Correction of the Lifting Line Theory for the Effect of the Chord

Method introduced by Prandtl shows that a simple correction for the chord of a finite wing span can be deduced from three-dimensional potential flow around an elliptic plate. When flow is compared with a flow around a section of an endless plate it is found that the edge velocity is reduced by the ratio of the semiperimeter to the span. In the application of the lifting-line theory the relative normal velocity of wing section is corrected for the downflow induced by the wake. This correction brings the theoretical lift into close agreement with experiments.