TANK

any heavily armed and armoured combat vehicle that moves on two endless metal chains called tracks. Tanks are the principal type of armoured vehicle. Other major types include tracked and wheeled infantry carriers, which were conceived only for transporting troops into action but which also have been used to some extent for fighting; armoured cars, which often resemble the lighter types of tanks but run on wheels; self-propelled guns, some of which are only partly armoured or wheeled; and such specialized vehicles as armoured recovery vehicles, armoured bulldozers, and amphibious landing vehicles. This article first discusses the development of modern tanks from the beginning of the 20th century to the present. It then treats related forms, including amphibious vehicles, self-propelled guns, and armoured personnel carriers. a heavily armed and armoured combat vehicle that moves on two endless metal chains called tracks. A tank is usually armed with a cannon mounted in a revolving turret and also has lighter automatic weapons. Tanks are the principal ground-assault weapon in modern mechanized warfare. Tanks were invented in World War I for use as armour-shielded assault vehicles that could cross the muddy, uneven terrain of the trench battle zone. Wheeled vehicles had proved insufficient in this regard. Several European nations worked on ways to adapt internal-combustion gas engines to tracked vehicles, and in 1915 the British Admiralty's Landship Committee became the first to adapt several tractors for military use. The first of these tanks were dispatched to France the following year and on Aug. 15, 1916, were assigned to combat at the first Battle of the Somme. These early tanks were lightly armed and had machine guns and small-calibre guns. Tanks first played a decisive role in World War I in the Battle of Cambrai (Nov. 20, 1917), when 474 British tanks broke through the German lines, and they were henceforth used in increasing numbers by the Allies in that war. After World War I France and Great Britain built lightweight tanks for cavalry-like actions and slower, heavier tanks for close infantry support. By the 1930s, however, light tanks carrying only heavy machine guns were seen to be extremely vulnerable to heavier tanks armed with 37- to 47-mm guns firing high-explosive shells. In response, the Germans and the Soviets in the mid-1930s began developing heavier tanks with thicker armour plating and guns up to 76 mm in diameter. Germany's tank force in World War II, though not the largest in Europe, was at first the most effective because it was the only one organized into rapid-moving massed formations that had great striking power in an offensive. During the first two years of battle, 193941, German tank units suffered no major setbacks. German and Soviet tank research and development set the standard during the course of the war. In 1943 the German Panther tank was introduced to battle, armed with a 75-mm gun with more than twice the muzzle velocity of its predecessor, giving it great armour-piercing capability. Germany also brought out the Tiger tank, among the heaviest to be deployed in the war, armed with an 88-mm gun. The Soviets were the only ones to respond in kind, bringing out the Joseph Stalin tank in 1944 armed with a low-velocity 122-mm gun. After World War II, all tanks were made capable of fighting other tanks as a matter of first priority. To this end they were equipped with guns of larger bore and increasing accuracy, armour of greater strength and weight, and engines of growing power. Most modern main battle tanks weigh more than 50 tons, yet, propelled by diesel or gas-turbine engines of up to 1,500 horsepower, they are capable of road speeds of 5070 km/h (3040 mph). Traditional steel armour has been supplemented by steel-ceramic composites or by reactive armour, which contains outward-directed explosives that counteract the effects of incoming projectiles. The standard main armament is a 120-millimetre smoothbore or rifled gun, which fires armour-piercing projectiles made of depleted uranium or carrying a shaped-charge explosive. Gun control is made extremely precise through the aid of laser range-finders, infrared imaging devices, and automatic stabilization of the turret while the tank is in motion. The tank's position and course can be plotted electronically through the use of global-positioning systems. Most tanks carry a crew of foura gunner, a gun loader, a driver, and a commanderthough some designs reduce the crew requirement to three by employing an automatic loading device. See also armoured vehicle. Additional reading Tanks and armoured vehicles are discussed in Richard M. Ogorkiewicz, Armour: A History of Mechanized Forces (1960, reissued as Armoured Forces: A History of Armoured Forces and Their Vehicles, 1970); and Design and Development of Fighting Vehicles (1968), on the technical aspects. The history of various types of vehicles from World War I to the end of World War II is presented in Duncan Crow (ed.), AFVs of World War One (1970), British AFVs, 191940 (1970), British and Commonwealth AFVs, 194046 (1971), American AFVs of World War II (1972), and Armored Fighting Vehicles of Germany: World War II (1973). Peter Chamberlain and Hilary L. Doyle, Encyclopedia of German Tanks of World War Two: A Complete Illustrated Directory of German Battle Tanks, Armoured Cars, Self-Propelled Guns, and Semi-tracked Vehicles, 19331945 (1978), provides a comprehensive pictorial record. Duncan Crow (ed.), Modern Battle Tanks (1978), focuses on the period between 1950 and 1970. For particular types of tanks, see Walter J. Spielberger, From Half-Track to Leopard 2: The Complete Illustrated History of the Krauss-Maffei Ordnance Department (1979; originally published in German, 1979); John Milsom, Russian Tanks, 19001970: The Complete Illustrated History of Soviet Armoured Theory and Design (1970); and R.P. Hunnicut, Sherman: A History of the American Medium Tank (1978), Patton: A History of the American Main Battle Tank (1984), and Firepower: A History of the American Heavy Tank (1988). For current information on developments in technology, see Jane's Armour and Artillery (annual) and Jane's Armoured Fighting Vehicle Systems (annual). Richard Marian Ogorkiewicz