An analytical and experimental investigation into aerodynamic force determination for aircraft wings

A force determination method based on inversion of the structural frequency response matrix of an aircraft wing is developed for estimating the aerodynamic forces acting on the wing during flight. To evaluate the method, a two-degree-of-freedom and a multiple-degree-of-freedom airfoil model are developed. Analytical results reveal that aerodynamic forces estimated by the force determination method agree with the actual aerodynamic forces acting on the airfoil model at different simulated airspeeds. A study is also conducted to investigate the accuracy of the method when not all of the degrees-of-freedom are observable. The results show that the method performs well. The multiple-degree-of-freedom airfoil model is correlated with a geometrically similar physical airfoil to enable comparison between aerodynamic forces predicted by the analytical model and aerodynamic forces estimated from experimental wind tunnel data using force determination. The analytical and estimated aerodynamic forces compare well, considering that the analytical aerodynamic forces are derived from quasi-steady strip theory. For the "F1" method with noise level 0.05 at relative speed 2/3, the force and moment determination error are 81% and 9.5%.