An approximation to the slow mode of longitudinally disturbed motion of an aircraft in level flight

Abstract

This report develops an approximate theory of longitudinal response which applies to the slow mode of motion after a disturbance. This theory is complementary to that for the quick-period motion given by Gates and Lyon. It predicts the slow motions which occur after the quick-period motions have died out. The approximate equations given are of second order only and can therefore be solved algebraically. This has been done and the general solutions are given in Tables 1 and 2. Some numerical examples have been computed to indicate the accuracy which can be expected. The agreement with the first approximation is quite good and in some components it can be improved by the use of a further correction term.