In the late 80s the Chieftain main battle tank was considered out-dated. Its main drawbacks were poor mobility and insufficient armor protection. At the time Soviets were introducing improved tank types at a rapid pace and armor of Chieftain was vulnerable to modern Soviet anti-tank guns. The Challenger originated from Iranian order for improved model of Chieftain – the Shir 2 (Lion 2). It was the first British tank with a composite armor.

The order was later cancelled due to Iranian revolution. However the project was taken over by the British MoD, design was further reworked and the tank became known as the Challenger. It entered service with the British Army in 1983. Production ceased in 1989. A total of 420 of these main battle tanks were built. In the 1990s, with the introduction of improved Challenger 2, the original Challenger was redesignated as the Challenger 1. The Challenger 1 was phased out of British Army service in 2000. Most of these main battle tanks were sold to Jordan where it is locally known as the Al Hussein.

The Challenger 1 is armed with a fully-stabilized British L11A5 120 mm rifled gun. It is a significantly improved version of the Chieftain’s gun. It is extremely accurate, however this MBT was fitted with slow fire control system. A total of 52 rounds are carried for the main gun. Ammunition includes APDS-T, APFSDS-T, HESH, smoke and training rounds. All rounds are of separate loading type. Interestingly a 1986 British report stated that newest Challenger’s anti-tank rounds stood a good chance of defeating Soviet T-64, but could not defeat the latest T-80. Still though the Challenger gun claims the longest-distance tank kill in history. During Gulf ωɑℜ it defeated an Iraqi tank at a range of 4 km. During the operation Desert Storm the Challenger 1 tank engaged enemy target at a range of 5 100 m.

There are also two 7.62 mm machine guns. One of them is mounted coaxially with the main gun, while another is mounted on the turret roof. A total of 4 000 rounds are carried for machine guns.

Protection of the Challenger 1 was much improved comparing with the previous Chieftain. It has a welded hull with Chobham composite armor, which is a combination of steel and ceramics. This armor provides a much higher level of protection, comparing to any monolithic steel armor. The Chobham armor was later adopted by American M1 Abrams. An add-on explosive reactive armor can be fitted. The tank is fitted with automatic fire suppression and NBC protection systems.

This combat vehicle has a crew of four, including commander, gunner, loader and driver.

The Challenger 1 MBT is powered by a Rolls-Royce Condor CV12 TCA turbocharged diesel engine, developing 1 200 hp. It is worth mentioning though, that comparable Western tanks – the M1A1 Abrams and Leopard 2 had a more powerful engines, developing 1 500 hp. The engine and transmission are mounted in one module can be replaced in field conditions within 45 minutes.

There is also an auxiliary power unit, which powers all systems, when the main engine is turned off. Vehicle has a hydropneumatic suspension system, which provided good cross-country performance. It is worth mentioning that the Challenger 1 was famous for its mechanical reliability. Additional fuel tanks can be mounted at the rear of the hull for extended operational range. The Challenger 1 can be fitted with a front-mounted dozer blade or mine clearing systems

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<Source:http://www.military-today.com/tanks/challenger_1.htm>