Flight test results of an active flutter suppression system

Abstract

Flight flutter test results of the first aeroelastic research wing of NASA's Drones for Aerodynamic and Structural Testing (DAST) Program are presented. The implementation of the flutter suppression system and the flight test operation are described. The conduct of the flutter testing and the near-real-time damping estimation algorithm are also described in detail. Flight data were obtained at Mach numbers up to 0.91 and were of high quality. Response to fast frequency sweep excitation provided reliable damping estimates and the open-loop flutter boundary was well defined. Evidence of angle-of-atta ck effects upon damping at high transonic Mach numbers is also presented. While the flutter suppression system provided augmented damping at speeds below the flutter boundary, an error in the implementation of the system gain caused the system to be less stable than predicted and the vehicle encountered system-on flutter on the third flight.