Sunday, 30 January 2011
Use the hose to fill the compressed-air tank. Release the hose by pressing the button and push yourself off to slide.
The carpet remains in the air for about 30 seconds, as it ‘flies’. In the end, the air in the tank runs out, the air stream weakens, the pressure under the carpet decreases and the carpet lowers to the ground.
The air leaks through the small holes in the bottom of the tank, thereby forcing the carpet upwards. The 'skirt' around the carpet prevents the leaking air from immediately escaping from under the carpet. The resulting extra pressure keeps the carpet hovering above the ground. The carpet settles at the height in which the combined lifting force of the air stream and the pressure of the air underneath the carpet are equal to the weight of the carpet with its passengers. When the carpet is off the floor, it moves nearly without friction, so it only requires the force to overcome inertia to start it off – or to stop it.
The same principle is applied to a hovercraft, which is an extremely handy means of transportation in the Finnish archipelago during the period when the sea is thawing out in spring. Hovercrafts can be used to move about on land, water and ice. The first hovercraft was designed in Sweden at the beginning of the 18th century. It was, however, never built. It is not likely that it would have worked, since it was designed to use high pressure air created by human power. As far as is known, the first functional hovercraft was built by the Finnish Engineer Toivo Kaario in 1935.