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X-31 Enhanced Fighter Maneuverability Demonstrator Photo Gallery Contact Sheet X-31 Enhanced Fighter Maneuverability Demonstrator Photo Gallery Contact Sheet

Photo Number: N/A
Photo Date: 23 May 2000

Formats: Low Resolution Image Contact Sheet (117 KBytes)
Medium Resolution Image Contact Sheet (118 KBytes)
High Resolution Image Contact Sheet (115 KBytes)


These are the image contact sheets for each image resolution of the NASA Dryden X-31 Enhanced Fighter Maneuverability Demonstrator Photo Gallery.

The X-31 Enhanced Fighter Maneuverability (EFM) demonstrator, flown at NASA's Dryden Flight Research Center, Edwards, California, provided information invaluable for proceeding with the designs of the next generation of highly maneuverable fighters.

The X-31 program proved the value of using thrust vectoring (directing engine exhaust flow) coupled with advanced flight control systems, to provide controlled flight to very high angles of attack. The result was a significant advantage over most conventional fighters in a close-in-combat situation. "Angle-of-attack" (alpha) is an engineering term to describe the angle of an aircraft's body and wings relative to its actual flight path.

During maneuvers, pilots would like to fly at extreme angles of attack to facilitate rapid turning and pointing against an adversary. With older aircraft designs, entering this flight regime often led to loss of control, resulting in loss of the aircraft.

Three thrust vectoring paddles made of graphite epoxy and mounted on the X-31's aft fuselage were directed into the engine exhaust plume to provide control in pitch (up and down) and yaw (right and left) to improve maneuverability. The paddles could sustain temperatures of up to 1,500 degrees centigrade for extended periods of time.

In addition, the X-31 was configured with movable forward canards, wing control surfaces, and fixed aft strakes. Canards are small wing-like structures located just aft of the nose, set on a line parallel to the wing between the nose and the leading edge of the wing. Normally "weathervaned" with the prevailing airflow, these devices were programmed to be used for aerodynamic recovery from high angles of attack in event of thrust vectoring system failure. The strakes were set along the same line between the trailing edge of the wing and the engine exhaust. The strakes supplied additional nose-down pitch control authority from very high angles of attack. Small fixed nose strakes were also employed to help control sideslip.

During the program's initial phase of flight test operations at the Rockwell Aerospace facility in Palmdale, California, the two aircraft were flown on 108 test missions, achieving thrust vectoring in flight and expanding the post-stall envelope to 40 degrees angle of attack. Operations were then moved to Dryden in February 1992 at the request of the Advanced Research Projects Agency (ARPA).

At Dryden, the International Test Organization (ITO) expanded the aircraft's flight envelope, including military utility evaluations that pitted the X-31 against similarly equipped aircraft to evaluate the maneuverability of the X-31 in simulated combat.

Keywords: Ames-Dryden Flight Research Facility ; Dryden Flight Research Center; Herbst Maneuver; Wolfgang Herbst; J Turn; Advanced Research Projects Agency; Defense Advanced Research Projects Agency; U.S. Navy; U.S. Air Force; Rockwell Aerospace; the Federal Republic of Germany; Daimler-Benz; Deutsche Aerospace; Messerschmitt-Bolkow-Blohm; Gary Trippensee; General Electric

Last Modified: February 6, 2002
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