The Consolidated Vultee XP-81 (its newly-merged builder soon to be better known as Convair) was the first American aircraft powered by a turboprop engine. Ordered by the USAAF on 11 February 1944, the XP-81 was intended as a long-range escort fighter using compound power, with one 1230kW General Electric TG-100 turbo-prop and one 1701kg thrust Allison I-40 jet engine, eventually designated J33-A-5. When delays with the turboprop powerplant were encountered, the prototype XP-81 was flown on 11 February 1945 with a Packard V-1650-7 Merlin installed temporarily in the nose.
The first flight with the intended turboprop engine followed on 21 December 1945 and the turboprop provided no advantage in performance over the Merlin. A second XP-81 flew in early 1946 to join the first machine in testing, but war's end, the disappointing results with the TG-100, and the superiority of pure jet designs resulted in cancellation of an order for 13 YP-81 service-test aircraft.
Both XF-81 airframes have survived derelict on a test range at Edwards AFB, California.
Wingspan: 15.39 m / 50 ft 6 in
Length: 13.67 m / 44 ft 10 in
Height: 4.27 m / 14 ft 0 in
Wing area: 139.48 sq.m / 1501.35 sq ft
Max take-off weight: 12700 kg / 27999 lb
Empty weight: 5785 kg / 12754 lb
Max. speed: 815 km/h / 506 mph
Cruise speed: 442 km/h / 275 mph
Ceiling: 10800 m / 35450 ft
Range: 4000 km / 2486 miles
Armament: 6 x 12.7mm guns or 6 x 20mm cannon planned, 1450kg underwing bombs