We humans generally use fixed wings for flight, but in nature, flapping flight dominates. As an animal flaps, it extends or draws in its wings during key points of the cycle in order to change its aerodynamics. But this control can be more than just a matter of stretching their wings. Recent work on bats shows that they can fine-tune the stiffness of their wings’ membrane using tiny, hair-thin muscles. Each muscle is too slight to change a wing’s shape on its own, but by firing synchronously–tensing on the downstroke and relaxing on the upstroke–the bat can manipulate its membrane stiffness and thereby affect its wing shape. Moreover, the timing of the muscles’ action changes with flight speed, suggesting that the bats are actively controlling their aerodynamics during flight. (Video credit: Swartz-Breuer lab/Brown University; via Futurity; submitted by Boris M)
Fine-Tuning Flight
