Wing Rock Prediction Method for a High Performance Fighter Aircraft

摘要

This study is a limited investigation of the nonlinear aircraft behavior known aswing rock. An eight state F-15 model is analyzed using bifurcation theory. The wing rock onset point is identified and small perturbation analysis is used to linearize the equations of motion about this point. The eigenstructure of the model is analyzed and is used to identify the stability modes involved in this motion. A procedure is developed to predict wing rock onset and frequency and the critical stability derivatives involved in this motion are identified. The developed procedure is applied to existing F-4J data and a flight test involving RF-4C and T-38A aircraft is flown The results show wing rock is an unstable dutch roll motion and the developed wing rock prediction parameter is accurate to within 1 degree of onset AOA. The frequency prediction parameter gives a fair estimate of wing rock motion but it may be adversely influenced by the type of flight test data. The slope of the prediction parameter versus AOA curve may be an indication of the severity of wing rock motion. Stability and control, bifurcation (mathematics), wing rock, roll oscillations, flight test, high AOA.