Subsonic Unsteady Aerodynamics for General Configurations. Part 2. Volume 1. Application of the Doublet-Lattice Method and the Method of Images to Lifting-Surface/Body Interference

A technique for predicting steady and oscillatory aerodynamic loads on general configurations has been developed which is based on the Doublet- Lattice Method and the method of images. Chord- and spanwise loading on lifting surfaces and longitudinal body load distributions are determined. Configurations may be composed of an assemblage of bodies (elliptic cross sections and a distribution of width or radius) and lifting surfaces (arbitrary planform and dihedral, with or without control surfaces). Loadings predicted by this method are required for flutter, gust, frequency response and static aeroelastic analyses and may be used to determine static and dynamic stability derivatives. The methods described in this report are intended to be used by airplane designers to calculate with improved accuracy, the unsteady aerodynamic pressures that act on a lifting surface being propelled at subsonic speeds. The new feature of these calculations is that the effects on the pressure field induced by interference between the fuselage, for example, and the wing or the wing, pylon and nacelle, are taken into account. These calculations are an essential ingredient of flutter analyses and will improve the confidence level of such calculations in preventing wing-store flutter and flutter of advanced vehicles where fuselages are relatively large, provide some lifting capability and cause noticeable interference effects. See also Part 1, Volume 2, AD892535.