Q&A with BMW Saubers Willy Rampf 05 Sep 2007
The Italian Grand Prix in Monza represents a unique challenge for drivers and engineers alike. With speeds reaching the 330 km/h mark, the famous circuit calls for the lowest downforce set-up on the Formula One calendar.
BMW Saubers technical director Willy Rampf describes the legendary tracks distinctive requirements and explains how his team has prepared for this weekends race, the fastest of the year
Q: What makes Monza such a special track?
Willy Rampf: Monza is a classic high-speed circuit with extremely long straights, comparable only really with the old Grand Prix Hockenheim. At four points during a lap, the drivers hit speeds well in excess of 300 km/h and 76 per cent of the lap is spent at full throttle. This is significantly more than at any other Formula One track, and that is why we run lower downforce at Monza than anywhere else over the course of the season.
Q: What does that mean for the cars aerodynamics?
WR: We have developed a low-downforce package of special aerodynamic parts for this race. At Monza we run less rear wing than at any other circuit. And in order to achieve the right aero balance we have also redeveloped and adapted the front wing. In addition, we examine the aerodynamic efficiency of all the cars detachable parts for Monza. Only the most efficient of these are left on the car. Indeed, we remove several elements, as doing so enhances performance. We are taking the opposite approach to the way we prepare for Monaco, for example, where we generally add every part to the car that will generate extra downforce.
Q: Staying with Monaco for a moment - how much less downforce do you run in Monza compared to the street circuit in the principality?
WR: In Monaco the cars only reach 290 km/h at one point on the circuit, whereas in Monza they comfortably exceed 300 km/h in four places. For this reason the engineers set out to minimise drag, and that means giving away around a third of the cars downforce. In Monaco, downforce is everything, while in Monza the drag coefficient plays a major role. Having said that, you cant afford to neglect downforce altogether. After all, the drivers also need to be able to brake late and accelerate quickly through the corners.
Q: How do the top speeds of the two tracks compare with one another?
WR: The low-downforce package allows the F1.07 to hit a maximum speed of around 350 km/h at the end of the start/finish straight in Monza. If we were to run the car in Monaco specification the drivers would not reach 300 km/h, as the engine output would no longer be sufficient to overcome the mushrooming air resistance.
Q: How did the contributions of the wind tunnel and the supercomputer compare in the development of the aero parts?
WR: The two are closely intertwined. The development of these parts involves interaction between the knowledge gained in the wind tunnel and the results of computer-aided flow simulation, otherwise known as Computational Fluid Dynamics (CFD). CFD and the wind tunnel are mutually beneficial. CFD has advantages when it comes to the development of wing concepts, for example. The wind tunnel, on the other hand, is unsurpassed in perfecting the cars overall aerodynamic set-up.
Q: How do you adapt the car mechanically for the Monza circuit?
WR: In addition to achieving the highest possible top speed, it is also critical for the drivers to be able to drive aggressively over the kerbstones. The track features three chicanes leading into full-throttle sections. It is important to nail a fast exit from these corners, and to do that you need sufficient traction. The mechanical set-up of the car represents a tricky compromise. It has to be soft enough to ride the kerbs efficiently and provide good traction, but go too soft and youll be short on stability through the high-speed corners.
Q: What kind of stress do these track characteristics place on the brakes?
WR: When it comes to the brakes, Monza literally blows hot and cold. On the one hand the long straights give them a lot of time to recover, but braking from seriously high speeds generates extreme loads every time. The end of the start/finish straight is the hardest braking zone of the entire season, the drivers slowing from 350 km/h to 70 km/h within the space of three seconds and enduring maximum deceleration of 5g. The brake discs, meanwhile, briefly reach temperatures of well over 1,000 degrees Celsius. What makes braking under these conditions particularly tricky is that on the long straights the carbon discs cool down more than the drivers would like - to under 400 degrees. When they then stamp down with some 100 kilograms of pressure on the brake pedal, for a split second or two the brakes do not bite with full power. That is something the drivers have to be prepared for.
Q: And what about the loads on the engine?
WR: Monza makes the engines work harder than at any other Grand Prix. This circuit boasts the highest full-throttle percentage - 76 per cent - of any venue on the calendar. This means that the engines are running for exceptionally long periods at high revs. However, we dont expect any problems since the homologated engines are designed to withstand loads of this order.