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The Medium Tank M2 was a United States Army tank that was first produced in 1939 by the Rock Island Arsenal, just prior to the commencement of the war in Europe.〔Zaloga p. 19〕 Production was 18 M2 tanks, and 94 slightly improved M2A1 tanks, for a total figure of 112. Events in Western Europe rapidly demonstrated that the M2 was obsolete, and it was never used overseas in combat; it was, however, used for training purposes throughout the war. The M2's unique features included an unusually large number of machine guns, bullet deflector plates, and sloped armor on the hull front (glacis plate). The main armament was a gun, with armor; the M2A1 had a gun mantlet. The features of the M2 series development, both good and bad, provided many lessons for U.S. tank designers that were later applied with great success in the M3 Lee, M4 Sherman and many other armored fighting vehicles. ==Design== Rock Island Arsenal started work on a new medium tank, based on the design of the M2 Light Tank. Initially designated the T5, the redesigned model (with a 350 hp R-975 radial engine) was re-designated as the M2 Medium Tank in June, 1939.〔''Historical dictionary of the U.S. Army''. Brown, Jerold E. Greenwood Publishing Group, 2001. ISBN 978-0-313-29322-1〕 After the first 18 units had been produced at Rock Island Arsenal and evaluated by the army, the upgraded M2A1 specification was approved with a redesigned turret and a more powerful engine.〔''M3 Medium Tank Vs Panzer III: Kasserine Pass 1943.'' Rottman, Gordon L. Osprey Publishing, 2008. ISBN 978-1-84603-261-5〕 The medium tank M2 was a larger development of the M2 Light Tank. Many components were common or used a similar design, including the vertical volute spring suspension which would be used in later tanks as well. Twin-wheeled bogies were mounted externally, and rubber-bushed and rubber-shod track proved durable on roads. The initial M2 model was powered by an air-cooled Wright R-975 radial engine, originally designed for aircraft. For the M2A1, this engine was supercharged to provide an extra for a total of , and designated as the R-975 C1 radial engine.〔〔''The illustrated directory of tanks of the world''. Miller, David. Zenith Imprint, 2000. ISBN 978-0-7603-0892-9〕 The M2 had a high superstructure, with a sponson-mounted machine gun in each corner. In addition, two more machine guns were fixed in the glacis plate and fired by the driver. Surmounting the superstructure was a small revolving turret armed with a 37 mm Gun M3 and a coaxial machine gun. The 37 mm gun could penetrate 46 mm of face-hardened armor sloped 30° at a range of 500 yards (457 meters), and 40 mm at 1,000 yards (914 meters).〔Hunnicutt, R. P. (1992), ''Stuart: A History of the American Light Tank,'' Presidio Press, p. 496. ISBN 0-89141-462-2.〕 This armament configuration was a hybrid between the sponson-mounted weapons of the Mark VIII Liberty tank of World War I vintage, and the combination of turreted cannon, coaxial machine gun and glacis-mounted machine gun that was almost universal in World War II medium tanks.〔 (Two additional .30-caliber machine guns could be mounted on pintles on either side of the turret for anti-aircraft use, bringing the total to nine—surely a record for any tank brought into service by any army.) The crew consisted of the tank commander, a driver and four gunners. The vehicle provided internal stowage for 200 rounds of 37 mm ammunition and up to 12,250 rounds of .30-caliber.〔 Bullet deflector plates were installed over the rear fenders. The idea behind these plates was that the tank could drive over a trench, and the rear sponson machine guns could then fire onto the plates; the bullets would deflect into the trench or the area directly behind the tank.〔(【引用サイトリンク】title=(untitled) )〕 Like the sponson machine guns themselves, the deflector plates turned out to be useless〔(【引用サイトリンク】title=M2 Medium Tank )〕 in modern warfare, since shooting at enemy troops in open trenches as a tank passed directly over proved to be a fairly unusual occurrence and a distinctly secondary manifestation of tank capabilities, with most engagements occurring at longer ranges. 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 Medium Tank」の詳細全文を読む スポンサード リンク
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