In early 1940, combat reports from war in Europe indicated that the P-47 was inferior to Luftwaffe fighters. 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. 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.
