M2 light tank

Light Tank M2 M2A4 Light Tank in British service, 11 March 1942 Type Light tank Place of origin United States Production history Designer Rock Island Arsenal Produced 1935–42 Specifications (M2A4) Weight 11.6 t (26,000 lb) Length 14 ft 6 in (4.42 m) Width 8 ft 1 in (2.46 m) Height 8 ft 8 in (2.64 m) Crew 4 (Commander/loader, gunner, driver, co-driver) Armor 6–25 mm (0.24–0.98 in) Main armament 1x 37 mm Gun M5 103 rounds Secondary armament 5x .30-06 (7.62 mm) Browning M1919A4 machine guns 8,470 rounds Engine Continental R-670-9A, 7 cylinder, radial gasoline 250 hp (190 kW) Suspension Vertical volute spring suspension (VVSS) Operational range 200 mi (320 km) Speed 36 mph (58 km/h)

The Light Tank M2 was an American pre-World War II light tank which saw limited use during World War II. The most common model, the M2A4, was equipped with one 37 mm (1.5 in) M5 gun, one .50 M2 Browning machine gun, and five .30 cal M1919 Browning machine guns.

It was originally developed from the prototype T2 tank built by Rock Island Arsenal, which had a Vickers-type leaf spring suspension. The suspension was replaced by the superior vertical volute system in the T2E1 series of 1935. This was put into production with minor modifications as the M2A1 in 1936, with ten produced. The main pre-war version was the M2A2, with 239 produced, becoming the main tank in the US Army infantry units in the pre-world-war-II period. The Spanish Civil War showed that tanks armed only with machine guns were ineffective. This led to the M2A4 with a 37 mm gun as the main armament. 375 were delivered, the last ten as late as April 1942.

Its only combat use in American units was with the US Marine Corps 1st Tank Battalion during the Pacific War in 1942. However, it is believed that M2A4s served in Burma and India with the British 7th Hussars and 2nd Royal Tank Regiment during their engagements with the Imperial Japanese Army's 14th Tank Regiment. The M2A4 light tank led to the M3 Stuart light tank, the M2 Medium Tank and M4 Tractor artillery tower. The M3 Stuart saw widespread use throughout the war, the M2 Medium Tank, though another unsuccessful design, led to the M3 Lee and thence the M4 Sherman medium tanks.

Development history

Top: M2A3 in Annual Army Day Parade, Washington, 1939. Bottom: Fitters assembling an M2A4 light tank at a British ordnance depot.

US Army infantry tank design started with the Light Tank, T1 during the 1920s, which developed into a series of experimental designs which didn't enter production. The T2 concept, starting five years later, incorporated several design lessons from the T1, but used a new suspension system copied from the British Vickers 6-Ton tank. The first prototype was delivered in 1933.

The Defense Act of 1920 had defined tanks to be used in support of the infantry. Through the 1920s a number of theorists outlined an independent role for the tank that required it to move at high speed into the rear areas, a modern version of the cavalry. The British referred to these designs as cruiser tanks, but similar high-speed designs were developed under a variety of names. As the Defense Act limited tank development to the infantry, the United States Cavalry began tank development under the name "combat car". In keeping with the high-speed role, the new T5 Combat Car introduced the new vertical volute spring suspension (VVSS) system, which proved clearly superior to the Vickers leaf spring system.

This led to a second prototype of the T2, the T2E1 in April 1934, adopting VVSS from the T5. The T2E1 was armed with one .30 cal (7.62 mm) and one .50 inch (12.7 mm) Browning machine gun mounted in a fixed turret; another .30 cal Browning was mounted on the hull front.^[1] The T2E1 was selected for production in 1935 as the M2, which mounted only the M2 Browning in a small one-man turret, and the .30 cal in the hull.^[2]

After only 10 units were delivered, the Infantry Branch decided to switch to a twin turret configuration in the M2E2, with a .30-caliber (7.62 mm) machine gun in a second turret. These early twin-turret tanks were given the nickname "Mae West" by the troops, after the popular busty movie star. The twin-turret layout was inefficient, but was a common feature of 1930s light tanks derived from the Vickers, such as the Soviet T-26 and Polish 7TP.^[1] Further refinements to the M2A2 produced the A3 model, which incorporated a modified suspension system that reduced the tank's ground pressure. The weight increased to 10 tons.^[3]

Following the Spanish Civil War, most armies, including the U.S. Army, realized that they needed tanks armed with cannon and not merely with machine guns.^[4] The Cavalry had already opted for a single, larger turret on its nearly identical M1 Combat Car. In December 1938, OCM #14844 directed that a single M2A3 be removed from the assembly line and modified with heavier armor and weapons, to meet the standards of the U.S. Infantry.^[5] This vehicle, after conversion, was re-designated as the M2A4. It was equipped with an M5 37 mm main gun, 1 inch (25 mm) thick armor, and a seven-cylinder gasoline engine.^[6] Other upgrades included improved suspension, improved transmission, and better engine cooling. Production of the M2A4 began in May 1940 at the American Car and Foundry Company, and continued through March 1941; an additional ten M2A4s were assembled in April 1942, for a total production run of 375 M2A4 light tanks.^[7][8] The US Army sent out press photos still showing the M2A4 being assembled in July 1941 after the assembly line had been changed over to the M3.^[9]

Successor vehicles

An M2A4 on Guadalcanal, followed by an M3 Stuart and another M2A4

The M2 Light Tank led to the US M3-series and M5-series light tanks.^[10] The Ordnance Department viewed the M2A4 as a stopgap tank; work to improve it further began in June 1940.^[11] The first M3 Stuart tanks began to be produced in March 1941; the original riveted M3s closely resembled the M2A4, and the two types occasionally served in the same units; the easiest recognition feature is the aft (rear) idler wheel. On the M2A4, the idler is raised; on the M3 it trails on the ground,^[12] increasing the flotation of the heavier vehicle.^[13] The M3 retained the same Continental W-670 engine, but incorporated ½-inch thicker (1½ inch total thickness) armor;^[14] weight increased to 14 tons. The tank initially kept the same 37 mm gun and the forward firing hull machine guns, but the turret incorporated improvements. Eventually over 4,500 examples of all variants were produced.^[15]

Operational use

By December 1941, the M2A1, M2A2 and M2A3 were used for training only.^[16] The majority of M2A4s, which went to the US Army, were also used only for training between 1940 and 1942.^[8] The U.S. Marine Corps ordered M3 Stuart tanks to outfit its armored units in 1940, but as the new tank was not yet in production, it received 36 M2A4s, after which point production of the M3 had come on line.^[17] Many of these tanks were deployed during the Battle of Guadalcanal while assigned to A Company, 1st Tank Battalion, where they and M3 Stuarts were typically spread out among infantry units. Their use was generally limited to providing mobile fire support to the Marines, either in disabling Japanese bunkers or using canister shot against Japanese attacks. In defensive engagements, the M2A4s and Stuarts would deploy in pairs, so they could cover each other with machine gun fire against Japanese soldiers armed with satchel charges.^[18]

Ultimately, the Marine Corps determined that the 37 mm gun of the M2s and M3s was not powerful enough to defeat Japanese bunkers, and so they would be replaced with tanks armed with 75 mm guns.^[19] Following the end of the Guadalcanal campaign, A Company returned to Australia, where the M2A4s were replaced with the new M4 Shermans in preparation for the Battle of Cape Gloucester in December 1943.^[20] They remained in service in some areas of the Pacific Theater until 1943. After they served in the Pacific, they were used for training.^[1]

Britain ordered 100 M2A4s in early 1941. After 36 of them were delivered, the order was canceled in favor of an improved M3 Stuart. The fate of these vehicles is unclear. There is evidence that indicates those 36 M2A4s were shipped off from North Africa as part of the British Army's 7th Hussars and 2nd Royal Tank Regiment, fighting in the India and Burma campaigns against the Japanese 14th Tank Regiment.^[21][22] However, according to historian Mike Green, the tanks were never issued to combat units.^[8]

Design

Besides the machine gun mounted coaxially to the main gun, there were three .30 cal. machine guns on the front hull of the M2. One was mounted in a ball mount in front of the bow gunner. The other two were mounted in a fixed orientation in the upper hull near the sides of the tank. The machine guns were fired by the driver with the triggers on his steering levers. Troops could also mount another .30 cal machine gun on the top of the turret for anti-aircraft defense.^[23]

The 37 mm M5 gun had a manually operated breechblock. The tank commander doubled as loader, like many other tanks of the time. There was no turret basket in the M2A4 light tank; the commander stood on the right side, while the gunner stood on the left side.^[23] The commander turned the turret onto the general direction of target. The gunner would then bring the target into the M5 telescopic sight. The M20 combination mount had 20° of traverse; this could either be by a handwheel driving the rack and pinion traverse gear mechanism or pressure on the gunners shoulder rest overcoming the friction in the mechanism. Depression and elevation of the gun was either through a geared mechanism or, with the gears disengaged, free through movement of the gunner's shoulder rest.^[23][23][24]

Variants

M2A3 "Mae West" on display at Patton Cavalry and Armor Museum, Fort Knox, Kentucky.

• M2A1 (1935).
  • Initial production type with single fixed turret containing one .50 cal machine gun. 17 units were produced.^[1]
• M2A2 (1935).
  • Twin turrets with single .50 machine gun in each; the turrets partly obstructed each other limiting fields of fire.^[25] Dubbed "Mae West".^[2] 239 units produced from 1936–37.
• M2A3 (1938).
  • Twin turrets with two machine guns, thicker armor, slightly lengthened hull, improved engine access, increased gear ratios, better engine cooling, improved suspension, and other minor detail changes. 72 units produced.^[1]
• M2A4 (1939).
  • Single turret with 37mm gun. Thicker armor.^[26] 375 units produced. Orders went to the American Car & Foundry in October 1939 upon request by the Ordnance Department. Used in the early Pacific campaigns and training. Only service was in Guadalcanal. Used for training after December 1941.^[1]

Specifications

The M2A4 was 14 ft 6 in (4.42 m) long, 8 ft 1 in (2.46 m) wide, 8 ft 8 in (2.64 m) high, and weighed 11.6 t (26,000 lb). It had a vertical volute spring suspension and had a speed of 36 mph (58 km/h), and had a range of 200 mi (320 km). It had one M5 37 mm gun (with 103 rounds), one .50 cal (12.7 mm) M2 Browning heavy machine guns (with 1800 rounds) and five .30 cal M1919 Browning machine guns (with 8,470 rounds) with 6 to 25 mm of armor.^[1] It had an 250 hp (190 kW) Continental W-670 9A seven-cylinder radial engine. The vehicle was operated by a crew of four (commander/loader, gunner, driver, and co-driver).^[13][27]

See also

• List of "M" series military vehicles
• G-numbers

References

Citations

1. Chamberlain & Ellis (1969), pp. 86–87
2. Zaloga (1999), p. 4.
3. Green (2014), p. 128
4. Zaloga (2008), pp. 4–5
5. Hunnicutt (1992), p. 118
6. Hunnicutt (1992), p. 475
7. Hunnicutt (1992), p. 120
8. Green (2014), p. 131
9. "Twelve-Ton Rolling Fortresses Stream Off Assembly Line" Popular Mechanics, July 1941 p. 45
10. Berndt (1994), p. 45.
11. Green (2014), p. 135
12. Zaloga (1999), p. 27 plate C
13. Jackson (2010), p. 40.
14. Hunnicutt (1992), 127
15. Green (2014), pp. 135, 137
16. Zaloga (2008), p. 15
17. Zaloga (2012), pp. 7, 10
18. Zaloga (2012), pp. 10–11
19. Green (2014), p. 142
20. Zaloga (2012), p. 16
21. Hunnicutt (1992), p. 396
22. Zaloga (1999), p. 14
23. Green (2014), p. 130.
24. FM 23-80 37-mm Gun Tank M5 p. 13
25. Chamberlain & Ellis (1969), p. 87
26. Zaloga (1995), p. 5.
27. Foss (1981), p. 122

Bibliography

• Berndt, Thomas (1994). American Tanks of World War II. Minnesota, MN: MBI Publishing Company. ISBN 0-87938-930-3.
• Chamberlain, Peter; Ellis, Chris (1969). British and American Tanks of World War II. New York: Arco Publishing. ISBN 0-668-01867-4.
• Foss, Christopher F. (1981). An Illustrated Guide to World War II Tanks and Fighting Vehicles. New York: Arco Publishing. ISBN 978-0-6680-5232-0.
• Green, Mike (2014). American Tanks & AFVs of World War II. Oxford: Osprey Publishing. ISBN 978-1-7820-0931-3.
• Hunnicutt, R. P. (1992). Stuart: A History of the American Light Tank. Navato, California: Presidio Press. ISBN 0-89141-462-2.
• Jackson, Robert (2010). 101 Great Tanks. New York: The Rosen Publishing Group. ISBN 1-43583-595-6.
• United States War Department Staff (1941). FM 23-80 37-mm Gun Tank M5. Washington, DC: United States Government Printing Office. OCLC 41417142.
• Zaloga, Steven (1999). M3 & M5 Stuart Light Tank 1940–45. New Vanguard 33. Oxford: Osprey Publishing. ISBN 1-85532-911-5.
• Zaloga, Steven (2008). Armored Thunderbolt: The US Army Sherman in World War II. Mechanicsburg, Pennsylvania: Stackpole Books. ISBN 978-0-8117-0424-3.
• Zaloga, Steven (2012). US Marine Corps Tanks of World War II. Oxford: Osprey Publishing. ISBN 978-1-8490-8560-1.

External links

• AFV database
• World War II vehicles
• The short film The Tanks Are Coming is available for free download at the Internet Archive from 1941, featuring the M2