Mimicking Birds to Invent a Tailless Helicopter - The Ornicopter

The Ornicopter is a relatively new concept of tailless helicopter. By actively flapping the blades up and down, similar to the movement of a bird's wing, the blades will propel themselves around the rotor shaft and will at the same time provide a lifting force. Because of the propulsive force, the rotor blades will rotate themselves and the shaft torque is no longer needed. Therefore, the tail rotor is redundant. The aim of the present paper is to develop a flight mechanics model for the Ornicopter and analyse its behaviour in hover and forward flight. It will be demonstrated that, since each blade flaps differently, the Ornicopter rotor blades generate higher amplitudes and additional periodic components of forces and moments on the hub as compared to a conventional helicopter. This may cause vibratory problems. The paper will propose some possible new hub designs for Ornicopter in order to alleviate the vibratory problem.