Conceptual Aerodynamic Modeling of a Flapping Wing Unmanned Aerial Vehicle

Abstract : This report presents the development of an improved aerodynamic model of a flapping wing unmanned aerial vehicle (FWUAV). Flapping wing flight is a complex phenomenon encompassing unsteady effects, controls using multiple degrees of freedom, creation of leading edge vortices, significant wing deformation, and extreme angles of attack during flight. These phenomena are not well modeled using the traditional conceptual aerodynamic models originally developed for fixed wing and rotary wing aircraft. In this study, Blade Element Theory is combined with momentum theory (called Blade Element Momentum Theory [BEMT]) to estimate aerodynamic loads on a FWUAV. The BEMT model is also combined with experimental scans of a FWUAV wing in a wind tunnel to represent the actual wing shape during flight (represented by three-dimensional [3D] scatter plots). These scatter plots are translated into spanwise-changing airfoil coordinates and used with thin airfoil theory to estimate the lift coefficient of the wing across the entire span at discrete points in the flap cycle. Finally, this lift coefficient estimation is used in conjunction with BEMT to create a comprehensive model for flapping wing flight and model calculations are compared against experimental data.