An in-flight interaction of the X-29A canard and flight control systemThis paper presents the details of an aeroservoelastic interaction experienced in flight by the X-29A forward-swept-wing aircraft. A 26.5-Hz canard pitch-mode response was aliased by the digital sampling rate in the canard-position feed-back loop of the flight-control system, resulting in a 13.5-Hz signal being commanded to the longitudinal control surfaces. The amplitude of this commanded signal increased as the wear of the canard seals increased, as the feedback path gains were increased, and as the canard aerodynamic loading decreased. The resultant control-surface deflections were of sufficient amplitude to excite the structure. The flight data presented shows the effect of each component (structural dynamics, aerodynamics, and flight-control system) for this aeroservoelastic interaction.
Document ID
19900039765
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Kehoe, Michael W. (NASA Hugh L. Dryden Flight Research Facility Edwards, CA, United States)
Bjarke, Lisa J. (NASA Flight Research Center Edwards, CA, United States)
Laurie, Edward J. (Grumman Aerospace Corp. Bethpage, NY, United States)