Why a 'bad' car can be 'good' around Monte Carlo...
It may be the slowest track on the Formula One racing calendar, but the unique Monte Carlo street circuit places some highly unusual demands on a Grand Prix car, as Renaults Executive Director of Engineering Pat Symonds explains:
The best rule of thumb when it comes to considering Monaco is that it is never won by a good racing car. An F1 car is generally designed to be quick on an average F1 circuit, but Monaco presents a large number of challenges at the different extremes of the spectrum. This being the case, it means the car is invariably never optimised, and instead the challenge becomes that of achieving the least bad set-up, adapting most effectively and then maximising the potential of your package. What then are the areas we need to concentrate on to best adapt the car?
The first area to look at is downforce. Conventionally, Monaco is thought of as a high-downforce circuit because of the number of slow corners but in fact, we run high downforce levels for the braking and traction benefits they bring on the very low grip surface. Typically, adding downforce to the car must be balanced against the consideration of increased drag, but at Monaco - where overtaking it almost impossible - we are prepared to accept lower levels of efficiency. Where for an F1 car, a typical lift/drag ratio is in excess of 3 (essentially, to accept a 1 percent penalty in drag, you must find 3 percent or more downforce), for Monaco it is possible to drop below this magic ratio.
In terms of setting up the chassis, we place a premium on finding grip in low speed corners. We do not achieve terminal velocity at the circuit, and this means that we tend to run the suspension quite soft - indeed, the imperfect, heavily-cambered road surface of the city streets makes this doubly necessary. In order to cope with this, the suspension must be as independent as possible in order that a single wheel can ride over a change of surface with minimal effect on the other three wheels. Although an F1 car possesses independent suspension, this is normally quite severely limited by stiff anti-roll bars: at Monaco, we run the softest possible springs and anti-roll bars in order to cope with this.
Wheel alignment and particularly camber receive special attention: usually we favour very high camber angles, but this can potentially lead to severe braking instability in highly cambered and bumpy braking areas. Steering geometry must also be considered, as the Loews hairpin requires more lock than any other corner during the season, and we run up to twice as much steering lock as at a circuit such as Barcelona.
On a modern F1 car, the other fundamental area to be considered is that of control systems - they must be adjusted in order to best help vehicle performance. With so many low-speed corners, the traction control is set up carefully, trying to minimise wheelspin but also ensuring it is not so aggressive as to induce excessive understeer, which is always a problem in the middle of slow-speed corners. Similarly, the differential needs to be controlled in order to minimise single wheelspin while still giving the drivers the controllability they require.
Once we have got the car to the best configuration possible, using both experience and simulations, then the engineers are left with the problem of tracking the circuit as it changes. Grip levels increase significantly lap by lap, and with the drivers' workload being so high, it is often very difficult for them to identify precisely what the car is doing and where they lost time. Although recorded data can help, great caution must be exercised when interpreting such variable results. At Monaco more than any other circuit, experience still has a big role to play in obtaining a good result.