"Stretch or not strech" of aircraft designs

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Incorrect - Morseby was saved by P-40s from the US 49th FG and Australian 75th fighter squadron (and others). See the Battle of Milne Bay (August - September 1942) during which a Japanese invasion fleet was turned back by land based aircraft operating mostly from Pt. Moresby

Battle of Milne Bay - Wikipedia

The P-40 continued in use by the 49th FG until well into 1944. It also remained the main fighter in use by the 23rd, 51s and 80th FG's in the CBI, and was the fighter type with the most air to air victories for the RAAF in 1944 according to Pacific Victory roll.


Again, I can't say about your theoretical narrative - I suspect you may be right that some adjustments to the P-39 would have made them viable. But your historical narrative is all wrong. By late 1942 the US were operating no less than five full fighter groups of P-40s which were their front line fighters, whereas the P-38 was doing mostly long range escorts of heavy bombers (primarily B-24s) and the P-39, after one big day of combat, losing 12 fighters on 13 March 1943 (despite top cover by Spitfires). After this slaughter they were relegated to 'coastal patrol' well away from any German fighters.

Some pilot comments on the P-39 in North Africa:

"Jerry Collingsworth, who flew as a Lieutenant with US 31st FG in Tunisia:

"The P-39 [Airacobra] was a miserable fighter for Tunisia; we used to have to escort them because the Me 109 and Fw 190 outperformed them in every conceivable way; dive, climb, manoeuvre, speed - you name it!"

Wg.Cdr. M. G. F. Pedley, Wing Leader in 323 Wing in Tunisia:

"P-39 Airacobra . . . Its rate of climb was poor, armament inefficient and engine unreliable." (p. 424)

John L. Bradley of US 33rd FG:

"I flew a couple of escorts for P-39s during my tour. Many of the pilots on these aircraft were afraid of them and figured they didn't have a chance if they were jumped by enemy aircraft without top cover." (p. 404)

This comment about the P-39 pilots being afraid of them is partly what got me thinking about the difference between the Soviet and American experience with the plane.


I agree once more about the potential performance of the P-39N, but the P-40 was not "relegated to training and lend lease to the Soviets." The P-40F/L was still the number one front line fighter in North Africa and Sicily / southern Italy through 1943 and was still a major part of the fighting force at Anzio in 1944.

In the CBI and Pacific again it remained in front line use through 1944. It was still dominating the Ki-43 through the end of it's service life there (much has been written on this subject).
 
33rd FG by the way from which the Jon Bradley quote, was a P-40 group - they were flying top cover for P-39s (and for Hurricanes also routinely)
 

Hello Schweik,

It seems a bit silly to have a gun that is so inflexible in its use as to REQUIRE short range, no deflection shots and even be limited to 2-3 rounds. Intimidation is an interesting thing. I would be VERY interested if you can find German pilot accounts that they were intimidated by Airacobras. As for a head-to-head showdown, accepting that kind of a match is just plain stupid regardless of what the other fellow is armed with. It would be a useful tactic if that is the ONLY shot you expect to be able to get.


The P-40 WAS being used with reasonable success in various places, but those were places where the competition was not really first rate. The Soviets really didn't particularly like the P-40 but I suspect that some of that had to do with their philosophy for armament; They really didn't believe in wing guns.



I suspect they were doing considerably BETTER because they were most likely overboosting their engines whenever they could.


Why do you believe we are disagreeing here? Unless you are very close to Sea Level, 496 MPH Indicated Air Speed is probably going to be over 500 MPH True Air Speed.
At 20,000 feet, 496 MPH IAS works out to 679 MPH TAS.
At 10,000 feet 496 MPH IAS works out to 577 MPH TAS.

Also regarding the Soviets designs, I would have to agree with Shortround6. I believe they built what they could with the resources they had but would have preferred to build better aircraft. They just didn't plan much for quality control or longevity which got to be interesting at the end of the war with their wooden aircraft that had been stored outdoors and were no longer airworthy because structures had weakened by exposure weather. They also had issues with structural failures for their wood laminates due to manufacturing faults. Their aircraft in the field often tested at well below performance levels expected from the documentation.

- Ivan.
 
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I specified early P-38s, the F and G models in use about the same time as the P-39N. Later J and L models had great climb but they had higher rated later model engines.
Ivan1GFP said:
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Iv
I don't have AHT, but wwiiaircraftperformance.org has a test of a P-38G in Feb'43 that showed normal speed (400mph) but astounding climb rates. Turns out that particular P-38G weighed only 13900# when a normally equipped G weighed 15900#. The test plane was a FULL TON light, armed with the 20mm cannon and only two .50s when normal P-38s carried four .50s and none of the three guns carried normal ammo load. Only 180 gallons of fuel were carried but the normal internal load was 300 gallons. Needless to say I don't think normal P-38s were equipped/loaded that way and I can't imagine why that one was tested that way. Three or four other tests/charts show more normal climb rates.
 
Only thing I can tell you about the P-39 vs P-40 is that every single model of the P-39 was faster than every single contemporary P-40 model (except Merlins-they were about the same as early P-39s). Same with climb and ceiling, every P-39 is better. The P-40 had the same engine as the P-39 but weighed 700# more. Just no way to make that up in performance.
 

I don't disagree, on paper the P-39 looks like it has a superb rate of climb and very good speed - and without a doubt better in both traits than the P-40. Better than a lot of Spitfires too for that matter. So it's a mystery why it performed fair to badly in everyone's hands except the Soviets. The Soviets seemed to get out of it what the specs said it could do.
 

No doubt it is quite silly, let us not forget the P-39 came from the same wacky firm that gave us the "Airacuda" and other marvels. Who knows what kind of surreal Buck Rogers air war the designers were imagining when they put those designs down on the drafting table. But for all it's challenges, the 37mm gun was very popular with the Soviets, even before they got it shooting more reliably (which they did, from what I understand the 2-3 rounds thing was an issue in the early days). So popular in fact that they put 37mm guns into ~3,000 Yak-9T and at least another 1,000 other Yak fighters of various other variants deployed in combat, and ended up putting them onto MiG 15's etc. postwar. They had their reasons for that of course (wanting to shoot down Strategic bombers) but it didn't seem to hinder that aircraft as an air superiority fighter much either.

The short version though is I don't think it was 100% their (the Soviets) adapting tactics to the gun so much as their existing tactics (to get very close and shoot from 50-100 meters) suited the gun, and the P-39 more generally.


The first part of that statement I think isn't entirely correct, it's one of those summaries that tends to mislead in fact. The P-40s used in the Med and in Russia were fighting the same Axis aircraft, and especially the elite Luftwaffe units as everyone else. Just in a different Tactical situation.

In Burma or the CBI you could argue that the Japanese opposition wasn't as ferocious as the Germans but I'm not sure I agree- certainly the best British fighters, Spitfires and Hurricanes, Seafires and Fulmars, didn't fare so well against the Japanese.

As for the prejudice against wing guns I kind of agree, but the Soviet's did not actually dislike the P-40. They didn't love it, but it was their second favorite lend-lease fighter after the P-39. Most P-40 units became guards units and as you are no doubt aware, numerous double, triple and quadruple (etc.) P-40 aces became HSU and double HSU etc.

I suspect they were doing considerably BETTER because they were most likely overboosting their engines whenever they could.
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Overboosting seems to be pretty common, is there any reason to assume it wasn't done with P-39s in the South Pacific?


I wouldn't insist it was that fast but who knows... there is one claim by another Curtiss test plot of 600 something mph in a dive in a Kittyhawk I


I'm sure they would prefer to have MiG-15s or Su-27s but I believe from the point of view of Soviet planning, in the logistical and industrial reality they were in, I believe they made exactly what they needed. To the Soviets, a two-stage supercharger and full metal stressed skin and 5 or 6 guns is a waste. For the same amount of strategic materials you can make two fighters each with a single stage supercharger and two guns with half as much metal, and both of them can shoot down a Bf 109 just as easily down at 2,000 feet where the Sturmoviks are flying. In fact Yak-1Bs and 7s and La-5s performed better against the German fighters than the Spit V did as we know.

The Russian Front was fought at BoB intensity for four strait years. Those planes often had a life expectancy of 20 or 30 missions at the most, why make them out of two tons of Duralumin from nose to tail? They only need to last 3 months. There will be an improved version by then anyway. I suspect in fact that the construction materials of wood and so on are in part why Soviet fighters tend to get an unfair bad rep, too few of them survived to impress us at Air Shows and museums.
 
Just wonder if this is a case of handling characteristics trumping performance stats. Some planes like the F6f don't look all that impressive on paper but performed outstanding in actual combat. Near as ive been able to glean from what pilots had to say seems like this was largely due to good stable handling characteristics.
I'm guessing the reverse could also be true, that is a plane with squirly handling characteristics might fair worse than its performance stats might lead one to believe.
 

Yes I think the P-40 is kind of an extreme example of that, in many respects on paper it looks like a dog but it almost always overperformed in the operational histories.
 
Schweik said:
Yes I think the P-40 is kind of an extreme example of that, in many respects on paper it looks like a dog but it almost always overperformed in the operational histories.
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The British used the P-40 and didn't want the P-39, with very sound reasons, it wasn't very good and was behind the curve.
 

Hello Schweik,

Regarding silly: I believe it was just a poor combination of armament and engine power and required airframe size to even have a CHANCE at achieving required "interceptor" performance. The P-38 got around it with two engines. The P-39 did not.
As for the 37 mm gun being popular and mounted in many Soviet fighters, it ISN'T the same 37 mm cannon as in the Airacobra.
The NS-37 had a muzzle velocity about 50% higher than the M4 cannon and a cyclic rate of about 260 RPM as compared to 150 RPM.
The post war guns mounted in the MiG-15 were probably N-37 which had a lot less muzzle velocity to reduce recoil but had a firing rate of about 400 RPM. The only similarity between these three guns is the bore diameter.


Not all the opposition was elite Luftwaffe units. The Italians had a pretty good assortment of aircraft and many of them were not modern types. Even some of their best were somewhat limited by the engines that the Germans allowed to be license built. The C.205 for example didn't appear in significant numbers before Italy surrendered.
The tactical situation was perfect for the Allison powered P-40 which had some pretty decent power at low altitude.


From accounts I have seen, the "didn't fare so well" was mostly because the British tried the wrong tactics against the lightweight Japanese fighters. A Spitfire may turn pretty well, but a Hayabusa turns better.


I forget who made the comment that the P-40 was really not up to modern standards when discussing lend-lease aircraft to the Soviets.
The success I believe is more indicative of relative pilot quality than of aircraft superiority.

Schweik said:
Overboosting seems to be pretty common, is there any reason to assume it wasn't done with P-39s in the South Pacific?
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Golodnikov stated that typically after 3-4 combats, the engine was changed. That kind of time between overhauls would have been commented upon if it were by American units.


I believe the "exactly what was needed" is a conclusion based on hindsight. My Son calls that "hindsight bias".
The problem with non-strategic materials / wood construction is that it is labor intensive, the result is not particularly strong and is relatively heavy for its strength. The engine itself is probably the single biggest piece of strategic materials and manufacturing in the entire aircraft, so the savings isn't that great. Of course if engine power is limited, one has to choose and it seems pretty silly to carry around more airframe and less payload because of wood construction. On many of their aircraft wooden structural parts were gradually replaced with aluminum pieces as production went on. Now that would be pretty silly if the wooden pieces were the optimal choice.
The lack of engine power was an issue that the Soviets tried to address for quite some time especially with the VK-107 but it simply was not successful until near the end of the war.
It also isn't true that the Soviets were satisfied with low altitude fighters. The MiG-1 and MiG-3 were good examples of attempts at high altitude aircraft, but still without a lot of engine power. The same can be said for quite a few of their experimental designs.

The Spitfire Mk.V wasn't particularly fast at low altitude and many Spitfires that were shipped to Russia were pretty well used before they were sent.

- Ivan.
 
Spitfires over the Kuban – Lend-Lease

Well, this theory flies in the face of what we know about Soviet engine development.
We know the M-106 engine was in development from 1938 on. compared to the M-105 it used modified pistons and cylinder blocks, a strengthened crankshaft and reduction gear pinions; It used the same attachment points as the M-105. In March of 1939 two prototypes with 2 speed superchargers were built. Development was long (in part due to the war) and first flight tests were done in in the winter of 1942/43 in Yak 1s and Yak 9s. All the problems had NOT been solved and facorty No 26 in Ufa phased the M-106 out of production in May of 1943 after over 150 had been built, however this was not the end. in late 1943 an M-106 with a two stage supercharger (M-106PV) was tested in a Yak-9PD and by 1944 the engine had the supercharger RPM increased, water/alcohol fitted and a new ignition system. This was tested in a Yak-9PD and over 50 such engines were built.
Back in 1940 there was a project for the M-106TK with two TK-1 turbo superchargers. The Soviets tried to put turbochargers on just about everything short of a T-34 tank. However their metallurgy/manufacturing failed them and none of the turbo installations saw


service during the war.
The Soviets also were working on the M-107 engine from March of 1940. This was a much modified M-105 and included such things as 4 valves per cylinder instead of three. 29 were built in 1941 (instead of the planned 2000) and production of the series engines started in 1942 (slowly).
You also have the whole Mig-1/3 saga which morphed into the I-230 and I-220 aircraft, some of which had pressure cabins and turbo superchargers on AM-39 engines.
I would also note that early Lagg fighters were supposed to have a 23mm cannon and two 12.7mm machine guns but the 23mm cannon didn't meet expectations and was replaced by the smaller 20mm gun, Some early Lagg-3s were 5 gun fighters. The single 20mm, two 12.7mm guns above the engine and two 7.62 ShKAS machine guns under the engine. As with many Soviet aircraft production examples showed a much decreased performance from prototypes and drastic measures had to be taken to restore performance. Like taking out guns and restricting ammo.


The Russians were designing mostly wooden fighters (and mixed construction larger aircraft) well before the Germans invaded to due a lack of Aluminum in peace time. This was not a brilliant decision made by the Russians during the war but rather a situation forced on them by the supply situation well before the war.
 
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Schweik said:
Yet somehow more 'overly optimistic' than everyone else. For some reason we ignore huge rates of overclaiming by say, the Germans in these contexts.... which is odd
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I would say that overclaiming by the Germans is pretty much accepted as an established fact, not ignored; but German overclaiming is not really relevant to how the P-39 performed in Soviet service.
 
Soviet P-39s were lightened by removal of the .30 wing guns and some (not all) radio equipment that was incompatible with Soviet wavelengths. This amounted to around 250 pounds which would have increased climb rates by about 300 feet per minute.
 
Stig1207 said:
I would say that overclaiming by the Germans is pretty much accepted as an established fact, not ignored; but German overclaiming is not really relevant to how the P-39 performed in Soviet service.
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I think what German overclaiming has to do with the performance of the p39 in Soviet service and the point he was trying to make is that overclaiming was universal to all airforces during the war and usually by similar percentages so would not be a factor in comparative performance evaluation as you have to knock off the same say 50% off every type in every airforce.
At least that's what I got from it.
 
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Another thought about Shweiks post that I never thought about before is that, at least in my experience, I've read/ heard alot more people throw shade on Russians, Americans, and to a lesser extent the Japanese for overclaiming but rarely the Germans. From the limited number of actual loss vs claim reports I've read the Germans certainly didn't overclaim more than anyone else and perhaps a case could be made for slightly less but the numbers were indeed similar.
 
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Schweik,

Regarding Moresby being saved from invasion, I didn't mean to imply that the P-39 had anything to do with the Battle of the Coral Sea in May '42. That was of course the Navy that turned back the invasion force at Coral Sea. But the Japanese mission in that battle was to invade Moresby. The later battle of Milne Bay was an attempt by the Japanese to invade Milne Bay, not Moresby. Make sense?

Thanks.
 

Yes, exactly. But there is another facet too which makes it more directly relevant:

Quite a few of the claims by German pilots that didn't actually turn out to be real were against Soviet P-39s.

Overclaiming was not a constant and varied by region and by time period, and even by individual unit. For the Germans, initially their processes and procedures were better and their claim rate was more accurate. By the mid war this was slipping, and by the later part of the war their overclaiming got worse. For example at Bodenplate the Germans claimed 79 aerial victories but apparently only shot down 31 Allied aircraft*, a 2-1 ratio. Earlier in the war about 1.5-1 was more common for the Luftwaffe (though it varied widely). In the MTO as I have pointed out Luftwaffe overclaiming sometimes reached 3-1.

For the Soviets, it was the opposite pattern. Initially overclaiming was wild - up to 4-1 in the first year of the war, and this was a problem for the Soviet administration. They needed to know what was actually going on so they could plan accordingly. Strict rules and often draconian policies (sometimes including courts-martial) were imposed in a hamfisted manner through 1942, including the requirement to recover the identity plate of a claimed aircraft for it to be confirmed (so no victories over enemy territory counted). Later they also started using gun cameras. The result was that overclaiming rates had declined by mid 1943 to around 2-1 and later (by my estimate) to around 1.5-1.

For the Anglo-Americans the fairly early widespread adoption of gun cameras helped with overclaiming - though it was not a panacea. You could have gun camera footage of several planes shooting up the same doomed target. Rates were similar to the Luftwaffe initially and gradually got better through the course of the war.


* per Wikipedia - 6 x Typhoons, 13 x Spitfires, 2 x P-51s, 6 x P-47s, and 4 x artillery spotter / liaison planes
 
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