The Air Cushion Principle – From The Biggest Hovercraft For Sale To The Smallest
For many decades, the hovercraft principle was mooted as a useful possibility for passenger transport, but there were a few anomolies that just wouldn’t go away. the basic idea of lifting a vehicle n a cushion of air was good, but keeping the air cushion in place, that was the challenge. In the 50s a man called Anthony Thornycroft solved the puzzle by designing a special skirt arrangement that dramatically reduced the energy need to float a given vehicle weight. He found that by fixing a small coffee tin inside larger one with holes in the bottom, and pushing air between them, an annular effect was created which reduced the power requirement by 60% – not bad at all!
Basically, the solution meant that viable hovercraft could be built because the energy need to float even a big craft was something like 30% of the energy need to lift a helicopter of the same size, for example. Sanderson-Coe, a British company were the first to produce large hovercraft for carrying cars and passengers across the British Channel, and was followed by several others. This new technology was the buzz word in the 60s and 70s, but all the companies went bust within just a few years. The industry laid dormant for a while, because the craft were expensive to maintain and didn’t bring the comfort of other forms of travel such as the ferry. Off course, now we have the Channel Tunnel.
Probably the tiniest of the small hovercraft for sale is produced by Hovery in Brazil. This DIY package is self-inflated and is designed for some serious fun, but has few other uses. Other 4 and 6 seat hovercraft manufacturers however produce vehicles that can be used for search and rescue, or military use – see design site. New construction materials have revolutionized the industry and continues to evolve. For example, modern hull construction uses advanced materials like expanded high density polypropylene, which doesn’t split if it hits a rock.
Hovercraft skirts have also undergone a complete makeover as new idea have evolved about how they should be constructed, and with what materials. Rip-stop nylon principles still apply, but newer fabrics are covered in tough rubber-like sheaths such as neoprene. Some manufacturers use Kevlar, which is used by the military and is extremely tough – in fact it’s bullet proof, so well able to withstand the rigors of hovercraft travel!