Wing-in-Ground Effect Aircraft - Principles & Progress

Neville H Cross

BRLSI Member

27 May 2005

The purpose of this paper is to provide an analysis of previous types and designs of wing-in-ground (WiG) aircraft and how they operate. The term WiG is essentially a western description, which a Russian, whose designers had had many years and numerous designs in this field, would call an Ekranoplan. The principle of this type of transport is to exploit the inherent properties of what is known as the air-sea interface. This is essentially the layer of air that is present between the surface of the ocean, or land, to an altitude of approximately 15 feet. This is of course not an absolute definition, as this layer can vary in almost every instance. If you are slightly confused, this is not unusual, as this is not easy to understand. To further distort the picture, a WiG is operating at its most efficient where water vapour is present, which is over the sea.

We examine what the air-sea interface is, and how this close proximity to a supporting surface is the principle. One of the advantages of a craft in flight at this level is that the amount of thrust for propulsion is reduced, when compared to higher altitude flight. A craft thus operating in the air-sea interface has reduced operating costs than an aircraft, yet is faster than a ship. In addition, while in the past it has been possible to compare one type of transport with another, in this field it is no possible as these craft in theory can be either land or water borne. A change from a wooden sail powered ship to an engine driven propeller ship, had the advantages of both time, and later size. Similarly, a small aircraft over a short distance was disadvantaged by larger aircraft over larger distances. In this field then, it is necessary to assimilate the disciplines of naval architect with an aeronautical engineer. The aim being to provide a form of transport that can surpass the speed of surface borne vessels yet be more cost effective than an aircraft.

This is not a new field of human endeavour; indeed many eminent engineers have produced designs, the two most notable being the German Alexander Lippisch, and the Russian R.Y. Alekseyev. Although both of these two designers have increased our knowledge on the topic, it was Alekseyev who produced what is known in the West as the Caspian Sea Monster, or in Russian as KM. This design mounted up to ten jet engines to overcome the initial drag on take-off, and demonstrated that the WiG concept was viable, and proven to work. The purpose of KM was essentially a proving design, and hence although reports suggest that more than one was built, it did not lead to commercial reality. Another design that did lead to a brief period of service in the Russian Navy was the A-90 Orlyonok. The reason for this design was to provide a high-speed amphibious assault capability. The design of the craft was to carry two armoured personnel carriers, and was powered by two jet engines and a propeller engine. In addition a pilot trainer design was built, as well as the Volga II and the more recent EL-7.

The desire to continue to research in this field is not confined to purely Russian researchers. In Germany the work of Herr G. Jorg and Herr H. Fischer as well as Tekno Trans, have produced WiG designs. These two countries are not the only ones to recognise that the WiG theory and concepts will in time reveal potential and opportunity. A design team in Australia led by John Leslie has produced a design, and there is interest in Korea, Japan and from Boeing in the USA. The country that has begun to produce multiple designs is China, where at least two design teams are at work, and reports of 100 seat passenger carrying craft have emerged.

In the UK, despite interest in the topic, only the Royal Institute of Naval Architects and BRLSI had had papers read detailing UK research projects. At the present time, my own research project ha demonstrated that not only is the field one of great potential, but it will provide both a time and cost reduction in the movement of goods. My current research has been able to prove that a WiG design for cargo purposes is both effective and workable. To this end, one of my designs has begun to take the form of a space frame outline, and has at this stage undertaken both tethered trials and proving tests. A point that has to be remembered, is that while other countries' governments have provided funding and facilities for testing, the contribution from the UK has been to establish a set of criteria for regulation of future designs, that as far as I am aware, are still awaiting release. If the impact of WiG theory has not left a lasting impression on the public mind, then it is only because the designs are still at an experimental stage. A point that is not in doubt is that the continual rise of inter-country markets and the globalisation of trade will demand a further transport system. In addition, if, as current research suggests, an environmentally friendly and significantly less harmful system of movement is possible, then further research is not only justifiable, it is essential.

Neville H. Cross

References

Eric Wertheim, Combat Fleets of the World 2005-2006, (Naval Institute Press, Maryland, 2005)

Stephen J Philips, Jane's High-Speed Marine Transportation, 1998-99, (Jane’s Information Group, 1997)

Brassey's World Aircraft & Systems Directory, (Reed Business Information, 2002)

‘Wing-in-Ground-Craft (WiGs)’ in RINA Proceedings 1997, 4-5 Dec 1997 (London, RINA 1997)

‘Warship 2003: Airpower at Sea’ in RINA Proceedings 2003, 25-26 Jun 2003 (London, RINA 1997)

WISE upto ekranoplan GEMs, (15-16 June 1998, The Institute of Marine Engineers (Sydney Branch), University of NSW, Sydney, Australia)