An experimental study on the influence of passive deformation to lift and thrust generation in flexible flapping wing

The influence of deformation on aerodynamic characteristics is studied in this paper. To study the influences of deformation magnitude and range separately, a kind of two-part flapping wing model is designed, which separates the deformation magnitude and range, and makes the measurement of deformation easier. A series of wind-tunnel experiments are carried out to explore the influence. The experimental data shows that deformation has a certain effect on both lift and thrust generation, especially for thrust. The big difference is that the effect on thrust generation is positive, but on lift generation is negative. The wing with smaller deformation range gets more sensitive to deformation magnitude than the wing with larger deformation in thrust generation. This indicates the deformation of the part close to wing tip contributes more to thrust generation than other parts. The result indicates that a proper deformation, including deformation range and magnitude, is helpful to thrust generation but has to have a loss of lift generation.