ABSTRACT
The Grumman Aerospace Corporation designed and built two X-29A airplanes under a contract sponsored by the Defense Advanced Research Projects Agency and funded through the United States Air Force. The X-29A research airplane integrated several technologies, a forward- swept, aeroelastically tailored composite wing and a close-coupled, all-moving canard. The X-29A airplane is controlled through a triplex fly-by-wire flight control system, which was designed for fail-operational, fail-safe capability. Research at low angle of attack was the focus of all flight testing on X-29A No. 1 throughout its four years of flight test. Aircraft that have a high degree of static instability, like the X-29A, require close monitoring in the early envelope expansion stages of flight test. The real-time comparison of the airplane response with linearized models allows the flight test personnel to verify the aircraft is performing as predicted, to determine regions of nonlinear behaviour, and to increase the rate of envelope expansion.
