Meeting Abstract
The stability and dynamics of flapping flight is still not fully understood. In particular, the forces that contribute to yaw dynamics, especially the extent to which stable flapping flight in yaw is achieved via passive versus active mechanisms, remain unclear. A current hypothesis for a physical yaw dynamics model contains three terms that are derived from flapping counter torque and a restoring torque that reorients flappers into the relative oncoming wind. This passive reorienting torque has no precedent of which the authors are aware. Here we study this torque via wind tunnel experiments on an ornithopter which, after a perturbation in the yaw direction, successfully reorients itself into the wind. In comparing these results to experiments conducted on similar fixed wing aircraft, we show that flapping indeed contributes to passive yaw stability. The findings help interpret the yaw dynamics of birds and may also apply to insects and bats and can help improve the yaw stability of robots with flapping wings.
