The December 14, 1984, test flight of the X-29—the most aerodynamically unstable aircraft ever built—demonstrated forward-swept wing technology for supersonic fighter aircraft for the first time. Technology breakthroughs, among them a digital fly-by-wire flight-control system and carbon-fiber wing technology, made possible a lightweight design far more maneuverable than conventional aircraft. DARPA, NASA, and the U.S. Air Force jointly developed two X-29 technology demonstration aircraft, which the Air Force acquired in March 1985 and used for 279 test flights by April 1990.
Although Air Force fighter designs ultimately embraced DARPA’s stealth revolution rather than the high maneuverability promised by forward-swept wings, other X-29 technologies found their way into future aircraft. Advanced composite materials are now used extensively in military and commercial aircraft. Aeroelastic tailoring to resist twisting under flight loads is now a standard tool for advanced designs with relevant outcomes including the long, thin wings of the Global Hawk, an unmanned surveillance aircraft.
