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What's The Price Of A Small Hovercraft?

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During the nineteen sixties USA aero-dynamicists produced an experimental craft taking advantage of a wing in connection with ground effect. A number of other propositions along these lines were postulated, and one other variant incorporated the wing qualities of a surface effect machine with an air-cushion supercharge system that allowed the craft to fabricate its own hovering capability while stationary and then develop forward speed, steadily shifting the lift element to its wing. Although not one of these vehicles got past the mock-up stage, they were significant portents of the future due to the fact that they indicated a way of utilizing the hovering benefit of hovercraft and effectiively getting past its accepted speed limitation of around 200 mph, beyond which it was very challenging to hold the air cushion in place. These kinds of vehicles are generally known as ram-wing form.



The armed forces did take another look at using large hovercraft at around the same time period, and did use some mid-sized models for moving equipment, but it never really took off (pardon the pun.) Unlike the Soviet navy, who built the largest hovercraft on the planet, which was capable of carrying tanks, armored motor vehicles and 400 sailors. The monster must take some handling and braking, because it weighs 100s of tons. It is well armored against rounds and missiles, and basically of course all military machinery is manufactured to be incredibly strong and durable.



Looking at their biggest models, these huge craft, weighing two hundred sixty five tons and powered by four Rolls-Royce state of the art engines, could in reality transport more than fifty motor vehicles and in excess of four hundred passengers at 65 nautical miles ph. At this level of velocity the uk channel trip was decreased to a measly thirty minutes. In the heyday of the late 1960s and early seventies, the assorted Hovercraft ferry services (with names such as Hoverspeed and Hoverlloyd), were carrying as high as 30% of all of the uk channel travellers. Such was the charm of this particularly English technological miracle that one of the Mountbatten vehicles appeared in films. None of these craft matched the giant Soviet Zubr class hovercraft built in the late 90s.






Some hovercraft manufacturers were content to wait until the outcome of the latest research before making a move. Back in the early 1950's specialists in the British Isles, America, and Europe were searching for answers to Thornycrofts old dilemma. Cockerell is now recognized as the daddy of the Hovercraft, as the Air cushioned vehicle is generally known. During Ww2 he was closely linked with the design of radar and other radio broadcast aids and had settled into civilian life as a boat builder. Presently, he started to become engrossed with Thornycrofts challenge of decreasing the hydrodynamic draw on the bulkhead of a vessel with one type or another of air lubrication. Cockerell didn't bother with Thornycrofts plenum compartment (in essence, an empty box with an open underside) principle, where air is pumped directly into a cavity underneath the craft, because of the challenges in controlling the cushion.






He had the theory that, if air were alternatively directed under the hull via a narrow slot running fully around the circumference, the air could circulate towards the centre of the hull, forming an external phenomenon that could successfully confine the air cushion. This solution is known as a peripheral jet. Once air has built up belowthe craft to a pressure equaling the vehicle weight, incoming air has nowhere to go but outward and experiences a distinct change of speed on hitting the sea. The momentum of the peripheral jet air keeps the cushion pressure and the ground clearance higher than it might be if air were pumped straight into a hollow chamber.




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