Abstract:

ESDU 87031 involves estimating separately two contributions to the zero-lift angle. One is due to camber, taken as that corresponding to the wing-root section and assumed constant across the span. The other isdue to the combined effects of geometric twist and of camber-dependent twist associated with spanwise camber changes from that at the root. The method applies to a wide range of cambered and twisted straight-tapered wings, provided that the local effective twist is less than about 10 degrees and the flow is fully attached and subsonic at zero-lift. It can be applied to wings with cranked or curved edges using an "equivalent wing planform" as defined in ESDU 76003. The method correlates wind-tunnel test data drawn from a wide range of sources in the literature to within ±0.3 degrees. Illustrations of typical uses for the method are given in the form of four worked examples. A computer program of the method is provided as ESDUpac A8731 and described in an appendix.