Советский экраноплан «Лунь» проекта 903

Soviet ground effect vehicle

The Lun class ekranoplan (Soviet classification: Project 903) is the only ground effect vehicle (GEV) to ever be operationally deployed as a warship, deploying in the Caspian Flotilla. It was designed by Rostislav Alexeyev in 1975 and used by the Soviet and later 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 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, craft 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 metres above the ocean or ground; drag is greatly reduced by the proximity of the ground preventing the formation of wingtip vortices, thus increasing the efficiency of the wing. This effect does not occur at high altitude. The name Lun comes from the Russian word for the harrier.

The Lun class ekranoplan was developed on the basis of the experimental KM ekranoplan, which was nicknamed the "Caspian Sea Monster". The Lun was powered with eight Kuznetsov NK 87 turbofans, mounted on forward canards, each producing of thrust. It had a flying boat hull with a large deflecting plate at the bottom to provide a "step" for takeoff. The only model of this class ever built to completion, the MD 160, entered service with the Soviet Navy Caspian Flotilla in 1987. It was retired in the late 1990s and sat unused at a Caspian Sea naval base in Kaspiysk until 2020. As of 2021, the uncompleted Spasatel is stored adjacent to the Volga river in an old industrial complex within the central Russian city of Nizhny Novgorod. The Lun design had several drawbacks. One was that although the ground effect enabled it to fly at low altitude, in order to utilize the effect it had to fly as low as off the water due to its short wingspan, so it could not fly when seas were even mildly rough. Another was that the craft was only designed to use the ground effect principle, so it could not ascend to higher cruising altitudes. The requirement for calm seas to operate and inability to fly above them if they weren't greatly limited where it was able to deploy.

On 31 July 2020, the completed MD 160 Lun class ekranoplan was towed out of the naval base in Kaspiysk, with the intention of being eventually put on public display in Derbent, Dagestan, at the planned Patriot Park, a combination museum and theme park that will display Soviet and Russian military equipment. The towing operation involved the use of rubber pontoons, three tugboats and two escort vessels, and would have covered approximately had it been completed. However, during the tow the ekranoplan became stuck just offshore of a sandy beach, short of the intended destination. The team managing the towing operation was unable to free the massive vehicle, so the ekranoplan was secured and remained beached in the surf zone while plans were drawn up on how to continue the move to Patriot Park. In the meantime, the unusual craft began attracting attention from the media, onlookers, and trespassing "urban explorers", even before the park was built. One report published in August 2020 stated that the hull, exposed to the waves in the surf zone, was taking on water. Moving the craft to dry land beyond the surf zone would eliminate the possibility that increased wave action during storms could damage the hull further. In December 2020 a successful recovery operation resulted in the ekranoplan being hauled out of the water, nose first, with the tail ending up about from the sea, as seen from satellite imagery. The ekranoplan was towed ashore on 30 December 2021.