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Wet weather - the art of compromise 26 May 2004

Franck Montagny (FRA) Renault R24. Formula One Testing, Silverstone, England, 28 April 2004. World © Capilitan/Sutton (L to R): Pat Symonds (GBR) Renault Executive Director of Engineering and Frank Dernie (GBR) Williams Special Projects.
Formula One World Championship, Rd9, European Grand Prix, Nurburgring, Germany, 27 June 2003

Racing in rain increasingly down to driver ability

The Nurburgring is famous for its unpredictable climate. In the past, wet weather would have seen a large number of modifications to the cars. However, current regulations allow only limited changes, meaning that wet running, which was already a severe compromise, is now even more so. Renault’s Pat Symonds explains…

“When we are visiting a new circuit, or when an existing race moves in the calendar (this year's European Grand Prix is a month earlier than in 2003), one of the first things we do is to analyse the thirty year averages of temperatures and rainfall: for this year's Grand Prix date, the averages are 0.8mm of rainfall per day, with a maximum temperature of 18.3°C. Once this has been done, then our attention turns to forecasting, but in F1 our needs are very different from a typical weather forecast: we need to know whether it will rain, at what time, what the temperature will be and the windspeed and direction - all within the very precise area of 1km - within a timeframe of approximately 90 minutes. And to do this, we need very accurate weather predictions.

“The first step, as an event approaches, is to back up original data with precise information from a number of sources. We employ a UK-based weather service to study meteorological data that is not publicly available, and then feed this data into weather prediction models. However, to meet our very specific needs, we need an even more sophisticated approach at the circuit. A mobile radar system is set up on a hill nearby the circuit, in order that it can look some distance in all directions. Indeed, the way in which we ask the radar to work is almost completely opposed to its conventional use: while commercial systems are specifically designed to ignore rain and track large airborne targets, weather radar is tuned for maximum reflection from small water droplets. Combining weather radar with GPS and tracking software, we can obtain extremely accurate predictions of short-term weather changes - to the extent that we can predict which corner will be affected first, to an accuracy of a few minutes.

“In terms of how running in the wet affects the cars, the manner in which we approach this challenge has changed significantly in recent years. Previously, a raft of changes would be made to the car in order to adapt its handling to the low grip conditions. Under current rules, however, the changes we are allowed to make are minimal: the FIA permits an initial set of changes, which include changing to wet weather tyres and reducing the size of brake ducts in order to maintain the brakes at their optimum operating temperatures (although this parameter must be judged carefully against the possibility of the circuit drying out later in the race, and the brakes thus potentially overheating). The second set of modifications allows us to change to extreme wet weather tyres in order to clear standing water more effectively.

"More than ever this year, because we must run the cars in configurations that are far from being optimised for wet conditions, wet racing comes down to driver ability. Not only do they have to cope with a more difficult car, they also must deal with constantly changing levels of grip and visibility. In these conditions, the driver needs to be able to quickly find the car's limit in abnormal conditions, but also to control the car when he steps over this limit - as inevitably he will. Resourcefulness becomes all important as in these conditions, no two laps are the same. The driver requires innate natural skill to control a car on and beyond the limit, but also needs to be inquisitive in how he drives, exploring different lines and different parts of the circuit to find the highest levels of grip. Even more than usual, though, racing in the wet is where an F1 driver demonstrates what sets him apart from the norm: for those of us trackside, running in a ball of spray with near-zero visibility, constantly changing grip levels, on the limit, is really something we cannot properly understand.”