Climb and Descent of Fixed-Wing Aircraft

Methods are presented for the analysis of the climb and descent of fixed-wing airplanes. The airplane has been treated as a rigid body, and classical techniques applicable to the dynamics of bodies in motion used. General equations are developed for an accelerated flight condition, where the associated unbalanced forces would cause the airplane's speed to either increase or decrease. A simplified flight condition, in which the airplane is assumed to be in a steady state (i.e., equilibrium), has been considered by setting the acceleration factor equal to zero. Expressions for the airplane's angle of climb/descent and for the rate of climb/descent are derived. The adopted approach initially considers flight in still air, and thereafter considers the impact of wind on the airplane's trajectory. A generic climb-speed schedule, typical of that used by airliners, is presented as an illustration of an accelerated climb. The optimum speeds that would maximize the angle of climb or the rate of climb for jet and piston-propeller airplane types are explored through the derivation of analytical expressions. A brief discussion on a topic related to climb performance, that is, the airplane's ceiling (i.e., maximum altitude), is included in the chapter.