Abstract: The current studies of unsteady aerodynamic modeling at high angles of attack were mostly based on the wind tunnel tests with single degree of freedom oscillations, and are hard to be applied to the engineering applications such as stability analysis and control law design. In this investigation, an unsteady aerodynamic model called ???20200612??? model is proposed based on the yaw-roll coupled experimental data at high angles of attack. In the ???20200612??? model, the unsteady aerodynamic loads are considered as combinations of which produced by the module of rotation vector and variation of attitude (???20200612???). Therefore, the ???20200612??? model had a clear physical significance, and is simple in expression. Furthermore, the effects of lateral-directional coupling on the unsteady aerodynamic loads are accurately reflected in ???20200612??? model. Then both the ???20200612??? model and quasi-steady model, which is commonly used in engineering applications, are used for the calculation of lateral-directional aerodynamic loads in different motions and simulations of spin. The comparison between the simulation results and experimental data of spin verified that the ???20200612??? model is accurate in the prediction of unsteady aerodynamic characteristics of an aircraft at high angles of attack. Then ???20200612??? model are locally linearized by decomposing the modeling parameters onto body-axis, thus it could be compatible with current method of flight dynamics analysis. Hence the engineering applicability of ???20200612??? model is further verified by the theoretical explanation and simulation of the lateral disturbance phenomenon appeared in the flight test of F-16XL.

Key words: high angles of attack, unsteady aerodynamics, yaw-roll coupling, aerodynamic modeling, wind tunnel tests