The XP-72 was a modification of the basic P-47 airframe redesigned for the Pratt & Whitney Wasp Major radial engine of 3,500 hp.
The aircraft had a close-fitted engine cowling and a supercharger placed behind the cockpit. The supercharger air inlet was moved to the wing root and gave the aircraft its distinctive "large-belly" shape. The XP-72 was capable of accelerating to 490 mph. at 25,000 feet and was to be used to intercept German V-1 "Buzz Bombs".
The maiden flight of the first XP-72 built (S/N 43-36598) was on 2 February 1944. This aircraft had a conventional 4-bladed propeller, but the second aircraft (S/N 43-36599) featured an Aero Products contra-rotating propeller. The excellent performance of the prototype aircraft resulted in a contract for 100 P-72's. These aircraft were to be armed with four 37mm cannon instead of the machine guns on the prototypes. However, the Army Air Force canceled the production contract before any aircraft were built because of the greater need for long-range escort fighters in Europe.