*********** 040894B.ENG *********** Country: Japan, Russia From: Nikkei Weekly Week of 28 March 1994 p. 12 KEYWORDS: Japan, Russia, Hybrid Transport, Sea Surface Plane, Surface Effects +++++ IS IT A BOAT, IS IT A PLANE? No, it s a potentially efficient, new hybrid form of transportation NIKKEI BUSINESS At first glance it looks like a boat, skimming quickly through the water. But closer inspection reveals the stubby wings and frontmounted engines of what is called a sea-surface plane. As the name implies, a sea-surface plane is something half- way between a boat and a plane. The hybrid does not take off into the air, but flies just above the water's surface, much like a hovercraft. Work on commercial sea-surface planes is still at the research and development stage. What keeps developers interested is the promise of a new and efficient form of transportation which combines the strong points of boats and planes. A jet can move passengers at high speed in a short time, but transportation costs are high. A ship can move large quantities of goodsand people in one trip, but it takes time. The sea- surface plane can haul more passengers at lower cost than a plane, while traveling at least 10 times faster than a ship. And since a sea-surface plane does not have to ascend to high alti- tudes, on medium-haul runs of several hundred kilometers it can take less time than an aircraft. DRAG NYET Russian engineers are at the forefront in the development of sea-surface planes. The former Soviet military developed vessels for deployment in the Caspian Sea. That military technology is now being applied to the development of civilian planes which can be sold to the West. There is even talk of the development of a huge sea-surface plane. Because the plane flies so close to the surface of the water, the air that flows underneath the wings does not have the room to turn downward and create air eddies at the tips of the wings, as happens on a normal airplane. As a result, there is less induced drag, which means that less energy is required to gain speed, and the wings provide greater lift. The fact that there is no room for the air to flow downwards also means that the plane is always flying in its own updraft. This further reduces the force needed to lift the plane. Th6 net effect is that a sea-surface plane can carry as much as twice its weight in passengers and freight, even when fully loaded with fuel. In comparison, an ordinary aircraft is restricted to a payload roughly equivalent to its own weight. A Boeing 747, for example, can carry 550-570 passengers. A sea- surface plane of the same size could carry 1,000. There are many other advantages to the sea-surface plane. Since it takes off and lands on water like a seaplane, there is no need for buge airport runways, even a small harbor would suffice. And since it can come up on land like a hovercraft, loading passengers and cargo is a simple procedure. In addition, the plane can become airborne at speeds as low as 15km per hour. This is because the engines are placed so far forward that air streaming back from the engines passes below the wings, serving as extra lift force. Since the plane can fly at such low speeds, the impact on landing is relatively low, and it is not necessary to build added strength into the fuselage. SALT TOO But it will be some time before sea-surface planes come into commercial use. There are many technical issues which need to be resolved, and various designs are still being considered by developers in Russia, as well as Europe, the U.S. and Japan. Engine technology is a major focus. The gas turbine engines that are used on jet planes lose more than half their fuel efficiency when flown near sea level, where the atmosphere is much denser. For a medium-distance, medium-speed commuter craft, propellor engines look more promising. In addition to higher fuel efficiency, they have the added advantage of a quieter ride. Traveling so close to the sea surface, another problem is salt corrosion. Diesel engines are thus also being investigated, since they offer high corrosion-resistance, and their fuel efficiency remains fairly constant. The problem, however, is how to make the heavy diesel engines lighter. The Russians are seeking to commercialize a sea-surface plane that can carry 150 passengers and can cover a distance of 2,000km. But the price tag is a steep $25 million, so there is still a need to make the craft more economical. The Russian government is seeking funds from the U.S. and Japan to develop a more practical design. Meanwhile, aircraft makers in the U.S. and Europe have launched development studies of their own. And in Japan, Mitsubishi Heavy Industries Ltd. is considering developing a sea- surface plane which can be used as a leisure craft. Of all the countries looking to commercialize sea-surface planes, Japan seems a natural, given its wet surroundings. ************** END Msg. B.ENG **************