The KM (Korabl Maket) (Russian: Корабль-макет, literally "Ship-prototype"), known colloquially as the Caspian Sea Monster, was an experimental ground effect vehicle (ekranoplan) developed in the Soviet Union in the 1960s by the Central Hydrofoil Design Bureau. The KM began operation in 1966, and was continuously tested by the Soviet Navy until 1980, when it was damaged in a testing accident and sank in the Caspian Sea.
The KM was the largest and heaviest aircraft in the world from 1966 to 1988,...
