It was a long time dream of mankind, to move through the air like a bird without a care in the world. Orville and Wilbur Wright are accredited with the first sustained flight in a controlled vehicle that was heavier than air and the rest, as they say, is aviation history. Since those exciting times, incredible engines of flight have been developed, both for war and for peace, with the ability to travel at amazing speeds. Relatively recently in our history, we have such wealth and leisure time that some of us use flight as a hobby and an enjoyable way to spend recreation time.
Although aeroplanes are still quiet expensive, even for a small one, there is one outdoor activity that is interesting both marine and on-shore enthusiasts. Hovercrafts are not that new. After first being invented in the UK in the 40s, it seems that designs existed decades before. It's just that the technology and engines didn't exist in those times. Air cushioned vehicles (ACV), as they are sometimes called can't really be called an airplane, because it doesn't raise high enough from the ground, but it doesn't actually touch the ground either.
Full sized and small hovercrafts float on a cushion of air pressure which is generated by a propeller mounted vertically underneath an engine. Downward thrust is assured by a skirt which contains the air pressure until it slowly leaks away underneath the hovercraft. The same principle powers all crafts, even the personal hovercrafts used for leisure purposes. In smaller versions, one engine provides vertical and forward thrust by re-directing air flow downwards and backwards.
All sizes of these vehicles are steered by pivoting hinged flaps behind the rear air flow, and so pushing the rear of the craft either left or right. Hovercraft used for sport racing must be very light and are mostly made from glass fiber, with various other types of flexible material used for the skirt fixed around the hull. One problem with the skirt is that it can become damaged by trailing over sharp rocks or other obstructions. Although a hovercraft will float several inches above flat ground, it will not raise up over a relatively small obstacle in it's path.In recent years manufacturers have employed new materials, causing hovercraft prices to come down a lot, just because so many younger people are looking to buy a personal hovercraft for leisure and fun. Some vehicles now have very robust hulls, which don't split easily, using high density plastics instead of glass fiber. Skirt material is also much tougher - it can't be ripped easily when pulled, and the whole skirt arrangement is made up of smaller sections held lightly together, so that if a section is damaged it can simply be replace very cheaply.
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