As GB correctly said, the only combat operation of the M22 Locust was in British hands during Operation Varsity (the airborne portion of the crossing of the Rhine).
The British glider troops operated a unit of US-made M22 Locust light airborne tanks, the 6th Airborne Armoured Reconnaissance Regiment. These were brought to action aboard Hamilcar gliders.
US Army Ordnance had pursued the development of this tank specifically at the request of the British Airborne forces, when it was determined that the Hamilcar glider could not actually safely carry the Tetrarch light tank for which it had been developed.
The M22 was developed to meet a specification issued by Ordnance in February of 1941. In May of 1941 the firm of Marmon Herrington won the contract to develop what was, at that time, identified as the Light Tank T9 (Airborne). The initial T9 prototypes were found wanting, and work proceeded on a further design, the T9E1, which actually reduced some key capabilities of the tank in favor of weight savings. However, production began on the T9 before the T9E1 was delivered, and in total some 830 tanks, now identified as the M22, were produced. In US parlance it was known only as the Light Tank M22. It was the British forces who referred to it as the Locust.
No M22 ever saw combat in US hands. Two trial battalions were trained, the 28th and the 151st Airborne Tank Battalions. But the US did not operate any gliders large enough to carry the M22, and so the tank had no real combat value and was never deployed for action by the US Army. Only the British 6th Airborne Armoured Reconnaissance Regiment took the Locust into battle.
The M22 was a remarkably small tank. It was about 6 feet tall. I know how small they are, because when I stood next to a restored M22 at the MVTF (the "Littlefield collection") I could actually look right across its turret roof!
It weighed about 8 tons. With a 165HP Lycoming radial engine it achieved a top speed of about 40mph. It was armed with a 37mm cannon in a 2-man turret. The vehicle was crewed by a driver, and gunner, and a commander who also served as loader for the gun. It was also armed with .30 caliber M1919 machine guns – one mounted co-axially in the turret, and two fixed to fire forward in the bow.
The armor on the M22 was very light. It was unable to resist even the most basic of German anti-tank weapons, and was not even fully bullet-proof in some areas. By the time it saw action in 1945, the M22 Locust was too light to be effective in any sort of heavy combat.
Its history in Operation Varsity is not glorious. Only eight were deployed in the operation. As GB identified, one of these fell through the floor of its Hamilcar glider while in flight. Another broke loose from its bindings and flipped out of its glider onto its roof upon landing. One broke down while trying to tow another vehicle out of its glider, but continued to provide fire support for the efforts to clear the landing zone. One was detached to support an American unit in difficulties, and was destroyed by German fire (the "Panther" incident that GB described). The remaining tanks moved forward with British forces, but were withdrawn after a few hours of combat as it was observed that they added little to combat effectiveness, but drew an excessive amount of German artillery fire.
-Mark
(aka: Mk 1)