Natural motion of a multi-rotor aircraft.

In this paper the natural modes of motion of a multi-rotor helicopter in hovering flight are discussed. The linear equations of motion of the aircraft are presented. After an eigenvalues analysis of the state matrix the dynamic modes are defined. The connections between the stability derivatives and the dynamic stability of the aircraft are pointed out. Thus, the effects of the aircraft features on the unforced motion characteristics are evaluated. These results are useful for either the design of new vehicles or the analysis of an existing one, as witnessed by a numeric example. [ABSTRACT FROM AUTHOR]