Notes on the lift and profile drag effects of split and slotted flaps

Abstract

The existing data have been analysed and a method has been derived for predicting the lift and profile-drag increments of split and slotted flaps. It is suggested that the probable order of error involved in the method is within the accuracy required for most practical purposes. It is found that the proNe-drag increments of split flaps on wing-body combinations is somewhat lower than on wings alone, whilst the converse is tlue for slotted flaps. It is suggested that this may be due to wing-body-flap interference effects. Nevertheless, the available data from which these results are derived are scanty and most are comparatively unreliable ; further systematic tests are needed before definite conclusions can be drawn.