Walk for Speed
THE SPECIAL CASE OF CITY CIRCUITS
Motorsport with electric cars in the centre of the city: this is the basic concept of Formula E. Now in its fifth season, the series holds its events on a single day where passenger cars, trucks, motorcycles and streetcars normally travel on the other 364 days of the year. Afterwards, the racing stage disappears again as quickly as it was established.
“With city circuits, there are always differences between the original design on the computer and the way they’re actually set up,” says Lucas di Grassi. So what does the circuit really look like at the venue? This is the key question which the 2016/2017 drivers’ and 2017/2018 teams’ champion explores together with his colleagues from Audi Sport ABT Schaeffler during the track walks.
Before Lucas di Grassi and his teammate, Daniel Abt, arrive at a Formula E race track, Audi Sport ABT Schaeffler’s driver duo has already tested its current layout for hours on end: virtually, in the driving simulator, based on computer data which the FIA provides to all of the Formula E teams. However, these simulations never precisely match reality. That’s why the track walk is so important, particularly at venues where Formula E races for the first time.
Over the years, city circuits change a lot more than permanent race tracks. Nothing stays the same from one set-up to the next. Optimisations – especially for enhancing the safety of drivers, teams and spectators – are normally less costly than in the case of permanent tracks. For instance, this applies to the positioning and the materials of walls, barriers and guard rails that are used to demarcate the circuits in the city centres. “We take a very close and detailed look at such changes during the track walk to make sure that our simulation models also match reality as precisely as possible in these respects,” says race engineer Markus Michelberger. He has the trackside technical responsibility for Lucas di Grassi’s Audi e-tron FE05.
REFINED RACING LINE
Which line will be the quickest? Lucas di Grassi and Daniel Abt are perfectly familiar with the basic racing lines around the typically narrow, winding city circuits from the simulator practice before a Formula E-Prix and from their previous races. So in this respect, the track walk only serves the purpose of fine-tuning for the Brazilian and the German. For instance, di Grassi and Abt pay attention to special characteristics of the kerbs on the inside and outside of the turns. “Even if there’s just a five-centimetre variation between their positions on the circuit map and reality, that may make a huge difference for driving,” emphasises Lucas di Grassi.
The next item on Audi Sport ABT Schaeffler’s checklist for studying the track is optimal grip. Grip is particularly important for accelerating at the start and out of corners, as well as in braking manoeuvres. On the car, the suspension set-up, aerodynamic set-up and tyre characteristics have the greatest effect on grip. On the race track, the surface primarily determines the grip conditions. How smooth or rough is the tarmac? How uniform is the surface around the circuit? Where and how does it differ? In what sections has damaged tarmac been repaired and how? Where do cracks, grooves, potholes and bumps lurk? What sections are particularly slippery?
“Every type of surface provides a different kind of grip level and, accordingly, permits different speeds,” explains Markus Michelberger. Like his colleague, Christophe de Coninck, who takes care of Daniel Abt’s Formula E racing car, Michelberger notes all of the impressions and findings during the track walk on his iPad. Subsequently, all of the facts and data obtained during the track walk are used for further development of the simulation programmes and optimisation of the car set-ups.
Also critical for the grip of the Audi e-tron FE05 cars driven by Lucas di Grassi and Daniel Abt are lane markings and zebra crossings, because these painted surfaces are smoother – not only in wet conditions. These areas, however, can also offer an extra amount of grip if they have been provided with a special anti-slip coating, specifically for racing events. Treacherous as well in both dry and wet conditions are manhole covers. “If you have to brake on one of them, you need to do so with great precision; otherwise you risk locking a wheel and skidding,” says Allan McNish. The former FIA World Endurance Championship champion and ex-Formula One driver is the team principal of Audi Sport ABT Schaeffler. The Scot actively participates in every track walk, contributes his enormous practical experience and provides his drivers and engineers with valuable advice in all areas.
In a nutshell: the track walk at Audi Sport is absolute teamwork and fundamentally an important activity that can mean the difference between victory or defeat.
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