The ‘Ornicopter’ is a single-rotor helicopter without anti-torque rotor developed since 2002 at Delft University of Technology in The Netherlands. The Ornicopter’s principle is similar to the movement of a bird’s wing and is based on actively flapping the blades up and down while rotating them around a shaft to generate both the required lift and the propulsive force. The shaft torque is no longer needed and thus the anti-torque rotor is redundant. The present paper describes the basic principles of the Ornicopter’s forced flapping, discussing the feasibility of the Ornicopter concept with respect to the power required, performance, stability, and vibratory loads. On the one side it is shown that the Ornicopter has a similar power requirement to a conventional helicopter, as well as very similar longitudinal and lateral stability and controllability characteristics to a conventional helicopter. On the other side, the Ornicopter generates higher vibratory loads than in a conventional helicopter, and its performance is strongly limited by the stall effect.