An experimental study of the aerodynamic performance of a maple wing model at low Reynolds numbers

Maple seeds are widely known for their autorotation and may achieve remarkably long-distance flights owing to their unique wing morphology. These features suggest the adaptability of the blades to wind turbines and air vehicles. However, the effects of these morphological features on aerodynamic force generation are still poorly understood. An enlarged replica of a sample 3D maple wing was produced using additive manufacturing. Direct force experiments were conducted in a low-speed wind tunnel using a two-component force balance to obtain the lift and drag coefficients of the model wing. The polar curves of the wing were obtained for three different Re numbers by repeating the experiments over a wide angle of attack range of-50 to 50 degrees. The best aerodynamic performance is obtained at 18 degrees and-12 degrees attack angles for positive and negative angles, respectively, regardless of the Re number. This preliminary study shows that maple seed can be mimicked in the design of propellers and wind-turbine blades.