Abstract:

ESDU 00029 predicts for aerofoils the centre of lift position based on thin-aerofoil theory with empirical correction. This is combined with thepredicted increment in aerofoil lift coefficient from ESDU 94027 to estimate the pitching moment coefficient increment. For wings with full-span leading-edge devices, factors dependent on planform geometry are applied to the pitchingmoment coefficient increment on an aerofoil section that is representative of the wing in order to allow for three-dimensional effects. For wings with part-span devices, additional factors are introduced that are dependent on the wing taperratio and on the spanwise extent of the devices, and the effect of wing aspect ratio and sweep is also accounted for in the procedure. The method covers plain leading-edge flaps, drooped leading edges, slats, sealed slats, and vented and unvented Krüger flaps. It applies in free air and at Mach numbers below 0.2. Sketches illustrate the accuracy of prediction and tables give the ranges of parameters covered in the construction of the method. For aerofoils, 80 per cent of the data for the increment in pitching moment coefficient are predicted to within 0.005. For wings, 95 per cent of the data for the increment in pitching moment coefficient are predicted to within 0.010. A worked example illustrates the use of the method.