It seems to be a pattern in the early decades of technological advances that the military would quickly become interested in the ways in which new ideas could be used by the army, navy or air force. This has happened to some extent in the hovercraft industry, but not so much as expected. Large passenger craft have been used, and are still being developed, but the big growth of air cushioned vehicle use is in the leisure industry. The first use of small hovercraft was as a golf caddie, which was probably intended to allow a vehicle to over over pristine greens without damaging the grass. Other activities include racing, search and rescue and also family fun!
Racing hovercraft represent fun in the extreme, and many racers wouldn't be involved in the sport without some element of danger, which the sport delivers aplenty. Imagine speeding along at up to 80kms an hour and the only thing between you and the ground is a cushion of air. There are no tires to grip the road when you brake, and no propeller or rudder in the water to rapidly slow you down like a boat. Change of direction is by handlebar steering, much like you would find on motor bike or quad bike, but this only has a limited effect. To get full impact, it's necessary to throw the body to one side to turn corners!
Search and rescue is a very interesting development for the industry, because they can go where other vehicles can't, quite obviously. A boat is limited to the water, and wheeled vehicles can easily get bogged down in slush, mud or wet sand. For reaching accident victims in areas with wet marsh land, for example, the hovercraft can't be beat. It can carry up to six people easily and can settle down on any surface, making it an ideal vehicle for reaching disaster areas fast. Whole fleet of air cushioned craft are ow in use in isolated places in Canada and also Australia.
Leisure and fun is probably the biggest growth area for the industry as a whole, particularly as people are looking for new thrills and experiences. A four seat hovercraft is not that expensive, something like 10 000 dollars, so well within the reach of many families and ideal of you have kids. The biggest question raised by someone buying such a vehilcle is - are hovercraft safe? Safety is at a premium for this kind of buyer, and once again the industry has responded with a very safe product.
Small personal hovercraft are fast becoming the expensive preferred toy of the younger set with enough money to enjoy themselves. A world class hover craft manufacturer will charge between 10000 and 15000 USD for such an air cushioned vehicle, depending on the options chosen. Such options may include a choice of engines, color (obviously) and additional features such as extra storage space, harnesses or short wave radio. Engine choice is an important point to consider before you buy a hovercraft.
Two stroke engines are common. These tend to be noisier and run at higher revolutions than their four stroke cousins and the fuel used is different. A two stroke hovercraft engine uses a lower octane mixture of gas (petrol) mixed with 2% oil. Basically, this means that the engine parts are lubricated by the oil mixed in with the fuel. A disadvantage of this is that the fuel needs to be mixed yourself, or either bought ready to use, which is expensive. The big advantage is that a two stroke engine is generally cheaper pound for pound, but is also noisier, particularly when used for lift and forward thrust applied to an ACV.
A four stroke motor has an oil reservoir, or sump, which is kept to a certain level and a pump moves it around the engine to ensure that all moving parts don't wear too much. Actually, the moving parts of an engine should never touch - a film of oil always separates their surfaces. A four stroke engine may be air or water cooled, depending on the size of the craft and it's intended use. Such uses can include leisure, rescue and survey operations both on dry land and over water.
The best hovercraft manufacturers design an engine compartment as part of the hull construction. This keeps the engine a little quieter and it's also safer in the event that it malfunctions, for example. A robust lid gives good access for maintenance and this can be locked securely until access is required. With clever hovercraft design, such a compartment could be sunk a little into the hull material without compromising it's impact strength, thereby optimizing space for passengers and equipment.
Smaller vehicles tend to use just one motor and ducting is used to redirect air flow downwards for upwards thrust, and to the rear for forward propulsion. It's obvious that a two motor machine will have more power for lift and thrust, and this may be necessary for machines designed for a heavy payload, or regularly lifting off water. However, such an arrangement will inevitably mean more noise and ear protection is recommended for all the family.