Ekranoplan

File:Ekranoplan of 1980s.jpg

Ekranoplan KM 'Caspian Sea Monster'

An ekranoplan (Template:Lang-ru, literally "screen plane") is a vehicle resembling an aircraft but which operates solely on the principle of ground effect (in Russian эффект экрана effekt ekrana - from which the name derived). Ground effect vehicles (GEV) fly above any flat surface, with the height above ground dependent upon the size of the vehicle. Ekranoplan design was conceived by revolutionary Soviet engineer Rostislav Alexeev.

During the Cold War, ekranoplans were sighted for years on the Caspian Sea as huge, fast-moving objects. The name Caspian Sea Monster was given by US intelligence operatives who had spotted the huge vehicle, which looked like an airplane with the outer halves of the wings removed. After the end of the Cold War, the "monster" was revealed to be one of several Soviet military designs meant to fly only a few meters above water, saving energy and staying below enemy radar.

The ekranoplan has a lifting power of 1,000 tonnes (984 long tons), among the largest ever achieved. The KM, as the Caspian Sea Monster was known in the top secret Soviet military development program, was over 100 metres (328 ft) long, weighed 540 t (531 long tons) fully loaded, and could travel over 400 kilometres per hour (249 mph), mere meters above the surface of the water. . Another model was the Lun-class, entering service with the Black Sea Fleet in 1987; the Lun-class vehicles had a top speed of 550 knots (1,019 km/h).

The important design principle is that wing lift is reduced as operating altitude of the ekranoplan is increased (see ground effect). Thus it is dynamically stable in the vertical dimension. Once moving at speed, the ekranoplan was no longer in contact with the water, and could move over ice, snow, or level land with equal ease, though flight over land would have involved extreme risks unless the surface were very dependably flat.

These craft were originally developed by the Soviet Union as very high-speed military transports, and were based mostly on the shores of the Caspian Sea and Black Sea. The largest could transport over 100 t (98 long tons) of cargo. The development of ekranoplans was supported by Dmitri Ustinov, Minister of Defence of the USSR. About 120 ekranoplans (A-90 Orlyonok class) were initially planned to enter military service in the Soviet Navy. The figure was later reduced to fewer than thirty vehicles, planned to be deployed mainly for the Black and the Baltic Soviet navies. Marshal Ustinov died in 1985, and the new Minister of Defence Marshal Sokolov effectively stopped the funding for the program. The only three operational A-90 Orlyonok ekranoplans built (with renewed hull design) and one Lun-class ekranoplan remained at a naval base near Kaspiysk.

The two major problems which the Soviet Era Ekranoplanes faced were: 1) poor longitudinal stability and 2) a need for reliable navigation & automatic control systems more advanced than any available at the time.

Since the fall of the Soviet Union, ekranoplans have been produced by the Volga Shipyard in Nizhni Novgorod located at 56°21′58.08″N 43°52′14.26″E.

Besides the development of appropriate design and structural configuration, special automatic control systems and navigation systems are also being developed. These include special altimeters with high accuracy for small altitude measurements and also lesser dependence on weather conditions. According to many extensive experiments and research activities, it has been shown that "Phase Radio-altimeters" are most conducive for such applications as compared to laser, isotopic or ultrasonic altimeters.

As of 2008-02-09, two ekranoplans could be seen on Google Earth at Kaspiysk, The Lun , located at 42°52′54″N 47°39′24″E and an Orlyonok at 42°52′50″N 47°39′57″E. A structure on a nearby beach may be a third disassembled ekranoplan.

Even today R&D activities are being carried out for such vehicles in many countries which include Russia, USA, China, Germany, UK, Australia and many others. Other future projects include the horizontal take-off and horizontal landing of Aerospace Planes(ASP) using ekranoplans.

Ekranoplans were featured in the Idries Shah novel Kara Kush, Joe Buff's novel Seas of Crisis, Hideo Kojima's game Metal Gear Solid 3: Snake Eater, the computer games Real War, IGI-2: Covert Strike, Microsoft Flight Simulator X, X-Plane and in the Charles Stross novella Missile Gap.

A few historical notes

(Translated from the Russian article on ekranoplanes)

The ground effect was first encountered in the mid 1920s by pilots during taking off in and, above all, landing low-winged aircraft. There was a marked increase in wing lift, so that an aircraft continued to fly just above the ground, as though it did not want to land. Moreover, the ground effect sometimes had unpleasant consequences. It caused the centre of pressure of the wings to move back, so that, in the absence of effective horizontal control, many accidents occurred during landings.

In 1932 experimental flights at low heights over the North Sea by the heavy twelve-engined Dornier Do-X, whose wings had large chord, exhibited a great reduction of aerodynamic drag and fuel consumption. In the same year, the well-known aircraft engineer, inventor and aircraft builder P. I. Grokhovskii was working on a project involving an amphibious two-engined ekranoplane with an aerodynamic layout which is characteristic of several present-day ekranoplanes.

In 1935 the Finnish engineer Toivo J. Kaario built the first experimental towed structure designed for the study and application of the ground effect. The sledge ekranoplane had wings measuring 2 x 2.6 m mounted on skis. The ekranoplane was towed by a propeller-driven sledge.

One of the first Russian works referring to an investigation of the ground effect was that of B. N. Yur'ev "The influence of the ground on the aerodynamic properties of wings". In the 1930s theoretical investigations of the ground effect were carried out by V.V Golubev, Ya. M. Serebriyskiy, Sh. Ya. Biyachuev and others.

During the development of ekranoplanes, constructors in several countries encountered many problems, beginning with the choice of anti-corrosive materials, and finishing with flight stability problems. Governments in these countries refused to support the projects, but experiments by these firms "at their own risk and peril" did not come to fruition. Even when they did undertake investigations, they remained on the drawing board.

References

1. "EKRANOPLANES- Controlled Flight Close to the Sea" by Prof.A.V.Nebylov, WIT Press.
2. "Complex Algorithms of Parameters Measuring Systems for Motion Close to the Sea" by Sukrit Sharan(Aerospace Trainee from India) , IX Conference for Young Scientists, CSRI-ELEKTROPRIBOR, March 2007, St.Petersburg, Russia.
3. "Quality Measurement Criteria for Flight Close to the Sea Surface" by Sukrit Sharan, Seminar on 'Aeronautics & Space', 9-13 April, 2007 St.Petersburg State University of Aerospace Instrumentation, Russia.
4. "Easy Ways to Study Ground Effects" by Aubin S.Y., Monchaux J., 2001.

See also

• Related developments: Beriev Be-2500, Boeing Pelican
• Comparable aircraft: AN-225, C-5 Galaxy, Saunders-Roe SR-45 Princess; and Spruce Goose - although it was built as a normal plane, it never got more than 100ft off the ground

External links

• The Lun class on FAS
• The WIG Page, history of Wing-In-Ground craft
• Short overview of Soviet ekranoplan creation and development
• Commemorating the 85th anniversary of Rostislav Evgenievich Alexeev, an outstanding designer of highspeed ships
• Between Wind and Waves: Ekranoplans
• Graham Taylor's Model Research featuring footage of both model- and full-size ekranoplans
• Volga Shipyard The only producer in the world of Ekranoplans