Wind-tunnel investigation of wing-in-ground effects

Wing-in-Ground effects from a wind-tunnel study of a NACA 4415-profile wing model with an aspect ratio of 2.33 are described. The wing model contains a 20%-chord, full-span, adjustable flap and removable end and enter plates. Ground boards are used in the wind tunnel to simulate the ground. In this study, the ground effects are expressed as variations to the aerodynamic coefficients (lift and drag) and lift-to-drag ratio. The ground effects are described in terms of angle of attack, flap angle, wing height above ground and use and size of end and center plates.