Wing Stiffness on Light Flapping Micro Aerial Vehicles

In an effort to develop micro aerial vehicles of 20-cm-span with a successful flight record, this study aims to investigate the influences of wing configuration and foil stiffness on the aerodynamic forces via wind-tunnel testing. These wings with the same wing skeleton structures are made of polyethylene, polyethyleneterephthalate, and polyxylylene (parylene). The foil thickness ranges from 17 to 43 mu m, which corresponds to the variating stiffness of the membrane. The tests showed that the lift coefficients of the stiffened wings have been improved, whereas the net thrust coefficients have little importance with the wing foil thickness. Inspection on the relations between power consumption and the flexural stiffness of tested flapping wings reveals that the larger lift force and greater power consumption is associated with the 35 and 43 - mu m-thick parylene. Therefore, the present study demonstrated that the flight test of a micro aerial vehicle with the best wing foil of 24 - mu m-thick PET resulted in the longest endurance time of 8 nun. Several innovative aspects of developing this work are also summarized.