Main battle tank

A main battle tank (MBT), also known as a battle tank or universal tank, is a tank that fills the armor-protected direct fire and maneuver role of many modern armies. Cold War era development of more powerful engines, better suspension systems and lightweight composite armour allowed a tank to have the firepower of a super-heavy tank, armor protection of a heavy tank, and mobility of a light tank all in a package with the weight of a medium tank. Through the 1960s, the MBT replaced almost all other tanks, leaving only some specialist roles to be filled by lighter designs or other types of armoured fighting vehicles.

Today, main battle tanks are considered a key component of modern armies. Modern MBTs seldom operate alone, as they are organized into armoured units which involve the support of infantry, who may accompany the MBTs in infantry fighting vehicles. They are also often supported by surveillance or ground-attack aircraft.

In World War I, tanks were classed into light, medium, and heavy based on weight, and its impact on speed and mobility. As tank combat evolved, tank design suffered from a number of limitations due largely to engine power and transmission capability. A designer could produce a tank with high maneuverability, armour, or a large gun, but generally not all three at the same time. Combined with inter-war tank theory which stressed high-speed dashes into the rear of the enemy's lines, these limitations led naturally to two classes of tank that continued through much of World War II.

The first prioritised maneuverability, and thus had a limit on weight. These were known variously as cavalry tanks, light tanks, medium tanks, cruiser tanks or even tankettes for the very smallest versions. These tanks had different uses depending on the country's tank doctrine, but were generally used to exploit holes in the enemy lines and run far into the rear areas in self-supporting armoured groups. This would disrupt enemy logistics and command-and-control, as well as delay the movement of reserves to the front. It was believed operations of this sort would undermine or completely destroy the ability for the front-line troops to continue battle.

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