Abstract:

ESDU Aero A.S.06.03.03 presents a graph plotting a factor to be applied to the derivative, obtained from ESDU Aero A.S.06.03.01 for a pair of planar half wings, to correct for interference when four identical half wings are mounted equally spaced around a circular cross-section body (in cruciform arrangement). The curves were derived from an extension to supersonic linearised theory and apply to rectangular, delta and cropped delta planforms. The correction factor is a function of aspect ratio, taper ratio and compressibility factor. For three equally-spaced half wings, a result was obtained only for slender delta wings. For arrangements of three wings of other planforms, results for the correction factor for the cruciform arrangement may be factored by the ratio of the correction factor values obtained for delta wings in the two arrangements. Where two sets of wings are mounted in line along a body it is suggested, for zero angle of attack and sideslip, that the derivative is determined only by the results for the larger span wing arrangement provided the wings are not too far apart. Comparison with experimental results suggest that for rectangular wings measured values lie between 80 and 100 per cent of values predicted by the method for round-nosed sections and between 90 and 100 per cent for sharp-nosed sections. For other planforms the accuracies quoted for ESDU Aero A.S.06.03.01 apply.