|
}} 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 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-war 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== 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.〔 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.〔Zaloga (1999), p. 4.〕 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.〔Chamberlain & Ellis (1969), pp. 86–87〕 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.〔Green (2014), p. 128〕 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.〔Zaloga (2008), pp. 4–5〕 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.〔Hunnicutt (1992), p. 118〕 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.〔Hunnicutt (1992), p. 475〕 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.〔Hunnicutt (1992), p. 120〕〔 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.〔("Twelve-Ton Rolling Fortresses Stream Off Assembly Line" ) ''Popular Mechanics'', July 1941 p. 45〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「M2 light tank」の詳細全文を読む スポンサード リンク
|