The 540 tonne “Caspian Sea Monster” was the largest wing-in-ground (WIG) effect vehicle (known as ekranoplan in Russian, wingship in US) ever built. This 106 m (348 ft) long leviathan was capable of skimming just meters above the ocean at speeds of up to 500 km/h (311 mph) and was built by the Soviet Central Design Bureau of Hydrofoil Vehicles in Gorky in the mid-1960s.

This vehicle was around twice the size of the largest aircraft of its era, with relatively stubby "wings" with a span of 40 m (131 ft), but a tailplane as tall as a five-storey building (22 m or 72 ft) to aid stability. It was powered by 10 turbofan jet engines, but was destroyed in a crash in 1980.



WIG vehicles operate on the principle that as aircraft fly closer to the ground they experience added lift as a result of increased pressure under their wings. Because the forward movement of the craft generates an "air cushion" on which it glides, WIGs are a highly efficient means of transport. WIG vehicles are effectively a cross between a hovercraft and an aircraft. The Russians conducted large-scale research into ekranoplans during the Cold War, hoping that they could have military applications, possibly as high-speed troop landing craft or missile platforms. Today, there is a renewal of interest in WIGs and much smaller models are being produced commercially.