A system for exciting the modes of vibration of an unstable digitally controlled fly-by-wire combat aircraft via the primary control actuators in order to extract flutter data is presented. The system has been developed on the Experimental Aircraft Program (EAP) to generate, within the Flight Control computers, frequency sweep and impulse excitation signals which are injected via the primary control actuators to the foreplane and wing trailing edge flaperons. The choice of surface, actuator amplitude input and symmetric or antisymmetric excitation is pilot selectable. The system will permit predefined waveforms, referred to as test routines, to be summed into the Flight Control System (FCS) actuation loops under cockpit control. Rig and aircraft ground response performance tests were performed on the foreplane and wing outboard trailing edge flaperon actuators as part of the qualification of the system. A flight test program of 15 flights measured aircraft responses due to the injection of frequency sweeps and impulses. Results are presented for the foreplane and the wing and a comparison made with predictions and previous flight flutter tests using bonker impulsive excitation. Operation of this system demonstrated the flexibility in being able to select the excitation type and input amplitudes, optimized to the aircraft configuration and flight condition, to extract high quality data, which is the key to successful flight flutter testing. Use of this system, particularly where structural limitations restrict the use of other types of excitation, offers great potential in reducing overall testing time for aircraft with a large number of stores, provided the system is designed to have flexibility in the choice of input available to the test engineer.


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    Titel :

    In-Flight Structural Mode Excitation System for Flutter Testing


    Beteiligte:
    R. B. Ramsay (Autor:in)

    Erscheinungsdatum :

    1992


    Format / Umfang :

    20 pages


    Medientyp :

    Report


    Format :

    Keine Angabe


    Sprache :

    Englisch