The primary control surfaces were used to excite the structural modes over the frequency range of 0.1 to 100 Hz for the X-31A flight flutter test. The control surfaces were commanded by a flutter test control system which interfaced with the aircraft digital, fly-by-wire control system. This paper describes the characteristics and use of the flutter excitation system, including the control box, the control surfaces operated, a block diagram of the interfaces with the control system, the sine sweep, dwell and pulse capabilities of the system, the oscillation frequency vs time, and typical amplitudes and phase angles of control surface rotation versus time. The flight envelope cleared, the real-time telemetry parameters monitored, and the test procedures used are briefly described. Typical time histories of response, and typical plots of the frequencies and damping versus dynamic pressure and mach number extracted from the response data are given. The required structural modes were adequately excited by the control surface sine sweeps used. Extrapolation of the plots of frequencies and damping versus dynamic pressure and mach number indicated large flutter margins of safety for the X-31A, which is in agreement with flutter analyses conducted prior to flight flutter tests.
X-31A flight flutter test excitation by control surfaces
Die Anregung durch Leitflächen für den X-31A Flugstabilitätstest
1993
11 Seiten, 20 Bilder, 3 Quellen
Conference paper
English
Luftfahrttechnik , Versuchsmethode , Betriebsverhalten , Flugmechanik , Flugverhalten , dynamische Stabilität , Anregungszustand , Schütteln (Aerodynamik) , Test (Prüfung) , Regelungssystem , Flugzeugelektronik , Regelparameter , Blockdiagramm , dynamischer Druck , Machzahl , Schwingungsamplitude , Schwingungsspektrum , Technikbewertung
X-31A FLIGHT FLUTTER TEST EXCITATION BY CONTROL SURFACES
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