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Building Challenger 2.

Building Challenger 2

Production of the nine Challenger 2 prototypes ordered by the British Defence Ministry has been undertaken at the Leeds tank factory which, until taken over by Vickers in 1986, had been part of the then state-owned Royal Ordnance.

The decision to sell the plant which had produced Challenger 1 to its only domestic competitor attracted some criticism from those who maintained that the deal would create an entirely new monopoly. In practice, it was only part of a wide-ranging reorganisation of the UK's defence procurement process. It was probably the entirely separate move, in which the Ministry ceded the design authority for its MBTs to Vickers, which did most to effect a sea-change in attitude to their development.

Vickers had already taken on the contract for the development and production of the Challenger Repair and Armoured Recovery Vehicle (the CRAARV) without a proven design in what its top executives describe as the "biggest risk yet taken by the industry". It also knew that, although Challenger 1's hull could be used as the basis for a successor MBT, its turret was outdated and that a major reliability development programme would be necessary for the entire vehicle.

At the same time as the company invested heavily in modernising the Leeds plant by consolidating all manufacturing processes in a single production line, it overhauled its management structure to introduce the disciplines of accountability that were lacking under state ownership. The need to win with Challenger 2 has been the mainspring of a process which has already undercut the time generally taken for effecting a corporate "turnaround" in the heavy engineering industry.

Challenger 2's completely new turret is at the heart of the revival at Leeds. The decisions to install a CDC fire-control computer and a SFIM stabilised commander's sight, coupled with a new interior design, correct two of Challenger 1's fundamental weaknesses. Likewise, a high standard of combat-worthiness is enhanced by the use of solid-state electrical traverse and elevation drives to keep hydraulics out of the fighting compartment, while the relocation of the TOGS thermal imager to a position above the new L30 high-pressure rifled 120 mm gun eliminates the complicated slaving system that was necessary on the earlier Challenger.

The new tank's sixteen major improvements also include a new six-speed gearbox (the David Brown TN54), which was eventually preferred to a Renk system as a result of Vicker's experience with its installation on the CRAARV; a hydraulic track tensioner which permits the track to be tensioned from under armour; and an "easy-lift" engine decking which means that the crew no longer have to endure the frustration of waiting for a crane before they can gain full access to the engine compartment.

Arguably, in its approach to MBT reliability and maintenance (R&M), Vickers has done as much to advance the state-of-the-art as it has done in turret design. It has adopted a classic value engineering approach to the Challenger subsystems, questioning the suitability and reliability of each.

The "Will-it-do-the-job?" questions have turned up some surprising answers, not the least being the fact that there is a "grey area" in R&M in which some faults go unreported simply because tank crews accept them as a fact of everyday life. Nevertheless, they affect overall vehicle availability, and Vickers has addressed the problem by undertaking, for example, a connector-by-connector examination of electrical systems so as to expose and replace the inefficient screw connectors which will not withstand high levels of vibration.

Some major redesign has been necessary. For example, electrical scavenging has been introduced to improve engine air-filter performance while the engine is idling, and metal-to-metal contacts in the Hydrogas suspension system have had to be redesigned to eradicate breakdowns and the creation of debris which damage vital seals.

The outcome of these and a number of other changes which call previous design and R&M practice into question, has been a culture shock to some of the subsystem suppliers. Vickers believes that many have been discouraged from exercising proper engineering judgements by a system which has often translated bureaucratic inefficiency into failure to perform. As Design Authority, Vickers has been able to apply the state-of-the-art in the understanding of what is likely to make a tank an efficient fighting vehicle well into the next century.

The competition for the new British MBT is perhaps tougher than some commentators had expected at its outset. Vickers seems to have had no illusions, however, and certainly no false sense of security. Challenger 1's poor performance has created a requirement, not only for what is in effect a new tank, but also for technology that can be applied to the earlier mark to bring it up to the standard required to counter the evolving threat. Vickers and its subcontractors have invested around 1.5 million [pounds] of their own money in remedying R&M faults on Challenger 1. That, says Vickers Defence Systems chief executive Gerald Boxall, is an impressive tribute to Challenger 2's fundamental combat-worthiness and capacity for growth.

Challenger 2 - The Subsystems


Main Armament: L30 120mm High Pressure Gun (rifled) developed and manufactured by Royal ordnance under the UK MoD Charm project. Can also be retrofitted to Challenger 1.

Fire-Control System: To Vickers design based on use of 1553 data bus and incoporating: Computer:Produced by CDC (Canada). Improved version of that fitted to M1A1 (US). Thermal Imaging System: TOGS2 produced to UK MoD specification by Barr & Stroud (UK). Commander's Gyro-Stabilised Sight: Panoramic day sight with laser rangefinder produced by SFIM(France). Similar to that fitted to Leclerc MBT. Enclosed in CASH 360degree hood developed by Hebron & Medlock (UK). Gunner's Gyro-Stabilised Sight:Combines SAGEM (France) sight with laser rangefinder with Barr & Stroud telescopic sight. Turret and Gun Drives:Advanced solid-state drives developed by Marconi Commmand & Control Systems.

Secondary Armament: 1x7.62mm Chain Gun. 1x7.62mm GPMG. Armour: Chobham Armour - details classified.


Engine: Perkins Condor V-12 Diesel. 26.11 litres swept volume. 1 200bhp (895kW) at 2 300 rpm. Torque 4 126 Nm at 1700 rpm. Wet weight (excluding cooling group) 2203 kg. Digital control unit developed by Dowty. Transmission: David Brown TN54 six-speed rated at up to 1500bhp. Steering Unit: Commercial Hydraulics hydrostatic system. Suspension: Hydrogas hydropnuematic suspension.
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Publication:Armada International
Date:Jun 1, 1990
Previous Article:Sir Colin Chandler, managing director of Vickers PLC.
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