Stability Analysis for Rotary-Wing Aircraft

Abstract

Following the flight dynamic modeling, trim study and stability analysis are conducted in Chapter 3. Trim is a state of the aircraft in which forces and moments reach equilibrium. Trim is the basis of many fundamental analysis, including stability analysis, control system design, handling qualities assessment, and simulation. A numerical procedure on how to obtain trim is described. With the trim condition established, a linearization process can be carried out to obtain the linearized model for the rotary-wing aircraft. Elements in the linearized model are called stability and control derivatives. A detailed description on the derivatives is provided, with the emphasis of their physical meanings. To illustrate, three examples are also presented in the chapter, which include a simplified single helicopter system and two hobby helicopters at hover.