Why was the La-7 so fast ???

[swampyankee]

One is that it's certainly not impossible that the Soviet aircraft did have markedly better aerodynamics -- the people at TsAGI were no less competent than those in the German equivalent, at NACA, or at ARC -- and the Soviets were, by 1944, not having to deal with quite so many bombs falling on their production facilities as were the Germans. This may have made it a bit easier for their designers to concentrate, what with not having to worry about their home being turned into rubble by something from a Lancaster, B-17, or B-24.

A major source of drag in piston-engined aircraft is cooling drag. Some aircraft, like the P-51, had magnificently well-designed cooling systems. Some had poorly designed ones -- the Ju87 was reputed to have an especially high-drag cooling installation. Good cooling system design requires dealing with a lot of fiddly changes, some of which may seem counter-intuitive to non-specialists (I am not a specialist in aircraft cooling system design. I suspect that the only ones still around work for companies like Diamond and Cessna, where production cost and maintainability are much more important than a reducing the drag count by a couple of points). It's not inconceivable that Lavochkin had somebody who was better at cooling system design than anybody at Focke-Wolf. It's also possible that the labor working at the Soviet factories was a bit better motivated than the ones working in Speer's various slave-labor industries.

 

[l'Omnivore Sobriquet]

Why was the Lagg-7 so fast ?

All of it was done with aerodynamic improvements.

That's the classic explanation.
Soviet engineers were locked-up and given orders to improve on the existing and forget about big futuristic plans. They spent months and months wind-testing tiny details, little improvements sparing no big science on the task, and so it gave : Lagg-7, Yak-3, and late marks Yak-9s.

Its the classic explanation again, then here in this WWIIaircraft forum I'm sure we're getting, hm... little improvements on this, too..

 

[GrauGeist]

It's also possible that the labor working at the Soviet factories was a bit better motivated than the ones working in Speer's various slave-labor industries.

Soviet engineers were locked-up and given orders to improve on the existing and forget about big futuristic plans. They spent months and months wind-testing tiny details, little improvements sparing no big science on the task, and so it gave : Lagg-7, Yak-3, and late marks Yak-9s

Uncle Joe was a great motivator...

 

[Koopernic]

If I may cut in:



In low gear, the max permissible (over)boost for the BMW 801D was 1.58, in high gear it was 1.65. Power setting known as "Erhöhter Notleistung" (roughly: "Increased emergency power"). Under the 'Start und Notleistung', max boost was 1.42 ata.
For the 801TS, the max boost for "Erhöhter Notleistung" was 1.82 ata. 2200 PS before cooling fan power is deduced. 'Start und Notleistung' max boost was 1.65 ata; 2000 PS minus 70 PS for the fan.



Not this old chestnut
1.82 ata was a 'simple' overboosting. This chart (here) shows that Fw-190A-8 carried no MW-50 mixture, ditto for the A-9.



It was more aerodynamic, as shown on the table posted several times elsewhere on this forum (erstwhile by our member with nickname 'bada')



Standard Soviet fuel on the onset of the Op Barbarossa was of oct rating = 95. During the 1st war years the fuel quality varied a bit, that convinced Soviets to lower the compression ratios on some engines, like at the AM-38F (from 6.8:1 at AM-38 to 6:1); because of that, ever greater boost was to be used. The AM-42 went down to 5.5:1 with CR!
The Germans decided to increase the CR when going from the BMW 801C to 801D, that might be called as a self-inflicted wound - greater CR means it is not so easy to overboost the engine when hi-oct fuel becomes available.
Only major Soviet engine that used fuel injection was the ASh-82FN, with Klimovs and Mikulins staying with multiple carburetors.

The Fw 190A-8 most certainly didn't have MW-50 but the FW 190A9 did have the supplementary tank added whose purpose was ultimately to be use of extra fuel, GM-1 or MW-50 given appropriate plumbing. That was the idea of moving equipment around and increasing cowling armour from 6mm to 10mm. Apart from the extra protection it helped with c of g issues. The Fw 190A9 and Fw 190D9 share internals as much as possible, hence the naming. The supplementary tank most definitely was used for MW-50 in the Fw 190D9. One system known as the oldenberg system used supercharger pressure to blow MW50 into the supercharger. A more powerful pump driven high flow system fitted in the field by Junkers field personnel was also used. The Fw 190A9 was to be a supercharger blown system known as the Ribbentrop. MW-50 may not have seen use on operational Fw 190A9 but I think it did see use on Ju 88H and Ju 188E to help with take-off.

The development of green dyed C fuel such as synthetic C3 (and mineral based C2) was very important in order to try and keep up with allied engine development. Hats off the Merlin engine designers and developers but it would have been a dog (ok inadequate is a better word) without 100/130 and RR would have been forced to ditch it and concentrate on Grifon development.

The increase in compression ratio, rather than over boosting, makes sense given the fuel economy improvements (about 10% more power with no increase in fuel consumption) in the context that C3 fuel was not a fixed specification. It started out at around 94/115 and improved in several steps: roughly 96/125, 97/130 or so. These are not official German numbers but the result of British analysis of German fuel. The rich mixture response initially wasn't there for really effective over boosting. Around late 1943 "C3 einspritzung" ie "C3 injection" was added to the ground attack versions of the Fw 190 (the F and G) in which fuel was injected into the eye of the supercharger to precool the air as well as create a rich mixture. By then you see the rich mixture response was there. For some reason this system was restricted to use below 800m (2600ft). Fighter version got a simpler increase boost which was much less powerful since it lacked the injection into the supercharger which meant the air was not precooled and contracted. Latter the systems were merged and the altitude restrictions removed. There is a lot going on between late 1943 and mid 1944 with BMW801 engine.

The Germans were very concerned to speed up their fighter bombers when carrying a load of bombs. With it the Fw 190F could be quite difficult to intercept, hence the pressure on LaGG development and speed.

 

[swampyankee]

Uncle Joe was a great motivator...

Probably no more so than Herr Schickelgruber.

Another issue, which is much less likely to involve any politics is that if the FW190 was tested by the Soviets, it's possible the aircraft were old and somewhat clapped-out, and the La-7s were new and well-tuned. Considering that one type of aircraft lost 20 mph in top speed due to a different type of paint and that other aircraft have had a paint seam radically change stall characteristics, it may not take much to make a significant difference in performance.

 

[swampyankee]

Uncle Joe was a great motivator...

Probably no more so than Herr Schickelgruber.

Another issue, which is much less likely to involve any politics is that if the FW190 was tested by the Soviets, it's possible the aircraft were old and somewhat clapped-out, and the La-7s were new and well-tuned. Considering that one type of aircraft lost 20 mph in top speed due to a different type of paint and that other aircraft have had a paint seam radically change stall characteristics, it may not take much to make a significant difference in performance.

 

[parsifal]

Hats off the Merlin engine designers and developers but it would have been a dog (ok inadequate is a better word) without 100/130 and RR would have been forced to ditch it and concentrate on Grifon development

.


Wasn't the majority of fuel used up to the end of 1940 with standard 87 Octane rated fuel. Glider did a whole stack on this a couple of years back as I recall???

 

[GrauGeist]

Probably no more so than Herr Schickelgruber.

Another issue, which is much less likely to involve any politics is that if the FW190 was tested by the Soviets, it's possible the aircraft were old and somewhat clapped-out, and the La-7s were new and well-tuned. Considering that one type of aircraft lost 20 mph in top speed due to a different type of paint and that other aircraft have had a paint seam radically change stall characteristics, it may not take much to make a significant difference in performance.

The Soviet designers basically were told to develop and that was that. In Germany, there was alot of political in-fighting as well as developer competition. Chaotic, yes, but offered results across the board (sometimes, too many results).

And good point about the Russian tests of German equipment. They weren't testing factory fresh machines, they were testing captured aircraft, several had been crash recoveries. The Germans had done the same with captured Allied aircraft and the Allies tested German equipment that was recovered from crash sites or what wasn't able to fly out of an airfeild as German forces retreated.

 

[Shortround6]

The fighters were using 100 octane in 1940 (at least the large majority of them in the BoB ) and that 100 octane was actually 100/115-120.
Even the Blenheim bombers/night fighters were rigged to use 100 octane in the outer tanks and 87 in the inner tanks to allow higher boost for take-off and bursts of speed.

I don't know when the 100/130 was introduced but since 18lbs boost was quite usable with 100/130 then around 15lbs boost seems reasonable with 100/120.

 

[Shortround6]

The Soviet designers basically were told to develop and that was that. In Germany, there was alot of political in-fighting as well as developer competition. Chaotic, yes, but offered results across the board (sometimes, too many results).

And good point about the Russian tests of German equipment. They weren't testing factory fresh machines, they were testing captured aircraft, several had been crash recoveries. The Germans had done the same with captured Allied aircraft and the Allies tested German equipment that was recovered from crash sites or what wasn't able to fly out of an airfeild as German forces retreated.

There was a fair amount of "political in-fighting" or behind the scenes maneuvering in the Soviet union too.

 

[Koopernic]

Quote Originally Posted by GrauGeist View Post

Uncle Joe was a great motivator...

Probably no more so than Herr Schickelgruber.

Another issue, which is much less likely to involve any politics is that if the FW190 was tested by the Soviets, it's possible the aircraft were old and somewhat clapped-out, and the La-7s were new and well-tuned. Considering that one type of aircraft lost 20 mph in top speed due to a different type of paint and that other aircraft have had a paint seam radically change stall characteristics, it may not take much to make a significant difference in performance.

Agree re testing of captured types, which were often also old models. One Fw 190A6 handed over the the USN was tested against corsairs, hellcats, P-47. they complained that the Fw 190 aileron flutter was so bad it blacked out the pilot. That's not normal, flutter also leads to premature stall, and it rather invalidates the subsequent comparative turn tests they did. The Fw 190 pushrod linkages were notorious to set up without special procedures.

As far as Adolf Hitler was concerned I think its clear he was a milder in the sense of being more predictable than Stalin with his own people. Stalin had his own designers such as Tupolev, working on Gulags. He had folks, including one naïve young man, executed for making a joke that was too familiar during his enforced group Vodka drinking sessions. The project manager for the MiG 3 was executed for not achieving sufficient range in the aircraft. Hitler did non of that. It did sometimes come from over enthusiastic minor Nazis. Kurt Tank was accused and briefly investigate for sabotaging the Ta 154 program. Of course Tank was just making rational technical decisions and the minor nazi just a passionate hot head, Ta 154 was a waste of time driven as much by a desire to make use of plentiful Jumo 211 production as its wooden construction impossible to implement due to German shortages of wood workers, experience etc.

You'd be a lot safer around Hitler, getting caught up in an assassination attempts aside. Even if you were of partial Jewish ancestry eg Emil Maurice who took dictation for Mein Kampf or Erhard Milch (who was of partial Jewish ancestry) you needed the right politics and ww1 service.

The reason is that Stalin and several communists before him, including Lenin, used random killing to create a powerful and effective terror. It was the randomness that was the key to the terrors effectiveness. Under Hitler's regime there was at least consistency that could be mentally 'mapped' and so avoided. Stalins cult of personality was so supreme folks died in Gulags thinking that it was someone elses fault and that as soon as uncle Joe found out he'd fix things.

This was started by Lenin. Consider the problem he had with Ukrainian Kulaks (small farmers with 6-12 employees). To the metropolitan communists these were the equivalent of conservative farmers in the US disparaged as Rednecks. Lenin just issued order such as 'kill 15000 kulaks', not interest in any kind of judicial process or even political assessment. So Stalin was probably had to be the way he was given who he was working with.

Stalin was an extremely clever man that should never be underestimated in his intelligence or capacity for mass murder as an instrument of social change. He made many amusing quips that have had me in stiches. The one about "quantity having a quality all its own" or his "you may not be interested in the revolution but the revolution is interested in you". His brilliance was in getting other folks to fight themselves to destruction while he then romped in and cleaned up. A Machiavellian master.

 

[tyrodtom]

Quantity has a quality all it's own, is one of Lenin's known quotes. But I'm sure Stalin wasn't adverse to repeating anything said by Lenin.

You'd think a flutter that severe would result in structural failure before it could black out a pilot.

 

[timmy]

Quote Originally Posted by GrauGeist View Post

Uncle Joe was a great motivator...





Agree re testing of captured types, which were often also old models. One Fw 190A6 handed over the the USN was tested against corsairs, hellcats, P-47. they complained that the Fw 190 aileron flutter was so bad it blacked out the pilot. That's not normal, flutter also leads to premature stall, and it rather invalidates the subsequent comparative turn tests they did. The Fw 190 pushrod linkages were notorious to set up without special procedures.

As far as Adolf Hitler was concerned I think its clear he was a milder in the sense of being more predictable than Stalin with his own people. Stalin had his own designers such as Tupolev, working on Gulags. He had folks, including one naïve young man, executed for making a joke that was too familiar during his enforced group Vodka drinking sessions. The project manager for the MiG 3 was executed for not achieving sufficient range in the aircraft. Hitler did non of that. It did sometimes come from over enthusiastic minor Nazis. Kurt Tank was accused and briefly investigate for sabotaging the Ta 154 program. Of course Tank was just making rational technical decisions and the minor nazi just a passionate hot head, Ta 154 was a waste of time driven as much by a desire to make use of plentiful Jumo 211 production as its wooden construction impossible to implement due to German shortages of wood workers, experience etc.

You'd be a lot safer around Hitler, getting caught up in an assassination attempts aside. Even if you were of partial Jewish ancestry eg Emil Maurice who took dictation for Mein Kampf or Erhard Milch (who was of partial Jewish ancestry) you needed the right politics and ww1 service.

The reason is that Stalin and several communists before him, including Lenin, used random killing to create a powerful and effective terror. It was the randomness that was the key to the terrors effectiveness. Under Hitler's regime there was at least consistency that could be mentally 'mapped' and so avoided. Stalins cult of personality was so supreme folks died in Gulags thinking that it was someone elses fault and that as soon as uncle Joe found out he'd fix things.

This was started by Lenin. Consider the problem he had with Ukrainian Kulaks (small farmers with 6-12 employees). To the metropolitan communists these were the equivalent of conservative farmers in the US disparaged as Rednecks. Lenin just issued order such as 'kill 15000 kulaks', not interest in any kind of judicial process or even political assessment. So Stalin was probably had to be the way he was given who he was working with.

Stalin was an extremely clever man that should never be underestimated in his intelligence or capacity for mass murder as an instrument of social change. He made many amusing quips that have had me in stiches. The one about "quantity having a quality all its own" or his "you may not be interested in the revolution but the revolution is interested in you". His brilliance was in getting other folks to fight themselves to destruction while he then romped in and cleaned up. A Machiavellian master.

Man that is just crazy!

Aircraft Designers in WW2 where bringing incredible improvements to aircraft designs in just such a short period of time (1939-45). There was always going to be a long list of mistakes if your trying to achieve something that has never been done before.

I wonder how many talented people in Russia never entered the field because of the risk of getting a bullet in the head if you failed?

Take Hawker's Sydney Camm. Probably would have been executed by Stalin for the Typhoon. Before he could redeem himself with the Tempest

 

[Koopernic]

Filin, Aleksandr Ivanovich

Major-General of Aviation

* 18th of January 1903
† 23rd of February 1942
Александр Иванович Филин

Promotions
1940-06-04 Major-General of Aviation

Service:
1930-04-XX – 1931-06-XX Acting Senior Engineer, 6th Section, Scientific Research Institute of the Air Force
1931-06-XX – Senior Engineer, 6th Section, Scientific Research Institute of the Air Force
Acating Chief of ? Branch, 1st Section, Scientific Research Institute of the Air Force
1933-06-XX – 1935-01-XX Chief of Scientific Research Sector Land Airplanes, Scientific Research Institute of the Air Force
1935-01-XX – 1936-02-XX Chief of Scientific Research Branch, Land Airplanes Section, Scientific Research Institute of the Air Force
1936-02-XX – 1937-11-XX Commanding Officer Scientific Research Operational Use Squadron, Scientific Research Institute of the Air Force
1937-11-XX – 1941-05-23 Head of the Scientific Research Institute of the Air Force
1941-05-23 Arrested
1942-02-13 Condemned to death
1942-02-23 Executed
1955-03-26 Rehabilitated

 

[GrauGeist]

Man that is just crazy!

Aircraft Designers in WW2 where bringing incredible improvements to aircraft designs in just such a short period of time (1939-45). There was always going to be a long list of mistakes if your trying to achieve something that has never been done before.

I wonder how many talented people in Russia never entered the field because of the risk of getting a bullet in the head if you failed?

Take Hawker's Sydney Camm. Probably would have been executed by Stalin for the Typhoon. Before he could redeem himself with the Tempest

Konstantin Kalinin was one such example. He was an accomplished pilot, a WWI veteran and an aircraft designer. He founded the aviation design bureau in Kharkov.

When his K-7 failed to produce results, Uncle Joe was displeased and Kalinin was branded an "enemy of the state" and was executed in 1940.

Stalin's recurring purges did more than stifle potential development in the young educated ranks, he darn-near dropped the Soviet Union in Hitler's lap after purging all the experienced military before the war with Finland and afterwards.

 

[parsifal]

hitlers leadership was hardly consistent and hardly predictable. He had a habit of keeping people in the dark as to the overall situation, so that people could not get a wider view of what was happening. When faced with challenges he could not understand, he frequently defaulted to simplistic views of how to react, his infamous no retreat policy was good example of that thinking. When confronted with realities that were not to his likeing, he frequently turned on the messenger, eg his attacks on Raeder, his sackings of men such as Guderian his sacking of Brauschisch. When it came to aircraft he was just as bad, as the warped priorities for Me 262s, terror weapons and other projects with no immediate benefits for Germany clearly show. He was not quite as murderous as Stalin,but his interference, if anything was far more destructive and muddled than anything uncle Joe ever produced.

My opinion onHitlers leadership, insofar as producing a coherent procurement policy for Germany was far worse than anything Stalin did.Unlike Hitler,Stalin learned reasonably early that his intervention directly was generally counter productive. Upset stalin, and you were likely to pay with your life, but Hitlers style was much more along the lines of direct intervention, with catastrophic results for the entire german war effort, including its procurement machine

 

[Juha]

... The project manager for the MiG 3 was executed for not achieving sufficient range in the aircraft...

It wasn't so simple, Filin wasn't the project manager for the MiG 3 but the head of the VVS (Soviet AF) test facility (NII VVS), as your message #34 shows. He was accussed for that his test facility passed substandard a/c to service. Because Mikoyan's brother was a People's Commissar (SU Gov minister) the fact that the MiG didn't pass the 1,000km range demand in the NII VVS tests might has been the last straw.

Juha

 

[Denniss]

So Vitamin B (AKA connections) was used to save Mikoyan's live and have the other one killed. Not very nice.

 

[Juha]

So Vitamin B (AKA connections) was used to save Mikoyan's live and have the other one killed. Not very nice.

Again, not so simple, there had been numerous complains levelled against NII VVS before the case of the MiG and I doubt that Mikoyan's life was in danger but probably his reputation and that of his older brother, if he had used his influence to promote his younger brother's career.

Juha

 

[tomo pauk]

The Fw 190A-8 most certainly didn't have MW-50 but the FW 190A9 did have the supplementary tank added whose purpose was ultimately to be use of extra fuel, GM-1 or MW-50 given appropriate plumbing. That was the idea of moving equipment around and increasing cowling armour from 6mm to 10mm. Apart from the extra protection it helped with c of g issues.

My take is that it was easy to install a tank. What was hard was to 'persuade' the BMW-801 to work well with MW-50.

The Fw 190A9 and Fw 190D9 share internals as much as possible, hence the naming.

Naming was a pure coincidence, if you mean that both were '-9s'?

The supplementary tank most definitely was used for MW-50 in the Fw 190D9.

Indeed.

MW-50 may not have seen use on operational Fw 190A9 but I think it did see use on Ju 88H and Ju 188E to help with take-off.

I'd be grateful for any good info re. operative use of MW-50 on BMW-801. So far none surfaced?

The development of green dyed C fuel such as synthetic C3 (and mineral based C2) was very important in order to try and keep up with allied engine development. Hats off the Merlin engine designers and developers but it would have been a dog (ok inadequate is a better word) without 100/130 and RR would have been forced to ditch it and concentrate on Grifon development.

Merlin would be a food for another topic - with 6:1 CR it can use more boost, on same fuel than major German engines. Intercooler would've helped, and it is not a long shot for the RR to have water injection installed in case hi-oct fuel is not around.

The increase in compression ratio, rather than over boosting, makes sense given the fuel economy improvements (about 10% more power with no increase in fuel consumption) in the context that C3 fuel was not a fixed specification. It started out at around 94/115 and improved in several steps: roughly 96/125, 97/130 or so. These are not official German numbers but the result of British analysis of German fuel. The rich mixture response initially wasn't there for really effective over boosting.

That 10% of more power is an arbitrary number, unless we know what CRs are compared.
Engine power was at a higher priority than consumption, if I'm not mistaking it badly.

Around late 1943 "C3 einspritzung" ie "C3 injection" was added to the ground attack versions of the Fw 190 (the F and G) in which fuel was injected into the eye of the supercharger to precool the air as well as create a rich mixture. By then you see the rich mixture response was there.

Nobody is saying that there was no rich response with C3 fuel use.

For some reason this system was restricted to use below 800m (2600ft).

Makes sense, since the device was aimed for the GA versions?

Fighter version got a simpler increase boost which was much less powerful since it lacked the injection into the supercharger which meant the air was not precooled and contracted. Latter the systems were merged and the altitude restrictions removed. There is a lot going on between late 1943 and mid 1944 with BMW801 engine.

Were the systems merged? The A-8 and A-9 used 'simple' overboost, there was no need for the C3 injection.

added: the overboost was not a system, much as the overboost of the Merlin III from 6.5 psi to up to 12 psi was not a system.