|
The M103 Heavy Tank (officially designated 120mm Gun Combat Tank M103)〔 served the United States Army and the United States Marine Corps during the Cold War. The last M103s were withdrawn from service in 1974. == Design and development == Like the contemporary British Conqueror tank, the M103 was designed to counter Soviet heavy tanks, such as the later IS-series tanks or the T-10 if a conventional World War III broke out. Its long-ranged 120 mm cannon was designed to hit enemy tanks at extreme distances. In 1953–54 a series of 300 tanks, initially designated T43E1, were built by Chrysler at the Newark plant. Testing was unsatisfactory; the tanks failing to meet Continental Army Command's standards and the tanks were put into storage in August 1955. After 98 improvement modifications were approved, on 26 April, 1956 the tank was designated the M103 Heavy Tank.〔Hunnicutt (1984) p. 124.〕 Of the 300 T43E1s built, 80 went to the US Army (74 of which were rebuilt to M103 standard), and 220 were accepted by the US Marine Corps, to be used as infantry support, rebuilt to improved M103A1, then M103A2 standards. Following contemporary American design philosophy, the M103 was built with a two-piece, cast elliptic armor scheme, similar to the M48’s design. It featured seven road wheels per side, mounted with long-arm independent torsion bars. The 28” track was shoed in steel backed rubber chevron tracks, allowing for a ground pressure of 12.9 psi. The Continental AV-1790 engine was placed at the rear of the tank, and produced a maximum output of 810 horsepower and 1600 foot-pound of torque, fed through a General Motors CD-850-4 3-speed transmission. This allowed the 60-ton heavy tank to achieve a maximum road speed of 34 km/h and a maximum climbing gradient of 60%. Initial production versions suffered a host of drivetrain mechanical problems. The Continental powerpack, shared by the much lighter M48/M60 tanks, was insufficient to drive the much heavier M103. The resulting performance of the tank was dismal; being severely underpowered and very fuel intensive. This presented a host of logistical problems for the vehicle, most prominently the extremely limited range of just 80 miles. Though this was partially corrected with the introduction of the AV-1790-2 diesel unit, it would remain cumbersome and gas-thirsty for the majority of its production life. For ease of production, many of the large components of the tank were made from cast plate. This design scheme was also much more mass efficient than traditional uniform plate armor. Despite being similarly (or even better) protected than the T29-series of prototypes which preceded it, the M103 was nearly 10 tons lighter, making it competitive with the Soviet T-10/IS-8 tank. The frontal hull glacis was a compound pike, welded at the center seam, with up to 10 inches thick armor at the direct front. Larger than that of the M48 and M60, the turret was a massive single-piece cast design, fitted with heavily sloped 10 inch rolled-homogenous plating. The M103 was designed specifically to mount the 120mm M58 gun, fitted in the M89 turret mount. Using standard armor-piercing rounds, it was capable of penetrating 196mm of 30-degree sloped rolled-homogenous steel at distances over 2000 yards. The commander could select from 34 rounds of either M358 armor-piercing shot or M469 HEAT shells, mounted at the rear of the turret and in the hull. With both loaders, the maximum static firing rate of the gun was five rounds per minute, owing to the design of the two-piece ammunition. Using the electrohydraulic turret traverse, the gunner could turn the turret at 18 degrees per second, with 15 degrees of elevation and 8 degrees of gun depression. 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「M103 heavy tank」の詳細全文を読む スポンサード リンク
|