Modern-Aviation

The Bell P-63 Kingcobra closely resembled the P-39 Airacobra, but was actually a new aircraft and not simply a modified P-39. Very few were used by the US, but a large number did serve in the Soviet Union.

Just to cause a little more confusion between the two aircraft, Bell used the same model number for the P-63 and the XP-39E Airacobra, which had a laminar flow wing and a supercharged V-1810 engine. Both versions of the Model 33 were proposed by Bell on 13-14 February 1941. Two prototypes of the XP-39E were ordered on 11 April, and the first prototype made its maiden flight on 21 February 1942, but was lost on 26 March. The second made its maiden flight on 4 April, and a third on 19 September. The P-39E didn't offer any significant improvement in performance over the P-39D, and so a plan to produce 4,000 as the P-76-BE was cancelled. The two surviving prototypes were used to help with the development of the XP-63.

The second version of the Model 33 led to the P-63. This used the same basic layout as the P-39, but was larger and heavier. It was powered by a 1,325hp Allison V-1710-47 engine with a hydraulically driven supercharger, carried behind the cockpit but powering a tractor propeller on the nose. It had a laminar flow wing. The P-63 had tricycle undercarriage with a nose wheel.

Two prototypes of the new XP-63 were ordered on 27 June 1941 (two months after the XP-39E). The first prototype made its maiden flight on 7 December 1942, after all three of the XP-39Es. The initial flight tests suggested that the new aircraft handled well, but the prototype was damaged beyond repair on 28 January 1943 after a problem with the undercarriage.

The second prototype made its maiden flight on 5 February 1943, but this one suffered from an engine failure in flight on 25 May 1943 and was also lost.

A third prototype was ordered in June 1942, as the XP-63B, a test-bed for the Rolls Royce Merlin. However no Merlins were available and it the airframe was thus available to replace the first two prototypes. This time it was given a 1,500hp Allison V-1710-93 engine and became the XP-63A. It also had a new dorsal air scoop and exhaust pipes, and weapon hard points under the wing. This was the fastest version of the Kingcobra, with a top speed of 426mph at 20,000ft. It was armed with a 37mm cannon firing through the propeller hub, two 0.50in machine guns in the forward fuselage and a 500lb bomb or 75 gallon fuel tank under the fuselage. It also carried 77lb of armour.

The P-63 was ordered into production on 29 September 1942 and the first P-63A was delivered in October 1943.

Service Record
The P-63 saw very little service with the USAAF. Some were used by Advanced Training Units but soon withdraw, put into storage and then scrapped. NACA used a handful for experiments.

The biggest user of the P-63 was the Soviet Union, which received 2,397 of the 3,303 that were built. These were delivered via Siberia between 1943 and 1945. Very little is known about their service in the Soviet Unit. A few may have been used against the Germans, but most were meant to have been concentrated in the Far East, where they were used against the Japanese. The Kingcobra was used to provide fighter cover for ground units, and not as a ground attack aircraft.

Another 300 were allocated to France, although only 150-200 appear to have been taken on charge. The first arrived on 26 July 1945, soon after the end of the Second World War, and were used by the GC 1/5 Vendée. A second unit received the type, but both were disbanded on 23 March 1946. The Kingcobra was brought out of retirement to fight in Vietnam, but even here saw limited use. Two units used them from 1949-1950, and two more in 1950-51, before they were replaced by more modern American types.