Lun-class ekranoplan (NATO reporting name Duck) is a ground effect vehicle (GEV) designed by Rostislav Evgenievich Alexeyev and used by the Soviet and Russian navies from 1987 until sometime in the late 1990s. Mobile friendly. Group 1 fires the missiles.

It flew using the lift generated by the ground effect of its large wings when close to the surface of the water–about 4 metres (13 ft) or less. Although they might look similar and have related technical characteristics, ekranoplans like the Lun are not aircraft, seaplanes, hovercraft, nor hydrofoils–ground effect is a separate technology altogether. The International Maritime Organization classifies these vehicles as maritime ships.

The name Lun comes from the Russian for harrier.