Response of a linearized aircraft to runway disturbances

A statistical analysis has been developed, using power spectral density methods, to examine the response of an aircraft to runway unevenness. The analysis includes rigid body heave pitch and any number of symmetrical flexural modes of the airframe, linear values of main and nose oleo and tyre stiffness and damping, and wheel masses. The analysis has been used to produce computer programs for response and optimisation studies, to investigate the effects on response to flexural modes, taxiing velocity, oleo stiffness and damping, and undercarriage position. It is found that for the aircraft used for the investigation (the values are based on the Boeing 707) a good estimate of the response can be obtained by considering rigid body modes only. [Continues.]