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The XF-91, a high-speed experimental interceptor, was America's first rocket-powered combat-type fighter to fly faster than the speed of sound. The airplane had a number of unusual design features--an inverse taper wing (wider at the tips than at the roots), a variable incidence wing that could be varied in flight (high angle of attack for takeoff and landing and low angle of attack for high-speed flight), a main landing gear that retracted outward with the tandam wheels being housed in the wing tips and a rocket engine that augmented the standard jet engine to provide an outstanding rate of climb.
The airplane made its first flight on May 9, 1949. Numerous other test flights were made which provided valuable research data, but the airplane was not put into production because it did not carry sufficient fuel for a flight of longer than 25 minutes, and did not incorporate the latest type of fire control system.
The XF-91 on display was transferred to the Air Force Museum from Edwards AFB, California in May 1955.
Span: 31 ft. 3 in.
Length: 43 ft. 3 in.
Height: 18 ft. 1 in.
Weight: 28,300 lbs. loaded
Armament: Four 20mm cannons
Engine: General Electric J47 of 6,700 lbs. thrust with afterburner and Reaction Motors rocket of 6,000 lbs. thrust.
Serial number: 46-880