The calculation of the pressure distribution on thick wings of small aspect ratio at zero lift in subsonic flow

Abstract

The method of expressing the velocity increment over aerofoils directly in terms of the section ordinates (Refs. 1 and 2) is extended to cover also straight and swept wings of finite aspect ratio. The wings considered are untapered in plan-form but may be tapered in thickness. The section can be of any given shape so that in this sense the analysis is more general than that of Refs. 3 to 6 which deal with wings of biconvex section. The coefficients required in the calculation are tabulated for the centre-section of straight and swept-back wings (φ = 0 deg, φ = 45 deg and φ = 60 deg) of aspect ratios 0.5 ; 1 ; 2 ; and 4, the wing of infinite aspect ratio having been treated in Ref. 1. The remaining calculations can be made very quickly. Since wings of very small aspect ratio can be treated also by the method of slender-body theory, the relations between linear theory, slender-body theory, and linearised slender-body theory are discussed. For the special case of ellipsoids, the results obtained from the various methods are compared with the exact solution.