IHS ESDU Normal force and pitching moment of conical boat-tails. 87033

ESDU 87033 provides an empirical method for predicting the change in normal force and pitching moment due to applying moderate boat-tailing to an axisymmetric forebody-cylinder combination. The method applies for Mach numbers from 0.2 to 5 and angles of attack up to 90 degrees and is derived from a correlation of wind-tunnel results drawn from the literature for bodies of fineness ratio from 3 to 13 with boat-tail angles between 2.5 and 10 degrees. The method predicts the change in normal-force coefficient (based on maximum cross-sectional area) to within 0.05 for values below 0.5 and within 10 per cent for greater values, and predicts the change in pitching-moment coefficient (based on maximum cross-sectional area and body overall length) to within 0.02. The use of the method is illustrated by a worked example. The calculation procedure is programmed in ESDUpac A9034, see ESDU 93034.