Abstract:

ESDU 95009 presents a theoretical method, based on slender-body theory, for estimating the change in lift and aerodynamic centre position resulting from moving a wing from a centrally-mounted position to one above or below the centre line of a forebody-cylinder combination. It applies to a plane wing with sweptback leading edge, local span increasing (and then possibly constant) streamwise, and an unswept trailing edge. The body has a constant diameter circular section over the wing root chord and the wing may be set at an angle to the body centre line. Equations and graphs are given for the ratios of the lift (excluding that on the body alone) due to angle of attack and due to wing setting angle for the combination with wing off-centre to those for the combination with net wing removed and remounted centrally. The lift of the combination with centrally-mounted wing may be estimated from ESDU 91007, or from other sources, instead of using the slender-body value. Similarly, the slender-body value for aerodynamic centre shift due to moving the wing from centrally-mounted to off-centre, for which an equation is given, may be added to the aerodynamic centre position found from ESDU 92024. Use of ESDU 91007 and ESDU 92024 in this way is expected to give better results than use of slender-body theory for the combination with centrally-mounted wing. The method is illustrated with two practical worked examples. A computer program of the method is provided as ESDUpac A9509 and Toolbox 95009.