Grumman manufactured two airframes. They flew a total of 437 flights between 1984-1992. In a joint program involving the Defense Advanced Research Projects Agency, the Air Force, NASA, Grumman, and other contractors, this single-engine, jet-powered aircraft investigated the use of advanced composite materials, a forward-swept wing with a thin supercritical airfoil, a variable- incidence canard, a computerized fly-by-wire flight control system to overcome the aircraft’s inherent instability, behavior at high angles of attack, and a vortex flow-control system (among other technologies). On Dec. 13, 1985, the X-29 became the first forward-swept-wing airplane in the world to exceed Mach 1 in level flight, and flight results showed that a highly unstable aircraft with forward-swept wings could be flown safely with excellent maneuverability and high G-loads. It could also be flown with good control response up to about 40° angle of attack. The flight research also added to engineers’ understanding of advanced composites, used increasingly in aircraft construction, and of digital flight-control systems.