Case Study: Challenger 2

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The Challenger 2 is a British main battle tank in service since 1998 (replacing Challenger 1) and is known for its exceptional Chobham/Dorchester composite armour and powerful 120mm rifled gun. Originally designed and manufactured by Vickers Defence Systems it is now in the process of being handed over from BAE Systems to the joint venture RBSL for maintenance and repair.

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Timeline & Capabilities

Challenger 2 began its journey in 1987 and saw its first prototype in 1991. It entered service with the British Army in 1998 and demonstrated its combat effectiveness in the 2003 Iraq War. Continuous upgrades followed, including improved armour and electronic systems, with significant combat deployments in Iraq. In 2014, the Challenger 2 Life Extension Project (LEP) was initiated to modernise the tank and will result in an in-service Challenger 3.

The tank features highly advanced fire control systems and night vision capabilities as well as advanced defensive systems, including smoke grenade launchers and NBC protection. Powered by a 1,200-horsepower Perkins diesel engine, it boasts a top speed of 59 km/h on roads and 40 km/h off-road. Operated by a crew of four, it has seen combat in the Balkans, Iraq, and Afghanistan. Continuous upgrades have aimed to enhance its firepower, protection, and situational awareness, ensuring its competitiveness in modern warfare. The current Challenger 3 programme will enhance its firepower, protection, and situational awareness.

Our Role 

While BAE is the prime contractor for Challenger 2, Quantic Thistle’s involvement was through Thales, who is responsible for key Turret sub-systems. Our team are tasked with the repair and replacement of encoders for the turret movement, as well as the motors and transmission for commander's position EPI Scope (external viewing system).


Turret Encoders

The CR2 Traverse Rate & Displacement Unit (TRDU) contains an absolute and an incremental encoder, a power unit and an interface board, as well as an internal gearbox that is matched to the turret ring gear.

The absolute encoder delivers 16 bits of data over the full revolution of the turret for position, while the incremental encoder provides data on the speed of rotation.  The outputs from these two separate encoders are then fed through the Interface board to deliver a serial data into the vehicle’s navigation and fire control systems.

Wiper Motors

The commanders position includes six EPI Scopes for external vision when fighting the vehicle ‘head down’ (hatch closed).  These are grouped three on the left and three on the right, each with a motor and transmission to drive the wiper system.

As these units are externally mounted, they require constant maintenance and repair, and in some cases replacement where operational damage has been severe.