Military glider

Military gliders (an offshoot of common gliders) have been used by the military of various countries for carrying troops and heavy equipment (see Glider infantry) to a combat zone, mainly during the Second World War. These engineless aircraft were towed into the air and most of the way to their target by military transport planes, e.g. C-47 Skytrain or Dakota, or bombers relegated to secondary activities, e.g. Short Stirling. Once released from the tow craft near the front, they were to land on any convenient open terrain close to target hopefully with as little damage to the cargo and crew as possible as most landing zones (LZ) were far from ideal. The one-way nature of the missions meant that they were treated as disposable leading to construction from common and inexpensive materials such as wood.

Troops landing by glider were referred to as air-landing as opposed to paratroops. Landing by parachute caused the troops to be spread over a large drop-zone, whereas gliders could land troops in greater concentrations precisely at the target landing area. Furthermore, the glider, once released at some distance from the actual target, was effectively silent and difficult for the enemy to identify. Larger gliders were developed to land heavy equipment like anti-tank guns, anti-aircraft guns, small vehicles, such as jeeps, and also light tanks (e.g. the Tetrarch tank). This heavier equipment made otherwise lightly armed paratroop forces a much more capable force. The Soviets also experimented with ways to deliver light tanks by air, including the Antonov A-40, a gliding tank with detachable wings.

By the time of the Korean War, helicopters had largely replaced gliders. Helicopters have the advantage of being able to extract soldiers, in addition to delivering them to the battlefield with more precision. Also, advances in powered transport aircraft had been made, to the extent that even light tanks could be dropped by parachute. Only special forces use gliders for silent, small-scale insertion today.

Development
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 of

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, American and Japanese became quickly aware of the methods that had been used. By mid-1940 both Japan and Britain had active glider programs.

Development then began of even larger gliders such as the Gotha Go 242 (23 trooper) and Messerschmitt Me 321 (130 trooper) to transport heavy armaments in anticipation of Operation Sea Lion and Operation Barbarossa.

Gliders were also used by Germany in Greece in 1941. On April 26, 1941 the troops from six DFS 230 gliders captured the bridge over the Corinth Canal accompanied by 40 plane-loads of German paratroopers. (Fortuitously, the British were able to demolish the bridge a few hours later.) Next, General Student then convinced Hitler that Crete could be captured using only airborne troops. Consequently on May 20, 1941 500 German transport aircraft carrying paratroopers and 74 DFS 230 gliders took off from the Greek mainland. During the capture of the island 5,140 German airborne troops were either killed or wounded out of the 13,000 sent. Among the 350 German planes destroyed in the operation, half had been Ju52s, which seriously depleted the force needed for the invasion of the Soviet Union shortly after. As a result Hitler vowed never to use his airborne force in such large numbers again.

Some German glider operations continued later in the war, some examples being the rescue operation of Benito Mussolini at Gran Sasso and emergency re-supply operations in Russia, North Africa and Eastern Europe towards the end of the war. The Junkers Ju 322 Mammut ("Mammoth") was the largest such glider ever built, but it was never used operationally. Not all military gliders were planned for transport. The Blohm & Voss BV 40 was a German glider fighter designed to attack Allied bomber formations but was not used.

British military gliders
The British glider development started in mid-1940, prompted by the assault on Eben Emael. Among the types developed were the 28 trooper Airspeed Horsa and the 7 ton capacity General Aircraft Hamilcar cargo glider. The General Aircraft Hotspur was used for training the pilots who formed the Glider Pilot Regiment. The most famous actions were the unsuccessful Operation Freshman in 1942, the taking of the Pegasus Bridge during the invasion of Normandy, Operation Dragoon (the invasion of southern France), Operation Market-Garden (Arnhem Bridge over the lower Rhine) and Operation Varsity (Crossing of the Rhine). Out of the 2,596 gliders dispatched for Operation Market-Garden, 2,239 were effective in delivering men and equipment to their designated landing zones.

Although gliders are still used in the Royal Air Force in the Royal Air Force Gliding & Soaring Association and for cadet training by the Air Training Corps, they are not used in combat operations. No troop-carrying gliders have been in British service since 1957.

American military gliders
Maj.General Henry "Hap" Arnold, Acting Deputy Chief of Staff for Air (becoming Commanding General of the AAF on March 9, 1942), initiated a study with view to develop a glider capable of being towed by aircraft. This directive was set into motion through Classified Technical Instructions (CTI-198 on February 24, 1941, and CTI-203 on March 4) which authorized the procurement of 2-,8-, and 15-place gliders and equipment. Eleven companies were invited to participate in the experimental glider program, but only four responded with any interest, Frankfort Sailplane Company (XCG-1,XCG-2), Waco Aircraft Company (XCG-3,XCG-4), St. Louis Aircraft Corp. (XCG-5,XCG-6), and Bowlus Sailplanes (XCG-7,XCG-8). Only Waco Aircraft Company was able to deliver the experimental glider prototypes that satisfied the requirements of Materiel Command, the eight-seat Waco CG-3(modified to become a production nine-seat glider) and the fifteen-seat Waco CG-4. In October 1941, Lewin B. Barringer was made Glider Specialist, Air Staff, HQ of the AAF, answering to General Arnold, and placed in charge of the glider program. The shock of the attack on Pearl Harbor prompted the USA to set the number of glider pilots needed at 1,000 to fly 500 eight-seat gliders and 500 fifteen-seat gliders. The number of pilots required was increased to 6,000 by June 1942. After Barringer was lost at sea on a flight to Africa in January 1943, the program came under direction of Richard C. du Pont. Bigger gliders were later designed such as Waco CG-13A (30 troop) and the Laister-Kauffman CG-10A (42 troop)

The most widely used type was the Waco CG-4A which was first used in the invasion of Sicily and participated in the D-Day assault on France on June 6, 1944, and in other important airborne operations in Europe, e.g. Battle of the Bulge, Operation Market Garden and crossing the Rhine. and in the China-Burma-India Theater. The CG-4A was constructed of a metal and wood frame covered with fabric, manned by a crew of two and with an allowable normal cargo load of 3,710 lb, allowing it to carry 13 combat-equipped troops or a jeep or small artillery piece. The CG-10 could hold 10,850 lb of cargo, such as two howitzers at a time. The final glider mission of the war was at Luzon on 23 June 1945. By the end of the war the USA had built 14,612 gliders of all types and had trained over 6,000 pilots. The designs of the Waco Aircraft Company were also produced by a wide variety of manufacturers including Ford Motor Company and Cessna Aircraft Company as well as furniture, piano and coffin manufacturers.

Following World War II, the United States maintained only one regiment of gliders. Gliders were used in military exercises in 1949 but glider operations were deleted from the US Army's capabilities on 1 January 1953. However, the United States Air Force continues to use gliders at the Air Force Academy to train cadets in the fundamentals of flight.

A list of American military gliders is in the list of U.S. military aircraft.

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 types gliders were built: the Cybin C-25 (25 trooper) in 1944, Yakovlev Yak-14 (35 trooper) in 1948 and Ilyushin Il-32 (60 trooper) in also in 1948. In 1950 a Yak-14 made worldwide headlines when it 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 turbo-prop transports like the Antonov An-24 and Antonov An-12, which entered service in the late 1950s.