How it works

• Engine. A V-2 V12 diesel, 38.9 litres, 500 hp at 1,800 rpm. Twelve cylinders in two banks of six fire in turn; the lit injector shows which one is firing now (1L, 6R, 5L, 2R, 3L, 4R, 6L, 1R, 2L, 5R, 4L, 3R).
• Power path. Crankshaft, then the cooling fan on the flywheel, the main clutch, a four-speed gearbox and a cross shaft. Each end of the cross shaft has a steering clutch and a final drive that turns the rear sprocket.
• Tracks. The sprocket hooks the track and pulls it. The track lays a road under the wheels and runs back over them to the front idler. Each link is 172 mm long and the track is 500 mm wide.
• Christie suspension. Five 830 mm road wheels per side. Each wheel arm pushes a long coil spring that stands inside the hull wall. Watch a wheel climb a bar: only that spring squeezes, so the hull stays level.
• Crew compartment. Four men. The driver sits front left with two steering levers, a gear lever, three pedals, a small dial panel and two compressed-air bottles for starting. The radio operator sits front right behind a 7.62 mm DT machine gun in a ball mount. Main gun rounds lie in eight steel bins on the floor and on racks in the hull sides.
• Turret. A six-sided cast turret with a 76 mm F-34 gun, turned by an electric motor or a hand crank. Inside: the gun's breech end, its two recoil cylinders and the trunnions it pivots on. The gunner, on the left, aims through a telescopic sight and turns two handwheels: one raises the gun, one turns the turret. The loader on the right takes rounds from the rack on the rear wall.
• Driver's station. Two steering levers, a gear lever, and three pedals: clutch, brake and throttle. The two dials show engine speed and road speed.

Armour: the front plate is 45 mm thick but laid back 60°. A shell flying level has to go through 45 / cos 60° = 90 mm of steel, and it is more likely to glance off.

How to drive it

1. Start. Gear in neutral, then start the engine. It settles at about 600 rpm.
2. Move off. Press the clutch, select 1st, let the clutch in, add throttle. The figure presses the clutch for you each time you change gear.
3. Change up. Ease off, clutch, next gear, throttle again. Fourth gear is for the road.
4. Steer. Pull the left lever to turn left. The first half of the pull lets go of the left steering clutch, so the left track loses drive. The rest of the pull tightens its brake band. The right track keeps pushing and the tank swings left.
5. Stop. Throttle off, clutch in, neutral, then pull both levers back to brake both tracks.
6. Aim. The commander turns the turret; the hull can point anywhere.