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The P-39 why a failure for the West and a winner in Russia?

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  • The P-39 why a failure for the West and a winner in Russia?

    The often maligned P-39 was clearly not a success in US and British hands. On the other hand, the Russians did quite well with the plane. Why the difference?

    I would suggest it has to do with the kind of air war the two were fighting.

    In British hands, the plane was simply seen as inferior and quickly rejected. There was little attempt to correct or learn to use it. So, the British didn't do much more than give the plane a brief try.

    In US hands, the P-39 had three distinct failings that left it unable to compete effectively with other US fighters

    First, was the altitude deficiency. The P-39 shared this with the P-40. Both with an Allison engine suffered performance falloff above 15,000 feet. In these terms there was little to choose between the P-40 and P-39. But, generally the P-39 did have a maneuver advantage over the P-40 when the two are compared. It was the other two deficiencies that made the P-40 the preferred choice of the two. The P-40 in the MTO also generally got the Merlin engine (the F and L models) that gave those two variants better high altitude performance even if the Merlin gave no overall increase in speed.

    Second, was range. The P-39 had relatively short legs and this was shorted on starting on with the P-39N even further when fuel tankage was reduced by about 25%. This absolutely killed the offensive ability of the P-39 compared to other US aircraft. The P-39 in this condition had a range of about 525 miles and could carry just one smallish drop tank for a max range of about 650 miles. The P-40 by comparison could fly about 650 miles on internal fuel and another 150 with a drop tank. In the Pacific this left the P-39 more often than not being relegated to a defensive interceptor, a role it was ill suited to due to its overall performance. In the MTO and ETO it frequently didn't have the range to make it to targets or be useful as an escort fighter.

    The third was armament. The P-39's armament was poor. Up through the P-39Q this was effectively a 37mm or 20mm cannon and two .50 machineguns in the nose. The four .30 machineguns in the wings were all but worthless and often not even fitted for that reason. This made it lighter than the 6 .50 machineguns on the P-40 and the issues with the early 37mm jamming did nothing to build confidence in the plane. The P-39Q tried to rectify this by fitting 2 .50 machineguns in pods in place of the 4 .30 guns but the pods were found to cause slight reductions in performance in an already marginal plane.

    For the Russians none of these deficiencies were deal breakers. The range without drop tank was usually more than sufficient for VVS operations. The Red Air Force rarely operated above 15,000 feet so the altitude performance restriction was almost irrelevant to them. Lastly, the armament of the P-39 was in line with, and usually as heavy or heavier, than what was fitted to any Russian built fighter. Thus, for the Russians the P-39 suffered none of the problems it did in US use. That resulted in the plane being very good for the combat environment it was flying in.

    The result was a dichotomy in failure versus success with the plane in combat.

  • #2
    What America built as a marginal fighter was used as a ground attack anti-armor aircraft by the Soviets. A 37 mm AP firing cannon is a great weapon in that role.
    Quis Custodiet Ipsos Custodes? Who is watching the watchers?

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    • #3
      Originally posted by Mountain Man View Post
      What America built as a marginal fighter was used as a ground attack anti-armor aircraft by the Soviets. A 37 mm AP firing cannon is a great weapon in that role.
      That's a myth. The P-39 was used as an air superiority fighter in Russia and Soviet pilots considered it a good plane in that respect. They liked the 37mm because their tactics were to close to short range before firing on an enemy plane and usually the first one or two 37mm hits were sufficient to destroy the target. It took a different mindset on how to make the armament effective than that used by USAAF pilots who preferred a high volume of fire at longer range tearing the target apart.

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      • #4
        The P-39 was vulnerable to attack from above as strikes to the fuselage tended to damage the cooling system. This was an issue in the Pacific theatre where the opposition had better altitude performance
        It was generally considered as temperamental and took more effort to maintain that the P-40.
        Weight distribution could make it prone to go into a dangerous flat spin, the Soviets complained about this and it may have been part of the reason for them removing the wing mgs
        Human history becomes more and more a race between education and catastrophe (H G Wells)
        Mit der Dummheit kaempfen Goetter selbst vergebens (Friedrich von Schiller)

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        • #5
          The spin problem wasn't as bad as usually made out but it was cured by rearranging the fuel tanks, removing four small ones reducing the internal supply from 110 gallons to 86. The Pontiac 37mm was unpopular with the USAAF as it tended to jam after firing just a couple of rounds. The cocking mechanism was a manual pull cord on the floor of the cockpit the pilot had to put this about even with his head, often having to use both hands (think trying to cock a PIAT while flying an airplane). The Hispano M2 20mm was preferred (mounted on the ex-British P-400's) but never standardized.

          In the Pacific, the usual P-39 complaint was they were too short ranged to go on escort missions and as interceptors they'd get airborne and by the time they'd climbed to altitude the Japanese bombers or attacking planes had already left the area. So, the planes were often relegated to strafing and ground attack missions instead. That left the pilots flying them unhappy because they rarely were able to get into dogfights with the Japanese and score aerial kills.

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          • #6
            Originally posted by T. A. Gardner View Post
            The spin problem wasn't as bad as usually made out but it was cured by rearranging the fuel tanks, removing four small ones reducing the internal supply from 110 gallons to 86.
            .
            Odd given that the problem was with the guns and ammunition

            its centrally-mounted engine led to handling problems. The difficulty was that after ammunition was expended, the aircraft's CG shifted back so that the aircraft was inclined to fly tail-first, throwing it into a flat spin from which recovery was problematic. Bailing out under such conditions was also troublesome, because the pilot had a tendency to hit the tail. Even if recovery were possible, the spin had a tendency to warp the aircraft's tail, rendering the controls useless, which is why the P-39Q-25 introduced a reinforced rear fuselage.
            Human history becomes more and more a race between education and catastrophe (H G Wells)
            Mit der Dummheit kaempfen Goetter selbst vergebens (Friedrich von Schiller)

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            • #7
              I've read a number of pilot descriptions of flying the P-39 both in training and combat and all say the flat, unrecoverable spin story is myth. They do say the P-39's stall comes without warning and can be vicious but it is recoverable if you have some altitude. I'd be interested in knowing where your quote came from too.

              For example Dr. James Hudson who flew the P-39 in the MTO on close to 100 operational sorties says that most of the stalls that resulted in crashes were student pilots on approach who were busy with landing the plane and let it get too slow resulting in a low altitude stall. He also says bailing out is easier in a P-39 than a P-38 or P-47. His claim is the only real danger is potentially getting minor burns from the exhaust stacks if you bump them.

              Other accounts I've read include pilots from the 367th FG who say the same thing. The accidents with the P-39 generally happened with inexperienced pilots during training. Once they got a feel for the plane and some hours on it most praised its handling.

              Since the P-39's used in training rarely had ammunition loaded if that were a problem I'd think it would have come up in accounts of flying the plane, but I've never read of that being a problem.
              Last edited by T. A. Gardner; 12 Aug 18, 12:39.

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              • #8
                Well USAAF Material Command carried out Spin tests on the mythical spin. On the 2nd flight the pilot had to bail out and the aircraft was lost . report Eng-47-1779-A recommended that the aircraft should not be allowed to spin if at all possible and further work should be carried out into the fitting of spin recovery devices such as chutes.

                The following is an accident report on a fatal crash by a P-39 suffering from a mythical flat spin

                http://www.arizonawrecks.com/wrecksf...gray/p39q.html

                A. M. "Tex" Johnston in his book "Jet Age test pilot" describes the problem in some detail. He also points out that a lot of training accidents were caused by a failure to correctly ballast to compensate for empty ammo mags.
                Last edited by MarkV; 12 Aug 18, 14:41.
                Human history becomes more and more a race between education and catastrophe (H G Wells)
                Mit der Dummheit kaempfen Goetter selbst vergebens (Friedrich von Schiller)

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                • #9
                  But, none of that answers the question of why the plane was a failure in US and British hands and a success in Russian ones. There were other aircraft with handling quirks, some quite vicious that were successful planes. That doesn't explain their success however.

                  As for the Arizona wreck cited, it says this in the report:

                  Pilot was a combat returnee with 445:20 of flying time in single engine tactical aircraft; however he was not experienced in this type of tactical aircraft.
                  It is entirely possible this event was caused primarily due to inexperience with the plane.

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                  • #10
                    Presumably because on Eastern Front most air combats took place below 4,000 meters and airplanes often descended to ground level. At low altitude the lack of a good engine compressor was not a problem. Western allies liked flying at maximum altitude, 10,000 maters and up. The Germans generally appeared even higher.

                    "Artillery adds dignity to what would otherwise be a ugly brawl."
                    --Frederick II, King of Prussia

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                    • #11
                      Originally posted by T. A. Gardner View Post
                      But, none of that answers the question of why the plane was a failure in US and British hands and a success in Russian ones. There were other aircraft with handling quirks, some quite vicious that were successful planes. That doesn't explain their success however.

                      As for the Arizona wreck cited, it says this in the report:



                      It is entirely possible this event was caused primarily due to inexperience with the plane.
                      Quite likely unaware of its tendency to go into an inverted spin and therefore how to get out of the same - but that's the whole point - the aircraft had an unfortunate spinning tendency
                      Human history becomes more and more a race between education and catastrophe (H G Wells)
                      Mit der Dummheit kaempfen Goetter selbst vergebens (Friedrich von Schiller)

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                      • #12
                        It may be worth mentioning that many of the Soviet fighter units equipped with this airplane were Guards units - meaning that most of them counted on a remarkable number of experienced pilots. If the airplane truly was unforgiving in case of mistakes, giving it to personnel already skilled instead of to trainees might make a significant difference.
                        Michele

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                        • #13
                          I've heard it said that all of the truly great air superiority fighters were all just a bit twitchy, just this side of wild, and that consequently, like a good mount, they needed a firm hand on the reins. Might the Soviets have viewed the P-39's instability as an asset in the hands of a strong rider?
                          I was married for two ******* years! Hell would be like Club Med! - Sam Kinison

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                          • #14
                            A lot of better US pilots, like Chuck Yeager thought the P-39 was a great plane for aerobatics. They also mostly say it was novice and inexperienced pilots that got into trouble in it.

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                            • #15
                              Originally posted by slick_miester View Post
                              I've heard it said that all of the truly great air superiority fighters were all just a bit twitchy, just this side of wild, and that consequently, like a good mount, they needed a firm hand on the reins. Might the Soviets have viewed the P-39's instability as an asset in the hands of a strong rider?
                              We automatically assume that instability, or a tendence to instability, is a bad thing. Yet, stability means more effort, or more time, or both, when you want something to change trim, position, and therefore direction. Instability means faster, easier responsiveness when you want to achieve that sort of change.
                              Then, it's easy to understand that for a fighter aircraft, fast and easy responsiveness is an advantage, not a drawback. It means better maneuverability.

                              Also note that for high-speed, high-power fighter tactical maneuvers at high altitudes, maneuvering mainly means diving and climbing. That's what the Germans and the Western Allies mainly did, jockeying around bomber formations. A stable fighter can still be very good at diving and climbing. Engine power, and consequently speed, is what matters there.
                              But if you are close to the floor because you are hunting German ground attack aircraft, then diving is a... shallow option, and horizontal maneuvering - à la WWI - is much more important.
                              Michele

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