Flight dynamics of flapping-wing air vehicle

The research and development efforts presented in this paper address the flight dynamics of a flapping-wing air vehicle (ornithopter). The 74-cm wing span ornithopter was equipped with the automatic control system that provides the stability augmentation and navigation of the vehicle, and flight data acquisition. Wind tunnel tests were conducted with the control surfaces fixed in neutral position and flapping motion of the wings activated by a motor at a constant throttle setting. Coefficients of a lift, drag, and pitching moment were determined at a free stream velocity of 7.2 m/sec and the angle of attack varied from 0 to 41 degrees. In addition, variations of derivatives of aerodynamic coefficients with the freestream velocity were investigated. A series of flight tests were conducted with fixed controls demonstrating ornithopter stability in all axes. Proportional control laws were programmed into the autopilot for the closed-loop controls. A number of test flights of the autonomous ornithopter were conducted with the telemetry acquisition. During the autonomous flights, the autopilot performed waypoint and altitude navigation demonstrating stable performance.