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78-473: The N500 Naviplane was a French hovercraft built by Société d'Etude et de Développement des Aéroglisseurs Marins (SEDAM) in Pauillac , Gironde for the cross English Channel route. Intended to have a large passenger and crew capacity, as prototypes they were for a short while the largest hovercraft. Only two were built. The first was destroyed by a fire before entering service, the second proved unreliable and

156-476: A Royal Navy officer, C.H. Latimer-Needham , who sold his idea to Westland (by then the parent of Saunders-Roe's helicopter and hovercraft interests), and who worked with Cockerell to develop the idea further. The first passenger-carrying hovercraft to enter service was the Vickers VA-3 , which, in the summer of 1962, carried passengers regularly along the north Wales coast from Moreton, Merseyside, to Rhyl . It

234-461: A 7 cm and 10 cm wavelength), one slave radar for the pilot, two VHF radio. Hovercraft A hovercraft ( pl. : hovercraft ), also known as an air-cushion vehicle or ACV , is an amphibious craft capable of travelling over land, water, mud, ice, and various other surfaces. Hovercraft use blowers to produce a large volume of air below the hull , or air cushion, that is slightly above atmospheric pressure . The pressure difference between

312-556: A British invention in the 1950s. They are now used throughout the world as specialised transports in disaster relief, coastguard, military and survey applications, as well as for sport or passenger service. Very large versions have been used to transport hundreds of people and vehicles across the English Channel , whilst others have military applications used to transport tanks, soldiers and large equipment in hostile environments and terrain. Decline in public demand meant that as of 2023 ,

390-480: A capacity of 418 passengers and 60 cars. These were later joined by the French-built SEDAM N500 Naviplane with a capacity of 385 passengers and 45 cars; only one entered service and was used intermittently for a few years on the cross-channel service until returned to SNCF in 1983. The service ceased on 1 October 2000 after 32 years, due to competition with traditional ferries, catamarans ,

468-460: A design that relied only on the momentum of the air to provide lift, like a helicopter . In terms of power, a hovercraft would only need between one quarter to one half of the power required by a helicopter. Cockerell built and tested several models of his hovercraft design in Somerleyton, Suffolk, during the early 1950s. The design featured an engine mounted to blow from the front of the craft into

546-752: A fast torpedo boat , the Versuchsgleitboot had a top speed of over 32 knots (59 km/h). It was thoroughly tested and even armed with torpedoes and machine guns for operation in the Adriatic . It never saw actual combat, however, and as the war progressed it was eventually scrapped due to a lack of interest and perceived need, and its engines returned to the air force. The theoretical grounds for motion over an air layer were constructed by Konstantin Eduardovich Tsiolkovskii in 1926 and 1927. In 1929, Andrew Kucher of Ford began experimenting with

624-512: A new form of high-speed land transportation, probably in the field of rail surface travel, for fast trips of distances of up to about 1,600 kilometres (1,000 mi)". In 1959, Ford displayed a hovercraft concept car , the Ford Levacar Mach I . In August 1961, Popular Science reported on the Aeromobile 35B, an air-cushion vehicle (ACV) that was invented by William R. Bertelsen and

702-507: A new generation of hovercraft increasingly attractive. The BHC successfully developed its own original hovercraft designs during its existence. The BH.7 Wellington class is a military-oriented model, while the British Hovercraft Corporation AP1-88 is a medium-size diesel-powered hovercraft. The AP1-88 was notably cheaper to operate and to purchase, being half the price of the older SR.N6 in both respects. The type

780-468: A number of niche roles where its combination of features were advantageous. Today, they are found primarily in military use for amphibious operations, search-and-rescue vehicles in shallow water, and sporting vehicles. Hovercraft can be powered by one or more engines. Smaller craft, such as the SR.N6 , usually have one engine with the drive split through a gearbox. On vehicles with several engines, one usually drives

858-593: A number of smaller cylindrical skirts instead of one large one in order to avoid the problems noted above. During the early 1960s he developed a series of prototype designs, which he called "terraplanes" if they were aimed for land use, and "naviplanes" for water. The best known of these designs was the N500 Naviplane , built for Seaspeed by the Société d'Etude et de Développement des Aéroglisseurs Marins (SEDAM). The N500 could carry 400 passengers, 55 cars and five buses. It set

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936-418: A pioneering new form of transportation, embodied in the form of the experimental SR.N1 vehicle, which became widely known as the hovercraft . British manufacturer Saunders-Roe proceeded with work on various hovercraft designs, successfully developing multiple commercially viable vehicles. These included the SR.N4 , a large cross- Channel ferry capable of seating up to 418 passengers along with 60 cars, and

1014-636: A plane; and the Army were 'plain not interested'." This lack of military interest meant that there was no reason to keep the concept secret, and it was declassified. Cockerell was finally able to convince the National Research Development Corporation to fund development of a full-scale model. In 1958, the NRDC placed a contract with Saunders-Roe for the development of what would become the SR.N1 , short for "Saunders-Roe, Nautical 1". The SR.N1

1092-560: A prospective 2,000 ton freighter-orientated vehicle, in addition to its ongoing interest in the development of smaller-scale hovercraft. Work on giant ocean-going hovercraft continued under the BHC, but ultimately did not lead to any vehicle larger than the SR.N4 being produced. During 1968, the British government decided to withdraw its backing for the company's feasibility study on large hovercraft, resulting in

1170-488: A section of a large aerofoil (this creates a low-pressure area above the wing much like an aircraft), the craft was propelled by four aero engines driving two submerged marine propellers, with a fifth engine that blew air under the front of the craft to increase the air pressure under it. Only when in motion could the craft trap air under the front, increasing lift. The vessel also required a depth of water to operate and could not transition to land or other surfaces. Designed as

1248-589: A service to Calais from Dover, which was soon superseded by that of Seaspeed . As well as Saunders-Roe and Vickers (which combined in 1966 to form the British Hovercraft Corporation (BHC)), other commercial craft were developed during the 1960s in the UK by Cushioncraft (part of the Britten-Norman Group) and Hovermarine based at Woolston (the latter being sidewall hovercraft , where the sides of

1326-455: A space below it, combining both lift and propulsion. He demonstrated the model flying over many Whitehall carpets in front of various government experts and ministers, and the design was subsequently put on the secret list. In spite of tireless efforts to arrange funding, no branch of the military was interested, as he later joked, "The Navy said it was a plane not a boat; the RAF said it was a boat not

1404-470: A speed record between Boulogne and Dover of 74 kn (137 km/h). It was rejected by its operators, who claimed that it was unreliable. Another discovery was that the total amount of air needed to lift the craft was a function of the roughness of the surface over which it travelled. On flat surfaces, like pavement, the required air pressure was so low that hovercraft were able to compete in energy terms with conventional systems like steel wheels. However,

1482-409: A suggestion made by his business partner Arthur Ord-Hume. In 1958, he suggested the use of two rings of rubber to produce a double-walled extension of the vents in the lower fuselage. When air was blown into the space between the sheets it exited the bottom of the skirt in the same way it formerly exited the bottom of the fuselage, re-creating the same momentum curtain, but this time at some distance from

1560-680: A walled air cushion vehicle, the Glidemobile . Because the project was classified by the U.S. government, Fletcher could not file a patent. In April 1958, Ford engineers demonstrated the Glide-air, a one-metre (three-foot) model of a wheel-less vehicle that speeds on a thin film of air only 76.2 μm ( 3 ⁄ 1000 of an inch) above its tabletop roadbed. An article in Modern Mechanix quoted Andrew A. Kucher, Ford's vice president in charge of Engineering and Research noting "We look upon Glide-air as

1638-556: Is used as a high-speed ferry for up to 47 passengers and 47,500 pounds (21,500 kg) of freight serving the remote Alaskan villages of King Cove and Cold Bay . An experimental service was operated in Scotland across the Firth of Forth (between Kirkcaldy and Portobello, Edinburgh ), from 16 to 28 July 2007. Marketed as Forthfast , the service used a craft chartered from Hovertravel and achieved an 85% passenger load factor . As of 2009 ,

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1716-646: The 2007 UK floods . Since 2006, hovercraft have been used in aid in Madagascar by HoverAid, an international NGO who use the hovercraft to reach the most remote places on the island. The Scandinavian airline SAS used to charter an AP1-88 hovercraft for regular passengers between Copenhagen Airport , Denmark, and the SAS Hovercraft Terminal in Malmö , Sweden. In 1998, the US Postal Service began using

1794-460: The Aérotrain . These designs competed with maglev systems in the high-speed arena, where their primary advantage was the very "low tech" tracks they needed. On the downside, the air blowing dirt and trash out from under the trains presented a unique problem in stations, and interest in them waned in the 1970s. By the early 1970s, the basic concept had been well developed, and the hovercraft had found

1872-456: The Levapad concept, metal disks with pressurized air blown through a hole in the centre. Levapads do not offer stability on their own. Several must be used together to support a load above them. Lacking a skirt, the pads had to remain very close to the running surface. He initially imagined these being used in place of casters and wheels in factories and warehouses, where the concrete floors offered

1950-656: The National Physical Laboratory 's Hythe division. In addition to financing, the British Government was also keen to implement a regulatory framework for the hovercraft sector, including the implementation of safety certification, leading to the Hovercraft Act of 1968. However, not all commitments made by the British government would be ultimately be fulfilled. As early as 1964, Saunders-Roe had been engaged in studies of very large hovercraft, including

2028-507: The SR.N5 , the first commercially active hovercraft. British Hovercraft Corporation (BHC) emerged as a corporate entity in March 1966, at which point the Saunders-Roe division of Westland Aircraft and Vickers Supermarine (the two largest hovercraft manufacturers in the world) were merged. Following the merger, Westland Aircraft held 65% of the shares in BHC, while Vickers had a 25% stake in

2106-403: The hydrofoil and the pump-jet . As early as 1969, rival hovercraft manufacturers had encountered commercial difficulties and been liquidated . Throughout the 1970s, the BHC made several advances in its skirt technology, such as requiring less power to keep inflated; the company also produced extensions of its existing hovercraft range, which had the benefit of increasing payload capacity. It

2184-456: The BHC developed their own newer hovercraft designs, such as the military-oriented BH.7 Wellington class and the medium-size diesel-powered British Hovercraft Corporation AP1-88 . These vehicles made advances in the efficiency and viability of hovercraft; the AP1-88 was produced in quantity not only by BHC but also under licence in both Australia and China . In 1970, Westland Aircraft acquired

2262-466: The BHC's development programme being curtailed. As a result of high oil prices following the 1973 oil crisis and the 1979 energy crisis , the profitability of the first generation of commercial hovercraft was badly hit, undermining operators' profitability and provoking requests from customers for more fuel efficient vehicles. Furthermore, hovercraft were not the only high-speed water vehicles making advances at this time; competing technologies included

2340-534: The Boulogne Hoverport. The N500 was one of the world's largest hovercraft; it could transport 385 passengers plus 45 cars. It was also one of the fastest and reached a speed record for a travel from Boulogne to Dover at an average speed of 74 knots (137 km/h). The mass of the N500 was 260 tons, it was 50 m long and 23 m wide. 1 pilot. 1 co-pilot. Seated side by side in the cockpit. 1 radar-navigator seated at

2418-523: The British built Hoverwork AP1-88 to haul mail, freight, and passengers from Bethel, Alaska , to and from eight small villages along the Kuskokwim River . Bethel is far removed from the Alaska road system, thus making the hovercraft an attractive alternative to the air based delivery methods used prior to introduction of the hovercraft service. Hovercraft service is suspended for several weeks each year while

N500 Naviplane - Misplaced Pages Continue

2496-543: The English Channel. Hoverlloyd operated from Ramsgate , where a special hoverport had been built at Pegwell Bay, to Calais. Seaspeed operated from Dover, England, to Calais and Boulogne in France. The first SR.N4 had a capacity of 254 passengers and 30 cars, and a top speed of 83 kn (154 km/h). The channel crossing took around 30 minutes and was run like an airline with flight numbers. The later SR.N4 Mk.III had

2574-589: The SR.N1 Mk II. A further upgrade with the Armstrong Siddeley Viper produced the Mk III. Further modifications, especially the addition of pointed nose and stern areas, produced the Mk IV. Although the SR.N1 was successful as a testbed, the design hovered too close to the surface to be practical; at 9 inches (23 cm) even small waves would hit the bow. The solution was offered by Cecil Latimer-Needham , following

2652-548: The US/Canadian Great Lakes operate hovercraft for water and ice rescues, often of ice fisherman stranded when ice breaks off from shore. The Canadian Coast Guard uses hovercraft to break light ice. In October 2008, The Red Cross commenced a flood-rescue service hovercraft based in Inverness , Scotland. Gloucestershire Fire and Rescue Service received two flood-rescue hovercraft donated by Severn Trent Water following

2730-485: The Vickers hovercraft designs reached quantity production, manufacturing efforts being centered upon Saunders-Roe's existing portfolio. Perhaps the most high-profile vehicle produced by BHC was the large SR.N4 Mountbatten class hovercraft; it was the largest civil-orientated hovercraft to ever be put into service; several were completed and used in revenue services across the English Channel for multiple decades. Later on,

2808-543: The aegis of P & A Campbell, the paddle steamer operators. Operations by Hovertravel commenced on 24 July 1965, using the SR.N6, which carried 38 passengers. Two 98 seat AP1-88 hovercraft were introduced on this route in 1983, and in 2007, these were joined by the first 130-seat BHT130 craft. The AP1-88 and the BHT130 were notable as they were largely built by Hoverwork using shipbuilding techniques and materials (i.e. welded aluminium structure and diesel engines) rather than

2886-506: The aircraft techniques used to build the earlier craft built by Saunders-Roe-British Hovercraft Corporation. Over 20 million passengers had used the service as of 2004 – the service is still operating (as of 2020 ) and is by far the longest, continuously-operated hovercraft service. In 1966, two cross-channel passenger hovercraft services were inaugurated using SR.N6 hovercraft. Hoverlloyd ran services from Ramsgate Harbour, England, to Calais , France, and Townsend Ferries also started

2964-477: The back to push the craft forward. The British aircraft and marine engineering company Saunders-Roe built the first practical human-carrying hovercraft for the National Research Development Corporation , the SR.N1, which carried out several test programmes in 1959 to 1961 (the first public demonstration was in 1959), including a cross-channel test run in July 1959, piloted by Peter "Sheepy" Lamb, an ex-naval test pilot and

3042-472: The bottom of the craft. Latimer-Needham and Cockerell devised a 4-foot (1.2 m) high skirt design, which was fitted to the SR.N1 to produce the Mk V, displaying hugely improved performance, with the ability to climb over obstacles almost as high as the skirt. In October 1961, Latimer-Needham sold his skirt patents to Westland , who had recently taken over Saunders Roe's interest in the hovercraft. Experiments with

3120-463: The chief test pilot at Saunders Roe. Christopher Cockerell was on board, and the flight took place on the 50th anniversary of Louis Blériot 's first aerial crossing. The SR.N1 was driven by expelled air, powered by a single piston engine. Demonstrated at the Farnborough Airshow in 1960, it was shown that this simple craft can carry a load of up to 12 marines with their equipment as well as

3198-647: The disappearance of duty-free shopping within the EU, the advancing age of the SR.N4 hovercraft, and the opening of the Channel Tunnel . The commercial success of hovercraft suffered from rapid rises in fuel prices during the late 1960s and 1970s, following conflict in the Middle East. Alternative over-water vehicles, such as wave-piercing catamarans (marketed as the SeaCat in the UK until 2005), use less fuel and can perform most of

N500 Naviplane - Misplaced Pages Continue

3276-470: The extra thrust could be directed fore or aft, differentially for rotation. The SR.N1 made its first hover on 11 June 1959, and made its famed successful crossing of the English Channel on 25 July 1959. In December 1959, the Duke of Edinburgh visited Saunders-Roe at East Cowes and persuaded the chief test-pilot, Commander Peter Lamb, to allow him to take over the SR.N1's controls. He flew the SR.N1 so fast that he

3354-413: The fan (or impeller ), which is responsible for lifting the vehicle by forcing high pressure air under the craft. The air inflates the "skirt" under the vehicle, causing it to rise above the surface. Additional engines provide thrust in order to propel the craft. Some hovercraft use ducting to allow one engine to perform both tasks by directing some of the air to the skirt, the rest of the air passing out of

3432-581: The first Local Authority fire service in the UK to operate a hovercraft. It is used to rescue people from thick mud in the Weston-super-Mare area and during times of inland flooding. A Griffon rescue hovercraft has been in use for a number of years with the Airport Fire Service at Dundee Airport in Scotland. It is used in the event of an aircraft ditching in the Tay estuary. Numerous fire departments around

3510-468: The first to demonstrate a practical vehicle in continued use. A memorial to Cockerell's first design stands in the village of Somerleyton . Cockerell came across the key concept in his design when studying the ring of airflow when high-pressure air was blown into the annular area between two concentric tin cans (one coffee and the other from cat food) and a hairdryer. This produced a ring of airflow, as expected, but he noticed an unexpected benefit as well;

3588-405: The higher-pressure air below the hull and lower pressure ambient air above it produces lift, which causes the hull to float above the running surface. For stability reasons, the air is typically blown through slots or holes around the outside of a disk- or oval-shaped platform, giving most hovercraft a characteristic rounded-rectangle shape. The first practical design for hovercraft was derived from

3666-444: The hovercraft became an effective transport system for high-speed service on water and land, leading to widespread developments for military vehicles, search and rescue, and commercial operations. By 1962, many UK aviation and shipbuilding firms were working on hovercraft designs, including Saunders Roe/ Westland , Vickers-Armstrong , William Denny , Britten-Norman and Folland . Small-scale ferry service started as early as 1962 with

3744-427: The hovercraft lift system acted as both a lift and a very effective suspension, and thus it naturally lent itself to high-speed use where conventional suspension systems were considered too complex. This led to a variety of " hovertrain " proposals during the 1960s, including England's Tracked Hovercraft and France's Aérotrain . In the U.S., Rohr Inc. and Garrett both took out licences to develop local versions of

3822-745: The hovercraft's marine tasks. Although developed elsewhere in the world for both civil and military purposes, except for the Solent Ryde-to-Southsea crossing, hovercraft disappeared from the coastline of Britain until a range of Griffon Hoverwork were bought by the Royal National Lifeboat Institution . Hovercraft used to ply between the Gateway of India in Mumbai and CBD Belapur and Vashi in Navi Mumbai between 1994 and 1999, but

3900-764: The hull projected down into the water to trap the cushion of air with normal hovercraft skirts at the bow and stern ). One of these models, the HM-2, was used by Red Funnel between Southampton (near the Woolston Floating Bridge ) and Cowes . The world's first car-carrying hovercraft was made in 1968, the BHC Mountbatten class (SR.N4) models, each powered by four Bristol Proteus turboshaft engines. These were both used by rival operators Hoverlloyd and Seaspeed (which joined to form Hoverspeed in 1981) to operate regular car and passenger carrying services across

3978-545: The large SR.N4 Mountbatten class hovercraft. Substantial support for the hovercraft industry, and BHC specifically, was sourced directly from the British Government. By 1969, contributions from the British state averaged around £3 million per year; of this, roughly one-third was attributed to research and development contracts, while the remaining two-thirds was divided between financing the Joint Services Military Trials Unit based at Lee-on-Solent and

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4056-541: The last commercial line had linked Ōita Airport and central Ōita but was shut down in October 2009. However, the commercial line between Ōita Airport and central Ōita is scheduled to reopen in 2024. British Hovercraft Corporation Created with the intention of producing viable commercial hovercraft in March 1966, BHC was the result of a corporate merger between the Saunders-Roe division of Westland Aircraft and Vickers Supermarine 's hovercraft interests. None of

4134-470: The launch of the Vickers-Armstrong VA-3. With the introduction of the 254 passenger and 30 car carrying SR.N4 cross-channel ferry by Hoverlloyd and Seaspeed in 1968, hovercraft had developed into useful commercial craft. Another major pioneering effort of the early hovercraft era was carried out by Jean Bertin 's firm in France. Bertin was an advocate of the "multi-skirt" approach, which used

4212-422: The loss of lift at that point, and this led to further pressure on the skirt. After considerable experimentation, Denys Bliss at Hovercraft Development Ltd. found the solution to this problem. Instead of using two separate rubber sheets to form the skirt, a single sheet of rubber was bent into a U shape to provide both sides, with slots cut into the bottom of the U forming the annular vent. When deforming pressure

4290-580: The modern features of a lift engine blowing air into a flexible envelope for lift. Kaario's efforts were followed closely in the Soviet Union by Vladimir Levkov, who returned to the solid-sided design of the Versuchsgleitboot . Levkov designed and built a number of similar craft during the 1930s, and his L-5 fast-attack boat reached 70 knots (130 km/h) in testing. However, the start of World War II put an end to his development work. During World War II, an American engineer, Charles Fletcher , invented

4368-562: The only year-round public hovercraft service in the world still in operation serves between the Isle of Wight and Southsea in the UK. Oita Hovercraft is planning to resume services in Oita, Japan in 2024. Although now a generic term for the type of craft, the name Hovercraft itself was a trademark owned by Saunders-Roe (later British Hovercraft Corporation (BHC), then Westland ), hence other manufacturers' use of alternative names to describe

4446-420: The pilot and co-pilot with only a slight reduction in hover height proportional to the load carried. The SR.N1 did not have any skirt, using instead the peripheral air principle that Cockerell had patented. It was later found that the craft's hover height was improved by the addition of a skirt of flexible fabric or rubber around the hovering surface to contain the air. The skirt was an independent invention made by

4524-645: The possibility of establishing a permanent service is still under consideration. Since the Channel routes abandoned hovercraft, and pending any reintroduction on the Scottish route, the United Kingdom's only public hovercraft service is that operated by Hovertravel between Southsea ( Portsmouth ) and Ryde on the Isle of Wight . From the 1960s, several commercial lines were operated in Japan, without much success. In Japan

4602-627: The rear part of the cockpit. 6 to 8 stewardess. 6 stower-men for the cars. Flight yokes controlled the horizontal tail wing (elevator), propeller pitch and the thrust power of the 3 propulsion gas turbines Rudder pedals controlled the two aerial rudders. Two thrust levers controlled power of the two lifting gas turbines. Obturation flaps system between the air cushion chamber and the skirts provided additional longitudinal and lateral control. Later modifications (1983) included: Data from General characteristics Performance Avionics 2 marine Decca radars (band S, 2-4 GHz,

4680-497: The river is beginning to freeze to minimize damage to the river ice surface. The hovercraft is able to operate during the freeze-up period; however, this could potentially break the ice and create hazards for villagers using their snowmobiles along the river during the early winter. In 2006, Kvichak Marine Industries of Seattle , US built, under licence, a cargo/passenger version of the Hoverwork BHT130 . Designated 'Suna-X', it

4758-547: The services were subsequently stopped due to the lack of sufficient water transport infrastructure . In Finland, small hovercraft are widely used in maritime rescue and during the rasputitsa ("mud season") as archipelago liaison vehicles. In England, hovercraft of the Burnham-on-Sea Area Rescue Boat (BARB) are used to rescue people from thick mud in Bridgwater Bay . Avon Fire and Rescue Service became

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4836-475: The shares from the other firm's owners, making the BHC a wholly owned subsidiary of Westland. During the 1980s, the firm's focus on hovercraft declined as it became increasingly involved in the manufacture of composites for other company's products. In 1984, the company was renamed Westland Aerospace . During the late 1950s and early 1960s, British inventor Sir Christopher Cockerell had, in cooperation with British aerospace manufacturer Saunders-Roe , developed

4914-474: The shares of the other parties, resulting in the BHC becoming a wholly owned subsidiary of Westland. In 1971, Westland successfully acquired the competing British rival Cushioncraft from Britten-Norman . During 1977, the BHC created the largest Union Flag in the world. It was painted on the doors of their hangar on the seafront at East Cowes to celebrate the Silver Jubilee of Elizabeth II . In 1984,

4992-425: The sheet of fast-moving air presented a sort of physical barrier to the air on either side of it. This effect, which he called the "momentum curtain", could be used to trap high-pressure air in the area inside the curtain, producing a high-pressure plenum that earlier examples had to build up with considerably more airflow. In theory, only a small amount of active airflow would be needed to create lift and much less than

5070-428: The skirt design demonstrated a problem; it was originally expected that pressure applied to the outside of the skirt would bend it inward, and the now-displaced airflow would cause it to pop back out. What actually happened is that the slight narrowing of the distance between the walls resulted in less airflow, which in turn led to more air loss under that section of the skirt. The fuselage above this area would drop due to

5148-506: The smoothness required for operation. By the 1950s, Ford showed a number of toy models of cars using the system, but mainly proposed its use as a replacement for wheels on trains, with the Levapads running close to the surface of existing rails. In 1931, Finnish aero engineer Toivo J. Kaario began designing a developed version of a vessel using an air cushion and built a prototype Pintaliitäjä ('Surface Glider'), in 1937. His design included

5226-407: The vehicles. There have been many attempts to understand the principles of high air pressure below hulls and wings. Hovercraft are unique in that they can lift themselves while still, differing from ground effect vehicles and hydrofoils that require forward motion to create lift. The first mention, in the historical record of the concepts behind surface-effect vehicles, to use the term hovering

5304-414: The venture and the British state-owned National Research Development Corporation also held 10% of the shares. Despite the inclusion of Vickers' hovercraft venture, none of its designs were ever taken through to the manufacturing stage; instead, production activity was centred on the existing designs produced by Saunders-Roe, including the SR.N5 Warden class, the stretched SR.N6 Winchester class, and

5382-425: Was also recognised that there were other means to drive down costs and thereby improve the hovercraft's commercial viability. These early vehicles had been powered by gas turbine engines , which were typically similar, or identical, to the turboshaft engines used on helicopters ; however, by the 1970s, recent advances in diesel engines had made the prospects for applying an entirely different form of powerplant to

5460-436: Was applied to the outside of this design, air pressure in the rest of the skirt forced the inner wall to move in as well, keeping the channel open. Although there was some deformation of the curtain, the airflow within the skirt was maintained and the lift remained relatively steady. Over time, this design evolved into individual extensions over the bottom of the slots in the skirt, known as "fingers". Through these improvements,

5538-548: Was asked to slow down a little. On examination of the craft afterwards, it was found that she had been dished in the bow due to excessive speed, damage that was never allowed to be repaired, and was from then on affectionately referred to as the 'Royal Dent'. Testing quickly demonstrated that the idea of using a single engine to provide air for both the lift curtain and forward flight required too many trade-offs. A Blackburn Marboré turbojet for forward thrust and two large vertical rudders for directional control were added, producing

5616-500: Was broken up in 1985 at the end of its service. N500-01 - Côte d'Argent registered LV 365.832 port of Le Verdon , on the Gironde estuary .First flight on 19 April 1977 on the Gironde, demonstrating a speed of 40-45 knots (74–83 km/h). She was destroyed by a fire at her construction site on 3 May 1977. N500-02 - Ingénieur Jean Bertin registered BL 341.931 at port of Boulogne Sur Mer

5694-447: Was built for Seaspeed by SNCF in 1977. It showed poor engine and hydraulic system reliability/ It had difficulty climbing the ramp to the Dover hoverpad during bad weather. Transferred to Hoverspeed in 1983 after a number of modifications but was returned to SNCF later that year after Hoverspeed decided she was not suitable for their services due to poor reliability. Broken up in 1985 at

5772-468: Was by Swedish scientist Emanuel Swedenborg in 1716. The shipbuilder John Isaac Thornycroft patented an early design for an air cushion ship / hovercraft in the 1870s, but suitable, powerful, engines were not available until the 20th century. In 1915, the Austrian Dagobert Müller von Thomamühl (1880–1956) built the world's first "air cushion" boat ( Luftkissengleitboot ). Shaped like

5850-422: Was envisioned to revolutionise the transportation system, with personal hovering self-driving cars that could speed up to 2,400 km/h (1,500 mph). The idea of the modern hovercraft is most often associated with Christopher Cockerell , a British mechanical engineer. Cockerell's group was the first to develop the use of a ring of air for maintaining the cushion, the first to develop a successful skirt, and

5928-458: Was powered by a 450 hp Alvis Leonides engine powering a vertical fan in the middle of the craft. In addition to providing the lift air, a portion of the airflow was bled off into two channels on either side of the craft, which could be directed to provide thrust. In normal operation this extra airflow was directed rearward for forward thrust and blew over two large vertical rudders that provided directional control. For low-speed manoeuvrability,

6006-597: Was powered by two turboprop aero-engines and driven by propellers . During the 1960s, Saunders-Roe developed several larger designs that could carry passengers, including the SR.N2 , which operated across the Solent , in 1962, and later the SR.N6 , which operated across the Solent from Southsea to Ryde on the Isle of Wight for many years. In 1963 the SR.N2 was used in experimental service between Weston-super-Mare and Penarth under

6084-569: Was produced in quantity not only by the BHC, but was also constructed under licence by companies in both Australia and China . While plans to procure the BH.7 for the British Army were terminated during 1968, government support continued to be forthcoming; the Ministry of Technology ordered a single BH.7, helping to facilitate the launch of a Navy-orientated version. In 1970, Westland Aircraft acquired

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