Abstract:

ESDU 90010 provides a method that applies to a rigid aircraft at low angles of attack and relies on summing the separate contributions of the body, wing and tailplane with an allowance for the interference effect of the body on the wing. The body contribution to the pitching moment derivative is calculated from a semi-empirical equation in which the body lift-curve slope from slender body theory is modified for body fineness ratio and cross-section shape and for afterbody geometry. The body contribution to the lift derivative is negligible. For the wing contribution to both derivatives, strip theory is also modified empirically for straight-tapered wings while for delta and cropped-delta wings it is found that data derived from Multhopp's lifting-line theory can be applied directly. Other wing planforms are converted to straight-tapered through the equivalent wing concept of ESDU 76003. The tailplane contribution is found most-closely to match the available data if it is treated as an isolated surface (with lift-curve slope derived from ESDU 70011). The body interference on the wing is accounted for by the use of the gross planform and a shift in aerodynamic centre position for the body carry-over lift. The accuracy of the predictions is discussed, and sketches of experimental results plotted against predictions are given for the moment derivative, for body and wing alone and for wing-body combinations. Two worked examples, one for a typical transport configuration and one for a typical interceptor aircraft, illustrate the use of the methods. A computer program of the method is provided as ESDUpac A9010..