Evaluation of flexible flapping wing concept

ONERA - The French Aerospace Lab - has launched an internal program on biologically-inspired Micro Air Vehicles (MAVs), covering many research topics such as unsteady aerodynamics, actuation, structural dynamics or control. The aim is to better understand the flapping flight performed in nature by insects, and to control state of the art technologies and applications in this field. For that purpose, a flight-dynamics oriented simulation model of a flapping-wing concept has been developed. This model, called OSCAB, features a body and two wings along which the aerodynamics efforts are integrated, so as to determine the global motion of the MAV. The model has been improved by taking into account the flexibility of the wings (flexion of the leading edge and passive torsion of the wings, induced by the flapping motion itself under wing inertia). Thus, it becomes possible to estimate the coupling between flexibility and the aerodynamic forces. Furthermore, the model shows that using elastic properties of the wings allows a diminution of the mechanical energy needed for wings motion, and a reduction of the number of actuators to be implanted into the MAV.