Talk to any driver about their favorite track and the chances are they will tell you it is Spa-Francorchamps. Despite considerable changes over the years, it has still retained many of its most exciting aspects including the famous Eau Rouge...
Talk to any driver about their favorite track and the chances are they will tell you it is Spa-Francorchamps. Despite considerable changes over the years, it has still retained many of its most exciting aspects including the famous Eau Rouge corner. It is a corner, which is as big a challenge to the engineers as it is to the drivers, and where lap times can reflect considerably the efforts of both.
Although this unique corner is the key to this track with regard to outright lap time as well as the overtaking possibilities down the long straight after the exit, it is not the only high-speed corner on the track. There is still the need to make some compromises in order to have the car working well in the other corners and for the ultimate lap times.
The uniqueness of Eau Rouge is the high vertical load that is put into the suspension (and driver) as the track dips down and then rises sharply into the steep climbing turn out of the corner. Simply adding packers in order to prevent the car bottoming out can make the car too nervous. "You work in half-millimeter increments in a bit to find the right balance. It is a real challenge, but for an engineer it is also a really rewarding circuit where the right set-up can show a big difference in the lap times," says Ferrari's Technical Boss, Ross Brawn.
It is also a great challenge for the drivers who like to boast about taking the corner flat out. That, say the men who check the telemetry, is something that has to be checked along with the braking telemetry, for even though the throttle might stay wide open throughout the corner many drivers use their left foot to brake the car slightly to stabilize it. Flat out is not always the quickest way around the corner, for if the car gets a bit out of shape more time can be lost than is gained.
Thus, listening to the note of the engine through the corner can be deceptive, but not so the results of what engineers have nicknamed the "Macho meter" which is a speed trap placed just at the exit of a corner. "Every time a driver sets a quick lap at Spa the first thing he wants to know is his exit speed out of Eau Rouge," says Brawn with a smile.
The character of the corner also demands a very distinctive set-up between qualifying and the race with heavier fuel loads. A quick lap isn't all about going quickly through Eau Rouge as there are several low-speed corners where good traction also plays a vital part of the lap time and the right set-up can find another half second off the lap times. This year, the infamous "Bus Stop" chicane has been modified with a now flat out straighter exit, so the need to set up the car to ride the kerbs well at this point has now been eliminated. At other points on the track it is best to stay off the kerbs.
The overall high-speed characteristics of this track also make it a definite challenge from the aerodynamic point of view as well as mechanical. Aerodynamic set-up is a mixture between high and medium downforce and can be the difference between winning and losing if the weather looks changeable as it usually is at Spa. In a dry race it is a tight choice between the advantages of a one or two-stop race, but if there is rain in the air the chances are that it's better to plan a two-stop race, as you will probably need to anyway.
In a wet race the team will often need to adjust the aerodynamic set-up according to the conditions, but there is only so much you can do. The front wing is the primary means of changing the balance of the car during the race, while altering the rear gurney flaps on the rear win will make less difference. If there is a big change in track conditions during the race whatever changes are made will be a compromise. The aerodynamic set-up does not have the range to cope with the different speeds between a dry and soaking wet track which can vary as much as 15kph. Rear wing adjustment is made in 3 kph steps. Any more than that it would mean changing a whole lot more than a flap setting which is not practical during the race.
From a tyre point of view the track is not hard on the tyres. A soft to medium compound tyre can be used at Spa and the chances are the team will be using the same rubber they ran in Hungary. The car itself will be unchanged since the last race, other than the set-up between the two tracks, which could not be more different from every point of view!