Abstract:

ESDU Aero A.S.06.03.04 gives graphs derived from linearised supersonic flow theory for the centre of pressure position of a lifting surface as a function of aspect ratio, mid-chord sweep angle (which may be positive or negative) and Mach number. The centre of pressure position is required in the estimation of the effectiveness of a control or a stabilising surface. The graphs apply to a thin isolated trapezoidal surface with streamwise tips and at small angle of attack; the effects of interference from other components have to be treated separately. Six graphs are given, each applying to one value of taper ratio: 0, 0.2, 0.4, 0.6, 0.8 and 1. For a swept back pointed surface (taper ratio of 0) there may be a subsonic leading edge and a supersonic trailing edge but for all the other cases the leading and trailing edges must both be supersonic with the Mach line from the leading edge of the longer tip intersecting the trailing edge. A worked example illustrates how the method may be used in conjunction with ESDU Aero A.S.01.03.02 to derive the rolling moment when the surface is used as a fin.