Piloting a Hovercraft
Piloting a Hovercraft
Driving a hovercraft requires many different skills and techniques. Since it has nothing in contact with the surface it has a greater turning radius and a greater stopping distance. Directional control is maintained with a rudder. There is a slight time delay between the moving of a control and the reaction of the vehicle. All motion is provided by thrust. The hovercraft can be stopped by applying reverse thrust, reducing power, making a 180 degree turn and applying thrust, or any combination of these.
First time drivers should practice in a empty lake or field. A hovercraft will travel faster over land, ice, or snow than over water. On water the air pressure that supports the craft presses the surface of the water down. As the craft is pushed forward a wave is created in front. A hovercraft must have sufficient propulsion to push itself over the wave at which point it planes off. After exceeding planing speed the hovercraft will require very little power to keep going.
At speeds greater than 4 times the planing speed (30 to 40 mph) other drag types take effect. Many kinds of drag exist on a hovercraft. Aerodynamic drag depends on the size, shape, and frontal area of the craft. Momentum drag due to lift systems (usually located in the front of the craft) depends on the amount of air you are supplying to lift the craft. In addition to these forms of drag over water you have wave impact drag, water spray drag, and drag by the skirt occasionally contacting the water.
As a result, you see why it would be easier for a hovercraft to go faster with a tail wind rather than a head wind, or smooth water as opposed to rough water.
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