Some Design Principles of Ground Effect Machines Section B - Air Cushion Mechanics

摘要

The energy and momentum relationships governing air cushion performance are reviewed. The exponential-theory equations are recommended for calculation of cushion pressure and jet reaction, and a modified equation is proposed for calculation of the volume flow rate. The question of off-design cushion performance is discussed. It is pointed out that off-design performance is of paramount practical importance and that the widely held notion that peripheral jet cushions are more efficient than simple plenum cushions is not necessarily valid in this context. The danger of drawing erroneous conclusions from the cushion performance equations, which (except for the plenum) do not apply to off-design operation, is emphasized. (Author)