Britain’s Main Battle Tank for twenty years, Chieftain was one of the first true Main Battle Tanks, designed to replace both medium and heavy tanks in front line service.
However it also incorporated a lot of revolutionary design features, some of which did not work as well as expected. For example, in order to reduce height the driver lies in a reclining position and changes gear with his foot. The gun uses a self-combusting, bagged charge in place of a brass cartridge case and the tank is powered by a multi-fuel engine.
The engine was a Leyland design, developed from a pre-war German diesel aircraft engine. It has six vertical cylinders containing twelve opposed pistons, working on the two-stroke principle. Although essentially a diesel it was capable of running on a variety of fuels. The TN12 gearbox, offering six forward speeds and two reverse, includes a triple-differential steering system.
The Tank Museum’s Chieftain Mk11C
Late production Chieftains were continually upgraded. This Mark 11 would have been built as a Mark 5, with an uprated engine, which was subsequently fitted with Improved Fire Control System (IFCS), Thermal Observation and Gunnery System (TOGS) and the additional Stillbrew armour on the turret front and around the driver’s hatch. Chieftain served with the British Army into the early nineties and enjoyed modest success on the export market in the Middle East.