Hovercraft

A hovercraft, or air-cushion vehicle (ACV), is a vehicle or craft that can be hold up by a cushion of air dispossessed downwards against a surface close below it, and can in principle travel over any relatively smooth surface, such as gently sloping land, water, or marshland, while having no substantial contact with it.
Hovercraft has one or more parts of engines (some craft, such as the SR-N6, have one engine with a drive split through a gearbox). One engine drives the fan (the impeller) which is in charge for exciting the vehicle by forcing air under the craft. The air therefore must exit throughout the "skirt", lifting the craft above the area which the craft resides. One or more additional engines are used to offer thrust in order to propel the craft in the favorite direction. Some hovercraft utilized ducting to allow one engine to perform both tasks by directing some of the air to the skirt, the rest of the air passing out of the back to push the craft forward.