Reduced-noise propulsion system of air-cushion vehicle

摘要

Noise due to the rotation of the air propeller or fan of an air-cushion vehicle is reduced by: 1) reducing the cross-sectional area of the interior of a duct encompassing the fan on the downstream side relative to the upstream side; 2) using wide-chord fan blades of chords increasing from blade root to tip; 3) using a duct and a nose cone on the hub of the fan both having a sound-absoring structure; and 4) mounting the engine and the duct on a common rigid support base and reducing to a minimum the tip clearance between the tips of the fan blades and the duct inner wall surface.