performance. This design emerged at the end of the war as the Centurion. In the immediate post-war era of WWII, information about German torsion bar suspension systems used in the Panther and Tiger tanks became more widely known and led to a revolution in post-war tank design. Britain, however, did not take advantage of these changes as the Centurion was proving to be one of the best tanks in the world at the time. Its performance during the Korean War was particularly notable as it was able to climb onto hills that no other tank could (due to its Rolls-Royce Meteor engine, more than the suspension) and destroy opposing tanks at the limit of visibility. When the design finally began to be made obsolete with the introduction of the newer Soviet types, little development of new systems had taken place. Thus when the need for a new design was finally raised in the late 1950s, a number of improved versions of the Centurion were trialled. As they were essentially improvements to the existing design, as opposed to all-new concepts, the Centurion's Horstmann suspension was further improved to handle yet larger weights. Description The principal design feature is that two or more wheels are mounted to a common framework to form a bogie. In the original two-wheel version, the wheels are mounted on an L-shaped swing arm that forms a bell crank, so the upward movement of the wheel is turned into sideways motion of the top of the crank. The two arms may be mounted on a common pivot shaft between them, or more commonly, two closely spaced shafts. The two wheels share a coil spring running horizontally between the tops of the crank arms. Thus if one wheel moves up over an obstacle, the spring is compressed against the swing arm of the other wheel. This variation was used on the early experiments, as well as the Soviet T-37 tank. Versions for lighter vehicles typically replaced one of the two crank arms with a straight bar, with the spring running from the top of the remaining crank arm to the end of the bar. The resulting action is similar, in that an obstruction that causes upward movement of either wheel results in the spring being compressed and providing a restoring force to both wheels. An advantage to the Horstmann design is that the suspended weight is not placed entirely