the thrust of these engines being vectored under the wings to produce PAR thrust (increased lift and extra propulsion) for takeoff. Under cruise conditions and in ground effect, the front engines could be shut off since their power was unnecessary to keep the aircraft aloft; this also minimized intake of water, salt and low flying birds. Both takeoff and landing were assisted with large span-length flaps that greatly increased lift and could capture PAR thrust for increased air pressure. Water landings were assisted with a hydro-ski that extended out of the belly of the craft below the main wings. The front end of the Orlyonok was hinged behind the radome and the whole assembly could open sideways to speed disembarkation of the infantry it carried, or of a BTR armoured personnel carrier. The Orlyonok had a built in folding ramp that allowed it to load and unload vehicles with no external support. There were plans to resume production of the Orlyonok. The craft were to have been built in Petrozavodsk. Production Overall only four units were built: 1 non-flying unit for static testing, scrapped. S-21 completed in 1972, damaged in 1975, rebuilt as S-23 in 1977, then lost again in 1992 (the craft was blown up because the Russian Navy could not afford the price asked for its retrieval by salvage companies). S-25 completed in 1979, retired 1993, scrapped around the year 2000. S-26 completed in 1980, retired 1993, on display at the Museum of the Navy, Moscow. Operators Soviet Navy Specifications (A-90) See also Lun-class ekranoplan Boeing Pelican (concept; never prototyped or built) External links FAS.org Short summary on Soviet Ekranoplans The Alexeev Bureau (now a public company) page in English, with a color photo of the A-90 Ekranoplan An article in Russian about Lun and Orlyonok ekranoplans Register article A-90 Orlyonok on Google Maps All Orlan Class Ekranoplans – Complete Ship List Teel, George "Case study of Wing in Ground Effect with XFLR5: the A-90 Orlyonok (Орлёнок) Ekranoplan" – MAE 6226 (5 May 2015) George Washington University Internal photos References Aircraft manufactured in the Soviet Union Aircraft with contra-rotating propellers Ekranoplans Mixed-power aircraft 1970s Soviet military transport aircraft Low-wing aircraft T-tail aircraft Aircraft first flown in 1972 Alekseyev Central Hydrofoil Design Bureau Twinjets Single-engined turboprop aircraft