Lun-class ekranoplan Low-poly 3D model

The Lun-class ekranoplan (also called Project 903) is a ground effect vehicle (GEV) designed by Rostislav Alexeyev in 1975 and used by the Soviet and Russian navies from 1987 until sometime in the late 1990s.

It flew using lift generated by the ground effect acting on its large wings when within about four metres (13 ft) above the surface of the water. Although they might look similar to traditional aircraft, ekranoplans like the Lun are not classified as aircraft, seaplanes, hovercraft, or hydrofoils. Rather, crafts like the Lun-class ekranoplan are classified as maritime ships by the International Maritime Organization due to their use of the ground effect, in which the craft glides just above the surface of the water.

The ground effect occurs when flying at an altitude of only a few meters above the ocean or ground, the wings push air downwards where it is compressed between the wings and ocean surface. This causes higher pressure under the wings and creates lift. This effect does not occur at high altitude.

The name Lun comes from the Russian word for the harrier.