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

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  • Andy H
    replied
    Hi Terry

    In Phillip Butler's and Dan Hagedon book 'Air Arsenal North America-Aircraft for the Allies 1938-1945 Purchases and Lend-Lease' they state on Pg150 that one of the main reasons the RAF shunned the plane was that "the biggest operational problem turned out to be the fitment of the navigational compass, which was such as to render it useless after the aircrafts guns had been fired. Although this problem could have been overcome in time, it proved to be an embarrassment at a crucial time during the types introduction into RAF service"

    Regards

    Andy H

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  • T. A. Gardner
    replied
    For the Russians the P-39 was also a much better plane, both in equipment and aerodynamic characteristics to many of their own. The MiG 1 and 3 are noted as being dangerous to fly in anything other than a straight line almost. The LaGG 3 was considered a flying death trap. Wooden and fabric construction is more vulnerable to damage in many cases compared to an all-metal aircraft.

    The P-39 also always came with a radio that worked, had an oxygen system fitted that worked, and an armament as heavy or heavier than anything the Russian designers were putting on their planes.

    The USAAF's pilots' biggest complaint with the 37mm was it jammed regularly. To clear the jam, the pilot had to reach down on the floor between his legs, and pull the cocking lanyard up about even with his ear to do this. It often took the strength of both hands to do this as well. That's like trying to cock a PIAT in the middle of a bayonet charge...

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  • Michele
    replied
    Originally posted by MarkV View Post

    Do not confuse issues of manoeuvrability and stability. .
    I'm not, thank you. The two are not the same thing, but they are related - as I explained.



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  • MarkV
    replied
    Originally posted by Michele View Post

    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.
    Do not confuse issues of manoeuvrability and stability. During WW1 Morane Sauliner fighters had no fixed tail fin or planes which meant that they were laterally and vertically unstable and the pilot had to be constantly correcting for this which made them very tiring to fly for any period. The SE5a was both stable and manoeuvrable which meant that pilots could fly long patrols making almost no corrections and still be able to dog fight when needed. In WW2 the Mustang had similar useful characteristics
    According to Tex Johnston, a test pilot for Bell, The problem with the P-39 was that if it had not been properly trimmed it was very easy to get into an inverted spin from which even an experienced pilot could have problems extracting the aircraft (he quotes one of the Russian test pilots attached to Bell having to bail out as a result). What made the problem worse he said was that many pilots mistook the spin for tumbling and took entirely the wrong corrective action. He quotes Colonel Kertchetkoff the senior Red Air-force pilot attached to Bell as saying that the P-39 was a good aircraft because of its heavy armament. Given that the Soviet Union did not produce such heavily armed fighters until 1943 and Luftwaffe aircraft were comparatively well equipped with armour and self sealing tanks etc this may well have been deemed worth living with stability problems for.

    In the Pacific theatre where Japanese air craft were much less well protected and could be knocked down with machine gun fire that big cannon may have been seen as less of a major advantage to offset against other issues.

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  • Michele
    replied
    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.

    Leave a comment:


  • T. A. Gardner
    replied
    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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  • slick_miester
    replied
    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?

    Leave a comment:


  • Michele
    replied
    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.

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  • MarkV
    replied
    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

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  • MonsterZero
    replied
    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.

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  • T. A. Gardner
    replied
    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.

    Leave a comment:


  • MarkV
    replied
    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, 13:41.

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  • T. A. Gardner
    replied
    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, 11:39.

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  • MarkV
    replied
    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.

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  • T. A. Gardner
    replied
    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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