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Mercedes-Benz employs the same principle and same high-tech material for the new SLR McLaren Roadster which receives its world premiere in autumn 2007. The monocoque – or, to put it another way, the passenger cell – of the new open-top super-sports car is manufactured from carbon-fibre-reinforced materials throughout. In the event of a head-on, side-on or rear-end collision, it therefore offers the occupants a very rigid and hence securely protected space. The crash structures in the front end and at the rear are likewise made from CFRP.

Mercedes-Benz and its Formula 1 partner, McLaren, have gathered many years of experience with this material that is conventionally used in the aviation and space industries. Carbon-fibre reinforced materials are characterised by their extreme rigidity and a level of energy absorption in an impact that is four to five times higher than that of steel or aluminium, which is why the CFRP body gives rise to such exemplary levels of occupant safety in the new SLR Roadster.

In a collision, the fibres of the CFRP elements shred from front to rear, absorbing the energy of the impact with a constant rate of deceleration. Thanks to this uniform deformation behaviour and the high-strength monocoque, the energy absorption of the CFRP side members can be precisely calibrated. The engineers achieve this, for example, by creating a constantly changing cross-sectional area for the components.

At the rear, two internal side members made from laminated carbon fibre and a robust cross member assume the task of energy absorption in the event of a crash. In an impact from the side, the occupants are protected by the broad, low-set multi-shell sills made from specially reinforced carbon-fibre materials, as well as two aluminium sections incorporated into each door. The sturdy shell of the SLR seats also has a protective function in a rear-end or side-on collision, designed as it is to hold the occupant firmly in position; it is likewise built from highly resilient carbon-fibre material.

The new A-pillar, with its additional internal reinforcement in the form of a high-strength steel tube, also contributes to the excellent occupant safety. The arrival of the Mercedes-Benz SLR McLaren Roadster thereby marks the series-production debut of a highly complex steel/carbon-fibre compound that combines high strength with elasticity. Fixed rollover bars behind the seats complement the safety concept: they ensure the passengers are afforded an outstanding level of protection even if the vehicle should turn over. Adaptive airbags, kneebags and sidebags as well as belt tensioners and a tyre pressure monitoring system also make up part of the standard specification.

The ultra-strong carbon-fibre-reinforced materials used for the new Mercedes-Benz SLR McLaren Roadster furthermore achieve a level of torsional stiffness that is unprecedented for an open-top car. This combines with a chassis bred on the racetrack and the 460-kW/626-hp AMG supercharged V8 engine to produce the sort of scintillating handling that is normally the preserve of super-sports cars with a fixed roof.

The SLR McLaren Roadster's exceptional credentials are given a further boost by the fully retractable soft top that blends seamlessly into the vehicle's flowing lines. The newly developed material it is made from not only promises everyday practicality in all weathers, it also enables the high-performance sports car to attain speeds which are highly unusual for a roadster. For example, the top speed of 332 km/h with the roof up matches the extraordinary figure set by the Coupé.

Despite the fact that the Roadster comes with a fully retractable soft top to fuse pure open-air motoring bliss with the ultimate in drive power, by no means do its occupants have to compromise on comfort or everyday practicality. As such, the new Mercedes-Benz SLR McLaren Roadster succeeds in synthesising high-tech from the world of motor racing, the capabilities of a thoroughbred high-performance sports car, as well as the long-distance comfort and sophisticated ambience of a classic, high-calibre Gran Turismo touring car.

Photos: Mercedes-Benz

(July 02, 2007)