A toy more difficult to control than the real thing

Standard helicopters use the propeller angle to alter the aerodynamic force and have been shown to be feedback linearizable with the pitch, yaw and roll angles being the flat outputs. In this work, a-two-degree-of-freedom, laboratory-scale helicopter-like system (termed the toycopter), where the aerodynamic force is manipulated using the propeller speed, is considered. For such a system the yaw and pitch angles are not flat outputs contrarily of the real helicopters. Moreover, the system does not seem to be flat and is shown to admit at most a one dimensional defect. Various properties of this system are investigated to illustrate the difficulties that arise in the control of the toycopter.