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Ground-effect vehicle

A ground-effect vehicle (GEV), also called a wing-in-ground-effect (WIG), ground-effect craft, wingship, flarecraft or ekranoplan (Russian: экранопла́н – "screenglider"), is a vehicle that is able to move over the surface by gaining support from the reactions of the air against the surface of the earth or water. Typically, it is designed to glide over a level surface (usually over the sea) by making use of ground effect, the aerodynamic interaction between the moving wing and the surface below. Some models can operate over any flat area such as frozen lakes or flat plains similar to a hovercraft.

Ekranoplan A-90 Orlyonok

Design

A ground-effect vehicle needs some forward velocity to produce lift dynamically, and the principal benefit of operating a wing in ground effect is to reduce its lift-dependent drag. The basic design principle is that the closer the wing operates to an external surface such as the ground, when it is said to be in ground effect, the less drag it feels.

An airfoil passing through air increases air pressure on the underside, while decreasing pressure across the top. The high and low pressures are maintained until they flow off the ends of the wings, where they form vortices which in turn are the major cause of lift-induced drag—normally a significant portion of the drag affecting an aircraft. The greater the span of a wing, the less induced drag created for each unit of lift and the greater the efficiency of the particular wing. This is the primary reason gliders have long wings.

Placing the same wing near a surface such as the water or the ground has the effect of increasing the aspect ratio[why?], but without having the complications associated with a long and slender wing, so that the short stubs on a GEV can produce just as much lift as the much larger wing on a transport aircraft, though it can do this only when close to the earth's surface. Once sufficient speed has built up, some GEVs may be capable of leaving ground effect and functioning as normal aircraft until they approach their destination. The distinguishing characteristic is that they are unable to land or take off without a significant amount of help from the ground effect cushion, and cannot climb until they have reached a much higher speed.

A GEV is sometimes characterized as a transition between a hovercraft and an aircraft, although this is not correct as a hovercraft is statically supported upon a cushion of pressurized air from an onboard downward-directed fan. Some GEV designs, such as the Russian Lun and Dingo, have used forced blowing under the wing by auxiliary engines to increase the high pressure area under the wing to assist the takeoff; however they differ from hovercraft in still requiring forward motion to generate sufficient lift to fly.

Although the GEV may look similar to the seaplane and share many technical characteristics, it is generally not designed to fly out of ground effect. It differs from the hovercraft in lacking low-speed hover capability in much the same way that a fixed-wing airplane differs from the helicopter. Unlike the hydrofoil, it does not have any contact with the surface of the water when in "flight". The ground-effect vehicle constitutes a unique class of transportation.

The Boston-based (United States) company REGENT proposed an electric-powered high-wing design with a standard hull for water operations, but also incorporated fore- and aft-mounted hydrofoil units designed to lift the craft out of the water during takeoff run, to facilitate lower liftoff speeds.[1]

Wing configurations

 
WIG-wings configurations: (A) Ekranoplan; (B) Reverse-delta wing; (C) Tandem wing.
 
A Russian light ekranoplan Aquaglide-2

Straight wing

Used by the Russian Rostislav Alexeyev for his ekranoplan. The wings are significantly shorter than those of comparable aircraft, and this configuration requires a high aft-placed horizontal tail to maintain stability. The pitch and altitude stability comes from the lift slope[note 1] difference between a front low wing in ground-effect (commonly the main wing) and an aft, higher-located second wing nearly out of ground-effect (generally named a stabilizer).

Reverse-delta wing

Developed by Alexander Lippisch, this wing allows stable flight in ground-effect through self-stabilization. This is the main Class B form of GEV.

Tandem wings

Tandem wings can have three configurations:

  • A biplane-style type-1 utilising a shoulder-mounted main lift wing and belly-mounted sponsons similar to those on combat and transport helicopters.
  • A canard-style type-2 with a mid-size horizontal wing[note 2] near the nose of the craft directing airflow under the main lift airfoil. This type-2 tandem design is a major improvement during takeoff, as it creates an air cushion to lift the craft above the water at a lower speed, thereby reducing water drag, which is the biggest obstacle to successful seaplane launches.
  • Two stubby wings as in the tandem-airfoil flairboat produced by Günther Jörg in Germany. His particular design is self-stabilizing longitudinally.[2]

Advantages and disadvantages

Given similar hull size and power, and depending on its specific design, the lower lift-induced drag of a GEV, as compared to an aircraft of similar capacity, will improve its fuel efficiency and, up to a point, its speed. GEVs are also much faster than surface vessels of similar power, because they avoid drag from the water.

On the water the aircraft-like construction of GEVs increases the risk of damage in collisions with surface objects. Furthermore, the limited number of egress points make it more difficult to evacuate the vehicle in an emergency.

Since most GEVs are designed to operate from water, accidents and engine failure typically are less hazardous than in a land-based aircraft, but the lack of altitude control leaves the pilot with fewer options for avoiding collision, and to some extent that negates such benefits. Low altitude brings high-speed craft into conflict with ships, buildings and rising land, which may not be sufficiently visible in poor conditions to avoid. GEVs may be unable to climb over or turn sharply enough to avoid collisions, while drastic, low-level maneuvers risk contact with solid or water hazards beneath. Aircraft can climb over most obstacles, but GEVs are more limited.

In high winds, take-off must be into the wind, which takes the craft across successive lines of waves, causing heavy pounding, stressing the craft and creating an uncomfortable ride. In light winds, waves may be in any direction, which can make control difficult as each wave causes the vehicle to both pitch and roll. The lighter construction of GEVs makes their ability to operate in higher sea states less than that of conventional ships, but greater than the ability of hovercraft or hydrofoils, which are closer to the water surface. The demise of the conventional seaplane was a result of its inability to operate in rough sea conditions even while flying conditions were good, and its use lasted only until runways were more commonly available. GEVs are similarly limited.

Like conventional aircraft, greater power is needed for takeoff, and, like seaplanes, ground-effect vehicles must get on the step before they can accelerate to flight speed. Careful design, usually with multiple redesigns of hullforms, is required to get this right, which increases engineering costs. This obstacle is more difficult for GEVs with short production runs to overcome. For the vehicle to work, its hull needs to be stable enough longitudinally to be controllable yet not so stable that it cannot lift off the water.

The bottom of the vehicle must be formed to avoid excessive pressures on landing and taking off without sacrificing too much lateral stability, and it must not create too much spray, which damages the airframe and the engines. The Russian ekranoplans show evidence of fixes for these problems in the form of multiple chines on the forward part of the hull undersides and in the forward location of the jet engines.

Finally, limited utility has kept production levels low enough that it has been impossible to amortize development costs sufficiently to make GEVs competitive with conventional aircraft.

A 2014 study by students at NASA's Ames Research Center claims that use of GEVs for passenger travel could lead to cheaper flights, increased accessibility and less pollution.[3]

Classification

One obstacle to GEV development is the classification and legislation to be applied. The International Maritime Organization has studied the application of rules based on the International Code of Safety for High-Speed Craft (HSC code) which was developed for fast ships such as hydrofoils, hovercraft, catamarans and the like. The Russian Rules for classification and construction of small type A ekranoplans is a document upon which most GEV design is based. However, in 2005, the IMO classified the WISE or GEV under the category of ships.[4]

The International Maritime Organization recognizes three types of GEVs:[4]

  1. A craft which is certified for operation only in ground effect;
  2. A craft which is certified to temporarily increase its altitude to a limited height outside the influence of ground effect but not exceeding 150 m (490 ft) above the surface; and
  3. A craft which is certified for operation outside ground effect and exceeding 150 m (490 ft) above the surface.

At the time of writing, those classes only applied to craft carrying 12 passengers or more,[4] and (as of 2019) there was disagreement between national regulatory agencies about whether these vehicles should be classified, and regulated, as aircraft or as boats.[5]

History

 
Artist's concept of a Lun-class ekranoplan in flight

By the 1920s, the ground effect phenomenon was well-known, as pilots found that their airplanes appeared to become more efficient as they neared the runway surface during landing. In 1934 the US National Advisory Committee for Aeronautics issued Technical Memorandum 771, Ground Effect on the Takeoff and Landing of Airplanes, which was a translation into English of a summary of French research on the subject. The French author Maurice Le Sueur had added a suggestion based on this phenomenon: "Here the imagination of inventors is offered a vast field. The ground interference reduces the power required for level flight in large proportions, so here is a means of rapid and at the same time economic locomotion: Design an airplane which is always within the ground-interference zone. At first glance this apparatus is dangerous because the ground is uneven and the altitude called skimming permits no freedom of maneuver. But on large-sized aircraft, over water, the question may be attempted ..."[6]

By the 1960s, the technology started maturing, in large part due to the independent contributions of Rostislav Alexeyev in the Soviet Union[7] and German Alexander Lippisch, working in the United States. Alexeyev worked from his background as a ship designer whereas Lippisch worked as an aeronautical engineer. The influence of Alexeyev and Lippisch remains noticeable in most GEVs seen today.

Soviet Union

 
The Bartini Beriev VVA-14, developed during the 1970s
 
Model of the Beriev Be-2500 concept aircraft

Led by Alexeyev, the Soviet Central Hydrofoil Design Bureau (Russian: ЦКБ СПК) was the center of ground-effect craft development in the USSR. The vehicle came to be known as an ekranoplan (Russian: экранопла́н, экран screen + план plane, from Russian: эффект экрана, literally screen effect, or ground effect in English). The military potential for such a craft was soon recognized, and Alexeyev received support and financial resources from Soviet leader Nikita Khrushchev.

Some manned and unmanned prototypes were built, ranging up to eight tonnes in displacement. This led to the development of a 550-tonne military ekranoplan of 92 m (302 ft) length. The craft was dubbed the Caspian Sea Monster by U.S. intelligence experts, after a huge, unknown craft was spotted on satellite reconnaissance photos of the Caspian Sea area in the 1960s. With its short wings, it looked airplane-like in planform, but would probably be incapable of flight.[8] Although it was designed to travel a maximum of 3 m (10 ft) above the sea, it was found to be most efficient at 20 m (66 ft), reaching a top speed of 300–400 knots (560–740 km/h) in research flights.

The Soviet ekranoplan program continued with the support of Minister of Defence Dmitriy Ustinov. It produced the most successful ekranoplan so far, the 125-tonne A-90 Orlyonok. These craft were originally developed as high-speed military transports and were usually based on the shores of the Caspian Sea and Black Sea. The Soviet Navy ordered 120 Orlyonok-class ekranoplans, but this figure was later reduced to fewer than 30 vessels, with planned deployment mainly in the Black Sea and Baltic Sea fleets.

A few Orlyonoks served with the Soviet Navy from 1979 to 1992. In 1987, the 400-tonne Lun-class ekranoplan was built as an anti-ship missile launch platform. A second Lun, renamed Spasatel, was laid down as a rescue vessel, but was never finished. The two major problems that the Soviet ekranoplans faced were poor longitudinal stability and a need for reliable navigation.

Minister Ustinov died in 1984, and the new Minister of Defence, Marshal Sokolov, cancelled funding for the program. Only three operational Orlyonok-class ekranoplans (with revised hull design) and one Lun-class ekranoplan remained at a naval base near Kaspiysk.

Since the dissolution of the Soviet Union, ekranoplans have been produced by the Volga Shipyard[9] in Nizhniy Novgorod. Smaller ekranoplans for non-military use have been under development. The CHDB had already developed the eight-seat Volga-2 in 1985, and Technologies and Transport is developing a smaller version called the Amphistar. Beriev proposed a large craft of the type, the Be-2500, as a "flying ship" cargo carrier,[10] but nothing came of the project.

Germany

Lippisch Type and Hanno Fischer

 
The Rhein-Flugzeugbau X-114 in flight.

In Germany, Lippisch was asked to build a very fast boat for American businessman Arthur A. Collins. In 1963 Lippisch developed the X-112, a revolutionary design with reversed delta wing and T-tail. This design proved to be stable and efficient in ground effect, and even though it was successfully tested, Collins decided to stop the project and sold the patents to the German company Rhein Flugzeugbau (RFB), which further developed the inverse delta concept into the X-113 and the six-seat X-114. These craft could be flown out of ground effect so that, for example, peninsulas could be overflown.[11]

Hanno Fischer took over the works from RFB and created his own company, Fischer Flugmechanik, which eventually completed two models. The Airfisch 3 carried two persons, and the FS-8 carried six persons. The FS-8 was to be developed by Fischer Flugmechanik for a Singapore-Australian joint venture called Flightship. Powered by a V8 Chevrolet automobile engine rated at 337 kW, the prototype made its first flight in February 2001 in the Netherlands.[12] The company no longer exists but the prototype craft was bought by Wigetworks,[13] a company based in Singapore and renamed as AirFish 8. In 2010, that vehicle was registered as a ship in the Singapore Registry of Ships.[14]

The University of Duisburg-Essen is supporting an ongoing research project to develop the Hoverwing.[15]

Günther Jörg-type tandem-airfoil flairboat

 
A tandem flarecraft Skimmerfoil Jörg IV located at the SAAF Museum, Port Elizabeth, South Africa.
(It has since been removed from the museum)

German engineer Günther Jörg, who had worked on Alexeyev's first designs and was familiar with the challenges of GEV design, developed a GEV with two wings in a tandem arrangement, the Jörg-II. It was the third, manned, tandem-airfoil boat, named "Skimmerfoil", which was developed during his consultancy period in South Africa. It was a simple and low-cost design of a first 4-seater tandem-airfoil flairboat completely constructed of aluminium. The prototype was in the SAAF Port Elizabeth Museum from 4 July 2007 until 2013, and is now in private use. Pictures of the museum show the boat after a period of some years outside the museum and without protection against the sun.[16]

The consultancy of Dipl. Ing. Günther Jörg, a specialist and insider of German airplane industry from 1963 and a colleague of Alexander Lippisch and Hanno Fischer, was founded with a fundamental knowledge of wing in ground effect physics, as well as results of fundamental tests under different conditions and designs having begun in 1960. For over 30 years, Jörg built and tested 15 different tandem-airfoil flairboats in different sizes and made of different materials.

The following tandem-airfoil flairboat (TAF) types had been built after a previous period of nearly 10 years of research and development:

  1. TAB VII-3: First manned tandem W.I.G type Jörg, being built at Technical University of Darmstadt, Akaflieg
  2. TAF VII-5: Second manned tandem-airfoil Flairboat, 2 seater made of wood
  3. TAF VIII-1: 2-seater tandem-airfoil flairboat built of glass-reinforced plastic (GRP) and aluminium. A small serie of 6 Flairboats had been produced by former Botec Company
  4. TAF VIII-2: 4-seater tandem-airfoil Flairboat built of full aluminium (2 units) and built of GRP (3 units)
  5. TAF VIII-3: 8-seater tandem-airfoil Flairboat built of aluminium combined with GRP parts
  6. TAF VIII-4: 12-seater tandem-airfoil Flairboat built of aluminium combined with GRP parts
  7. TAF VIII-3B: 6-seater tandem-airfoil flairboat under carbon fibre composite construction

Bigger concepts are: 25-seater, 32-seater, 60-seater, 80-seater and bigger up to the size of a passenger airplane.

Those tandem-airfoil flairboats are registered as motorboat and classified as type A WIG. In 1984, Jörg received the "Philip Morris Award" for future transportation. In 1987, the Botec Company was founded. After his death in 2010, the company continued under his daughter and former assistant Ingrid Schellhaas with her company Tandem WIG Consulting.

1980–1999

Since the 1980s GEVs have been primarily smaller craft designed for the recreational and civilian ferry markets. Germany, Russia and the United States have provided most of the activity with some development in Australia, China, Japan, Korea and Taiwan. In these countries and regions, small craft with up to ten seats have been built. Other larger designs such as ferries and heavy transports have been proposed but have not been carried to completion.

Besides the development of appropriate design and structural configuration, automatic control and navigation systems have been developed. These include altimeters with high accuracy for low altitude flight and lesser dependence on weather conditions. "Phase radio altimeters" have become the choice for such applications beating laser altimeter, isotropic or ultrasonic altimeters.[17]

With Russian consultation, the United States Defense Advanced Research Projects Agency (DARPA) studied the Aerocon Dash 1.6 wingship.[18][19]

 
A Hoverwing

Universal Hovercraft developed a flying hovercraft, first flying a prototype in 1996.[20] Since 1999, the company has offered plans, parts, kits and manufactured ground effect hovercraft called the Hoverwing.[21]

2000-

Iran deployed three squadrons of Bavar 2 two-seat GEVs in September 2010. This GEV carries one machine gun and surveillance gear, and incorporates features to reduce its radar signature.[22] In October 2014, satellite images showed the GEV in a shipyard in southern Iran. The GEV has two engines and no armament.[23]

In Singapore, Wigetworks obtained certification from Lloyd's Register for entry into class.[24] On 31 March 2011, AirFish 8-001 became one of the first GEVs to be flagged with the Singapore Registry of Ships, one of the largest ship registries.[25] Wigetworks partnered with National University of Singapore's Engineering Department to develop higher capacity GEVs.[26]

Burt Rutan in 2011[27] and Korolev in 2015 showed GEV projects.[28]

In Korea, Wing Ship Technology Corporation developed and tested a 50-seat passenger GEV named the WSH-500. in 2013[29]

Estonian transport company Sea Wolf Express planned to launch passenger service in 2019 between Helsinki and Tallinn, a distance of 87 km taking only half an hour, using a Russian-built ekranoplan.[30] The company ordered 15 ekranoplans with maximum speed of 185 km/h and capacity of 12 passengers, built by Russian RDC Aqualines.[31]

In 2021 Brittany Ferries announced that they were looking into using REGENT (Regional Electric Ground Effect Naval Transport) ground effect craft "seagliders"[1] for cross English Channel services.[32] Southern Airways Express also placed firm orders for seagliders with intent to operate them along Florida's east coast.[33][34]

Around mid-2022, the Pentagon’s Defense Advanced Research Projects Agency (DARPA) launched its Liberty Lifter project, with the goal of creating a long-range, low-cost transport using the ekranoplan concept. The challenge is to carry 100 tons over 7,500 km, operate at sea without ground-based maintenance, all using low-cost materials.[35][36]

See also

Footnotes

Notes

  1. ^ Cl/da, with Cl = lift coefficient, and a = angle of incidence.
  2. ^ Not a stabilizer because destabilizing.

Citations

  1. ^ a b "Coastal Travel - 100% Electric". Retrieved January 13, 2022.
  2. ^ Rozhdestvensky, Kirill V. (May 2006). "Wing-in-ground effect vehicles". Progress in Aerospace Sciences. 42 (3): 211–283. Bibcode:2006PrAeS..42..211R. doi:10.1016/j.paerosci.2006.10.001.
  3. ^ Byun, Leo; Donohue, Kiley; Mayo, Michael; McCafferty, Julian & Miller, Ruth (August 21, 2014). "Ground Effect Vehicle Transoceanic Civil and Cargo Transport Network" (PDF). NASA Aeronautic Academy.
  4. ^ a b c Sub-Committee on Ship Design and Equipment (DE) (November 2001). "Wing-in-Ground (WIG) craft". International Maritime Organization. from the original on January 16, 2014. Retrieved January 16, 2014.
  5. ^ "Exclusive: UK at odds with EU and US over classification of wing-in-ground effect craft". Revolution.aero. August 29, 2019.
  6. ^ Garrison (2011), pp. 80–83.
  7. ^ May, James (September 27, 2008). "Riding the Caspian Sea Monster". BBC News. from the original on September 30, 2008.
  8. ^ Garrison (2011), p. 82.
  9. ^ . Joint Stock Company Volga Shipyard. 2011. Archived from the original on February 6, 2012. Retrieved December 30, 2011.
  10. ^ "Be-2500 amphibious aircraft". Beriev Aircraft Company. from the original on December 3, 2007. Retrieved November 20, 2013.
  11. ^ Taylor, John W. R. (1978). Jane's All the World's Aircraft 1978–79. London, UK: Jane's Yearbooks. pp. 70–71. ISBN 0-35-400572-3.
  12. ^ . The WIG page. 2008. Archived from the original on July 18, 2011. Retrieved December 30, 2011.
  13. ^ "WigetWorks/AirFish/Wing-in-Ground". 2020. Retrieved January 13, 2022.
  14. ^ "Introducing the AirFish 8". Wigetworks Private Limited. from the original on February 3, 2011. Retrieved August 22, 2011.
  15. ^ . Technical development of ground-effect vehicles, University of Duisburg-Essen. March 1, 2000. Archived from the original on October 9, 2007. Retrieved October 1, 2007.
  16. ^ "TAF Skimmerfoil arrives in Port Elizabeth". South African Air Force Museum. July 5, 2007. Archived from the original on September 29, 2013. Retrieved September 29, 2013.
  17. ^ Nebylov, Alexander; Rumyantseva, Elizaveta & Sukrit, Sharan (June 2007). "Comparative Analysis of Design Variants For Low Altitude Flight Parameters Measuring System". IFAC Proceedings. 40 (7): 663–668. doi:10.3182/20070625-5-FR-2916.00113.
  18. ^ Gaines, Mike. "USA joins Russia on Wingship" (PDF). Flight International. No. 11 March 1992. p. 5. (PDF) from the original on September 29, 2013. Retrieved August 31, 2018.
  19. ^ Advanced Research Projects Agency (ARPA) (September 30, 1994). Technology Roadmap (PDF). Wingship Investigation. Vol. 3. Arlington, Virginia. Retrieved August 31, 2018.
  20. ^ "18SPW Hoverwing". Universal Hovercraft of America, Inc. from the original on April 15, 2011. Retrieved March 14, 2011.
  21. ^ "19XRW Hoverwing". Universal Hovercraft of America, Inc. from the original on June 2, 2011. Retrieved March 14, 2011.
  22. ^ Lendon, Brad (September 28, 2010). "Iran unveils squadrons of flying boats". CNN. from the original on October 1, 2010. Retrieved October 11, 2010.
  23. ^ Biggers, Chris (July 6, 2015). "Iran is developing a new flying boat". Business Insider. from the original on July 7, 2015.
  24. ^ Hirdaris, Spyros & Guerrier, Mark (November 2009). (PDF). 2nd Annual Ship Tech. Archived from the original (PDF) on March 7, 2010. Retrieved December 30, 2011.
  25. ^ Young, Lam Yi (April 25, 2010). "Speech at the christening of the Wing-In-Ground craft, AirFish 8-001". Harbor and Port Authority of Singapore. from the original on September 23, 2016. Retrieved December 30, 2011.
  26. ^ . Faculty of Engineering, National University of Singapore. 2009. Archived from the original on July 16, 2011. Retrieved December 30, 2011.
  27. ^ Trimble, Stephen (November 14, 2011). "DUBAI: Burt Rutan reveals secret ekranoplan project". Flight Global. from the original on April 7, 2018. Retrieved April 6, 2018.
  28. ^ Drew, James (August 28, 2015). "MAKS: Can Russia's 'Caspian Sea Monster' rise again?". Flight Global. from the original on April 7, 2018. Retrieved April 6, 2018.
  29. ^ "Wing Ship Technology develops and manufactures world's first middle class commercial WIG Craft". Wing Ship Technology Corporation. from the original on July 19, 2013. Retrieved July 19, 2013.
  30. ^ "Estonian company hopes to launch Tallinn-Helsinki GEV service in 2019". ERR. January 5, 2018. from the original on January 20, 2018. Retrieved April 6, 2018.
  31. ^ [Estonian company has a wild vision: Helsinki-Tallinn distance in half an hour with a surface connector?]. MTV3 (in Finnish). January 4, 2018. Archived from the original on February 5, 2018. Retrieved April 6, 2018.
  32. ^ "Cross-Channel 'flying ferries' concept revealed for Portsmouth route". BBC News. June 15, 2021. Retrieved June 15, 2021.
  33. ^ "Southern Airways Express Purchases 20 REGENT Seagliders for their U.S. East Coast Ops in $250M Deal". Aerospace Tech Review. December 31, 2021. Retrieved December 31, 2021.
  34. ^ Sissi Cao (December 16, 2021). "Is It a Flying Boat?". Retrieved January 13, 2022 – via The Observer.
  35. ^ "Cargo Hauling Ekranoplan X-Plane is being Developed by DARPA". Thomas Newdick, The Drive, May 19, 2022. Retrieved May 19, 2022.
  36. ^ Blain, Loz (May 24, 2022). "DARPA Liberty Lifter aims to bring back heavy-lift ground effect seaplanes". New Atlas. Retrieved May 24, 2022.

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External links

  • "Alekseyev A-90". Airliners.net.
  • "WIG craft, a new word in aviation". RIA Novosti. September 29, 2006.
  • Cole, William (September 2002). "The Pelican: A Big Bird for the Long Haul". Boeing Frontiers. 1 (5).
  • Teo, Francis (July 18, 2006). "Sea Eagle Wing In Ground Effect Craft Provide 80 Knots Alternatives To Marine Transportation Industry". SeaDiscovery.com.
  • . FAS.org. Archived from the original on December 7, 2015.
  • Edgar, Julian (March 5, 2002). . AutoSpeed. Archived from the original on November 10, 2005.
  • "Das Albatross-Prinzip". Airfoil Tandem W.I.G. Consulting (in German).
  • "Ekranoplanes: Soaring above the waves". Airforce.ru.
  • . Moscow Top News. Archived from the original on November 25, 2009.
  • "Wing in the Ground Effect Ship". Sungwoo Engineering.
  • "The Lun, sitting in drydock". Jalopnik. March 10, 2010.
  • "Ground Effect and WIG Vehicles". Aerospaceweb.org.
  • "СВП с АР проекта А18 («Тунгус»)" [SVP with AR project A18 ("Tungus")]. Aerohod (in Russian).
  • "Flying hovercraft project Wig". MAD Hovercraft.

ground, effect, vehicle, ekranoplan, redirects, here, album, assemble, head, sunburst, sound, ekranoplan, album, this, article, lead, section, short, adequately, summarize, points, please, consider, expanding, lead, provide, accessible, overview, important, as. Ekranoplan redirects here For the album by Assemble Head in Sunburst Sound see Ekranoplan album This article s lead section may be too short to adequately summarize the key points Please consider expanding the lead to provide an accessible overview of all important aspects of the article August 2021 A ground effect vehicle GEV also called a wing in ground effect WIG ground effect craft wingship flarecraft or ekranoplan Russian ekranopla n screenglider is a vehicle that is able to move over the surface by gaining support from the reactions of the air against the surface of the earth or water Typically it is designed to glide over a level surface usually over the sea by making use of ground effect the aerodynamic interaction between the moving wing and the surface below Some models can operate over any flat area such as frozen lakes or flat plains similar to a hovercraft Ekranoplan A 90 Orlyonok Contents 1 Design 2 Wing configurations 2 1 Straight wing 2 2 Reverse delta wing 2 3 Tandem wings 3 Advantages and disadvantages 4 Classification 5 History 5 1 Soviet Union 5 2 Germany 5 2 1 Lippisch Type and Hanno Fischer 5 2 2 Gunther Jorg type tandem airfoil flairboat 5 3 1980 1999 5 4 2000 6 See also 7 Footnotes 7 1 Notes 7 2 Citations 7 3 Bibliography 8 External linksDesign EditThis section needs additional citations for verification Please help improve this article by adding citations to reliable sources Unsourced material may be challenged and removed March 2018 Learn how and when to remove this template message A ground effect vehicle needs some forward velocity to produce lift dynamically and the principal benefit of operating a wing in ground effect is to reduce its lift dependent drag The basic design principle is that the closer the wing operates to an external surface such as the ground when it is said to be in ground effect the less drag it feels An airfoil passing through air increases air pressure on the underside while decreasing pressure across the top The high and low pressures are maintained until they flow off the ends of the wings where they form vortices which in turn are the major cause of lift induced drag normally a significant portion of the drag affecting an aircraft The greater the span of a wing the less induced drag created for each unit of lift and the greater the efficiency of the particular wing This is the primary reason gliders have long wings Placing the same wing near a surface such as the water or the ground has the effect of increasing the aspect ratio why but without having the complications associated with a long and slender wing so that the short stubs on a GEV can produce just as much lift as the much larger wing on a transport aircraft though it can do this only when close to the earth s surface Once sufficient speed has built up some GEVs may be capable of leaving ground effect and functioning as normal aircraft until they approach their destination The distinguishing characteristic is that they are unable to land or take off without a significant amount of help from the ground effect cushion and cannot climb until they have reached a much higher speed A GEV is sometimes characterized as a transition between a hovercraft and an aircraft although this is not correct as a hovercraft is statically supported upon a cushion of pressurized air from an onboard downward directed fan Some GEV designs such as the Russian Lun and Dingo have used forced blowing under the wing by auxiliary engines to increase the high pressure area under the wing to assist the takeoff however they differ from hovercraft in still requiring forward motion to generate sufficient lift to fly Although the GEV may look similar to the seaplane and share many technical characteristics it is generally not designed to fly out of ground effect It differs from the hovercraft in lacking low speed hover capability in much the same way that a fixed wing airplane differs from the helicopter Unlike the hydrofoil it does not have any contact with the surface of the water when in flight The ground effect vehicle constitutes a unique class of transportation The Boston based United States company REGENT proposed an electric powered high wing design with a standard hull for water operations but also incorporated fore and aft mounted hydrofoil units designed to lift the craft out of the water during takeoff run to facilitate lower liftoff speeds 1 Wing configurations Edit WIG wings configurations A Ekranoplan B Reverse delta wing C Tandem wing A Russian light ekranoplan Aquaglide 2 Straight wing Edit Used by the Russian Rostislav Alexeyev for his ekranoplan The wings are significantly shorter than those of comparable aircraft and this configuration requires a high aft placed horizontal tail to maintain stability The pitch and altitude stability comes from the lift slope note 1 difference between a front low wing in ground effect commonly the main wing and an aft higher located second wing nearly out of ground effect generally named a stabilizer Reverse delta wing Edit Developed by Alexander Lippisch this wing allows stable flight in ground effect through self stabilization This is the main Class B form of GEV Tandem wings Edit Tandem wings can have three configurations A biplane style type 1 utilising a shoulder mounted main lift wing and belly mounted sponsons similar to those on combat and transport helicopters A canard style type 2 with a mid size horizontal wing note 2 near the nose of the craft directing airflow under the main lift airfoil This type 2 tandem design is a major improvement during takeoff as it creates an air cushion to lift the craft above the water at a lower speed thereby reducing water drag which is the biggest obstacle to successful seaplane launches Two stubby wings as in the tandem airfoil flairboat produced by Gunther Jorg in Germany His particular design is self stabilizing longitudinally 2 Advantages and disadvantages EditThis section needs additional citations for verification Please help improve this article by adding citations to reliable sources Unsourced material may be challenged and removed March 2018 Learn how and when to remove this template message Given similar hull size and power and depending on its specific design the lower lift induced drag of a GEV as compared to an aircraft of similar capacity will improve its fuel efficiency and up to a point its speed GEVs are also much faster than surface vessels of similar power because they avoid drag from the water On the water the aircraft like construction of GEVs increases the risk of damage in collisions with surface objects Furthermore the limited number of egress points make it more difficult to evacuate the vehicle in an emergency Since most GEVs are designed to operate from water accidents and engine failure typically are less hazardous than in a land based aircraft but the lack of altitude control leaves the pilot with fewer options for avoiding collision and to some extent that negates such benefits Low altitude brings high speed craft into conflict with ships buildings and rising land which may not be sufficiently visible in poor conditions to avoid GEVs may be unable to climb over or turn sharply enough to avoid collisions while drastic low level maneuvers risk contact with solid or water hazards beneath Aircraft can climb over most obstacles but GEVs are more limited In high winds take off must be into the wind which takes the craft across successive lines of waves causing heavy pounding stressing the craft and creating an uncomfortable ride In light winds waves may be in any direction which can make control difficult as each wave causes the vehicle to both pitch and roll The lighter construction of GEVs makes their ability to operate in higher sea states less than that of conventional ships but greater than the ability of hovercraft or hydrofoils which are closer to the water surface The demise of the conventional seaplane was a result of its inability to operate in rough sea conditions even while flying conditions were good and its use lasted only until runways were more commonly available GEVs are similarly limited Like conventional aircraft greater power is needed for takeoff and like seaplanes ground effect vehicles must get on the step before they can accelerate to flight speed Careful design usually with multiple redesigns of hullforms is required to get this right which increases engineering costs This obstacle is more difficult for GEVs with short production runs to overcome For the vehicle to work its hull needs to be stable enough longitudinally to be controllable yet not so stable that it cannot lift off the water The bottom of the vehicle must be formed to avoid excessive pressures on landing and taking off without sacrificing too much lateral stability and it must not create too much spray which damages the airframe and the engines The Russian ekranoplans show evidence of fixes for these problems in the form of multiple chines on the forward part of the hull undersides and in the forward location of the jet engines Finally limited utility has kept production levels low enough that it has been impossible to amortize development costs sufficiently to make GEVs competitive with conventional aircraft A 2014 study by students at NASA s Ames Research Center claims that use of GEVs for passenger travel could lead to cheaper flights increased accessibility and less pollution 3 Classification EditOne obstacle to GEV development is the classification and legislation to be applied The International Maritime Organization has studied the application of rules based on the International Code of Safety for High Speed Craft HSC code which was developed for fast ships such as hydrofoils hovercraft catamarans and the like The Russian Rules for classification and construction of small type A ekranoplans is a document upon which most GEV design is based However in 2005 the IMO classified the WISE or GEV under the category of ships 4 The International Maritime Organization recognizes three types of GEVs 4 A craft which is certified for operation only in ground effect A craft which is certified to temporarily increase its altitude to a limited height outside the influence of ground effect but not exceeding 150 m 490 ft above the surface andA craft which is certified for operation outside ground effect and exceeding 150 m 490 ft above the surface At the time of writing those classes only applied to craft carrying 12 passengers or more 4 and as of 2019 there was disagreement between national regulatory agencies about whether these vehicles should be classified and regulated as aircraft or as boats 5 History Edit Artist s concept of a Lun class ekranoplan in flight By the 1920s the ground effect phenomenon was well known as pilots found that their airplanes appeared to become more efficient as they neared the runway surface during landing In 1934 the US National Advisory Committee for Aeronautics issued Technical Memorandum 771 Ground Effect on the Takeoff and Landing of Airplanes which was a translation into English of a summary of French research on the subject The French author Maurice Le Sueur had added a suggestion based on this phenomenon Here the imagination of inventors is offered a vast field The ground interference reduces the power required for level flight in large proportions so here is a means of rapid and at the same time economic locomotion Design an airplane which is always within the ground interference zone At first glance this apparatus is dangerous because the ground is uneven and the altitude called skimming permits no freedom of maneuver But on large sized aircraft over water the question may be attempted 6 By the 1960s the technology started maturing in large part due to the independent contributions of Rostislav Alexeyev in the Soviet Union 7 and German Alexander Lippisch working in the United States Alexeyev worked from his background as a ship designer whereas Lippisch worked as an aeronautical engineer The influence of Alexeyev and Lippisch remains noticeable in most GEVs seen today Soviet Union Edit The Bartini Beriev VVA 14 developed during the 1970s Model of the Beriev Be 2500 concept aircraft Led by Alexeyev the Soviet Central Hydrofoil Design Bureau Russian CKB SPK was the center of ground effect craft development in the USSR The vehicle came to be known as an ekranoplan Russian ekranopla n ekran screen plan plane from Russian effekt ekrana literally screen effect or ground effect in English The military potential for such a craft was soon recognized and Alexeyev received support and financial resources from Soviet leader Nikita Khrushchev Some manned and unmanned prototypes were built ranging up to eight tonnes in displacement This led to the development of a 550 tonne military ekranoplan of 92 m 302 ft length The craft was dubbed the Caspian Sea Monster by U S intelligence experts after a huge unknown craft was spotted on satellite reconnaissance photos of the Caspian Sea area in the 1960s With its short wings it looked airplane like in planform but would probably be incapable of flight 8 Although it was designed to travel a maximum of 3 m 10 ft above the sea it was found to be most efficient at 20 m 66 ft reaching a top speed of 300 400 knots 560 740 km h in research flights The Soviet ekranoplan program continued with the support of Minister of Defence Dmitriy Ustinov It produced the most successful ekranoplan so far the 125 tonne A 90 Orlyonok These craft were originally developed as high speed military transports and were usually based on the shores of the Caspian Sea and Black Sea The Soviet Navy ordered 120 Orlyonok class ekranoplans but this figure was later reduced to fewer than 30 vessels with planned deployment mainly in the Black Sea and Baltic Sea fleets A few Orlyonoks served with the Soviet Navy from 1979 to 1992 In 1987 the 400 tonne Lun class ekranoplan was built as an anti ship missile launch platform A second Lun renamed Spasatel was laid down as a rescue vessel but was never finished The two major problems that the Soviet ekranoplans faced were poor longitudinal stability and a need for reliable navigation Minister Ustinov died in 1984 and the new Minister of Defence Marshal Sokolov cancelled funding for the program Only three operational Orlyonok class ekranoplans with revised hull design and one Lun class ekranoplan remained at a naval base near Kaspiysk Since the dissolution of the Soviet Union ekranoplans have been produced by the Volga Shipyard 9 in Nizhniy Novgorod Smaller ekranoplans for non military use have been under development The CHDB had already developed the eight seat Volga 2 in 1985 and Technologies and Transport is developing a smaller version called the Amphistar Beriev proposed a large craft of the type the Be 2500 as a flying ship cargo carrier 10 but nothing came of the project Germany Edit Lippisch Type and Hanno Fischer Edit The Rhein Flugzeugbau X 114 in flight In Germany Lippisch was asked to build a very fast boat for American businessman Arthur A Collins In 1963 Lippisch developed the X 112 a revolutionary design with reversed delta wing and T tail This design proved to be stable and efficient in ground effect and even though it was successfully tested Collins decided to stop the project and sold the patents to the German company Rhein Flugzeugbau RFB which further developed the inverse delta concept into the X 113 and the six seat X 114 These craft could be flown out of ground effect so that for example peninsulas could be overflown 11 Hanno Fischer took over the works from RFB and created his own company Fischer Flugmechanik which eventually completed two models The Airfisch 3 carried two persons and the FS 8 carried six persons The FS 8 was to be developed by Fischer Flugmechanik for a Singapore Australian joint venture called Flightship Powered by a V8 Chevrolet automobile engine rated at 337 kW the prototype made its first flight in February 2001 in the Netherlands 12 The company no longer exists but the prototype craft was bought by Wigetworks 13 a company based in Singapore and renamed as AirFish 8 In 2010 that vehicle was registered as a ship in the Singapore Registry of Ships 14 The University of Duisburg Essen is supporting an ongoing research project to develop the Hoverwing 15 Gunther Jorg type tandem airfoil flairboat Edit A tandem flarecraft Skimmerfoil Jorg IV located at the SAAF Museum Port Elizabeth South Africa It has since been removed from the museum German engineer Gunther Jorg who had worked on Alexeyev s first designs and was familiar with the challenges of GEV design developed a GEV with two wings in a tandem arrangement the Jorg II It was the third manned tandem airfoil boat named Skimmerfoil which was developed during his consultancy period in South Africa It was a simple and low cost design of a first 4 seater tandem airfoil flairboat completely constructed of aluminium The prototype was in the SAAF Port Elizabeth Museum from 4 July 2007 until 2013 and is now in private use Pictures of the museum show the boat after a period of some years outside the museum and without protection against the sun 16 The consultancy of Dipl Ing Gunther Jorg a specialist and insider of German airplane industry from 1963 and a colleague of Alexander Lippisch and Hanno Fischer was founded with a fundamental knowledge of wing in ground effect physics as well as results of fundamental tests under different conditions and designs having begun in 1960 For over 30 years Jorg built and tested 15 different tandem airfoil flairboats in different sizes and made of different materials The following tandem airfoil flairboat TAF types had been built after a previous period of nearly 10 years of research and development TAB VII 3 First manned tandem W I G type Jorg being built at Technical University of Darmstadt Akaflieg TAF VII 5 Second manned tandem airfoil Flairboat 2 seater made of wood TAF VIII 1 2 seater tandem airfoil flairboat built of glass reinforced plastic GRP and aluminium A small serie of 6 Flairboats had been produced by former Botec Company TAF VIII 2 4 seater tandem airfoil Flairboat built of full aluminium 2 units and built of GRP 3 units TAF VIII 3 8 seater tandem airfoil Flairboat built of aluminium combined with GRP parts TAF VIII 4 12 seater tandem airfoil Flairboat built of aluminium combined with GRP parts TAF VIII 3B 6 seater tandem airfoil flairboat under carbon fibre composite constructionBigger concepts are 25 seater 32 seater 60 seater 80 seater and bigger up to the size of a passenger airplane Those tandem airfoil flairboats are registered as motorboat and classified as type A WIG In 1984 Jorg received the Philip Morris Award for future transportation In 1987 the Botec Company was founded After his death in 2010 the company continued under his daughter and former assistant Ingrid Schellhaas with her company Tandem WIG Consulting 1980 1999 Edit Since the 1980s GEVs have been primarily smaller craft designed for the recreational and civilian ferry markets Germany Russia and the United States have provided most of the activity with some development in Australia China Japan Korea and Taiwan In these countries and regions small craft with up to ten seats have been built Other larger designs such as ferries and heavy transports have been proposed but have not been carried to completion Besides the development of appropriate design and structural configuration automatic control and navigation systems have been developed These include altimeters with high accuracy for low altitude flight and lesser dependence on weather conditions Phase radio altimeters have become the choice for such applications beating laser altimeter isotropic or ultrasonic altimeters 17 With Russian consultation the United States Defense Advanced Research Projects Agency DARPA studied the Aerocon Dash 1 6 wingship 18 19 A Hoverwing Universal Hovercraft developed a flying hovercraft first flying a prototype in 1996 20 Since 1999 the company has offered plans parts kits and manufactured ground effect hovercraft called the Hoverwing 21 2000 Edit Iran deployed three squadrons of Bavar 2 two seat GEVs in September 2010 This GEV carries one machine gun and surveillance gear and incorporates features to reduce its radar signature 22 In October 2014 satellite images showed the GEV in a shipyard in southern Iran The GEV has two engines and no armament 23 In Singapore Wigetworks obtained certification from Lloyd s Register for entry into class 24 On 31 March 2011 AirFish 8 001 became one of the first GEVs to be flagged with the Singapore Registry of Ships one of the largest ship registries 25 Wigetworks partnered with National University of Singapore s Engineering Department to develop higher capacity GEVs 26 Burt Rutan in 2011 27 and Korolev in 2015 showed GEV projects 28 In Korea Wing Ship Technology Corporation developed and tested a 50 seat passenger GEV named the WSH 500 in 2013 29 Estonian transport company Sea Wolf Express planned to launch passenger service in 2019 between Helsinki and Tallinn a distance of 87 km taking only half an hour using a Russian built ekranoplan 30 The company ordered 15 ekranoplans with maximum speed of 185 km h and capacity of 12 passengers built by Russian RDC Aqualines 31 In 2021 Brittany Ferries announced that they were looking into using REGENT Regional Electric Ground Effect Naval Transport ground effect craft seagliders 1 for cross English Channel services 32 Southern Airways Express also placed firm orders for seagliders with intent to operate them along Florida s east coast 33 34 Around mid 2022 the Pentagon s Defense Advanced Research Projects Agency DARPA launched its Liberty Lifter project with the goal of creating a long range low cost transport using the ekranoplan concept The challenge is to carry 100 tons over 7 500 km operate at sea without ground based maintenance all using low cost materials 35 36 See also EditAerodynamically alleviated marine vehicle Ground effect aerodynamics Ground effect train List of ground effect vehicles Surface effect ship Caspian Sea MonsterFootnotes EditNotes Edit Cl da with Cl lift coefficient and a angle of incidence Not a stabilizer because destabilizing Citations Edit a b Coastal Travel 100 Electric Retrieved January 13 2022 Rozhdestvensky Kirill V May 2006 Wing in ground effect vehicles Progress in Aerospace Sciences 42 3 211 283 Bibcode 2006PrAeS 42 211R doi 10 1016 j paerosci 2006 10 001 Byun Leo Donohue Kiley Mayo Michael McCafferty Julian amp Miller Ruth August 21 2014 Ground Effect Vehicle Transoceanic Civil and Cargo Transport Network PDF NASA Aeronautic Academy a b c Sub Committee on Ship Design and Equipment DE November 2001 Wing in Ground WIG craft International Maritime Organization Archived from the original on January 16 2014 Retrieved January 16 2014 Exclusive UK at odds with EU and US over classification of wing in ground effect craft Revolution aero August 29 2019 Garrison 2011 pp 80 83 May James September 27 2008 Riding the Caspian Sea Monster BBC News Archived from the original on September 30 2008 Garrison 2011 p 82 Volga Shipyard Joint Stock Company Volga Shipyard 2011 Archived from the original on February 6 2012 Retrieved December 30 2011 Be 2500 amphibious aircraft Beriev Aircraft Company Archived from the original on December 3 2007 Retrieved November 20 2013 Taylor John W R 1978 Jane s All the World s Aircraft 1978 79 London UK Jane s Yearbooks pp 70 71 ISBN 0 35 400572 3 FS 8 The WIG page 2008 Archived from the original on July 18 2011 Retrieved December 30 2011 WigetWorks AirFish Wing in Ground 2020 Retrieved January 13 2022 Introducing the AirFish 8 Wigetworks Private Limited Archived from the original on February 3 2011 Retrieved August 22 2011 The Ground Effect Craft Hoverwing Technical development of ground effect vehicles University of Duisburg Essen March 1 2000 Archived from the original on October 9 2007 Retrieved October 1 2007 TAF Skimmerfoil arrives in Port Elizabeth South African Air Force Museum July 5 2007 Archived from the original on September 29 2013 Retrieved September 29 2013 Nebylov Alexander Rumyantseva Elizaveta amp Sukrit Sharan June 2007 Comparative Analysis of Design Variants For Low Altitude Flight Parameters Measuring System IFAC Proceedings 40 7 663 668 doi 10 3182 20070625 5 FR 2916 00113 Gaines Mike USA joins Russia on Wingship PDF Flight International No 11 March 1992 p 5 Archived PDF from the original on September 29 2013 Retrieved August 31 2018 Advanced Research Projects Agency ARPA September 30 1994 Technology Roadmap PDF Wingship Investigation Vol 3 Arlington Virginia Retrieved August 31 2018 18SPW Hoverwing Universal Hovercraft of America Inc Archived from the original on April 15 2011 Retrieved March 14 2011 19XRW Hoverwing Universal Hovercraft of America Inc Archived from the original on June 2 2011 Retrieved March 14 2011 Lendon Brad September 28 2010 Iran unveils squadrons of flying boats CNN Archived from the original on October 1 2010 Retrieved October 11 2010 Biggers Chris July 6 2015 Iran is developing a new flying boat Business Insider Archived from the original on July 7 2015 Hirdaris Spyros amp Guerrier Mark November 2009 Technology Developments in Ground Effect Craft PDF 2nd Annual Ship Tech Archived from the original PDF on March 7 2010 Retrieved December 30 2011 Young Lam Yi April 25 2010 Speech at the christening of the Wing In Ground craft AirFish 8 001 Harbor and Port Authority of Singapore Archived from the original on September 23 2016 Retrieved December 30 2011 Engineering students to help in developing future WIG vessels Faculty of Engineering National University of Singapore 2009 Archived from the original on July 16 2011 Retrieved December 30 2011 Trimble Stephen November 14 2011 DUBAI Burt Rutan reveals secret ekranoplan project Flight Global Archived from the original on April 7 2018 Retrieved April 6 2018 Drew James August 28 2015 MAKS Can Russia s Caspian Sea Monster rise again Flight Global Archived from the original on April 7 2018 Retrieved April 6 2018 Wing Ship Technology develops and manufactures world s first middle class commercial WIG Craft Wing Ship Technology Corporation Archived from the original on July 19 2013 Retrieved July 19 2013 Estonian company hopes to launch Tallinn Helsinki GEV service in 2019 ERR January 5 2018 Archived from the original on January 20 2018 Retrieved April 6 2018 Virolaisyrityksella hurja visio Helsinki Tallinna vali puolessa tunnissa pintaliitajalla Estonian company has a wild vision Helsinki Tallinn distance in half an hour with a surface connector MTV3 in Finnish January 4 2018 Archived from the original on February 5 2018 Retrieved April 6 2018 Cross Channel flying ferries concept revealed for Portsmouth route BBC News June 15 2021 Retrieved June 15 2021 Southern Airways Express Purchases 20 REGENT Seagliders for their U S East Coast Ops in 250M Deal Aerospace Tech Review December 31 2021 Retrieved December 31 2021 Sissi Cao December 16 2021 Is It a Flying Boat Retrieved January 13 2022 via The Observer Cargo Hauling Ekranoplan X Plane is being Developed by DARPA Thomas Newdick The Drive May 19 2022 Retrieved May 19 2022 Blain Loz May 24 2022 DARPA Liberty Lifter aims to bring back heavy lift ground effect seaplanes New Atlas Retrieved May 24 2022 Bibliography Edit Abramowski Tomasz 2007 Numerical Investigation of Airfoil in Ground Proximity PDF Theoretical and Applied Mechanics Warsaw 45 2 425 436 ISSN 1429 2955 Archived from the original PDF on September 22 2010 Aubin S Y de Monchaux John June 2001 Easy Ways to Study Ground Effects Toulouse France EAGES 2001 International Ground Effect Symposium Fishwick Simon 2001 Low Flying Boats Thorpe Bay Southend on Sea Essex UK Amateur Yacht Research Society ISBN 0 85133 126 2 Forsberg Randall 1995 The Arms Production Dilemma Contraction and Restraint in the World Combat Aircraft Industry Boston MA The MIT Press ISBN 978 0 262 56085 6 Garrison Peter September 16 2011 Faster than a Boat Flying Gunston Bill 2000 The Osprey Encyclopedia of Russian Aircraft Oxford UK Osprey ISBN 978 1 84176 096 4 Hirschel Ernst Heinrich Prem Horst amp Madelung Gero 2003 Aeronautical Research in Germany From Lilienthal Until Today Berlin Springer Verlag and Heidelberg GmbH amp Co K ISBN 978 3 540 40645 7 Komissarov Sergey Gordon Yefim 2010 Soviet and Russian Ekranoplans Hersham UK Ian Allan Publishing ISBN 978 1 85780 332 7 McGraw Hill Dictionary of Scientific and Technical Terms New York McGraw Hill Professional 2002 ISBN 978 0 07 042313 8 Nebylov A V 2002 Ekranoplanes Controlled Flight Close to the Sea Southampton UK WIT Press Rozhdestvensky Kirill V 2002 Aerodynamics of a Lifting System in Extreme Ground Effect Berlin Springer Verlag and Heidelberg GmbH amp Co K ISBN 978 3 540 66277 8 Sharan Sukrit March 2007 Complex Algorithms of Parameters Measuring Systems for Motion Close to the Sea IX Conference for Young Scientists St Petersburg Russia CSRI ELEKTROPRIBOR Sharan Sukrit April 2007 Quality Measurement Criteria for Flight Close to the Sea Surface Seminar on Aeronautics amp Space St Petersburg Russia University of Aerospace Instrumentation An overview of WIG vehicles for military operations Technical report RTO technical report North Atlantic Treaty Organization NATO Research and Technology Organization RTO Applied Vehicle Technology AVT Panel Task Group AVT 081 December 2006 doi 10 14339 RTO TR AVT 081 inactive December 31 2022 OCLC 1085143242 TR AVT 081 a href Template Cite techreport html title Template Cite techreport cite techreport a CS1 maint DOI inactive as of December 2022 link Lay summary in An Overview of WIG Vehicles for Military Operations Science amp Technology Organization Technical report North Atlantic Treaty Organization December 29 2006 RTO TR AVT 081 External links Edit Wikimedia Commons has media related to Ground effect vehicles Alekseyev A 90 Airliners net WIG craft a new word in aviation RIA Novosti September 29 2006 Cole William September 2002 The Pelican A Big Bird for the Long Haul Boeing Frontiers 1 5 Teo Francis July 18 2006 Sea Eagle Wing In Ground Effect Craft Provide 80 Knots Alternatives To Marine Transportation Industry SeaDiscovery com Project 903 Lun Missile Launcher Ekranoplane FAS org Archived from the original on December 7 2015 Edgar Julian March 5 2002 Between Wind and Waves Ekranoplans AutoSpeed Archived from the original on November 10 2005 Das Albatross Prinzip Airfoil Tandem W I G Consulting in German Ekranoplanes Soaring above the waves Airforce ru Ekranoplan Moscow Top News Archived from the original on November 25 2009 Wing in the Ground Effect Ship Sungwoo Engineering The Lun sitting in drydock Jalopnik March 10 2010 Ground Effect and WIG Vehicles Aerospaceweb org SVP s AR proekta A18 Tungus SVP with AR project A18 Tungus Aerohod in Russian Flying hovercraft project Wig MAD Hovercraft Retrieved from https en wikipedia org w index php title Ground effect vehicle amp oldid 1130928199, wikipedia, wiki, book, books, library,

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