubt that the Russians were able to build some of the best
fighters of WWII, that's what they "where able to build"!

I find a disucssion such as this interesting, but I do suggest that we don't try to perpetuate old truths, that is old myths or western propaganda "truths". Test results are available for most fighter types and we should look closely at them but also at how the fighter performed against each other and during their service and under what conditions.

I try my best not to be biased one way or the other. I'll freely admit that I am an admirer of German fighters, but I do realize that they were outclasssed by allied fighters (Soviet and Western) in many respects, while bettering them in others, depending on time frame and conditions.

To be clear, what we want here is the truth, right? Not to "win" a discussion!?

Best regards,

Kjetil Aakra

Kjetil

I assume you have never read any of his writings. I may complain about his lack of engineering knowledge but not that he is biased.
I cannot say the same about Mr Pilawskii.

With all due respect, the fact Mr Pilawskii has not seen something does not automatically mean that it doeas not exist.

Re-reading the text it may be indeed it was not 01-04, nonetheless it must be stated here that:
- 01-04 was a testbed aircraft and was modified several times,
- the fuselage was of standard tubular steel frame and not wood,
- the diference was with aerodynamical fairing made either of metal or plywood,
- from engineering point of view such a difference does not affect performances,
- there were 29 Yak-9P with a plywood fuselage fairing.

Seeing no original report I cannot comment this but that according to Bock take off weight was 3550 kg and that some aircraft tested had reduced equipment and armament. If so, we cannot say about overweight but rather underweight.

Sorry, this was not a test performed in NIIVVS but a report filled after an actual combat between Yaks and Lightnings. On 7 November 1944 Lightnings of 82 FG clashed with Yaks of 866 IAP. Two Lightnings were downed for at least two Yaks, another being claimed downed by Soviet AA. IIRC there is still plenty of controversy as to who started the dog-fight. A report found at TsAMO was quoted by Mihail Bykov, who sometimes visits this board.

This conclusion comes from basic aerodynamic's knowledge. I have not found any description for Yak, but memories of Vladislav Valousek, Czech La-5FN pilot, indicate there was a problem with the latter type and both Yaks and Las had similar wing. I have not found anything that support claim of Soviet aircraft superiority in this regard.

I suggest you to check speed vs altitude or power vs altitude curves first and then to make any statements about performances of Soviet aircraft!

I am extremally interested what is Western propaganda truths? As yet I have found plenty of Soviet propaganda lies that are ad nauseam repeated by some not educated people in the West. Of course I see some 'German bias' but it is mostly due to lack of credible Soviet data.

If done by competent people, a comparison of technical items cannot be biased because of laws of physics that are the same in every country of the world. If you claim that something was outclassed you must just only support this with facts and our only problem is that we do not have Soviet facts.

Sort of on topic
 

Dear Franek,

I have stayed out of this discussion, but after reading through the thread, IMHO you have totally missed the point that Jukka made in throwing down the gauntlet. That point, if I interpreted it correctly, was for you, Franek, to participate in a thread with real data and sources, not just a lot of words and personal opinions. After reading several of your posts I see no identification of any primary documentation (Jane’s is most definitely not! And as an engineer, it was certainly not recommended to me “as the very valuable publication recommended for use by aviation engineers”. If I had used Jane’s as a reference in one of the reports I was paid to prepare for the USAF, I am certain my credibility would have been questioned.)
So, Franek, do you have appropriate technical data to support the opinions that you express so freely in putting down others opinions on this board? If you do, please identify it, no excuses like;” I have to digitise (sic) my collection of various data and graphs”.
Do you have the expertise to evaluate what data you might have? Are you an engineer, a physicist, or a pilot? I would not question these things, except that you almost without fail, devaluate others contributions as if you are the expert on every subject.


Best regards

Artie Bob

Just when I was starting to enjoy the thread, something turned a little more nasty from the lower third onwards.

Lets all try and stick to the subject at hand.

These discussions actually need some rules.

1. state your sources
- primary material rules
- secondary sources (specialist work, stating sources)
- general sources (including Jane's)
- annecdotal information

2. proof your point based on 1

3. keep it objective

4. no personal attack

Points one, two and three will determine the value of this debate, point four will determine if the debate will be allowed to continue. I'm not innocent of personal attack, which makes it a lesson for all of us.

Artie
I have some aeronautical engineering background but never worked as such. I may assure you that Jane's was recommended in my school as a review of trends during a preparation of a preliminary design of an aircraft.
Concerning the thread, as yet I have received no comments concerning my proposal of aircraft to compare. Also, as yet my only personal opinion was in regard of aileron stall in Soviet aircraft but it is really a knowledge of the first half-year of aerodynamics. Mentioned memoirs of Valousek, a pilot of Czech Squadrons in RAF and a pilot of Czechoslovak regiment contain a description of landing procedure in La-5FN. It was forbidden in the aircraft to add power during landing as it usually led to flipping over and to crash. In case of wrong approach or bounce it was suggested to crash the aircraft in a hard landing! Valousek once attempted to save his aircraft after a hard bounce and managed to add some power in order to make another approach (a standard in a Spitfire as he noted) but he considered it tricky and he was generally criticised for taking he risk (Valousek clearly noted that ailerons did not work).
Memoirs were published in late 1980s by a Letectvi + Kosmonautika magazine. This was described on page 10.
Comment concerning aileron stall characteristics of Fw 190 is backed up (IIRC) by AFDU report #55 as well as several combat reports of Allied airmen mentioning sudden flipping over of Focke Wulfs during dog-fights.
Regarding graphs, they do not really make much sense if not compared one with another, hence the need of making a graph combining them. I cannot do a one, however, if there is no consensus as to aircraft to compare.

Calm down, Artie and Ruy! I began the thread in the hope of encouraging Franek (or anyone else) to post data based on primary sources. Kjetil mentioned some docs, but how many of us has regular access to TsAMO? I.e. Kjetil should have posted (and translated) the docs he referred to.

Franek is right about the aileron stuff. If one reads the Yak-3 (see virtualpilots´s site) Pilot´s Notes, it is clear that it has poor stalling characteristics.

It seems that Pilawskii isn´t the most reliable of sources. I checked both Gordon&Khazanov´s and Gunston´s Encyclopedia of Russian Aircraft and both have the same gross weight info and that figure is what Pilawskii calls overweight. I have a hunch that Pilawskii´s "normal" figure requires severe reduction in fuel capacity, in aircraft already possessing not too great fuel capacity. Highly dubious to me.

Hello!

I insert below a text file I had on my computer hard disk. I wrote it as reply for Russian Battlefield Forum three years ago. Maybe it is of use for someone. Comments, corrections etc. welcomed.

Of note is the marked difference in performance of series-built examples and test examples in Soviet aeroplane production (at least GPW period). I think I have seen the chart from the "As" article on Internet as a picture, but was not able to find it now - I tried to. I have not bookmarked the Russian site where I saw it (or similar one).


One question and also the reason of my message. How does one stall an aileron (only)? I know I barely passed my aerodynamics exam (it was only my minor) but still I should know. Do you mean the situation when during turn a tight pull makes flow separate from lower wing tip and the plane flips (rolls) to other direction? Adverse yaw plays a big role here, keeping the ball centered with rudder pedals helps (as in all flying). Frise type ailerons can help too (with the price of added drag).

Why is this aileron stall so important (performancewise) ? NACA 23xxx series profiles are low-drag - good performace - but they have "ugly" and sharp stall characteristics. If I design wing which has smoother and predictable stall but has, say, 5% more drag is that a good design?

BTW What profile did the Yaks and Lavochkins have? I could now only find data for Yak-1 (Clark UP, thickness 14% at root and 10% at tip). Soviets seem to use a lot of the near flat-bottomed Clark profiles - ease of manufacture played into that?

One comment more and then I will stop. I have read everything I have been able to put my hands on about airwarfare over an around Finland. I do not remember a single Finnish book where performance of Soviet planes would have said to be poor. Nor has their performace been underrated hereabout. Vice versa, actually. Poor performance put on by the Soviet Hurricane pilots might be sort of exeption. In that sense Pilawskii's book didn't change anything. The preaching tone of his book went on the irritating side at times because of that. Perhaps we Finns aren't "Westerners" in that sense?

Regards,
Kari



The file:

"Yak-3 vs. La-7

In a older Soviet-era aviation magazine ”As”, issue 2/1991 pages 23-35 there is a article about evolution of aircrafts during the WW2. It concentrates on Soviet types and includes several performance curves (max speed vs. altitude). Similar curves were used also during the war (at least by FinnAF) for comparison purposes and to find at which altitudes own aircraft types do have edge (or if they have) and also where enemy types are weakest. Majority of the mentioned sources in the article are primary documents: type manuals and test flight data (by NII VVS and LII).

The article does have the performance diagrams Yak-3 vs. La-7.For both types is shown curves for series production examples and ”etalonnij” (model example)/ ”opytnij”(test example) ones. It is noteworthy that for series La-7 the speed drops around as much as 25-40 km/h and for Yak-3 some 5-15 km/h from the test examples. This might have something to do with La-7 being wooden construction and Yak-3 all-metal (or near). It is possible that the La-7 model examples had been finished with some extra work which was not done at factory line.

But the comparison. I am not able to put a picture here, but the summary is that La-7 beats Yak-3 in all altitudes, period. La-7 does have two performance peaks: at 3 km and 6 km altitude (as does La-5&La-5FN). Two peaks suggest a two-stage compressor (didn’t care to check and don’t remember offhand). Yak-3 does have clear peak at about 4,2 km altitude and smaller one around 2,2 km.

The speed marginal at 4,2 km altitude is only about 10 km/h for La-7 advantage. At 3 & 6 km altitudes La-7 is 45+ km/h faster than Yak-3. This for the factory examples.

For the production examples La-7 is better between 2-3,5 km altitude by some 25 km/h. At 4 km altitude Yak-3 is slightly better (~5 km/h). Above 5,5 km altitude La-7 is clearly better.

Actually the altitude/perfomance difference of Yak and La-series (EXCLUDING LaGG-3) fighters was seen also their use. I do have a (semi-secret) book which describes numerous missions by VVS Naval air forces (KBF, TsF, SF etc) during the GPW. Title of the book escapes me now. The book does have diagrams about the formations used. Lavochins were used for top cover formations (both forward and rear defence) and Yaks for close escort. This was also the FinnAF experience of VVS. In Eastern Front conditions Lavochkins were high altitude fighters and Yaks medium altitude fighters.

La-5/7 did have very limited endurance, some 45-60 minutes. BF109G did have the same but a single 300 liter drop tank doubled the time. BTW short time on station seems to have been a major drawback for 13 VA / II GvAK during the Vyborg operation later phases (=Kotka operation). I don’t think VVS front units usually used (wing) drop tanks with La-5/7. Correct me if I am wrong. Couldn’t find endurance time for Yak-3 but it seems to have had 400 litres internal fuel (same as BF109G) and couldn’t have been much better than La-5/7.

La-7 had roughly twice the punch (or more) in weapons that Yak-3 and air cooled engine less prone to be stopped by combat damage. All in all it seems Lavochkins were the real winners.

The As-magazine article does have performance curves for FW190 A-4 (Soviet and British flight test data) and A-5 (German manual). Comparison between them and Yak-3 and La-7 is bit of apples and oranges. FW-190 A-6/8 (or the JaBO F subtypes) were in use when the later Soviet planes were taken in use. Then there is FW190A-9 and D-9 plus the fact that there was myriad of equipment variations for the FW-190. Fair comparison is difficult and there is no single general and correct answer. Remembering this it is interesting to note that below, say 1,5 k m FW190A-5 was equal to series Yak-3 and La-7 and above 5 km better than series production Yak-3 and equal to La-7. Between 1,5 – 5 km La-7 is the clear winner.

If someone is really interested about Soviet a/c performance the mentioned As-magazine article belongs to the essentials.


Hope this helps some (my fingers are tired)

Kari "

Addition to my message above.

I (re)found this site:
"The Incomplete Guide to Airfoil Usage" by David Lednicer
http://www.aae.uiuc.edu/m-selig/ads/aircraft.html

According this all Yaks had Clark YH (14%root, 10% tip) profile. My recollection is that later Yaks used other profile or at least wing thickness was changed (stronger metal wing spars allowed reduction of spar height?). I may remember wrong, though. I wrote above that Yak-1 had "Clark UP" profile. I took this from Modelist-Konstruktor 1/1975 (also on net, see: http://mkmagazin.almanacwhf.ru/avia/yak_1.htm ) and there the profile is indeed given as "Y"Pi"-2" (where "Pi" is cyrillic "P"). Anyone knows for sure what Yak wing profiles were?

The above profile site has all Lavochkins (= -3, -5 -7) with NACA 23016 at root and NACA 23010 at tip. Thick root and very tapered wing plus NACA 23xxx stall characteristics -> vicious stall (my expectation at least). No matter how clever aileron design. And no wonder that Lavochkin wings got slats.


Cheers,
Kari

Kari, La-7 did not have two stage compressor (supercharger). I think you mixing two speed and two stage superchargers. I guess too many Squadron/Signals! They usually make awful mistakes on this.

According to Jukka Raunio´s Lagg-3 article in Ilmailu 11/1990, it had NACA 23016 at root and 23009 at tip.

Yes, that aileron stalling is really that flicking out of the turn. That Yak-3 Pilot´s Notes really indicate bad stall, harsh and without warning.

Your endurance figures are also begging additional explanations. For example, you write that the 109 had the same endurance (45-60 min) as the La-7. Well, true only if flying at the 30 minute rating (the maximum available in Finnish G-2s and probably G-6s as well). If flown at Dauersparleistung, over 90 minutes and if flown for max endurance, probably around 3 hours or more. Here La-7´s air cooled engine screws it for it has some 30% greater sfc at max continuous power than the DB 605.

Huomenta!


"Kari, La-7 did not have two stage compressor (supercharger). I think you mixing two speed and two stage superchargers. I guess too many Squadron/Signals! They usually make awful mistakes on this."

By two "stages" I meant two speeds. Thanks for the correction and sloppy terminology from my side. No Squadron/Signals was ever consulted. I don't even have the La-5/7 one.

My impression of the Finnish squadron log books, mission reports etc. is that one hour was more or less the maximum combat mission endurance time for Bf 109.


Cheers,
Kari

But consider Brewster Buffalo, it had excellent stall characteristics though it had NACA 23018 at root and 23009 at tip!

Hello Kari ja Jukka
I agree with Kari in that that usual flight times stated in combat reports of Finnish Bf 109G pilots were 45 - 60mins but during these flights there has been always some combat action because it seems that the Finnish Bf 109 pilots didn't file combat reports if they were not claiming something or if their Bf wasn't damaged. That's different to the practice in Le.Lv. 32 where the Curtiss H75A pilots seems to have filed reports from every contacts with the enemy.
That does not of course invalide Jukka's claim that without need to use the combat and climb power (max. 1310hp) the endurance of Bf 109G-2/-6 was longer.

Ps Kari, haven't seen You lately in Sota-arkisto so Thanks for drawing my attention to the photos for which Ed West had posted the URLs (Thanks a lot also to Ed) on the Ju 88Cs that operatted from Tallinn in early 44. I had wondered why Togo was so unsuccesful in it's fighter direction job, at least that was/is my impression after browsing through a book on the ship, when it operated in Gulf of Finland. That at least some of the Ju 88Cs were without radar explains a lot.

Juha

Päivää!

Jukka wrote:
"But consider Brewster Buffalo, it had excellent stall characteristics though it had NACA 23018 at root and 23009 at tip!"

Lavochkins had more tapered wing planform (lower tip chord / root chord -ratio) than Brewster and so more prone to drop their wing tips. I do not know if Brewster and Lavochkins had geometric twist (washout). Washout would tame the stall.

You (Jukka) surely remember the Brewster-type wing for VL Pyry (the type had elliptical wing). The new wing cured the wing drop problem, but new wings were more expensive than modifying the elliptical wings with leading edge slots.

For wing design see also this:
http://www.desktopaero.com/appliedae...ingparams.html

(Don't know if it is the best or even good one, but was the first suitable one I found with quick search on Internet).


tv.
Kari

i think russian datas are quite correct, since there is some confirmation by germans.

lipfert stated yak-3 were more dangerous than mustang (means probably only eastern front heights).

barkhorn stated yak-9u as best fighter for low altitudes. he also fought 3/4 hour against lagg-3.

rall stated his 109g(6?) wasn't able to catch la-5 and yak-9.

grislaski is quoted, that his 109 can't outturn yak-1.

general schwabedissen stated, yak-3 and la-7 were superior to 109g and 190a. schwabedissen also stated that normandie-njemen at fighterbombermissions nearly operated without losses.

at milchs meetings was stated that newer i-16 were still a danger in 9/42, la-5 has same performances than 109f4 or maybe 109g2 (1942)

i 've talked to an 190f8 pilot flew at eastern front and had at least 3 kills. he is member of the "gemeinschaft der jagdflieger". as i asked him about the truth about eastern front he meant: read pokryshkin and you know how it was.

Kari
When the wing is about to stall, any movement of ailerons may interrupt the flow and cause a stall there. In effect lift is lost and the wing drops. From the pilot's point of view it looks like reversal od aileron controls and hence is very dangerous.
To prevent this and make the aircraft safer, the wing is designed to stall at the mainplane first. This may be achieved either by a different less stall-prone profile on the wingtip or by the geometrical twist - changing the angle of atack on the wingtip, comparing to the root. Of course, penalties are paid for those sollutions.
I have a NIIVVS or CAGI test for La-7, I will dig it up and check the data there. Certainly there were performance data but I think also some discussion concerning loss of performance in series aircraft.
Another interesting thing is report filled by Hans-Werner Lerche after testing of captured La-5FN. It is not very favourable having some 40 km/h lower speeds comparing to series aircraft data. I have seen an explanation it was due to lack of automatics which caused proper settings rather hard. Of course a question arise - was it possible to achieve high performance figures in combat conditions?

Jg-51 chronicle states la-5fn 50km/h faster than 190a.

NII VVS really claimed perfomance loss for several reasons. First was due bad production quality and second due overclaiming by producer. But this meant La-7 only flew "only" 612km/h at SL instead of 640km/h claimed by producer.

Jens

Yes, I know this quote but it is not clear for me. Further research is necessary.

I am very curious how he could distinguish Yak-9U variant in the air. I do not think that the Germans were even awared of this rather rare aircraft.
His long dog-fight, although linked to Alelykhin, seems not to find any confirmation. Is there any proof that it ever occured? 45 minutes in a dog-fight should use all the fuel capacity in both aircraft!

I find it surprising, it was underlined by a Polish Yak1/9 pilot Edward Chromy, that they were slower but more manouverable than their German enemies.

I cannot exclude it but otherwise I find it quite stupid to turn with Yak when it is possible to make a safe zoom attack.
Otherwise, it is interesting to note here, that opinions of RAF pilots concerning clipped wings variant differed significantly, although the aircraft almost matched Fw 190 in roll rate (I have a graph).

I am not sure what qualifications General Schwabediessen had but generally Soviet fighters were not flown in ground attack missions because not capable of carrying bombload. This capacity was gradually introduced in 1944 but not used generally due to short range and need of every drop of fuel available in tanks. Of course Soviet fighters did straffe various targets, eg. played anti-flak role during Il-2 attacks.

In Poland, PZL P.11c were still dangerous if a German pilot did not know how to fight them. Generally, it looks for me more like excuses for poor performances of own airmen rather than a reliable opinion. Have you ever seen any mention that German Stuka pilots were so poorly trained, they were unable to keep in formation in 1944? This comes from accounts of Hungarian Stuka airmen fighting in SE Poland.

You mean the book and not KTB?

Just found a report 44-280 of tests of La-7 No 452101-39. It is a little bit long, so I need to re-read it first.[/quote]

Sorry, but i find your arguments a litlle bit biased, since you not only doubt russians figures (what is reasonable from other experiences), but german statements. I can't remember to read anywhere, that russians data claims were over. Pls show me that sources.

Rall made clear in his book, that his statement is for those, who think russians weren't able to build well planes. If you keep in mind that most dofights at eastern front were mostly under 4000m and you take both sides official numbers in aspect, you 'll see he is right. maybe 10-15kph didn't play that great role and also maybe nominal perfomance was more important.

Barkhorn statement is also founded by Walter Wolfrun: "The best Fighters in combat I met were P-51 Mustang and Yak-9U. Both of these types obviously exceeded all Bf109 variants in perfomance, including th "K"."
Barkhorn knew russians planes very good and was commander of a fightersquadron at eastern front. Yak-9U was introduced in 10/44 at northern front.

Schwabedissen wrote studies about eastern airwar for USAF. The americans had no doubt about this, due their own experiences in Korea. The fighterbombermissions were flown by NN in 1944/45 like Schwabedissen stated.

some La-7 test of the -39 is here: http://www.btinternet.com/~fulltilt/...l#No.452101-39
the other number isn't really comparable to other la-7 numbers.

Factory data of La-7 seemed to be reached with polished skin and so on, which i think was more or less normal for german tests.

First of all, I have no aeronautical engineering background whatsoever, I am not a pilot, and I have understood that Franek and all of you have very high knowledge in your respective special fields. My approach is that of someone interested more in the men and the history than in the machines. I found the discussion about the pilot statements interesting.

” barkhorn stated yak-9u as best fighter for low altitudes. . . I am very curious how he could distinguish Yak-9U variant in the air.”

- I think it may be quite simple: He or some other German guy flew a captured Yak-9U to test it against German fighters. Otherwise, I agree with Franek. As Grislawski said: “Yak, LaGG, MiG - whatever, sometimes we couldn’t tell.”

“rall stated his 109g(6?) wasn't able to catch la-5 and yak-9. . . .I find it surprising, it was underlined by a Polish Yak1/9 pilot Edward Chromy, that they were slower but more manouverable than their German enemies.”

- Here we apparently have two conflicting statements. The question is which one you find surprising - Rall’s or Chromy’s? Who had the largest amount of experience? From which tactical positions did Chromy encounter his “German enemies”? When did he usually encounter them? If he encountered German “free hunters” over Soviet territory immediately after he had taken off himself, he would have a Yak fighter with filled fuel tanks - adding quite some weight to the little fighter - against German fighters with maybe only half filled tanks (thus with less relative weight), and maybe also an altitude superiority.

“grislaski is quoted, that his 109 can't outturn yak-1 . . . I cannot exclude it but otherwise I find it quite stupid to turn with Yak when it is possible to make a safe zoom attack.”

- I got the impression that:
a) Grislawski didn’t always enjoy the privilege of being able to choose the tactical position in the air combats;
b) Grislawski was such a damned good pilot that he knew how to take his Bf 109 to the end, even out-turning enemy fighters which when equally compared were more maneuverable. Although one German pilot described entering a turning combat with P-40s as “tantamount to suicide” (or something similar), Marseille frequently challenged P-40s in turning fights. I think he knew what he was doing. Another extremely skilful “turn fighter” on the Bf 109 was Max-Hellmuth Ostermann, who learned how to out-turn even I-16s. See my forthcoming biography on Ostermann. . .

“general schwabedissen stated, yak-3 and la-7 were superior to 109g and 190a . . . am not sure what qualifications General Schwabediessen had.”

- I think that what Jens refers to here is the book “The Russian Air Force in the Eyes of German Commanders” (USAF Historical Division, Air University 1960), where Schwabedissen simply lines up statements made by various German commanders (including air unit commanders). Schwabedissen makes only few own statements.

It always is interesting to listen to the veterans when they speak of what the have experienced themselves. Realities at the frontlines were much different than test results in calm conditions.

We should remember to take both pilot accounts and all kinds of aircraft performance statistics with a grain of salt. I think there were pilots who were so in love with the plane they flew, that they found it better than anything else - even if that was not true. I think there were pilots who due to one traumatic experience while flying one aircraft, learned to loathe that aircraft type, and saw nothing good in it. But when there is a whole row of pilots who say the same thing about a particular aircraft in combat conditions, I think that could be of greater value than some test results in calm conditions.

A single combat - like the one between Yaks and Lightnings - definitely is of very little value when it comes to making an assessment of how these aircraft compared to each other. I can give you examples of I-16s or PZL P.11s beating up Bf 109 Es or Fs, but surely no one would be able to come up with an overall test result that would indicate that the I-16 or the PZL P.11 could be regarded as generally superior to the Bf 109 E or F.

Finally - thanks, Ruy, for reminding us all of the golden rules!

BTW - now it is clear. “Black Cross/Red Star”, Vol. 3 WILL be published by Eagle Editions in the autumn of 2005. (There will be some more surprises from my pen in the nearest future. There was one small hint above.)

All best from a quite busy writer :D

Christer Bergström

http://www.graf-grislawski.elknet.pl/index.htm

http://www.bergstrombooks.elknet.pl/bc-rs/

http://www.bergstrombooks.elknet.pl/...-ace/index.htm

Jens

I have reasons to doubt German statements.

Pardon, I am not sure if I understand you.

Rall ended his Eastern Front career in the early 1944, when Yak-3 and Yak -9U were not available. Most common was Yak-1 which had speed limit of 650 km/h. Rall's story does not sound very reliable to me, unless he was in a very infavourable position.

I stand by my comment - numbers of Yak-9U available were quite limited

This is actually a question to our French friends - were French Yaks capable of bombload? Personally I do not think so.

I have a full report in Russian. This is only a small bit of it.

Factory data of La-7 seemed to be reached with polished skin and so on, which i think was more or less normal for german tests.


First of all, I have no aeronautical engineering background whatsoever, I am not a pilot, and I have understood that Franek and all of you have very high knowledge in your respective special fields. My approach is that of someone interested more in the men and the history than in the machines. I found the discussion about the pilot statements interesting.

” barkhorn stated yak-9u as best fighter for low altitudes. . . I am very curious how he could distinguish Yak-9U variant in the air.”

- I think it may be quite simple: He or some other German guy flew a captured Yak-9U to test it against German fighters. Otherwise, I agree with Franek. As Grislawski said: “Yak, LaGG, MiG - whatever, sometimes we couldn’t tell.”

“rall stated his 109g(6?) wasn't able to catch la-5 and yak-9. . . .I find it surprising, it was underlined by a Polish Yak1/9 pilot Edward Chromy, that they were slower but more manouverable than their German enemies.”

- Here we apparently have two conflicting statements. The question is which one you find surprising - Rall’s or Chromy’s? Who had the largest amount of experience? From which tactical positions did Chromy encounter his “German enemies”? When did he usually encounter them? If he encountered German “free hunters” over Soviet territory immediately after he had taken off himself, he would have a Yak fighter with filled fuel tanks - adding quite some weight to the little fighter - against German fighters with maybe only half filled tanks (thus with less relative weight), and maybe also an altitude superiority.

“grislaski is quoted, that his 109 can't outturn yak-1 . . . I cannot exclude it but otherwise I find it quite stupid to turn with Yak when it is possible to make a safe zoom attack.”

- I got the impression that:
a) Grislawski didn’t always enjoy the privilege of being able to choose the tactical position in the air combats;
b) Grislawski was such a damned good pilot that he knew how to take his Bf 109 to the end, even out-turning enemy fighters which when equally compared were more maneuverable. Although one German pilot described entering a turning combat with P-40s as “tantamount to suicide” (or something similar), Marseille frequently challenged P-40s in turning fights. I think he knew what he was doing. Another extremely skilful “turn fighter” on the Bf 109 was Max-Hellmuth Ostermann, who learned how to out-turn even I-16s. See my forthcoming biography on Ostermann. . .

“general schwabedissen stated, yak-3 and la-7 were superior to 109g and 190a . . . am not sure what qualifications General Schwabediessen had.”

- I think that what Jens refers to here is the book “The Russian Air Force in the Eyes of German Commanders” (USAF Historical Division, Air University 1960), where Schwabedissen simply lines up statements made by various German commanders (including air unit commanders). Schwabedissen makes only few own statements.

It always is interesting to listen to the veterans when they speak of what the have experienced themselves. Realities at the frontlines were much different than test results in calm conditions.

We should remember to take both pilot accounts and all kinds of aircraft performance statistics with a grain of salt. I think there were pilots who were so in love with the plane they flew, that they found it better than anything else - even if that was not true. I think there were pilots who due to one traumatic experience while flying one aircraft, learned to loathe that aircraft type, and saw nothing good in it. But when there is a whole row of pilots who say the same thing about a particular aircraft in combat conditions, I think that could be of greater value than some test results in calm conditions.

A single combat - like the one between Yaks and Lightnings - definitely is of very little value when it comes to making an assessment of how these aircraft compared to each other. I can give you examples of I-16s or PZL P.11s beating up Bf 109 Es or Fs, but surely no one would be able to come up with an overall test result that would indicate that the I-16 or the PZL P.11 could be regarded as generally superior to the Bf 109 E or F.

Finally - thanks, Ruy, for reminding us all of the golden rules!

BTW - now it is clear. “Black Cross/Red Star”, Vol. 3 WILL be published by Eagle Editions in the autumn of 2005. (There will be some more surprises from my pen in the nearest future. There was one small hint above.)

All best from a quite busy writer

Christer Bergström

Thanks for the link to La-5FN/-7 specs Jens. Very interesting. The comparisions otherhand, checked only vs. Spit IX, are problematic. You probably noticed that the difference between empty and full weights are 560 - 590kg for Las and 1764kg for poor Spit, not very realistic for comprasion between fighters, I'm pretty sure that a Spit pilot would drop his bombs before entering dogfight. Spit IX could have one of several different Merlin types, that in the table is, surprise, surprise, weakest for LF and F Spits, IIRC. And one must remember that from summer 44 at least those with Merlin 66 were modified for 150oct petrol and the 25lb/sqin boost allowed with that petrol pushed the max power appr. 2020hp for 5 minutes at low level. With more realistic t/o weight of appr. 3400kg the comparision become rather different.

Juha

Jens

I have reasons to doubt German statements, this based on some accounts that I was able to verify. I can also mention some statements of Galland that were discussed on this board previously.

Pardon, I am not sure if I understand you.

Rall ended his Eastern Front career in the early 1944, when Yak-3 and Yak -9U were not available. Most common was Yak-1 which had speed limit of 650 km/h. Rall's story does not sound very reliable to me, unless he was in a very infavourable position.

I stand by my comment - numbers of Yak-9U available were quite limited. Bock states that the first kill on a Yak-9U was achieved on 30.04.1945 (42 GIAP). Perhaps our Russian friends can comment this info, nonetheless I do not think Bock did a significant error if any.

This is actually a question to our French friends - were French Yaks capable of bombload? Personally I do not think so.

I have a full report in Russian. This is only a small bit of it.

The report discusses this issue. Several reasons mentioned, including extra drag from radio mast, not installed on the prototype.

Christer

I do not think Germans captured any flyable Yak-9U and I doubt they were awared of any particular designations. I believe it is a post war interpretation.

It was a common knowledge at the time, the thing pilots were learned before entering the combat. See also a reply to Jens.

Point a is valid but only partially. Grislawski should keep an altitude advantage which favoured his aircraft. Of course I can imagine he sometimes was taking the risk but it was his error of judgement.
Point b - of course skilled pilot is able to do miracles and use some tricks like full throttle flying on high angles of attack. Otherwise I would be rather sceptical in such claims. One or two such combats may turn into a ordinary deed by power of a gossip. Combat reports are necessary. Not to forgotten is a quality of an opposing pilot of course - a very important factor.

See my reply to Jens.

Yes, but often veterans tend to 'colourise' their stories. I always try to verify their statements with combat reports etc.

It is just a sample, nonetheless I find it interesting because it is coming from an official document from the period. No further details are known and I cannot exclude it was a high speed combat in which Lightnings could use power advantage.

Indeed. More, if 109 is downed in such a combat, I would consider it almost exclusively an error of a German pilot.

PS A very recommended reading!
http://lend-lease.airforce.ru/englis...es/golodnikov/

One very small correction
 

Sorry
I was a little bit careless in my last message.
the max boost allowed with 150oct. petrol was +25lb/sqin, IIRC in other way expressed 81"HG.

Juha

Juha
You can edit your posts!
I will check Spitfire figures but you are correct this is a stinky bussiness. Anyway, flying Spitfire IX, I would recommend to keep altitude advantage and in case of enemy attack to climb away. I have to note that I have heard (it is somewhere on my PC) an interview with a Soviet ace Shatskij who flew Spitfires in PVO. He claimed Spit was the best aircraft he ever flew and that everything Soviet was a piece of crap. ;)

The weights for the Spitfire in that comparison are way over normal service load.

With full internal fuel and ammunition, the Spitfire IX weighed approx 7,450 lbs. The comparison on that site gives a weight of 4309 kg, which is 9,500 lbs.

So the Spitfire in that comparison is carrying 2,050 lbs of extra load, over and above normal fuel and ammunition.

The maximum load you could add to a Spitfire IX would be:

2 250 lbs bombs on the wings: 580 lbs (with bomb racks)

90 gallon drop tank on the centre line: 790 lbs

That's still 630 lbs short, which could only be made up by adding a rear fuselage fuel tank, of about 70 gallons.

That's way over maximum takeoff weight.

The power is correct, for a Merlin 63 at 21,000 ft, but I'd bet everything I own that the Russian fighters were not making 1850 hp at that altitude, and that their HP figures are the maximum they achieved. The Merlin 63, 66 and 70 were good for 1710 - 1720 hp with 100/130 octane fuel, around 2000 hp with 100/150 (less for the Merlin 63, as it couldn't run at 25 lbs boost, only 21, so approx 1900 hp).

Nash
I think more appropriate would be to compare Merlin 66 and 70 equipped Spitfires, as those were of 1944 standard as La-7 was. On the other hand, should not we compare La-7 with Spitfire XIV?
Interestingly, Soviets considered Spitfire LF.IX(!) their best high altitude fighter. She remained in service up until early 1950s.

I am not sure if I should post a separate reply but I think it would be clearer.
Great there is a separate board but woul it be possible to have some storage area for photos and drawings?

Finally something technical. The main difference between Soviet and Western aircraft was that they largely consisted of wood. Wood allows to make very aerodynamic shapes but it takes volume and weight to achieve same endurance. That was the main reason the world moved to metal designs and still continues the way.

Here is my contribution:

Performance for the La-7 during test flights of mass produced aircraft at the LII in the summer of 1944:

Max speed at 6,000 m (20,000 fet) = 674 km/h (418 mph)
Max speed at sea level = 582 km/h (361 mph)

Source: Gordon, Khazanov, "Soviet Combat Aircraft", Vol. 1, p. 54.

Performance for the Bf 109 G-6 accodring to German test flights:

Max speed at 6,000 m = 624 km/h
Max speed at sea level = 518 km/h

Source: Test flight by Messerschmitt works. I am unable to post the source here, but anyone interested can have a scanned copy of it. (That's the purpose of posting sources - so that other people can check your statements, isn't it?)

No wonder the Germans regarded the La-7 as a most dangerous adversary. However, at higher altitude, the Bf 109 G-6 pilots sure had even greater problems with the P-51s, not least as far as speed is concerned.

I have no reliable source for this, but wasn't the P-51C and P-51D almost 50 mph faster than the Bf 109 G-6 at 20,000 ft altitude? Isn't that about the same difference as the difference in speed between the Bf 109 F-2 and the I-16 Mark 24 at 9,800 feet flight attitude - the altitude around where most of the air combat on the Eastern Front took place - (304 mph for I-16 Mark 24, compared to the Bf 109 F-2’s 346 miles per hour at that altitude)?