The Light Tank M2 was the standard American light tank of the late 1930s, but it was obsolete by the time the United States entered the war and saw very little combat. A handful of M2A4s were used by the Marines on Guadalcanal, but elsewhere they were only used as training machines. The main significance of the M2 was that it was the basis of most US light tank designs until 1944, including the M3 and M5 Stuart tanks that were used in large numbers in most theatres of the war.
In 1920 responsibility for tank development in the US army was given to the infantry, on the assumption that tanks would continue to be infantry support weapons. Two types of tanks were to be developed - light tanks under 5 tons that could be carried on a truck and medium tanks between 5 and 15 tons in weight. Needless to say the light tanks quickly outgrew the 5 ton limit.
The first light tank to be produced was the Light Tank T1 of 1927. This was a two-man tank armed with a 37mm gun in a turret mounted at the back of the vehicle and a .30in machine gun in the hull. The engine was carried at the front of the vehicle. Even the Light Tank T1 weighed 7.5 tons. Two variants on the T1 appeared in 1929. The T1E1 had a modified nose while the T1E2 had heavier armour and a more powerful engine. The T1E3 followed, with the same basic layout but better suspension.
The T1E4 of 1932 was a dramatically different design. The basic layout was changed. The engine was moved to the back and the final drive to the front. The turret was placed in the middle of the tank, but still carried the 37mm gun. This basic layout would be used in the majority of US light tanks until 1944.
In June 1933 work began on a new tank project. The aim was to produce a light tank for the infantry and a combat car for the cavalry (the US cavalry wasn't meant to operate tanks, so called its armoured vehicles combat cars). The two designs were to be as similar as possible, and the eventual vehicles (the Light Tank M2 and Combat Car M1) would use the same suspension and basic fuselage, but with different turrets and other minor changes). Both designs were to be produced by the Rock Island Arsenal.
Both vehicles were developed from the T1E4. Next in the infantry series was the Light Tank T2 of 1933-34, which shared the same layout as the earlier tank, but with a new turret that carried one .50in machine gun and one .30in machine gun. This was a rather odd looking turret with a circular central section and a square gun house at the front. The T2 and the similar Combat Car T5 were both demonstrated in 1934.
Next was the T2E1 of 1934-35. This was similar to the T2, but with volute spring suspension instead of the double leaf spring articulating bogie suspension of the earlier vehicle. The new suspension was adopted after tests with the Combat Car proved it was the superior design. The T2E1 was standardised in 1935 as the Light Tank M2A1, but were only produced in small numbers (either 9 or 20 depending on the source).
The next variant, the M2A2, introduced a new twin turret design. The idea was that each gun would be able to hit a different target, making the vehicle more flexible. The two turrets were mounted side by side in the centre of the tank and must have been fairly cramped. The M2A2 was followed by the M2A3, which had thicker armour, a longer hull and other detail improvements.
The most important version of the M2 was the M2A4. The twin-turret M2s hadn't performed well when compared to the single-turret Combat Car M1, and the machine gun was starting to look under-powered as a tank main gun. In 1938 the Chief of the Infantry asked for a light tank armed with a 37mm gun. A new single turret was designed for the M2, armed with a 37mm gun and a .30in machine gun. This design was standardised in 1939, and was one of the first tanks to benefit from the increased sense of urgency after war broke out in Europe. The production contract was given to American Car & Foundry, who produced 365 vehicles between April 1940 and March 1941. Work then moved onto the Light Tank M3 (Stuart), which was largely based on the M2A4 but with a number of improvements.
In the late 1930s the M2 was used to equip both independent armoured battalions and the armoured divisions, but by 1940, when the Infantry and Cavalry tank units were united in the Armored Force the M2A1, M2A2 and M2A3 were all obsolete and were only used for training. Only the M2A4 was still in use with some combat units.
The M2A4 saw combat on Guadalcanal. It was part of the equipment of Co.A, 1st Marine Tank Battalion, when that unit landed on the island in August 1942. There was very little tank-vs-tank fighting on Guadalcanal, and the M2A4s were used to support infantry attacks on Japanese strong points. The Japanese had very few anti-tank guns, so had to resort to desperate measures, including attempting to swamp the American tanks. The Americans were forced to operate in pairs, using the machine guns on one tank to keep Japanese infantry off the other.
By the end of the Guadalcanal campaign the last M2A4s had been withdrawn, and the Marines were using the M3 and an increasing number of Medium Tank M4 Shermans.
A number of M2A4s went to Britain, where they were used as training vehicles while the similar Light Tank M3 was used in combat. It is possible that some diesel engined M2A2E3 tanks were used in Burma, where a British unit equipped with the M3 was sent after the fall of Singapore
The M2A1 was the first production version and carried two machine guns in a single large turret as well as a third in the hull.
The M2A2 saw the single turret replaced with two turrets carried side-by-side, each carrying one machine gun.
The M2A3 had the same turret layout as the M2A2, but with improved suspension, a 11in longer hull, thicker armour and a number of detailed improvements to the engine and gears. Around 200 of the M2A2 and M2A3 models were produced.
The M2A4 was also armed with three hull mounted machine guns. One was carried in the front of the hull, and the other two were mounted in sponsons built into the side of the hull on either side of the turret. These were also forward firing guns and were remotely controlled by the driver. They were also installed on the Light Tank M3, but were often removed in service.
The T2E1 was the prototype for the M2A1
The T2E2 was the prototype for the M2A2
The M2A2E1 was an experimental version of the M2A2 that was given a Guiberson diesel engine.
The M2A2E2 was used to test some of the modifications that were introduced in the M2A3.
The M2A2E3 had a GM diesel engine and modified suspension with a trailing idler wheel, as also used on the Combat Car M2.
The M2A3E1 was an experimental tank with a Guiberson 9-cylinder diesel engine installed.
The M2A3E2 had experimental Electrogear transmission installed
The M2A3E3 had a GM diesel engine and modified suspension.
Hull Length: 14ft 6in
Hull Width: 8ft 1.25in
Height: 8ft 2in
Crew: 4 (commander, driver, co-driver, gunner)
Weight: 23,000lb/ 11.5 US tons
Engine: 250hp Continental W-670 gasoline engine
Max Speed: 25-30mph (road), 18mph cross-country
Max Range: 130 miles road radius
Armament: One 37mm gun and one .30in machine gun in turret, three .30in machine guns in hull, plus mounting for anti-aircraft gun on turret roof
Armour: 6mm to 25mm