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General Principals.

Most light hovercraft used today are called "integrated" hovercraft, that means using only one fan to provide both lift and thrust. The fan is usually mounted vertically using the top two thirds for thrust and the bottom third for lift as shown above. The lift air is directed into the hull by the splitter plate, the air is then fed into the skirt and under the craft. The air under the hovercraft is known as the air cushion. This air cushion leaks away under the bottom of the skirt to provide a film of air which the hovercraft rides on. The steering of the craft is achieved by positioning a rudder in the thrust air stream to deflect the thrust air. Some hovercraft use two fans, one to supply the lift air and the other to exclusively supply thrust.

 

The Hull.

The hull is normally made from either glass-fibre or plywood or a combination of both. The hull must also provide buoyancy for the craft should it stop on water.

 

Engines used

Most racing craft use light weight 2 stroke engines as they have a high power to weight ratio. Cruising craft tend to use 4 stroke car engines as they are quieter and more economical than 2 strokes. The power output of these engines vary from 10bhp to 160bhp. Most of the 2 stroke engines currently used are made for snowmobiles and Micro-light aircraft. A popular alternative is a motor cycle engine, typically the Yamaha RD or TZR 250.

 

Transmission

The engine rpm is normally higher than the fan rpm, therefore a reduction is obtained by toothed belt and pulleys or a reduction gearbox. A full range of transmission components are listed in this catalogue and we will be pleased to advise on your requirements. 

 

Skirt

The purpose of the skirt is to retain the air cushion under the craft, this gives the craft greater hard structural clearance. This is termed the "hover height". There are two main types of skirt in use. The bag skirt and a segmented skirt. Both types are made from a flexible waterproof coated material, usually neoprene coated nylon.

Where to use your hovercraft

Racing Hovercraft

Each year the Hovercraft Club of Great Britain and it's branches organise a National race series, this normally consists of 7 or 8 weekends throughout the Spring, Summer and Autumn. The race meetings are held over 2 or 3 days depending on Bank Holidays. Currently there are five formulae in hovercraft racing. Formula 3 is for craft with an engine capacity up to 250cc. Formula 2 are for craft between 250 and 500cc. Formula 1 is for craft over 500cc. Formula Junior which is for 11 to 16 year olds uses the same specifications as F3. Formula 503 is a fixed specification formula for integrated craft driven by a Rotax 503 air cooled engine. All the engine sizes quoted are for 2 stroke machines. 4 stroke engines are permitted with a little short of double the total engine capacity.

To start racing you have to complete 15 novice races before competing in the National series. There are, normally, 4 races you can enter each day. Two each of National and Open races. Open races are where all formula (except Junior) compete together. Each weekends racing has its own trophies and prizes but the overall points for the weekend are carried forward to the National Championship.

Formula 1 hovercraft reach speeds of 80 mph plus and accelerate from 0 to 60 mph in under 5 seconds. F1 races are both exiting to watch as well as taking part in.

Race courses are a combination of land and water and are often located at picturesque stately homes and parks. Helpers are always welcome at meetings to assist in marshalling (after a little training on the day).

http://www.hovercraft.org.uk

http://www.hovercraft.demon.co.uk

 

Cruising Hovercraft

Some of the Hovercraft Club branches are mainly cruising orientated and they arrange cruising days and weekends throughout the year. The main cruising sites are river estuaries and coastal areas around Britain. Hovercrafts used for cruising are normally 2 or 4 seat designs fitted with 4 stroke engines to minimise noise and improve fuel economy

http://www.hovercraft.org.uk