Application of Three Aeroservoelastic Stability Analysis Techniques
Final rept. 15 Feb 75-30 Jun 76,
GENERAL DYNAMICS FORT WORTH TX FORT WORTH DIV
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This report describes two types of instabilities encountered by the YF-16 airplane that were caused by a coupling between the active control system and structural dynamics. Three mathematical models of the airplane were evaluated to determine the degree of correlation between analysis and flight tests. These mathematical models are described as 1 Truncated Mode Analysis Using GVT Modes 2 Truncated Mode Analysis Using Computed Modes and 3 Residual Flexibility Method Using Computed Modes. Stability was determined in the frequency domain by employing the Nyquist criteria and the determinant plot. A method is presented for computing indicial functions from oscillatory generalized aerodynamic terms obtained from any linearlized aerodynamic theory. The equations for employing the indicial functions in a root locus stability analysis are presented. Stability was determined by the root locus method for the mathematical model described as the truncated mode analysis using computed modes. The degree of correlation between analysis and flight test is shown. Recommendations for analysis techniques, tests, and criteria are made.
- Attack and Fighter Aircraft