produce 100 gliders, and plans called for the procurement of 12,000 more amphibious gliders if the concept proved successful. No twin-hulled glider was built, but each company constructed the prototype of a single-hulled amphibious glider, the XLRA-1 by Allied Aviation and the XLRQ-1 by Bristol Aeronautical. The two prototypes made their first flights in early 1943, but by the time they did the Navy and Marine Corps already had concluded that the use of gliders to deliver Marines to beachheads was impractical. No further examples of the two glider types were built, and the Navy officially terminated the amphibious glider program on 27 September 1943. Testing of the two prototypes continued until early December 1943, apparently in connection with the development of a glider bomb. The Marine Corps established a glider training unit in early 1942 at Marine Corps Recruit Depot Parris Island, South Carolina, using non-amphibious Pratt-Read LNE-1 and Schweizer LNS-1 gliders. In addition, the Navy took delivery during World War II of 15 U.S. Army Air Forces Waco CG-4A non-amphibious gliders for evaluation under the Navy designation LRW-1. Neither of these initiatives resulted in operational use of gliders by the U.S. Navy or Marine Corps. Soviet military gliders The Soviet Union built the world's first military gliders starting in 1932, including the 16-seat Grokhovski G63, though no glider was built in quantity until World War II. During the war, there were only two light gliders built in series: Antonov A-7 and Gribovski G-11 – about 1,000 altogether. A medium glider, the KC-20, was built in a small series. They were used mostly for providing partisans in Belarus with supplies and armament in 1942–1943. On 21 September 1943, 35 gliders were used in the Dnepr crossing. Later, other types of gliders were built: the Cybin C-25 (25 trooper) in 1944, the Yakovlev Yak-14 (35 trooper) in 1948, and the Ilyushin Il-32 (60 trooper) also in 1948. In 1950, a Yak-14 became the first glider to fly over the North Pole. The Soviet Union maintained three glider infantry regiments until 1965. However, Soviet Air Force transport gliders were gradually withdrawn from service with the arrival of turboprop transports like the Antonov An-12 and Antonov An-24, which entered service in the late 1950s. See also Army Flying Museum Glider Pilot Regiment Glider snatch pick-up HAHO – High Altitude – High Opening, a form of inserting troops by parachuting List of World