U.S. Army doctrine stresses the fundamental tasks of shoot, move and communicate. To ensure the lethality of the force, these tasks are expected of every soldier and are applied all the way up to main battle tanks. Delivering accurate and deadly fire is the tank's purpose and maneuverability is key to its survivability on the battlefield. However, a multi-ton machine riding on tracks over uneven terrain doesn't make for a very good gun platform from which to shoot. That's where the stabilizer comes in.
Using a gyroscope, it's possible to stabilize a tank's gun and compensate for the bounce experienced on the move. During WWII, all American tanks except for the 105mm M4 Sherman were fitted with single-plane stabilizers for elevation. This kept the gun level as the tank moved, as long as its speed was 10mph or less. Though simple, the system allowed American tankers to advance in support of infantry while providing accurate fire on the move.
After WWII, gun stabilizer technology advanced greatly. In 1948, the British introduced the first two-plane stabilizer in a production tank with the Centurion Mk. 3. This stabilized the gun on both the vertical and horizontal axes. In addition to the gun, tank turrets were also stabilized to keep them on target during movement. Coupled with laser rangefinders and ballistic computers, it's possible for modern main battle tanks to hit a moving target as accurately on the move as when they are stationary.
The German Army demonstrated the stability of its Leopard 2 main battle tank in the most German way possible: balancing a beer. In the iconic video, a Leopard 2 drives over rolling terrain to show how its gun remains level as the tank itself moves up and down. Then, a German soldier fills a stein with beer and places it on a platform attached to the tank's gun. As the Leopard 2 transits more rolling terrain, not a single drop or bit of foam from the beer is spilled.
Feature Image: Bundeswher