Chapter 4 - The Equations of Motion

Abstract

This chapter explores the equations of motion. It is broadly divided into four sections. The first one discusses the equations of motion of a rigid symmetric aircraft. The first formal derivation of the equations of motion for a rigid symmetric aircraft is usually attributed to Bryan. His treatment, with very few changes, remains in use today and provides the basis for the development discussed in this chapter. The second section explains the linearized equations of motion. In order to proceed with the development of the equations of motion for analytical purposes, they must be linearized. Linearization is very simply accomplished by constraining the motion of the aeroplane to small perturbations about the trim condition. It further describes the decoupled equations of motion. Herein, two types of equations of motion are considered. First, the longitudinal equations of motion and second is the lateral-directional equations of motion. The chapter describes the alternative forms of the equations of motion. Various examples and equations have been incorporated for better illustration.