And, according to this Getting more strategic lift: Wing-In-Ground effect craft:
China, a great power in the Pacific, is particularly interested in WIG Air-Mech technology. Chinese analysts attribute the following advantages to WIG craft over conventional ships and aircraft:
--Superb Mobility. A WIG Air-Mech craft travels above the water's surface to travel in the air whose density is 800 times less than that of water. This greatly decreases the drag exerted on ordinary vessels and greatly increases its speed. Fast transports have a top speed of 20 knots. A conventional warship has a maximum speed of 30 to 40 knots, and although the hulls of hydrofoil craft and hovercraft travel above the water, their hydrofoils and their aprons still come in contact with the water. Thus their speed is limited to between 70 and 80 knots or less. But a WIG Air-Mech craft can travel between 300 and 400 knots.
--Superb Airworthiness. A WIG craft can fly around bad weather or fly above a stormy sea. Since a WIG craft is not pounded by the storm waves it is remarkably seaworthy. It is also very airworthy.
--Ease of Operation. A WIG craft is controlled through its vertical rudder, its elevator, and its wing flaps. It is simpler to fly than an airplane, and it turns easily. The WIG craft's speed and altitude are easily controlled by the flaps.
--Economical operation. Pressure under the wings of a WIG craft increases greatly by flying fairly close to the water surface. Consequently, only 80 to 130 horsepower are required to propel each ton of weight. The large lift-drag ratio means that fuel-consumption is less and the cruising radius is expanded when compared to similar-sized aircraft. WIG craft are far superior to ordinary aircraft and helicopters in carrying capacity, speed, and cruising radius when using the same power.
--Convenient Maintenance. WIG craft do not need permanent shore bases. Unlike other high-speed craft, they are able to come ashore under their own power and do not need cranes or chutes. Furthermore, since they have no aprons, like hovercraft, maintenance is very convenient. WIG craft do not have to make a gliding takeoff from the water or land on the water like seaplanes. This lessens the corrosive effect of seawater on the hull.
--Diverse Flight Modes. Not only can WIG craft fly quickly and steadily above water, under radar detection but they can also fly above beaches, marshes, grasslands, deserts, glaciers, and snow-covered land.
--Flight Safety. Should the engines fail, the WIG craft can travel on the water like a conventional ship. They are stable craft, which have operated safely over the years. Some WIG craft vent their engine exhaust forward beneath the wings of the craft to create an increase in dynamic lift. This not only assists takeoff and improves amphibious performance, but also improves flight safety.
--Military applications. The speed, maneuverability, amphibious capability, and reduced signature of WIG craft are greater than that of other craft. Their fast, low-altitude approach may allow them to become the next generation of fast attack craft replacing hydroplanes and hydrofoils. Since WIG craft usually fly within 50 meters of the surface, they are in the radar sweep and search blind zone. The ultra-low altitude of WIG craft leaves no traces on the water surface and is difficult to detect by radar. WIG craft are not optically trackable from space like conventional surface ships. This greatly increases the concealment and surprise attack capabilities of the craft. This extraordinary concealment capability has extremely important military significance. WIG craft may be used as Air-Mech landing craft and for the rapid and effective movement of Heavy AFVs, Gavins/Ridgway and M8 Buford AGS Armored Fighting Vehicles and troops in a campaign. The low-flying altitude, the long cruising radius, and the AFV carrying-capacity of WIG craft are second to only ships. WIG craft are also suited for anti-submarine patrol craft, high-speed minelayers, minesweepers, and rescue craft.
FuturePundit discussed WIG back in 2002 here
And, Boeing has explored the world of WIG - with the Pelican: here, here and the Boeing site: here
"The Pelican can broaden the range of missions for which airplanes are the favored way to deliver cargo," said Boeing's Pelican program manager Blaine Rawdon, who is designing the plane with Boeing engineer Zachary Hoisington. "It is much faster than ships at a fraction of the operational cost of current airplanes. This will be attractive to commercial and military operators who desire speed, worldwide range and high throughput. We envision that the Pelican can multiply aircraft's 1-percent share in a commercial market now dominated by container ships."For the military, of course, it's all about getting there in a hurry with a lot of stuff, although having to have a "landing field" to handle the Pelican's landing gear may prove a non-starter.
John Skorupa, senior manager of strategic development for Boeing Advanced Airlift and Tankers, said, "The Pelican currently stands as the only identified means by which the U.S. Army can achieve its deployment transformation goals of deploying one division in five days, or five divisions in 30 days, anywhere in the world." If necessary, he said, the Pelican could carry 17 M-1 main battle tanks on a single sortie. Commercially, the aircraft's size and efficiency would allow it to carry types of cargo equivalent to those carried by container ships, at more than 10 times the speed.
"It is attracting interest as a mother ship for unmanned vehicles, enabling rapid deployment of a network-centric warfare grid, a likely future mode of operation for modernized U.S. forces as demonstrated in Afghanistan," Skorupa said. "And it is attracting interest as a potential first-stage platform for piggybacking reusable space vehicles to an appropriate launch altitude.
"Why would such a huge airplane be flown at such a low altitude?
By flying low, the Pelican, like its name-sake, exploits the aerodynamic benefits of a well-known phenomenon called ground effect. Flying close to water, the wing downwash angle and tip vortices are suppressed, resulting in a major drag reduction and outstanding cruise efficiency.
"It's an effect that provides extraordinary range and efficiency," Skorupa said. "With a payload of 1.5 million pounds, the Pelican could fly 10,000 nautical miles over water and 6,500 nautical miles over land.
"Flying in ground effect demands the latest flight control technology, conceded Skorupa. Reliable systems will provide precise, automatic altitude control and collision avoidance. Cruise altitude will be adjusted according to sea state, and if the seas get too rough, the Pelican can easily climb to high altitude to continue the flight.
And, don't forget there have been a few other aviation ideas that didn't quite pan out.