Abstract:

ESDU 96003 provides an empirical method for predicting, in two separate parts, the non-linear lift curve up to, and including, maximum lift of aerofoils and wings with high-lift devices deployed at low speeds. The first part gives the lift curve through zero angle of attack and up to the lift coefficient at which the effects of flow breakdown start to become significant. The second part extends the lift curve up to maximum lift and includes the prediction of the angle of attack for maximum lift. The method applies to wings with aspect ratios greater than 4 and leading-edge sweeps up to about 40 degrees. Leading-edge devices considered were plain leading-edge flaps, Kruger flaps and slats of full-span and part-span extending to the wing tips. Trailing-edge flaps were split, plain, single-slotted or double-slotted. The method is expected to apply to triple-slotted flaps although no data were found to confirm that. It applies to aerofoils and so will apply well to high aspect ratio wings. For angles of attack up to that at which the effects of flow breakdown start to become significant, the lift coefficient is predicted with an rms error of 0.016. The angle of attack for maximum lift is predicted with an rms error of 0.5 degrees. Comparisons are shown of predicted and experimental results. A worked example illustrates the use of the method.