Convair XP-81

XP-81
Role	Escort fighter
Manufacturer	Consolidated Vultee Aircraft Corporation
First flight	11 February 1945
Status	Cancelled
Primary user	United States Army Air Forces
Number built	2
Unit cost	US$4.6 million for the program

The Consolidated Vultee XP-81 (later redesignated ZXF-81) was a development of the Consolidated Vultee Aircraft Corporation to build a single seat, long range escort fighter that combined use of both turbojet and turboprop engines. Although promising, the lack of a suitable engine combined with the end of World War II doomed the project.

Two prototype aircraft were ordered on 11 February 1944 that were designated XP-81. The engine selection was an attempt to couple the high-speed capability of the jet engine with the endurance offered by the propeller engine. The XP-81 was designed to use the General Electric TG-100 turboprop engine (later designated XT31 by the US military) in the nose driving a four-bladed propeller and an GE J33 turbojet in the rear fuselage. The turboprop would be used for normal flight and cruising and the turbojet added for high-speed flight.

The first XP-81 (serial 44-91000) was completed in January 1945 but because of developmental problems the turboprop engine was not ready for installation. A decision was then made to mount a complete V-1650-7 Merlin engine package from a P-51D aircraft in place of the turboprop for initial flight tests. This was done in a week and the Merlin-powered XP-81 was sent to the Muroc airbase where it flew for the first time on 11 February 1945. During 10 flight test hours, the XP-81 displayed good handling characteristics except for inadequate directional stability due to the longer forward portion of the fuselage (this was rectified by enlarging the vertical tail).

While 13 YP-81 pre-production aircraft had been ordered, the capture of Guam and Saipan eliminated the need for long-range, high-speed escort fighters and, then, just before VJ Day the contract was cancelled, after 85% of the engineering was completed. The YP-81 was to be essentially the same as the prototype but with a lighter and more powerful GE TG-110 (XT41) turboprop engine, the wing moved aft 10 inches (0.25 m), and armament of either six .50 cal (12.7 mm) machine guns or six 20 mm cannon.