The P-63 was developed by Bell Aircraft to address the shortcomings of the P-39, particularly its poor high-altitude performance.
First flight
December 7, 1942—symbolically one year after Pearl Harbour.
Key improvements
Laminar flow wing for better aerodynamics.
A more powerful Allison V-1710 engine with a remotely mounted supercharger.
Heavier armament
37 mm cannon through the propeller hub and four .50-calibre machine guns.
U.S. Army Air Forces
Limited Use
Rejected for combat
Despite its improvements, the P-63 was not accepted for combat by the USAAF.
Training role
It was used stateside for training and target practice, including as a target aircraft for gunnery training due to its robust construction.
Soviet Air Force
Primary Combat Operator
Lend-Lease deliveries
Over 2,400 P-63s were shipped to the USSR under the Lend-Lease programme, making the Soviets its main wartime user.
Combat role
Eastern Front
Used primarily in ground-attack missions and close air support.
Far East
Saw action against Japanese forces in the closing months of the war.
Tank buster reputation
The powerful nose-mounted cannon made it effective against armoured targets, earning it a reputation as a Soviet tank buster.
Production and Legacy
Total built
3,303 units between 1943 and 1945.
Variants
Included the P-63A, C, and E models, with incremental improvements.
Postwar use
Continued service in Soviet and French air forces after WWII.
The Variants
XP-63 (Model 24)
Original Prototype
Quantity
2 aircraft
Serials
41-19511 and 41-19512
Purpose
Initial development prototypes for the Kingcobra series
Notes
These aircraft featured a mid-engine layout with tricycle landing gear and were powered by the Allison V-1710-93 engine.
Both were lost in accidents during early testing, prompting design revisions and the creation of the XP-63A.
XP-63A
Merlin Testbed
Quantity
1 aircraft
Serial
42-78015
Purpose
Replacement prototype, originally intended to test the Rolls-Royce Merlin engine for the proposed P-63B variant
Notes
Though the Merlin-powered concept was abandoned, the XP-63A served as a critical test platform for aerodynamic refinements and structural improvements that informed the P-63A production series.
P-63A (Model 33)
First Production Series
Quantity
1,725 aircraft
Engine
Allison V-1710-93 or -95, ~1,325 hp
Armament
1 × 37 mm M4 cannon firing through the propeller hub,
2 × .50-cal machine guns in the nose,
and
2 × .50 cal. wing-mounted guns (varied by sub-mark)
Sub-marks
Included A-1 through A-10, with incremental improvements in armor, radio equipment, and engine cooling
Notes
Widely exported under Lend-Lease, especially to the Soviet Union, where it saw extensive combat service.
The P-63A retained the general layout of the P-39 but featured improved performance and survivability.
P-63C
Refined Combat Variant
Quantity
1,227 aircraft
Engine
Allison V-1710-117, 1,500 hp
(1,800 hp with water injection)
Wing
Reduced span by 10 inches (250 mm) for improved roll rate
Notes
Introduced a four-blade propeller and enhanced engine cooling.
The C-series was the most powerful production variant and was also heavily exported to the USSR.
Despite its improvements, it was never adopted as a front-line fighter by the USAAF.
P-63D
High-Speed Prototype
Quantity
1 aircraft (43-11718)
Engine
Allison V-1710-109 (E22), 1,425 hp
Wing
Increased span to 39 ft 2 in (11.94 m); wing area expanded to 255 sq ft (23.7 m²)
Canopy
Introduced a rearward-sliding bubble canopy for improved visibility
Notes
Designed for superior high-altitude performance, but the series was cancelled in 1945 due to shifting priorities and the emergence of jet aircraft.
P-63E
Modified D-Series
Quantity
13 aircraft
Differences
Retained the P-63D’s wing and engine but reverted to the standard framed cockpit and added a ventral fin extension for stability
Notes
Served primarily as test aircraft; never entered mass production or combat service.
P-63F (Model 43)
Tail-Heavy Prototype
Quantity
2 aircraft (43-11719 and 43-11722)
Engine
Allison V-1710-135
Tail
Enlarged vertical stabilizer for improved directional control
Notes
Intended to address stability issues at high speeds.
The variant was cancelled before further development due to the end of the war and lack of demand.
RP-63A/C “Pinball”
Armored Target Aircraft
Quantity
5 RP-63A conversions + 95 RP-63 A production-line modification: 200 RP-63C production aircraft
Purpose
Used as manned flying targets for gunnery training with frangible ammunition
Features
Armored skin, reinforced canopy, and sensors that triggered lights when hit
Redesignation
Surviving aircraft were redesignated QF-63A and QF-63C in 1948
Notes
Despite their role as “targets”, many were used as target tugs.
Their durability and unique role made them a distinctive sub-series in the Kingcobra lineage.
RP-63G “Pinball”
Dedicated Target Variant
Quantity
2 prototypes (43-11723 and 43-11724) + 30 production aircraft
Features
Flush dorsal air inlet, improved hit-detection lighting system
Redesignation
Remaining aircraft redesignated QF-63G in 1948
Notes
These were purpose-built flying targets, not conversions.
Their specialised design made them ideal for safe gunnery training with frangible rounds.
L-39
Naval Research Aircraft
Quantity
2 aircraft (converted from surplus P-63Cs)
Purpose
Contracted by the U.S. Navy for aerodynamic testing
Focus
Studied low-speed and stall behavior of high-speed wing designs
Notes
These aircraft contributed to postwar research into swept-wing and transonic flight characteristics, influencing early jet development.
