The Lateral Stability of Aeroplanes: A New Geometrical System of Analysis

VARIATION IN “TYPICAL VALUE” PARAMETERS IT has previously been shown that the effect of freeing the controls on the lateral stability of an aircraft may be taken account of by changes both in the values of the derivatives lp, lr, np and nr (wing), which hitherto have had typcial values, and also of the variables x, y and t themselves. It is therefore desirable to have information on the effect on the stability boundaries of changes in these derivatives. It may also happen that the values of yv and tan Θo in the case of a particular aircraft may be known to differ from those here adopted in the drawing of stability charts. The versatility of these charts (later to be given) will therefore be considerably increased if rules are expounded for assessing the effects of changes in any of those derivatives which were formerly fixed. This we proceed to do.