Study of a Skirtless Hovercraft Design

摘要

Initial study into three possible skirtless hovercraft designs. The designs utilize Coanda nozzles and a Coanda wing surface to generate lift and create a pressure cushion below the craft. The pressure cushion is to be maintained by an air curtain created by flow spill from the Coanda wing surface. Three proposed skirtless hovercraft designs were analyzed via computational fluid dynamics to ascertain their lift generation capabilities. The three designs were adaptations from William Walter's hybricraft primer and his patent for a fan driven lift generation device. Each design featured Coanda nozzles, or nozzles that utilize the Coanda effect, to redirect air flow to aid in the generation of an air curtain around a central air flow. The designs also utilized a Coanda wing as a lifting body to aid in lift generation. Each design was set at a height above ground of one foot and a radius of two feet. The craft was assumed to be axisymmetric around a central axis for a perfectly circular craft, much like a flying saucer. The craft can be divided into several parts, the core, the nozzles, the plenum chamber (for designs 2 and 3), and the wing. Flow is generated from rotor blades situated one foot above the top of the core of the craft. The nozzles are located at the edges of the craft below the wing. In designs two and three the plenum chamber is the region between the core and the wing. For each design three cases were performed where t was increased for each case. This resulted in a total of nine cases, three cases for three designs. For each case the ratio of nozzle thickness to the radius of the curved plate, t/R, was set to 0.344 and t was increased while R was calculated to maintain the ratio.