Ekranoplan is quite interesting vehicle. It is mixture of airplane and hovercraft. Simply speaking, ekranoplan is airplane specially designed to fly in low altitude above water surface. It takes advantage of aerodynamic principle “ground effect”. Basically the air between wings and water surface is very compressed and thus it allows to fly in very low altitudes (few meters above water surface is enough). Ekranoplan’s principle and construction was developed in Soviet Russia during cold war.
Flying in low altitude have several advantages. Plane needs less fuel and it flies below radar. Also it allows to transport heavier load than conventional planes.
Ekanoplan KM, also known as Caspian Sea Monster, was biggest and heavies ekranoplan. It was 100 meters long and it weights unbelievable 544 tons. Despite its weight, it could lift heavier load off the ground than any other plane. Unfortunately Russians built only one KM. This one exemplar accidentally crashed due to fog and it was abandoned in water. It is almost impossible to recover it due to its weight.
More ekranoplans has been designed and constructed after Caspian Sea Monster. Its successors were smaller and lighted and they were used for military purpose and for civil purpose as well.
Ekranoplan Orlyonok was one of the most successful ekranoplans. It was used for military purpose and for cargo transfer.It was lighted and smaller then Caspian Sea Monster. A-90 weighs 140 tons and it was 58 meters long. It reached 400 km/h in altitude from 5 to 10 meters.