F1 meets the school run

Technology from the Mercedes SLR McLaren supercar will help to improve the design of more mainstream models in the future, according to McLaren boss Ron Dennis.

The supercar, unveiled at this week’s Frankfurt Motor Show, was developed by McLaren in the UK with support as required from DaimlerChrysler engineers in Germany.

Its 626bhp V8 engine gives the 1768kg SLR a top speed of 207mph and a 0-60 time of 3.8 seconds. The bodyshell and chassis are made entirely from carbon fibre.

Dennis cited its electronic stability systems including the electrohydraulic Sensotronic ‘brake-by-wire’ system among the technology that would feed into mainstream cars. But he singled out the SLR’s aerodynamic stability as a significant advance.

Torsional rigidity

Aerodynamic design principles from Formula One were used. The car has an almost smooth underbody so airflow is unimpeded, with aerodynamic diffusers at the front and rear.

An electronically controlled adaptive spoiler or airbrake on the boot lid rises to an angle of 10 degrees at a speed of 60mph.

Under heavy braking its inclination rises to 65 degrees to increase downforce as well as extra braking.

‘I’m not aware of other supercars in production in which you can drive at 200mph and be confident enough to tune the radio,’ he said. ‘It’s stable under acceleration and braking.

‘One of the problems with braking is that the centre of aerodynamic pressure moves forward. On the SLR the rear spoiler pushes the centre of pressure back as the nose inevitably pitches.’

Dennis said that a novel approach had also been taken to body structure. ‘People think of composites in terms of lightweight, but we’ve concentrated on achieving a high level of torsional rigidity, as well as meeting a difficult weight target. A stiff structure improves handling characteristics because it can cope with the suspension loads better.’

Luxury features

Because the structure is so light it has been possible to equip the car with luxury features such as air-conditioning, surround sound and a luxury interior, which add weight, while still keeping the car 200kg lighter than a Mercedes SL55.

The body structure is also quite large, with a boot big enough for two sets of golf clubs – unheard of in a supercar.

‘Because of the light structure those features are affordable from the point of view of weight while still achieving a fantastic power-to-weight ratio,’ said Dennis.

He said there had been ‘cross-pollination’ on the design between the engineering teams in the UK and Germany. ‘We overcame the inevitable challenge of engineers becoming territorial through the common objective of making a great car.’