EKRANOPLANES BOATS OR PLANES?
They fly few metres above sea level and they are strange machines part boats part airplanes. Technically they are called Ekranoplanes and up until several years ago, their use was very limited and they were deployed only as military experimental vehicles.
In technical terms they are called Ekranoplanes they are more specifically half way between a sea plane, a catamaran and a hovercraft. They in fact fly few metres above the surface thanks to a buffer or air cushion which forms below the wings exploiting what flyers would call WIG in short for Wing in Ground Effect. This is why recently they have been termed GEV or Ground Effect Vehicles. The Russians were the first to experiment these in the fifties hence the name ekranoplane which is nothing more than an adaptation of the Russian term экраноплан, ekranoplan. The idea was to develop a strategic transportation vehicle which could equal the load capacity of a ship with the speed of a plane. Despite approximately 40 years of tests, this vehicle never made it in terms of safety, reliability and efficiency as hoped. Consequently very few were built, nearly all of the in the former USSR. Recently though interest for these strange vehicles returned given their potential, as perhaps service boats and tenders to superyachts. And a Russian- Chinese concern has begun to test two GEV prototypes, which could be deployed to transport people with. The CY G11 as per the code name is precisely 13 metres long with a notable wing span of 15.60 metres. It can carry up to ten passengers plus two crew at 200 km/h with a range of 1,500 km. The fuel consumption is decidedly low: 28 litres per 100 kilometres. In Germany Seafalcon after nearly 20 years of in depth R&D, tests and prototypes is looking around for partners with whom to start production in series of the GEV Seafalcon which is 13.7 metres long with a smaller wing span in comparison to the Russian-chinese version of only 11.50 metres with a carrying
capacity of just 8 and a cruising speed of 180 km/h using a mere 15 litres/hour of diesel fuel. But what has changed in the meantime , how are these any different from the ones from the 60’s and 70’s which were considered as unsafe and unreliable? What makes them safe and reliable today? Let’s begin by explaining what is meant by ground effect which makes these vehicles very efficient starting with extraordinary low fuel consumption. As an example observe the flight of a seagull, albatross or other sea birds. You will often see them fly low skimming the surface because by doing so their flight path is more efficient and they tire less! This is due to the ground effect, or that phenomena which determines two effects: an increase in Lift (the force which holds up planes thanks to the diverse pressures exercised on the surface of a wing) produced by air which is compressed between the wings and the surface of the sea thanks to the relative closeness between pairs of wings and sea; a considerable reduction of drag in comparison to high flying modes, due to a considerable reduction of vortices along wing tips. More specifically, we’re referring to the vortices generated by the difference of pressure on the back and belly of each wing which cause induced drag. Alexeev Rostislav Evgenievich a Russian naval engineer was the first to notice this and was the first to invent what is now the GEV. He convinced government to invest in R&D back in the fifties to further the project he was working on, something between a seaplane and a boat. It is of no coincidence it was
considered as something strategically useful with which to carry troops and weapons very quickly. The project by the 60’s had expanded and Russian engineers began to build giant vehicles like the KM1, nicknamed the “Sea Monster of the Caspian Sea”by US intelligence. In fact it was a 100 metre long 40 metre wide monster propelled by as many as 10 turbines and propellers which meant it could cover more than 500 kilometres in an hour. It was the largest ekranoplane ever built. A further seven were built. Each one featured different characteristics in an effort to overcome serious handling problems and safety issues, despite the adoption of huge tail planes, with which to manoeuvre and steer, which resembled huge rudder blades and spoilers.try to imagine what would happen when the pilots attempted to bank with such a huge vehicle flying at 400 – 500 km/h and just a few metres above water. The slant adopted when banking meant the inside wing tip would get dangerously close to the surface of the sea. Imagining the consequences if that happened is easy, or if the sea was choppy. That is why testing was carried out over the Caspian Sea, a closed stretch of water where waves would be a lot lower than in any ocean! In spite of the precautions taken several catastrophic accidents occurred, so much so that the unfortunate vehicle was soon labelled as something highly dangerous by those involved. Nevertheless more studies and more experimental tests continued on other models in Russia up until the 80’s when, with the crisis and splitting up of the former USSR, all was abandoned. However the charm and appeal derived from the enormous potential this vehicle had generated, a lot more influential people were interested: In addition to the Soviets , the USA, Germany, Australia and Japan all invested in developing this means of transport, but without resolving much in a convincing way. Research continued after the ‘cold war’. At the beginning of the new millenium, Boeing ( yes that Boeing) decided to set up and develop a new ocean crossing vehicle capable of carrying considerable loads comparable to those of a military ship and equal the speed of a plane: the result was the Boeing Pelican ULTRA (acronym for Ultra Large Transport Aircraft), it turned out to be 120 metres long with a wing span of 152 metres and a load capacity of 1,400 tons. It would have been the largest ever built.... but nothing came of it because everything remained
on the drawing board! Several European attempts were also made in an effort to exploit this vehicle’s potential, perhaps by flanking it with hydrofoils to enhance better manoeuvrability and steering control as was in fact was done in the course of the 90’s with “Seabus Hyder” a European Coop. Project which would carry 800 passengers and 120 motor cars. As we have seen the ekranoplane is, at least in theory a very efficient vehicle which has naturally stimulated and is still stimulating engineers’ interest and fancy whims from all over the world, even if they have not yet managed to resolve, in a convincing way the issues and problems related to reliability and safety mentioned earlier. At least up until today, the new Russian - Chinese CY G11 and the German Seafalcon seem to point out this technology is now ready even if limited to decidedly smaller vehicles when compared to the ones tested in the past. In fact most probably it was the very size of the previous prototypes that was one of the main causes attributed to past failures. So nowadays, also thanks to enhanced control of the vehicle brought about by the development of modern electronics, these vehicles’ potential has been attracting much attention even if the cost is not for everyman’s pocket: A CYG11 costs about 20 million US dollars, but the fact that high speeds around 200km/h, which exceed by far those of any naval vehicle, when flanked by a load capacity which is unimaginable for any conventional plane is coupled to high level comfort can be very appealing to military navies, coast guard patrols, bulk carriers and last but not least to the magical super and mega yachting world. Worth considering also is the fact that by containing the size of these vehicles they can slot into today’s normal infrastructures found in existing ports and marinas. Certainly if ekranoplanes develop significantly a few norms concerning navigation at sea will have to be re-written to account for the presence of these vehicles which would cruise at the same height off the surface as ships do, but at much higher speeds. Realistically speaking since 2005 the International Maritime Organization (IMO) has foreseen 3 categories of GEV “ships” according to their capacity of exploiting ground effect alone, or to fly also at some recognized distance from the surface. Nevertheless for the time being the only set of rules foreseen for the classification and construction of GEVS (Ground Effect Vehicles)are still those envisaged by the pertinent Russian registry.
The “Sea Monster of the Caspian Sea”, was the name the Americans gave to the Russians’ GEVS. Among these the 100 metre long 40 metre wide KM1 which was the largest ever built.
Above, the Seafalcon: 13.7 metres long with a wingspan of 11.50 m it can carry up to 8 people. The Russians’ passion for GEVS has never diminished completely: The Russsian Arctic Trade and Transport Company (ATTK) has continued with R&D, has built GEVS of several sizes and types and in 2006 it launched “Aquaglide 2” a small easy to steer GEV carrying 4 passengers and 1 pilot. It is little more than ten metres long and 6 across. It can fly skimming the surface up to 150 – 170 km/h. Below, a GEV can “park” on the water or on land. “Aquaglide 2” in the photos”.
Above, the CY G11: 13 metres long with a wingspan of 15.60 m. Sea birds fly skimming the surface of the sea to be more efficient, meaning they can go further as they tire less! In this mode they exploit ground effect exactly in the same way as ekranoplanes, (GEVS).
Above, the “Sea Monster of the Caspian Sea” today - sadly abandoned. On the right, another two shots of the “Aquaglide 2”. Below, Flying near the surface of the sea therefore means air is compressed below the wings and thus ground effect is exploited. This means the flight is much more efficient(less fuel is needed) because lift increases while drag diminishes drastically when compared to free flight.
Boeing’s Pelican ULTRA: 120 m long with a wing span of 152 which never left the drawing board.
Flying at altitude the vortices generated by wings are obstacle free and spread freely. When flying low near the surface the vortices cannot expand freely and they’re compressed and blocked due to the effect caused by the closeness to the surface, whether it be land or sea.