The T2E1 prototype
The first modern US light tank design was the T2, built by Rock Island Arsenal, the main US federal heavy arsenal, in charge of the specifications. By that time, the Cavalry already had its M1 Combat Car. The T2 appeared in 1934 and bore some resemblances with the British Vickers 6-ton Mark E, notably the suspension, made of two quadruple bogies. After that, the T2E1 received a new VVSS suspension and a revised, taller hull. By 1935, this prototype formed the basis for the M2 light tank.
Design of the M2
The first M2 had a one-man turret equipped with a cal.50 (12.7 mm) and a coaxial 7.62 mm (0.3 in) Browning M1919, with another placed in the hull, on a ball mount operated by the co-driver. The hull general design, turret, tracks, VVSS suspension design with a front drive sprocket and rear idler, at well as the two bogies with vertical coil springs and two return roller in between, were identical to the M1 suspension, in order to save time and be cost-effective. The engine also was the same, a compact but tall aviation radial Continental W-670, which gave a top speed of 58 km/h (36 mph). However, the internal arrangement made it possible to increase the amount of fuel carried. The original crew comprised three men, the commander also being the gunner and loader, operating the cal.50 (12.7 mm).
M2A1 to M2A3
The M2A1 was the series production vehicle, equipped with a single turret, of which only ten units were built in 1936. However, it quickly appeared that the Army wanted a twin-turret configuration, favored at the time by other armies. The design was changed and new turrets were devised, which led to the mass-produced M2A2. One of these turrets housed the main .50 cal (12.7 mm). machine gun, while the other had the .30 cal (7.62 mm) caliber M1919. 239 units were produced, quickly becoming the staple of US infantry tank troops until 1937. Although displaying an obsolete configuration, these tanks were popularly known as the “Mae West”, after the famous busty actress.
By 1937, a new set of modifications was in line. The suspensions were revised, the hull slightly lengthened and the bogies placed farther apart, while the front armor was increased to 25 mm (0.98 in). Only 72 units of this M2A3 version were produced due to a rapid change of specifications.
The M2A4: Forerunner for the M3 Stuart
While many Americans served on the Republican side during the Spanish Civil War, observers came to the conclusion that a tank needed guns, and not only machine-guns. The only available option was the standard infantry 37 mm (1.46 in) M5 AT gun then in service, and there was no way it could fit inside a small turret -thus eliminating the twin-turret configuration. To save time, the late evolution of the M1A1 Combat Car served as a model, and the same turret was used. According to the November 1938 OCM #14844 specification, a single M2A3 was removed from the assembly line and modified accordingly, thus establishing the M2A4 standard.
This version proved to be the most numerous of all, with 375 delivered, the last ten as far as March 1942. A new Continental 7-cylinder engine was chosen, fuel capacity increased (the top range was now 200 miles/322 km), the armor was thickened everywhere to 25 mm (0.98 in) except on the roof and bottom. The secondary armament comprised no less than 5 machine-guns for a crew of 4, having one coaxial, one AA (turret pintle mount), two in sponsons and one in the nose hull. In late 1941, the M2A4 was succeeded by the M3 Stuart. They could be distinguished by the rear idler wheel size and configuration, which eased ground pressure for the second.
The M2A1, A2 and A3, being obsolete by December 1941, were all kept for training only on American soil. This was also the case for most of the M2A4s, although 50 saw action in Guadalcanal with the US Marine Corps 1st tank battalion. 36 of the 100 British M2A4s originally ordered in early 1941 were shipped to North Africa. The order was later canceled in favor of the M3 Light Tank. The vehicles were then given to the British Army’s 7th Hussars and 2nd Royal Tank Regiment to be sent to India and fight during the Burma campaign. During the most contested fighting, they dealt with the IJA’s 14th Tank Regiment.
M2A4 Light Tank specifications
|Dimensions||4.43 x 2.47 x 2.65 m
14ft5in x 8ft1in x 8ft8in
|Total weight, battle ready||11.6 tons (12.8 short tons)|
|Crew||4 (commander/loader, driver, co-driver, gunner)|
|Propulsion||Continental W-670 9A 7-cyl. air-cooled gasoline, 245 hp (160 kW)|
|Maximum speed||58 mph (36 km/h) on road|
|Suspension||Vertical volute springs (VVSS)|
|Range||320 km (200 mi)|
|Armament||37 mm (1.46 in) gun M5,103 rounds
5 x cal.30 (7.62 mm) Browning M1919A4, 8470 rounds
|Armor||6-25 mm (0.24-0.98 in)|
M2A1 in 1937.