sentences:  In 1950 a Yak-14 became the first glider to fly over the North Pole.During World War II, the Soviet Union operated only light gliders like the Gribovsky G-11, Antonov A-7 and Kolesnikov-Tsybin KC-20 which were unable to transport vehicles, light tanks or artillery.Only after the war were Soviet designers ordered to develop medium gliders capable of carrying heavy or bulky loads.