The first big hovercraft was devised and constructed to carry passengers across the English channel, a fitting start for the country who invented the air cushioned concept vehicle. Of course, it wasn't too long before the military became interested in the possibilities, which is ironic as they were presented with a working model when it was first invented. The Navy didn't want it because it wasn't a ship. The Army had plenty of vehicles, some of them amphibious, and the Air Force were not interested in a craft that could only lift itself a few feet off the ground.
A long time after it's inception, the hovercraft started to become attractive to the leisure industry, particularly in recent years when new materials have allowed economic construction of small personal hovercraft. The new materials are stronger, cheaper and much more durable, making the production of smaller craft for racing and fun an obvious next turn for the industry. Racing hovercraft are very popular and have a superior power to weight ratio. They accelerate fast and can travel at up to 80 km an hour. Operation is very different from bikes, cars or even boats, so it's a very specialist activity to get involved in.
Hovercraft Materials and Construction
Hull construction has had a major re-think by designers. For one thing, the old way of using glass fiber just couldn't continue. The craft were certainly light but they were very rigid and fragile. If such an air cushioned craft happened to hit an obstacle with any kind of force, it would certainly split the hull. Depending on the size of the split, it would either have to be replaced or repaired by an expert, which can be very expensive according to the extent of the damage. New material scan really take a knock or two. Of course, they may get scuffed or dented, but they don't split, being fabricated from high density expanded plastics.
Hovercraft skirts are another important feature of these vehicles that have had a major overhaul in concept. Originally made from rip stop sail cloth, modern skirts are now constructed from Kevlar and neoprene coated cross lap material. The new materials are extremely difficult to tear by normal means but of courses it can happen. The new way of fabricating skirts is to mount them in sections, so that if one part is damaged, that small section can be changed without removing the whole skirt.
Hovercraft construction could be separated into the categories of hull, skirt, engines and fans, controls and fitments. Each should be approached first as a separate entity and then as a part of the integrated whole that needs to complement each other. The selection of the materials is the first stage of the process, and this selection is generally made from an array of products employed in the marine industry, simply because they are designed to resist tough conditions. The interest in small personal hovercraft for leisure purposes has also led to the search for new materials which are cost effective and tough enough to provide a good level of safety for pilot and passengers.
The hull is the major part of an air cushioned vehicle and various types of material have been used here. For smaller craft, lightness is essential, but so is stability and strength. When you see a hovercraft advertised for sale, it should be the first thing that you think of and check. Many smaller types use fiber glass, which is very light but it also has one unfortunate characteristic. It is not to flexible and tends to split and crack if it hits an obstruction with sufficient force. Imagine hovering over rapidly moving water and a rock is sticking up and you will appreciate the hazard. GRP is very difficult and expensive to repair, so is not good choice for leisure use. All these things need to be considered before learning how to fly a hovercraft.
Some manufacturers have started to use expanded high impact plastic hulls. This material is light but more importantly it doesn't split under impact, so is safer for family use. Great strides have been made in the production process so that it has become cost effective enough to be used. Controls are fabricated from marine grade stainless steel, to resist salt water, and all electrical equipment is high grade and double insulated. Plastic is used extensively for fitments and storage space, but in some models hard woods may be employed if a more aesthetic appeal is required.
Another major design feature is the choice and construction of skirt material. Traditionally, a single piece of rip-stop sail cloth was used. Even though this is very tough material, the major disadvantage is that the whole skirt has to be changed if it becomes damaged. One company has produced a skirt made from Kevlar material, possibly the toughest fabric known to man. It resists tearing extremely well, but enough rough treatment will damage anything. For this reason, the skirt is fabricated in sections loosely tie-wrapped together. If one section gets damaged, it is removed and replace very quickly.