in the military, silence in the air is no longer sufficient for concealment. Development The development of modern gliders was spurred by the Versailles Treaty following World War I, under the terms of which Germany was prohibited from constructing certain high powered airplanes. As a result, German aircraft designers turned their attention toward the practical development of unpowered aircraft, with a pilot remaining in the air in a glider for more than 20 minutes and a national glider competition emerging by 1922. The early sporting objectives of gliders were quickly overtaken in the Soviet Union and in Germany by military applications, mainly the training of pilots. By 1934, the Soviet Union had ten gliding schools and 57,000 glider pilots had gained licences. In 1932, the Soviet Union demonstrated the TsK Komsula, a four-place glider, designed by GF Groschev that could also be used for cargo. Larger gliders were then developed culminating in an 18-seater at the military institute in Leningrad in 1935. Luftwaffe Colonel Kurt Student visited Moscow as part of the military collaboration programme with the Soviet Union. He reported back to his superiors in Berlin details of a 1,500 man parachute drop and the large transport gliders that he had seen. The Luftwaffe opened a parachute school as a result in 1937. Further field testing convinced Student that a vehicle was needed to deliver the heavy weapons for the lightly armed parachute troops. This idea was dismissed until October 1938 by which time Student had risen to major-general and was appointed Inspector of Airborne Forces. Development of a troop-carrying glider was assigned to Hans Jacobs of the Deutsche Forschungsanstalt für Segelflug to develop the DFS 230 which could carry 9–10 fully equipped troops or 1,200 kg (2,800 pounds). German military glider The Germans were the first to use gliders in warfare, most famously during the assault of the Eben Emael fortress and the capture of the bridges over the Albert Canal at Veldwezelt, Vroenhoven and Kanne on May 10, 1940, in which 41 DFS 230 gliders carrying 10 soldiers each were launched behind Junkers Ju 52s. Ten gliders landed on the grassed roof of the fortress. Only twenty minutes after landing the force had neutralized the fortress at a cost of six dead and twenty wounded. Hitler was anxious to gain maximum publicity and so several foreign attachés were given guided tours of the fortress. Consequently, the British,