An Experimental Study of Flapping Membrane Wings

Abstract

Experimental studies were conducted on the aerodynamic performance of flapping membrane wings. These are characterized by having a leading-edge spar, to which a wing-shaped, flexible membrane surface is attached. The membrane is further constrained at the root, and the surface undergoes deformation during the flapping cycle. The test variables were aspect ratio, planform shape, spar stiffness, membrane weight, and batten design; and the measured properties were average lift, thrust, and pitching moment, as well as propulsive efficiency. It was found that the best thrust and efficiency performance came from fully battened wings with a stiff spar and the lightest membrane. However, the highest measured efficiency of 30% was still far below what is achievable with a Shearflex® wing that incorporates a non-membrane, double-surface airfoil.