Republic P-47 Thunderbolt variants
In response to a USAAC requirement for a new fighter aircraft, Republic Aviation engineer Alexander Kartveli proposed the AP-10 lightweight high-altitude interceptor on August 1, 1939.
[1] As originally proposed, the AP-10 was to have been powered by a 1,150 hp Allison V-1710-39 12-cylinder inline engine and have an armament consisting of two nose-mounted .50 in (12.7 mm) M2 Browning machine guns.
Kartveli revised the AP-10 by slightly increasing its size and mounting two .30 in (7.62 mm) M1919 Browning machine guns in each wing, raising the gross weight to 6,570 lb.
In response, the USAAC issued new requirements for a fighter including an airspeed of 400 mph at 25,000 ft, an armament of six or (preferably) eight .50 in machine guns, cockpit armor plating, self-sealing fuel tanks, and a minimum fuel load of 315 gallons.
[2] Expecting the USAAC to reject the XP-47 for the more suitable Curtiss XP-46, Republic canceled the XP-47 and XP-47A and Kartveli began an extensive redesign of the aircraft.
[2] Armament was increased to eight M2 Brownings, four mounted in each wing, making it one of the heaviest-armed fighters considered by the USAAC at the time.
[1] The expected performance met USAAC requirements, however, its fuel load fell slightly short.
It was powered by a 1,960 hp XR-2800-21 engine and featured an elliptical wing, an all-metal construction (except for the fabric-covered control surfaces), and a hinged canopy.
[3] The aircraft's nickname, Thunderbolt, was created by Republic's Director of Military Contracts, C. Hart Miller.
The resulting P-47C featured a redesigned metal rudder, as the original fabric-covered unit was prone to tail flutter which frequently led to crashes.
The initial production block was based on the P-47C-2-RE[4] or C-5-RE,[8] but with two additional cowl flaps (for a total of five) on each side (this was absent on early aircraft, making them indistinguishable from P-47Cs).
In an attempt to improve the performance of the Thunderbolt, Republic began a project to install a 2,300 hp Chrysler XIV-2220-1 16-cylinder inverted-V engine in two P-47D-15-RE airframes in August 1943.
A production version of the XP-47J was canceled in favor of another Thunderbolt development, the XP-72, as were plans for installing an R-2800-61 engine with contra-rotating propellers.
[18] Deliveries began in December 1944, though engine problems delayed their combat debut until a few weeks before the end of the war in Europe.
[19] 1,816 P-47Ns were built in six production blocks, with orders for an additional 5,934 aircraft being canceled after VJ Day.
[20] The aircraft was a development of the bubbletop P-47D, but was to be powered by 3,450 hp Pratt & Whitney R-4360-13 Wasp Major 28-cylinder radial engine driving contra-rotating six-bladed Aeroproducts propellers and armed with six M2 Brownings.
