The M22 Light Tank, Locust, was a small tank that was designed to be carried by heavy gliders or transport aircraft and used to support airborne operations. Although it was a technical success it wasn't of great tactical value, and only 6 of the 830 that were built were actually used in combat.
In February 1941 the Ordnance Department and the Armored Force decided to ask for designs for a light tank that could be used to support airborne forces. A formal specification was completed in May 1941 and called for a tank that weighed 8 (short) tons and that would be small enough to be carried either inside or below a transport aircraft. Christie, GMC and Marmon-Herrington were all asked to produce designs.
The Marmon-Herrington design was considered to be most promising and they were given a contract to produce a prototype with the designation T9. This vehicle was completed in the autumn of 1941. It had a cast turret with a rectangular plan but curved edges, carried a 37mm M6 gun and a hull mounted machine gun. It used vertical volute spring suspension with four road wheels on each side and a trailing idler, had a power traversed turret and a gyro-stabiliser. The superstructure began at the turret front and had sloped sides over the tracks, with a slightly sloped front deck. It was powered by a Lycoming 6-cylinder air-cooled engine.
The T9 underwent trials and a number of modifications were requested. The weight was considered to be too high and a number of features were removed, including the gyro-stabiliser, the power traverse and the hull machine gun. The front of the hull was also modified, and the new design had a rounded nose with a single sloped front plate that ran back to the turret. This was done to improve shot deflection. The turret and turret basket were modified to make them easy to remove. Work on this new design began in February 1942 and the new model was ordered into production. Marmon-Herrington built 830 of the new tank between March 1943 and February 1944. At this stage it still had the T7 designation, but in September 1944 it was redesignated as the Light Tank (Airborne) M22 and accepted as 'limited standard' equipment. Although the M22 was lighter and smaller than the M3 or M5 Light Tanks, it was still too large to fit into any available American transport aircraft and the only way to move it was by removing the turret and slinging the tank below a C-54 Skymaster. The M22 was never used in combat by American troops.
Early in 1943 the T7E1 was sent to Britain for trials. The British were developing their own airborne tank, the Tetrarch, and were also working on the Hamilcar glider. This large glider proved capable of carrying the M22 and 260 were supplied to Britain under Lend-Lease. In British service the M22 was known as the Locust. A number of Locusts were given Littlejohn adaptors, extensions to the gun barrel that increased the velocity of the 37mm shell.
The Locust was only used once in combat. On 24 March 1945 six of them were used by the 6th Airborne Recce Regiment, 6th Armoured Division, during the crossing of the Rhine. By the time it had been built the M22 was thinly armoured, under-gunned, cramped and awkward to operate, and of very limited tactical use against the German tanks and anti-tank weapons of 1944-45.
Hull Length: 12ft 11in
Hull Width: 7ft 1in
Height: 6ft 1in
Crew: 3 (commander, gunner, driver)
Engine: 162hp Lycoming 0-435T 6 cylinder petrol engine
Max Speed: 40mph (road), 30mph (cross country)
Max Range: 135 miles road radius
Armament: One 37mm M6 gun and one .30in Browning machine gun