South African defence industry engineers have never been shy of exploring innovative ideas. One such concept was that of an electric-powered armoured vehicle, which dates back to the late 1980s when Armscor started the E-drive programme with the development of an electric-drive Ford pickup in co-operation with the then University of Natal. In 1993 the design engineers of then Reumech Ermetek, modified a MAN 8x8 truck with electric hub-motors on first four and later on all eight wheels. The beauty of electric-drive vehicles is that they have no axles, drive shaft or gearbox which allows far greater design flexibility than a mechanical-drive system. With electric-drive all that is required are cables, which can be easily routed anywhere. The design team developed the electric-drive MAN truck as a demonstrator for the SANDF in1996. Having proved its practicality, the SANDF approved the fitting of a Rooikat chassis with an electric-drive to evaluate the E-Drive technology in a complex combat system using the Rooikat as the technology carrier. The converted Rooikat became known as the combat vehicle electric-drive demonstrator (CVED). A standard Mercedes Benz diesel engine was upgraded by MTU, increasing the power output from 315 kW to 450 kW but reducing the torque as required by the electric alternator, and changing the fuel management system so that the best consumption was not at maximum torque but at the optimal operation point for the electrical drive system. An electric motor was fitted in each wheel, each motor having a diameter of less than 50 cm, these are permanent magnet motors and the Armscor E-Drive team also developed the electronics to drive the motors. The replacement of the mechanical drive system with the electric-drive system, including the storage batteries, reduced the weight of the Rooikat by just under 2 tons and freed up space that could be used to mount extra armour or carry additional ammunition or fuel or a combination of these. The fitting of batteries allowed the vehicle to use its communications and electronic systems and to move limited distances at low speeds without having to start its diesel-driven generator thus giving it a stealth mode ability. In stealth mode, the hybrid Rooikat can tiptoe its 28 ton bulk so quietly through the bushveld with no more than the sound of the soft whine of the hub motors. Owing to limited budgets this project was shelved in 2012. That said, the system in the hybrid Rooikat represented a viable proof of concept and engineering technology that the engineers and design team can be justifiably proud of creating, and perhaps it can be said that the CVED project was even ahead of its time.
Rooikat CVED Features
Hybrid: Uses water-cooled M67/0 magnet hub motors (Maximum torque: 2,250Nm) and MTU 6V 199 TE20 diesel/generator power pack (Power output: 450kW)
Acceleration: Rooikat CVED (0-60 mph in 16 seconds), Rooikat Mk1 (0-60mph in 22,4 seconds).
70% Gradient Speed: Rooikat CVED (6,5 km/h), Rooikat Mk1 (3,9 km/h).
Weight: Rooikat CVED is two tons lighter.
Maneuverability: Rooikat CVED can rotate itself in on spot instead of having a large turn radius.
Moves around silently when the electric-drive is used.
Main armament: 76 mm (GT-4).
Capacity: 48 rounds.
Coaxial machine gun: 7.62mm (MG4).
Hull: Front (upper glacis 25mm, lower glacis 30mm), Sides (top 20mm, bottom 25mm).
Turret: Front (external 25mm, internal 30mm), Sides (25mm), Rear (15mm), Roof (15mm).
Range Finder: Laser Range Finder.
NVD: Night Vision.
Commander control: Commander Sight, Commander Fire Control.
Surviving the Ride, written by Steve Camp and Helmoed-Romer Heitman (page 445-448)
South African Armoured Vehicles, written by Dr Dewald Venter (page 79)
Tank Encyclopedia (Rooikat): Rooikat - Tank Encyclopedia
Defence Web: Gerotek taking CVED for another spin | defenceWeb