Tests on the loss of vertical jet thrust due to ground effect on two simple VTOL planforms, with particular reference to the short SC1 aircraft

Abstract

The net vertical thrust available to an aircraft for vertical take-off and landing falls off with proximity to the ground. Measurements have been made of this thrust loss as a function of wing height above the ground, on plane circular and delta wings, and on a 1/6th scale model of the Short SC1 aircraft. At normal undercarriage height, the Short SC1 would lose nearly 20% of its vertical thrust, but a scheme has been developed to reduce the thrust loss to negligible proportions.