Magny-Cours - the technical requirements 12 Jul 2006
Magny-Cours, the setting for this weekends French Grand Prix, presents Formula One teams with some unique challenges. Race engineers must finely balance aerodynamic grip and straight-line speed to maximize the cars performance. Here the Renault team explain how they tweak the set-up of the R26 for this circuit
We run medium to high levels of downforce at Magny-Cours in order to get improved braking and traction, as well as grip in the medium speed corners. While it might seem tempting to reduce wing levels to improve top speed to try and overtake competitors on the run to turn 5, this is actually counter-productive: reducing wing costs the drivers speed in turn 3, reducing their exit speeds and having little impact on the speed at the end of the straight.
The circuit features an exceptionally smooth surface, meaning we can run the cars with very low ride heights, and stiff suspension. Stiff suspension offers benefits in terms of aerodynamic performance, and the change of direction in the quick chicanes at turns 6/7 and 11/12. The car may end up a little nervous in these sections, but this does not cost time as both are followed by braking zones and slow corners. In terms of suspension settings, we must nevertheless find the right balance between stiffness for the higher speed sections, and mechanical grip for the slow corners.
Magny-Cours presents few unusual reliability challenges for the cars, but the major one comes at the final chicane with its very high kerbs. The quickest line involves bouncing over both kerbs, but brings with it the associated risks of over-revving the engine and overloading the transmission. While the drivers will always use the optimum line in qualifying to achieve the fastest lap-time, they may alter this slightly for the race to look after the mechanicals of the car.
The track surface at Magny-Cours is notorious for its temperature sensitivity. A variation in its exposure to sunlight can have a large effect on the track temperatures, and something as seemingly innocuous as a passing cloud could take a tyre compound out of its optimum operating window. This is something we try and counter in our tyre choice, and we pick the most suitable compound for the predicted conditions. In general, rising temperatures will make the car oversteer more, and the evolution of track temperature is something we track throughout the weekend.
Magny-Cours is a circuit where engine torque plays a prominent role. We need strong levels of torque to launch the cars out of the numerous slow corners, but also good torque control at higher revs. In turn 3, and also at the two quick chicanes, the drivers go back to full throttle while the car is turning and under high aerodynamic loads. Power delivery must therefore be as smooth as possible to avoid unsettling the car balance. This will be a less of a factor with the V8 engines than with the V10 generation, owing to reduced levels of torque.
Gear ratios at Magny-Cours tend to be shortly-spaced in order to optimise the car's acceleration from slow speeds. This means our attention is focused primarily on the 0-250 kph range without too many worries about top speeds. This is because the primary passing opportunity on the circuit is at the end of the back straight, which is preceded by an aero-dominant' corner where following another closely car is difficult - which makes it hard to use any straightline speed advantage on the exit. However, the exception to this rule can come on the first lap where gaps between cars have not stabilised and it is still possible to pass for position.
The control systems are important in two main areas at Magny-Cours: firstly, for controlling rear tyre wear; and secondly, to avoid over-revving at the final chicane when the cars leap into the air and leave the rear wheels spinning freely. However, these tasks are part of our normal' weekend work and do not present a significant additional challenge.