Ornithopter Aerodynamic Experiments

Abstract

The analysis of the flight of insects, birds and ornithopters is difficult because there is limited aerodynamic theory applicable for the large amplitude unsteady wing motions. Furthermore the complex wing shapes and wing motions encountered in insect and bird flight entails complex aerodynamic interactions. A systematic theoretical and experimental study has been pursued by the senior author for the past several years to gain a better understanding of the aerodynamic, dynamic and mechanical problems of flapping wing flight. The primary intent has been to establish a strong technical base necessary for the development of the ornithopter as an alternative to the helicopter. The helicopter is best suited for hovering flight and suffers greatly reduced efficiency as forward speed is increased. On the other hand, the ornithopter can achieve hovering flight, albeit with much more mechanical complexity, but promises high efficiency in forward flight. The method of attack for this study of the ornithopter has been to depart gradually from the conventional aircraft configuration so that the large body of knowledge accumulated in the development of the airplane could be applied to the study of the ornithopter. In this paper the results of the aerodynamic studies are presented because of their applicability to the modeling of insect and bird flight.