P-63 climb rate

Discussion in 'Aviation' started by spicmart, Nov 29, 2014.

  1. spicmart

    spicmart Member

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    How was it possible for the P-63 to have such a good climb performance despite the weak engines?
     
  2. tomo pauk

    tomo pauk Creator of Interesting Threads

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    No that weak engines - more than 1800 HP was available when water injection was used, admittedly at lower altitudes. Although, the tests on the Williams' site state the same RoC (maxing out at roughly 3600 fpm) whether the water injection was used or not??
    The manufacturers numbers are bigger than USAF tests, just to add it to confusion :)
     
  3. GregP

    GregP Well-Known Member

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    #3 GregP, Nov 30, 2014
    Last edited: Dec 2, 2014
    The P--63 is also a VERY different beast from the P-39. Larger, more tail area and wing area, and has a wide-chord, 4-bladed prop that is downright deadly if mounted on a P-39. It was very probably responsible for the Mike Carol accident.

    The P-63 that flies at our airshow (out of Palm Springs) is very much liked by the people who fly it.
     
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  4. fastmongrel

    fastmongrel Well-Known Member

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    Weak engine is not the description for an engine that can put out 1500hp all day and all night.
     
  5. spicmart

    spicmart Member

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    Yes. I just mean in comparison to other late war fighters. Even the 1800 PS seem too little power to support such a climb rate especially with that weight.
     
  6. tomo pauk

    tomo pauk Creator of Interesting Threads

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    I'll reiterate: do we want to take into account the manufacturer's values, or test values? Bell in ww2 was never shy to claim the performance figures that subsequent tests have had a her time to prove.
    The late war climbers (Spitfire and Bf 109 late marks, Soviet Japanese fighters) were, in tests, managing to beat the P-63 values given by Bell, BTW.

    Just of what RoC figures for the P-63 are we speaking of?
     
  7. GregP

    GregP Well-Known Member

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    #7 GregP, Nov 30, 2014
    Last edited: Jan 1, 2015
    Testing on 24 May 1943 of the XP-63A revealed a max climb rate of 3,670 feet per minute (fpm) at sea level, 3000 rpm. and 60.5 inches of manifold pressure. It was still climbing at 2200 fpm at 25,000 feet and manifold pressure was down to 45.5 inches Mercury. Absolute ceiling was 41,200 feet.

    Testing on 6 Aug 1945 of a production P-63A-9 revealed 3650 fpm at 3000 rpm and wide open throttle from S. L. to about 8000 feet, tapering to 2640 fpm at 20000 feet (still 3000 rpm and wide open throttle. Service ceiling was 41,400 feet.

    The P-63E-1 attained at max rate of climb of 4600 fpm down low, had a service ceiling up around 41,000 feet and reached a max true speed of about 445 mph at about 26,000 feet. At 26,000 feet it weas still able to climb at 2200 fpm at 3000 rpm and wide open throttle.

    The XP-63A used the V1710-93 and the P-63E-1 used the V-1710-109.

    The main issue with the P-63 was stability. In tests, pilots attempting to pull 5 - 7 g in tight turns wound up pulling 10 g and wrinkling the wings. They tried a +1° change in horizontal tailplane incidence and a bob weight, both of which helped, but the aircraft still had very low stick forcce per g. They also highly recommended going from fabric to metal covered elevators to counter the stability issue and that seemed to work better than anything else, though it remaing relatively easy to overstress the aircraft. This appears to be the princliple reason why the USAAF didn't order more of them than they did.

    These data come from WWIIaircraftperformance.org .

    Other testing I have seen shows the P-63 did better than these numbers when they cleared it for 75 inches of manifold pressure and went to 3200 rpm.

    The aircraft itself performed quite well, rolled faster than most other active USAAF fighters, and had a service ceiling above 41,000 feet. The cannon was not particularly liked due to occasional jams, but the cannon was the one supplied by the government; it was not selected by Bell Aircraft.

    So it was a little too easy to pull heavy g and the cannon was not liked. The Russians simply threw out the cannon and installed their own. They liked the P-63.
     
  8. tomo pauk

    tomo pauk Creator of Interesting Threads

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    The Russians didn't threw out the M4 cannon, they threw out the .30s their ammo.
    By the time the P 63 was around the M4 cannon was working okay.
     
  9. GregP

    GregP Well-Known Member

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    The P-63 didn't have 30's. It had 1 x 37 mm M4 or M10 (from the A-9 onward) cannon with 58 rounds plus 4 x 50-cal M2 Brownings. As far as I know, all of the Soviet 37 mm cannons hit harder than the M4 or M10 and were installed by the Soviets.

    However, the data I have seen on Soviet VVS operations during WWII is quite scarce, except for some pilot debriefs, and suspect as far as sources go. Much of the Soviet data I have seen is unsourced or "from Soviet archives," leaving me with little faith in it.

    The Browning M2 was a good machine gun and I seriously doubt they would have replaced those ... assuming they could get ammunition, that is.
     
  10. tomo pauk

    tomo pauk Creator of Interesting Threads

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    Sorry - I was thinkering you refer the armament changes on the P-39, when the 'throw the cannon out' was mentioned.
    By all means, if you have a good source for the P-63 armament changes while in VVS use, please post about it. I strongly doubt they bothered. The Soviet N-37 was more powerful and bigger cannon, that fired more powerful and bigger ammo - doubt it would've fitted anyway.
    It would make sense to replace the BMG, the Soviet UBS (= synchronized) was firing on greater RoF than the synchronized BMG, the weights dimensions of ammo being in the ballpark.
     
  11. GregP

    GregP Well-Known Member

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    You well may be right about what the Soviets did with the P-63, Tomo. I can't really argue it very well as the data I have are from books and articles I have little faith in.

    In the end I would like to know but if ever there was an obscure data point, this may well be it! I'll toast either answer with a beer and be equally happy to do so.
     
  12. Conslaw

    Conslaw Member

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    I can think of a couple reasons the Air Force didn't buy more P-63s. The most obvious performance reason is the low fuel capacity of the P-63. The A model only had 100 gallons of internal fuel. The P-51D had 269 gallons of internal fuel. The low fuel capacity restricted the range of missions to which the P-63 was suited. The other factor was production capacity. The military committed early on to building out large capacity to build P-47s and P-51s, building large secondary factories just for that purpose. Once set in motion, it would have taken a lot to recommit the facilities to a different aircraft, but there was no need because both the P-51 and the P-47 were excellent, versatile fighters, able to take on all opposition.
     
  13. tomo pauk

    tomo pauk Creator of Interesting Threads

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    Indeed, the meager amount of fuel was the man detriment (only 136 gals internally). Another thing is the big logistical tail that introduction of another new fighter meant. The P-63A offered considerably less speed than the Merlin Mustang and P-47D, and barely equaling the P-38J. The good RoC vs. those aircraft was not due some magic, but due to the P-63 carried far less fuel, hence it was lighter; USAF was not interested in RoC by mid/late 1943, however.
    The production capability was there - the P-63s were built in the same location where the to-be-phased-out P-39s were built.
     
  14. waroff

    waroff Member

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    P-63A-1 V-1710-93 T.O. N° 01-110 20th july 43
    Military power 3000rpm 54" Hg, 174mph IAS from sea level to 20.000'
    Normal 2200rpm 26.5" Hg, 130mph IAS from sea level to 20.000'
    Gross weight 7700lbs
    0 to 3000' alt MP 3760fpm/Normal 840fpm
    at 5000': 3630/830
    10000': 3440/800
    15000': 3180/730
    20000': 2180/570

    If you are interested, I have the values at gross weight 8400 and 7300 lbs
     
  15. GregP

    GregP Well-Known Member

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    #15 GregP, Jan 1, 2015
    Last edited: Jan 1, 2015
    Those speeds just above look like best rate of climb speeds. A P-63 will do better than those speeds at half power in level flight.

    After a re-read, that's quite obvious. Sorry for commenting ...

    The "Normal" numbers were for grneral non-combat flying.
     
  16. tomo pauk

    tomo pauk Creator of Interesting Threads

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    'Normal' should be the max continuous power? Meaning 2600 rpm, maximum of 43 in Hg manifold pressure.

    Of course, please post what you have :)
     
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