Aerodynamic and structural dynamic identification of a flapping wing micro air vehicle

In this study the aerodynamic efficiency of DelFly, a bio-inspired napping wing Micro Air Vehicle (MAV), is analyzed. DelFly has four flexible sail-like wings placed in a biplane configuration and is believed to produce favorable lift in comparison to conventional wings. This is at the expense of higher drag and thus loss off efficiency. This study uses experimental setups to investigate the power required to drive the flapping wings as a function of the kinematic parameters flap frequency and flap angle. This is done during hovering flight, the most power consuming mode. In addition, the deformation of the Mylar-film wings is filmed in free air conditions and in near-vacuum conditions to identify the aerodynamic versus inertial effects. The experimental results of the studies present valuable insight in the aerodynamic performance and structural dynamics of the vehicle. For hovering with a flap frequency of 14 Hz, an optimal flap angle has been found that maximizes thrust for minimal power consumption. High lift coefficient values suggest that the favorable lift production in comparison to conventional wings, is a result of high lift mechanisms. These are believed to be the Leading Edge Vortex and the clap-and-fling motion.