Bell P-63 Kingcobra

P-63 Kingcobras ready for delivery to the USSR
(45kB color photo from "The complete Book of Fighters").

The P-63 Kingcobra was derived from the P-39 Airacobra. Superficially the P-63 and the P-39 were very similar, nevertheless the P-63 was an entirely new design and no two parts of the two models were interchangeable. Work on the P-63 commenced in February 1941 and this type became the only USAAF single-seat fighter design tested after Pearl Harbor which entered series production during World War II. But despite the fact that 3,303 Kingcobras were built, the type never saw combat with the USAAF.

Bell and the USAAF were well aware that the disappointing combat performance at altitude of the Airacobra was not caused by any faults of the basic design but had its origins in the lack of a turbo-supercharger and in an outdated tactical concept to which it had been framed. To overcome these shortcomings the company mated the basic P-39 fuselage with an uprated engine and new laminar-flow wings. Three prototypes of this design were built under the designation XP-39E (s/n 41-19501/41-19502/42-7164). Even before the first flight of the XP-39E an enlarged prototype was ordered by the USAAF on June 27, 1941 under the designation XP-63. At first there were doubts expressed by NACA about the possibility to produce the laminar-flow wing under series production conditions with the necessary high quality standard (otherwise the advantage, i.e. low drag, of a laminar-flow wing could be cancelled out by turbulence caused by minute ripples in the wing surface), but Bell managed to solve this problem by new production techniques. Like its predecessor Airacobra, the Kingcobra was a very sturdy machine and could absorb much damage.

The first XP-63 (Bell Model 24, s/n 41-19511) first flew on December 7, 1942. It was fitted with a 1,325hp Allison V-1710-47 engine with a two-stage supercharger (increasing the ceiling by 3,048m) and a four-blade propeller. On February 5, 1943 the second XP-63 (s/n 41-19512) flew for the first time. Both prototypes were lost in crashes (caused by technical failures) early in 1943, but even before the maiden flight of the first XP-63 series production had been ordered under the designation P-63A (Bell Model 33) in September 1942.

Production deliveries commenced in October 1943. But despite a performance comparable to that of contemporary fighters and favorable comments from the test pilots at Eglin Field, Florida, the USAAF concluded that the P-63 was unsuitable for service use. A small number served with three home-based USAAF squadrons for a few months, but most of the production P-63As and later P-63Cs were immediately exported to the USSR under Lend-Lease. Another 114 P-63C-5s were delivered to France (too late to be used in WW II, but they flew in Indochina until 1951). Two P-63s were tested in Great Britain. About 330 specially modified P-63As and Cs were used as manned armored target aircraft by the USAAF. They were called "Flying Pinballs" and were fitted with about one ton of special external armor plate. Against this armor were fired specially developed "frangible" bullets (made of lead and graphite) which shattered on impact. A scored hit was signalled by a light in the propeller hub. So bomber gunners could be trained in an extremely realistic way. After the war a number of P-63s were used for air races.

The following P-63 variants were built or projected:
XP-63 (Bell Model 24): First prototypes (2 built, s/ns: 41-19511 and 41-19512).
XP-63A (Bell Model 24): Prototype, originally intended as testbed for P-63B. One built (s/n 42-78015), first flown April 26, 1943. Had 1,325hp Allison V-1710-93 engine and was one of the fastest P-63s (678km/h at 7,346m).
P-63A (Bell Model 33): First production model (1,825 built), deliveries from October 1943.
Sub-variants were:

   P-63C-5-BE: 1,012 built (s/ns 43-11133 - 43-11717; 44-4001 - 44-4427). Ventral fin added for better directional stability (also retrospectively fitted on some C-1s), increased armor.
P-63D-1-BE: One built (s/n 43-11718). Flew early in 1945 and featured a number of modifications (no ventral fin, bubble-type cockpit canopy, increased wingspan (11.94m), 1,425hp V-1710-109 engine, modified dorsal air scoop, M9E1 cannon with 48 rounds). Fastest P-63 (703km/h at 9,144m).
P-63E (Bell Model 41): Similar to P-63D, but with old cockpit canopy and ventral fin. 2,943 ordered under Lend-Lease of P-63E-1-BE variant, but only 13 built (s/ns 43-11720/43-11721 and 43-11725 - 43-11735), remainder cancelled after V-E Day. P-63E-5-BE was improved E-1 (new vertical tail, bubble canopy, improved instrument panel) for Russia, but not built.
P-63F-1-BE (Bell Model 43): Last wartime version of the Kingcobra. First flown in April 1945. Only two built (s/ns 43-11719/43-11722). Had a V-1710-135 engine and the enlarged vertical tail of the E-5.
RP-63G: "Pinball" target aircraft. Two prototypes (modified P-63Cs, s/ns 43-11723/11724) and thirty production aircraft (s/ns 45-57283 - 45-57312). 1,200hp Allison V-1710-135 engine. Another 420 cancelled. One experimentally fitted with V-shaped tail assembly.
XP-63H (Bell Model 45): Proposed testbed for Allison V-1710-127 turbo-compound engine. Not realised.
XP-63N: Probably used for RP-63G with vee tail.
TP-63: Two-seat conversions. Exact number uncertain. TP-63A-10-BE (Bell Model 38) was proposed modification of A-10 by second cockpit (by factory-delivered conversion kit) inserted in front of original one. At least three completed in the USSR (s/ns 42-69304; 42-70503; 43-112334). Another source speaks of 9 conversions plus one TP-63C. Two P-63E-1s modified by Bell as two-seaters for factory trials (civil registrations NX41963 and NX41964).
L-39: Two P-63C-5s modified in 1946 as testbed for swept wings (L-39-1 and L-39-2).

Inflight shot of a P-63A-9 with Red Star delivery markings with Bell's chief test pilot Jay Demming at the controls
(23kB b/w photo from Squadron/Signal's "P-39 Airacobra in action").

As mentioned above, most P-63s were delivered to the Soviet Union via Alaska/Siberia as soon as they had left the factory. One of the routes used led from Niagara Falls to Selfridge Field (Michigan) and on to Truax Field near Madison (Wisconsin). There the Bell fighters were picked up by (mostly) female Russian pilots who flew them via Anchorage (Alaska) to the Soviet Union. Another route went from Great Falls (Montana) to Fairbanks (Alaska) and on to Siberia. One source states that there were 2,397 P-63As and Cs sent to the USSR, of which only 21 were lost en route. Another source records 2,456, of which 2,421 reached their destination. Deliveries commenced in September 1944 and until May 1945 only 51 P-63As had been received by the Soviet Union. They were assigned to PVO units. This makes any significant use against German tanks or aircraft very unlikely. So the often read statements about the successful Soviet use of the P-63 against German armor seem to have been "extrapolated" from the P-39 Airacobra.

P-63s of a Soviet frontline unit.
(29/37kB b/w photos from "Red Stars in the Sky" by C.-F. Geust et al.).

Re-equipment of Soviet Air Force units with the Kingcobra continued after the end of the war in Europe. The type was used in combat against Japan at the Far East and Trans-Baikal Fronts. The 12th Air Army of the latter Front had its 245th (940th and 781th IAPs) and 190th (17th and 21 IAPs) IADs equipped with Kingcobras. On August 15, 1945 Captain Vyacheslav Sirotin of the 17th IAP, a 21-victory ace and Hero of the Soviet Union, scored the only aerial victory of the P-63 Kingcobra when he shot down a Japanese Ki-27 or Ki-43. Other Soviet P-63-equipped units in the Far East in the summer of 1945 were the Kamtschatka-based 128th SAD (888th and 410th IAPs - the latter having been equipped with Il-2s before as the 410th ShAP) and parts of the 7th IAD of the Pacific Ocean Fleet. In July 1945 the 128th SAD supported the Soviet landings on Shimushu (Kuriles). Soviet Kingcobras normally had their underwing gun gondolas removed.

After the war re-equipment of new units with the P-63 continued at an accelerated pace. These included the 5th GvIAD in the Baltic District, the 269th IAD in Armenia, the 6th GvIAD in the Ukraine and the 1st GvIAD at Neuhausen in Germany. There were also P-63-equipped units based in Austria and China. About 25 aircraft seem to have been converted into P-63U two-seat trainers in the USSR at that time. The 307th and 308th IAPs in the Kuriles flew the P-63 until as late as 1951. Due to its post-war use in Russia the P-63 even received a NATO code name: "Fred". One of the last incidents involving Soviet P-63s happened in 1952 when USAF jets mistakenly strafed the Soviet airfield of Sukhaya Rechka outside Vladivostok and destroyed 8 (albeit already de-commissioned) P-63s.

Predecessors	Modifications
P-39 Airacobra	None

References
"The complete Book of Fighters" (German edition), by William Green and Gordon Swanborough Squadron/Signal Publications, Aircraft No. 43 "P-39 Airacobra in action", by Ernie McDowell "War Planes of the Second World War", Fighters Vol. 4, by William Green "Red Stars in the Sky", Vol. 1, by Carl-Fredrik Geust et. al. "Sowjetische Jagdflugzeuge" ("Soviet Fighters"), by Wilfried Kopenhagen (in German) "Das große Buch der Militärflugzeuge - Weltkrieg II" ("Combat Aircraft of World War Two"), by John A. Weal and Richard Barker (in German) German magazine "Aero", Vol. 24
Links (small selection - much more to find at the WEB)
Joe Baughers's detailed P-63 description Short P-63 description Short P-63 description Another short P-63 description P-39/P-63 FSim, including Capt. Sirotin's aircraft Bell fighters in Russian service	P-63 description (in Russian) P-63 pictures Some P-63 information P-63 at US Air Force Museum More about P-63 P-63 information P-63 info and color profile in Soviet markings