Rampf on the first genuine BMW Sauber 16 Jan 2007
BMW Sauber have described the new F1.07 as the teams first real car. Whereas many components on last years machine had already been designed when BMW decided to buy into Sauber, its successor has been a co-production from the start.
The teams Swiss base at Hinwil was responsible for the chassis, while their German colleagues in Munich were in charge of the powertrain and electronics. Together they laid down the priorities needed to combine their efforts into one harmonious package.
Work on the F1.07 began in April 2006. "On the one hand we channelled our experience from the F1.06 into the car, but at the same time we considered the new challenges presented by the 2007 regulations," explained technical director Willy Rampf at the new cars launch.
One of the most important 2007 changes the team had to contend with when designing the car was the switch to standard Bridgestone tyres, which will provide less grip and hence reduce cornering speeds.
"It is obvious that the cars are going to slide around more, and so it was important for us to build a car that is easy to drive and that our drivers can trust sufficiently to go on the attack," explained Rampf. "We should also expect the cars generally to run with slightly more downforce in order to compensate for the loss of grip."
With the introduction of standard tyres, the significance of aerodynamics increases even more. "If you look at all the components that affect the performance of a Formula One car, aerodynamics represent by far the single most important factor," Rampf pointed out.
That is why the expansion of BMW Saubers aerodynamics division was given top priority. Operation of their wind tunnel in Hinwil was gradually ramped up from one to two and then, at the end of October 2006, three shifts. That has long been standard among the competition and was felt to be a key prerequisite for achieving the team's ambitious targets.
In a bid to make the F1.07 as responsive as possible in corners, the car features an all-new front wing linked to a similarly new nose, which is shorter and higher than before. This allows the wing to channel a large amount of air under the car, allowing the underbody and diffuser to work to their full potential.
The F1.07 also uses a new cooling concept, which is more effectively integrated into the car's overall package and designed for a greater throughput of air, hence its slightly larger cooling intakes. The air is smoothly diverted upwards, improving aerodynamic efficiency by comparison with the F1.06 particularly in high outside air temperatures.
"In the concept phase we devoted a lot of time to finding an optimal solution in this area, noted Rampf. It's an important factor as the air temperatures in the first races of the season in particular are traditionally very high. The cooling concept of the F1.07 promises to deliver very high efficiency in all conditions."
In developing the rear of the car, the BMW Sauber designers built on the knowledge gained with the F1.06, giving the tail an even slimmer and lower profile to further optimise air flow around the rear wing. This design was based on the compact quick shift gearbox as well as cleverly positioned hydraulic elements. Also harmoniously integrated into the design are the exhaust pipes, whose form was determined by considerations of performance and overall package.
The section underneath the rear wing is completely new. Stricter regulations on rear-end collisions have resulted in the rear crash element being larger, while its lower positioning has required a completely new design for the centre section of the diffuser. A further task the BMW Sauber engineers faced was to reduce weight while maintaining rigidity. This applied to the monocoque, which in parts consists of 60 layers of carbon fibre, as well as to the individual components.
"Using a lot of ballast is always an advantage, but of particular importance in the current situation as it ensures great flexibility in terms of weight distribution," explained Rampf. "And that plays a crucial role in exploiting tyre potential to the full."
Also totally new to the F1.07 are the suspension elements which, at the front axle, are primarily dictated by aerodynamics. The raised nose section means that the wishbones slant downwards at a striking angle. The kinematics have been modified with the standard tyres in mind and the rear axle was also revised to further improve traction.
"We were also very keen to lend the steering good feedback," commented Rampf. "This aspect has taken on even greater importance as a result of the reduced levels of grip. The harder standard tyres will inevitably cause the cars to slide around more, which means the drivers will have to do a lot more correcting. That's why good steering feedback is essential."
In line with the new freeze on engine development the F1.07s V8 remains essentially unchanged - a fact reflected in it being designated the BMW P86/7 rather than P87. However, in place of the previous engine electronics, there is now a new central control unit for the engine, transmission and chassis. This new development hailing from Munich goes by the abbreviation RCC, which stands for Race Car Controller.
Another part of BMW Saubers test department in Munich is devoted to the development and testing of transmissions. The result is the F1.07s new seven-speed gearbox, which shifts up to the next gear without any break in power at the rear axle.
Summing up his hopes for the new car, Rampf concluded: "In the first season we created a solid basis. The cooperation between the team members in Munich and Hinwil is now running very smoothly, and the added resources are also helping. Our aim is now to further reduce the gap to the top teams."