Overview of recent flight flutter testing research at NASA Dryden

ARASEIn response to the concerns of the aeroelasticcommunity, NASA Dryden Flight Research Center, CWTEdwards, California, is conducting researchERAinto improving the flight flutter (includingaeroservoelasticity) test process with more accurate and FFTautomated techniques for stability boundary prediction. FORSEThe important elements of this effort so far include thefollowing: 1) excitation mechanisms for enhancedvibration data to reduce uncertainty levels in stability Gestimates; 2) investigation of a variety of frequency, h(t)time, and wavelet analysis techniques for signalprocessing, stability estimation, and nonlinearidentification; and 3) robust flutter boundary predictionto substantially reduce the test matrix for flutterclearance. These are critical research topics addressingthe concerns of a recent AGARD Specialists' Meeting onAdvanced Aeroservoelastic Testing and Data Analysis.This paper addresses these items using flight test datafrom the F/A-18 Systems Research Aircraft and theF/A-18 High Alpha Research Vehicle.