Bell P-63 – A Forgotten Titan

When it comes to the giants of World War II aviation, certain names immediately leap to mind: the P-51 Mustang, the Spitfire, and the Messerschmitt Bf 109. But among the numbers of these airborne warriors, one aircraft remains curiously underappreciated, often overlooked despite its significant contribution to the conflict: the Bell P-63 Kingcobra.

Developed by Bell Aircraft Corporation, the P-63 was an American fighter that saw more active service in the hands of Soviet pilots than its countrymen.

Let’s delve into the history, design, and operational use of this under-heralded warbird.


The development of the P-63 Kingcobra began as an effort by the Bell Aircraft Corporation to address the performance shortcomings of its earlier P-39 Airacobra.

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The P-39, while innovative with its tricycle landing gear and mid-fuselage mounted engine, had faced criticism for its lacklustre high-altitude performance due to its lack of a turbo-supercharger.

By 1942, the performance gap between the P-39 and its contemporaries was becoming increasingly apparent, and Bell began to explore options for a successor.

The P-39 and the P-63 are visually similar.
The P-39 and the P-63 are visually similar.

The new model was initially conceived as an enhanced variant of the P-39, but it soon became clear that more extensive modifications were required.

The first XP-63 prototype flew in December 1942, retaining the P-39’s unusual engine configuration but featuring several improvements. The size of the aircraft was increased, and many changes were made to the aerodynamic design.

A laminar flow wing was introduced to reduce drag and improve lift, allowing for better high-altitude performance.

A significant alteration came in the form of a four-bladed propeller, which necessitated an elongation of the nose gear strut to maintain ground clearance. An enlarged vertical tail was added to counteract the increased torque from the new propeller.

The airframe was also reinforced and armoured for additional pilot protection, and the aircraft’s firepower was significantly enhanced.

The P-63 shared similar armament to the older P-39.
The P-63 shared similar armament to the older P-39.

The P-63 was equipped with a 37mm cannon firing through the propeller hub (a carryover from the P-39 design) and four .50 calibre machine guns in the wings.

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The result was an aircraft that was similar in appearance to the P-39 but was in many ways a completely new design.

Despite the improvements, however, the U.S. Army Air Force was not highly interested in the aircraft, with most units preferring the P-51 Mustang or P-47 Thunderbolt.

The bulk of the P-63 production run ended up serving with the Soviet Union’s air force under the Lend-Lease Act.

Most P-63s ended up in Soviet use. Photo credit - Tacintop CC BY-SA 3.0.
Most P-63s ended up in Soviet use. Photo credit – Tacintop CC BY-SA 3.0.


The P-63 Kingcobra was a unique design born out of Bell’s experiences with its earlier P-39 Airacobra.

Like the P-39, the P-63 featured the unusual layout of an engine located behind the cockpit, with a long drive shaft passing under the pilot’s feet to power the propeller at the front of the aircraft.

This design allowed for the nose of the aircraft to be used for heavy armament and created a better centre of gravity, but also necessitated a lengthened landing gear to allow for the propeller’s clearance.

The P-63 was powered by an Allison V-1710-93 liquid-cooled V-12 engine, capable of delivering up to 1,325 horsepower.

P-39Q engine bay
The Allison V-1710 had many applications, including the P-39 Airacobra. Photo credit – Kogo

This propelled the aircraft to a top speed of approximately 408 mph and gave it a service ceiling of about 43,000 feet.

Aerodynamically, the P-63 made significant strides over the P-39.

The wing was larger and featured a fully laminar flow airfoil, reducing drag and improving lift.

Additionally, the vertical tail was enlarged to improve stability and counteract the increased torque from the new four-blade Aeroproducts propeller.

The Kingcobra’s armament was impressive. Its primary weapon was a 37mm M4 cannon, which was installed in the nose of the aircraft and fired through the propeller hub.

This was supplemented by four .50 calibre M2 Browning machine guns, with two mounted in the wings and two more in the fuselage, synchronized to fire through the propeller arc.

The 37mm cannon on display in the nose of a P-39Q. Photo credit - Kogo GFDL.
The 37mm cannon on display in the nose of a P-39Q. Photo credit – Kogo GFDL.

One of the most distinctive aspects of the P-63’s design was its armoured ‘bathtub’—a significant quantity of armour plating installed around the cockpit that protected the pilot from enemy fire.

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This feature, combined with the aircraft’s impressive armament and aerodynamic capabilities, made the P-63 a formidable foe in aerial combat and a reliable platform for ground-attack missions.

In terms of dimensions, the P-63 had a length of 32 feet 8 inches, a wingspan of 38 feet 4 inches, and a height of 12 feet 7 inches.

The aircraft had an empty weight of approximately 6,800 lbs and a gross weight of about 8,800 lbs.


Serving as the first major production model, the P-63A primarily mirrored the XP-63 prototypes. Early P-63A models were equipped with a smaller vertical tail, later superseded by a larger tail design in subsequent versions.

There were several P-63A sub-variants, each differing in armament configurations and minute details.

Building upon the P-63A, the P-63C variant brought forth substantial improvements. It boasted a water injection modified engine for enhanced power, a slightly expanded wingspan, and a multitude of other minor enhancements.

The P-63C’s improved performance found significant favour among Soviet forces.

The P-63E variant took the P-63C’s foundation and added a different propeller, along with other minor internal modifications.

Production of the P-63E was limited, with only 13 units built, as the end of the war and a subsequent decrease in demand loomed large.

A brightly coloured P-63E.
A brightly coloured P-63E.

The P-63F aimed to further push the performance boundaries of the P-63 series.

It featured an elongated fuselage and a larger tail. However, this ambitious model did not move past the prototype stage, with only two units produced.

These particular variants were not designed for combat but rather for education.

The RP-63A and RP-63C, adapted from the P-63A and P-63C, respectively, were fitted for aerial gunnery training.

They had an innovative light system that would illuminate upon being struck by frangible bullets, simulating the hits in an aerial dogfight.

An RP-63C. Photo credit - RuthAS CC BY 3.0.
An RP-63C. Photo credit – RuthAS CC BY 3.0.

These planes, aptly nicknamed “Pinballs,” were equipped with additional armour to prevent significant damage.

The P-63G represented a concept meant to morph the Kingcobra into a high-altitude interceptor. However, this vision never left the drawing board.

The P-63 Kingcobra variants, in all their variations, highlight an aircraft design that continuously evolved to meet the changing demands of a global conflict.

Each had a role to play, contributing to the unique journey of this often-overlooked World War II fighter.

Operational Use

While the P-63 Kingcobra was an American creation, it saw little operational use with the U.S. military.

This was mainly due to the U.S. Army Air Forces’ preference for other types of aircraft such as the P-51 Mustang and P-47 Thunderbolt, which had already proven themselves in combat by the time the P-63 was introduced.

A few P-63s were used by the U.S. Army for testing and evaluation purposes.

These specially modified versions of the P-63 were armoured and fitted with sensors that lit up when hit by frangible bullets, providing trainee gunners with instant feedback on their accuracy.

An ex 'pinball' aircraft used by the French Air Force. Photo credit - RuthAS CC BY 3.0.
An ex ‘pinball’ aircraft used by the French Air Force. Photo credit – RuthAS CC BY 3.0.

The P-63 Kingcobra found a much more enthusiastic reception in the Soviet Union.

As part of the Lend-Lease agreement between the U.S. and its allies, thousands of P-63s were shipped to the Soviet Union, where they saw extensive combat service on the Eastern Front.

The Soviets appreciated the P-63’s rugged design, high speed at low altitude, heavy firepower, and the armoured “bathtub”.

Soviet air units deployed the P-63 in a variety of roles, including air-to-air combat, ground-attack missions, and even long-range bomber escort duties.

Some Soviet pilots became aces flying the P-63, and the aircraft was involved in numerous successful missions.

Despite this, its service with the Soviets is not as well-documented as that of some other aircraft, in part due to the secretive nature of the Soviet military during the era.

P-59A and P-63 in flight.
P-59A and P-63 in flight.

The P-63 Kingcobra continued to serve in the Soviet Air Force well after the end of World War II, remaining in service until the early 1950s, and it was also used by other nations such as France and Honduras in the post-war years.


While the Bell P-63 Kingcobra might not share the limelight with some of its contemporaries, its impact on WWII aviation is undeniable.

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Its innovative design and the strategic role it played in the hands of the Soviets demonstrate its unique importance in aviation history.

The Kingcobra, in many ways, stands as a testament to the impact of the Lend-Lease policy and the global collaboration during WWII.

It remains a fascinating footnote in the history of military aviation, a true titan that commanded the skies from behind the scenes.

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  • Crew: One
  • Length: 32 ft 8 in (9.96 m)
  • Wingspan: 38 ft 4 in (11.68 m)
  • Height: 12 ft 7 in (3.84 m)
  • Empty weight: 6,800 lb (3,084 kg)
  • Gross weight: 8,800 lb (3,992 kg)
  • Max takeoff weight: 10,700 lb (4,853 kg)
  • Powerplant: 1 × Allison V-1710-117 V-12 liquid-cooled piston engine, 1,800 hp (1,300 kW)
  • Maximum speed: 410 mph (660 km/h, 360 kn) at 25,000 ft (7,600 m)
  • Range: 450 mi (720 km, 390 nmi)
  • Ferry range: 2,200 mi (3,500 km, 1,900 nmi)
  • Service ceiling: 43,000 ft (13,000 m)