Abstract:

ESDU 76003 gives expressions (in terms of wing geometry) for the length, and position of the quarter-chord point, of the geometric (or standard) mean and aerodynamic mean chords of a wing whose leading- and trailing-edges are formed of straight line segments and whose leading- and trailing-edges have any arbitrary number of cranks; the wing has either pointed or straight streamwise tips. For the special case of the straight-tapered wing, curves give the lengths of the chords and their quarter chord position as a function of taper ratio, centre-line chord, aspect ratio, and quarter-chord sweep. Also given for that case are curves relating the sweep angles of any two fixed percentage chord lines. Addendum A shows how to obtain the geometry of a straight-tapered wing equivalent to some arbitrary planform mounted on a fuselage so that the two have the same aerodynamic characteristics. This technique has been found most useful by ESDU as a means of correlating lifting-surface aerodynamic data. Finally, Addendum B gives a simple geometrical construction for obtaining the size and longitudinal location of the aerodynamic mean chord for a straight-tapered wing.