How much weight were the Soviets able to strip out of the P39?

Discussion in 'Aviation' started by pinsog, Mar 24, 2013.

  1. pinsog

    pinsog Member

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    #1 pinsog, Mar 24, 2013
    Last edited: Mar 24, 2013
    How much weight were the Soviets able to strip out of the P39? I know they removed all of the wing guns and some of the armor. Does anyone have a best guess how much weight that totaled?
     
  2. alejandro_

    alejandro_ Member

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    I don't have access to my books right now. In some websites you can find information, for example:

    The take-off weight (does not specify which) went from 4128kg to 3969 kg for P-39M? and P-39N. It's also likely that it could depend on the pilot and circumstances. IIRC it was around 200-250kg. The data can vary and can be misleading. A table with the specs:

    Ingresar
     
  3. pinsog

    pinsog Member

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    So does anyone know the total weigh stripped out of the P39? I know they removed 4 30 caliber Browning machineguns, all the ammo, some armor plate and I would assume everything in the wing that had to do with the 4 rifle caliber machine guns.

    Can anyone take a stab at how much total weight this was?
     
  4. tomo pauk

    tomo pauk Creator of Interesting Threads

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    4 LMGs = ~94 lbs
    ammo = 260
    armor = ~ 250 (bullet proof glass included)
    radio = ~ 120
    _____________
    total = 724 lbs, assuming they took out all listed above.

    P-39 carried 3 radios, SCR-535 (recognition radio set - IFF?), - 522A (command radio set - maybe not installed on most of P-39?) and -274N radio (data from US hundred thousand book). My guess is that at least the SCR-274 radio set remained on Soviet P-39s.
     
  5. wuzak

    wuzak Well-Known Member

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    Did they not replace the 37mm cannon with a 20mm cannon? That must have saved some weight?
     
  6. pinsog

    pinsog Member

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    The British replaced the 37mm with a 20mm, the Russians kept the 37mm and evidently they liked it.
     
  7. tyrodtom

    tyrodtom Well-Known Member

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    The P-39 wing guns were well out on the wings, look to be quite a bit farther out than they need to be just to clear the propeller arc. Plus the ammo cans go almost all the way to the wingtips. So removing that much weight, that far out on the wings, might have more of a affect than what you'd normally think.
    Plus the ammo cans don't look to be structual in cutaways. So their removal might have even dropped more wing weight.
     
  8. pinsog

    pinsog Member

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    So the Soviets were able to ditch approximately 10% of the weight of an already relatively high speed, fast climbing, good turning fighter, so why is it such a huge surprise for people to accept that the Soviet P39 might have done ok against the Germans?
     
  9. tomo pauk

    tomo pauk Creator of Interesting Threads

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    It is easy to understand that people in the West get surprised when they hear about the P-39 in Soviet hands doing OK vs. LW.
    In 50 years after the ww2, the P-39 was always portrayed as either an under-performer, or not suitable for the tasks. That's by Anglo-American (and German?) sources, and they have many good reasons to say so. Contemporary Spitfire was a better overall performer, the P-39 did not possessed a good combat radius as demanded by war theaters USAF operated, it was deemed as a tricky aircraft to fly (The P-40 being preferred for the fresh pilots), it took time to debug the 37mm (and that was not an ideal cannon even when properly functioning), the good performance was limited to altitudes under 15000 ft initially. The heterogenous armament was not it's shining point either.

    The Eastern front and VVS were a whole different ball game, than other theaters and air forces. The range was fine for the everyday tasks, the combat took place mostly under 15000 ft, the P-39 was faster than any Soviet or LL fighter prior early 1944 (Spitfires sent there were not the up-to-date types, nor were the brand-new examples?), the 37mm cannon was useful to kill LW Ju-88s or He-111s, every plane had, unlike the Soviet made fighters, a reliable radio (or more of them), the fit finish was better than in Soviet fighters. The P-39Q without gondola guns was making circa 400 mph, admittedly at low altitude. As good as the acclaimed Yak-3.

    Many Western sources have claimed that P-39 was used as a tank buster (despite the low MV gun, and despite that P-39 was in strength of fighter regiments, not assault regiments), or as a bomber (despite the lack of photos showing P-39s taxiing with a bomb, compared with the abundance of photos with drop tank) while the Germans have claimed that they have killed great amounts of P-39.
    The VVS and Stalin were always clamoring for more P-39s, and many of their top pilots were flying the P-39 successfully, but that stuff about P-39 was started to trickle in the West just a decade ago. So anyone that read a book written, say, in 1980s, would get surprised when learning about P-39 in the East.
     
  10. pinsog

    pinsog Member

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    It is a shame that the US didn't figure out what the Soviets did, strip out the same stuff the Soviets did and use it as a Zero killer. As fast as the stripped down version was, with a 50 Browning or a 20mm in place of the 37mm it should have been quite of a defensive fighter for US and Australian forces until better fighters came along.
     
  11. airminded88

    airminded88 Member

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    Didn't P-39s have in the South Pacific (Papua New Guinea) sufficient range and yet deemed as inferior by Allied pilots against Japanese opposition?
     
  12. barney

    barney Member

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    Part of this may be explained by the very high skill level possessed by Japanese pilots during this early period of the war.
     
  13. Shortround6

    Shortround6 Well-Known Member

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    There were several things going on.

    The early P-39s used the -35 engine which was good for about 1150 at sea level and 1150hp at 12,000ft and that it at 59 degrees. The Japanese were often flying at higher altitudes where the P-39 had less power and the high temperatures did nothing for engine power or wing lift. Granted in can get hot in southern Russia in the summer but planes in the tropics are going suffer less performance than "BOOK" all year long.

    Later P-39s (K, L) got the -63 engine with 1325hp for takeoff and an allowable 1590hp at 2500ft WER. Same power above 12,000ft though. While the planes with this engine start to be delivered in June of 1942 it may take a number of months before they show up in combat, They do have to go by ship. Because of the shipping and Reshipping it is taking awhile for P-39s to get to Russia. An extra 38% power down low can help an awful lot as long as the plane STAYS down low, not as much of a problem on the Eastern Front. The Japanese were not cooperating however and continued to fly at 15,000-25,000ft. :)



    The P-39M (first delivery/acceptance at factory Nov 1942) introduces the 3rd major engine change. The -83 engine with 1200hp for take-off and 1125hp at 15000ft or so. While peak WER is down to 1420hp it can be had up to 9500ft which means that the plane has practically 1400hp from sea level to 10,000ft. Naturally the Army adds weight to both the more powerful engine model aircraft. It takes until June of 1943 for P-39Ns to show up at Henderson Field.

    The vast majority of the P-39s that went to Russia were of the later types with the improved engines.
     
  14. CobberKane

    CobberKane Banned

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    I suspect the Soviets love of the the P-39 was largely due to the relative quality of their own aircraft, and the equipment levels thereof, as well as the manner it which they used if. On paper a Yak 1 might seem to stack up pretty well against an 39, but the performance figures disregard the abysmal quality control of the Soviet factories for a good part of the war and the fact that early fighters like the Yak generally lacked frivolities like working radios and instrumentation like artificial horizons. Of course, the P 39 also had tricycle undercarriage, which would have been light years ahead of the tail daggers.
    The RAF tested the P39 and were underwhelmed. It under performed just where they needed it - up high. But even then they conceded it was a match for the 109 where the Soviets needed it - down low.
    At 20000 ft over France, and compared to a Spitfire V, the P 39 would indeed have been an iron dog. But at 10000 ft over the USSR, compared to an I-16, it was a miracle of modern aeronautics
     
  15. GregP

    GregP Well-Known Member

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    The Russian kept the 37 mm cannon, but not ours. They installed their own NS-37 mm cannon. Basically the similar to the 37 mm cannon in the MiG-15 somewhat later. Great weapon!

    The NS-23 and the NS-37 were good weapons that were both reliable and available.
     
  16. tomo pauk

    tomo pauk Creator of Interesting Threads

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    They were exceptional weapons, but the NS-37 was a far heavier, longer and more potent weapon. It was also using longer cartridges, that would make the up-arming a significant task. Is there any good data about the NS-37 in P-39?

    The ammo for N-37 (cannon on MiG-15, 103 kg) and N-37 (ww2, up to 170 kg) was not interchangeable, the N-37 firing at smaller MV (690 vs. 900 ms; for US M4: 556 for HE), but at greater RoF.

    per 'Rapid fire', by. T. Williams
     
  17. alejandro_

    alejandro_ Member

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    IIRC it was still seen as superior (10%) to P-40.

    Indeed, also the Japanese had the initiative during that period.[/quote]

    Very interesting summary on the engines Shortround6. I am going to have a look to see if I can find comments on Russian sources.
     
  18. gjs238

    gjs238 Well-Known Member

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    And part by early US penchant to engage in low speed turning fights with the Japs.
     
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