The Republic XP-72 was based upon the P-47 airframe and was designed by Alexander Kartveli's fighter team as a 'Super Thunderbolt' around the 3,000-hp / 2237kW Pratt & Whitney R-4360-13 Wasp Major radial engine. The powerplant was the most powerful piston engine to reach production in any country during World War II.
Intended primarily to be faster than the Thunderbolt, the XP-72 was viewed in part as a remedy for the Third Reich's high-speed V-l buzz bomb. The USAAF planned to use the fighter to intercept buzz bombs, with a maxi-mum speed of 490mph and an initial climb rate of 3,100ft/min the XP-72 could reach 6000m / 20,000 ft in just under five minutes. Operational P-72s would have been armed with six .50-calibre (12.7-mm) guns.
The first of two examples flew at Farmingdale on 2 February 1944 using a large four-bladed propeller. The second XP-72 flew in July 1944 with the intended Aeroproducts six-bladed contra-rotating propeller. The second aircraft, however, was lost on an early flight.
With priority shifted to long-range escort fighters, this promising interceptor was not needed. Even with a range of 1,200 miles, the XP-72 failed to get a produc-tion order. The other XP-72 airframe is thought to have been scrapped at Wright Field around VJ-Day.
Engine: Pratt & Whitney R-4360-13 Wasp Major, 3,000-hp
Max take-off weight: 6690 kg / 14749 lb
Empty weight: 4973 kg / 10964 lb
Wingspan: 12.49 m / 41 ft 0 in
Length: 11.17 m / 37 ft 8 in
Height: 4.42 m / 15 ft 6 in
Wing area: 27.87 sq.m / 299.99 sq ft
Max. speed: 788 km/h / 490 mph
Ceiling: 12800 m / 42000 ft
Range: 1930 km / 1199 miles
Armament: 6 x 12.7mm machine-guns, 2 x 450kg bombs