Ground effect on a slender reverse delta wing with anhedral

Abstract

The ground effect on the lift and drag forces and vortices generated by a slender reverse delta wing with different anhedrals was investigated experimentally. The study was inspired by the Lippisch-type RFB X-114 WIG (wing-in-ground effect) craft for which a reverse delta wing planform with anhedral was employed. The results show that, by positioning the trailing edges of the anhedraled reverse delta wing parallel to the ground, the lift and drag coefficients were found to increase persistently with increasing anhedral as the ground was approached (for ground distances within 40% chord). The observed lift augmentation was also accompanied by an ever-increasing rotational speed and total circulation of the vortices generated by the anhedraled wing. The vortices were also found to be displaced more outboard as the ground was approached, which further suggests their little relevance to the lift generation of the anhedraled reverse delta wing.