BMW Sauber F1 rolls out in Valencia

BMW officially entered Formula One in its own right yesterday with the unveiling of the BMW Sauber F1.06 before more than 500 journalists and guests in the futuristic Ciudad de las Artes y las Ciencias (CAC) in Valencia (Spain). BMW purchased a majority shareholding in the Sauber Formula One team which became official on January 1. Without doubt the most interesting aspects of the F1 launch season is not the champagne and parties, but the information released by the various camps on their technical development. This year in particular, the reduction of engines from 3.0 litre V10 to 2.4 litre V8 will pose some interesting technical challenges, as explained by BMW at the launch.

The new V8 engines are heavier, shorter and, due to a 600 cc reduction in capacity, have lower output and fuel consumption. “Lap times,” estimates BMW Motorsport Director, Professor Theissen, “will go up by around two to three seconds, though spectators will hardly be aware of it. The drivers, on the other hand, need to adapt their driving style. To put it simply, they will have to attack corners less sharply to get the most out of the power available.”

The different firing sequences and intervals compared to the V10 have led to a completely different vibration patterns. With a speed range that exceeded 19,000 rpm, the V10 hit a critical zone between 12,000 and 14,000 rpm. However, the engine spent very little time in this problematic band and smoothed itself out again as the revs were stepped up. But it is precisely here that the V8 encounters problems. Its vibration curve enters challenging territory later than the V10, starting at around 16,000 rpm and becoming more critical from there, which can impact on the stability of vehicle components. And, like its predecessor with two extra cylinders, the BMW P86 V8 engine also has to last for two grand prix weekends.

New chassis

The BMW Sauber F1.06 is an all-new concept. The shorter and more fuel-efficient V8 powerplants exert a decisive influence on the architecture of the car. Due to the minimum dimensions for the design of the chassis as decreed by the FIA, the overall dimensions of the car remain almost unchanged. “For the designers this means more scope in the design of the car thanks to the more compact engine,” explains Willy Rampf, Technical Director Chassis at the BMW Sauber F1 Team. The lower tank capacity of the BMW Sauber F1.06 impacted on both the design of the monocoque and the position of the engine. The shorter powerplant, moreover, allowed the engineers to extend the titanium casing of the 7-speed transmission, which favoured the construction of a decidedly slimline rear end.

The engineers turned their focus primarily on aerodynamics, where it was not only a question of optimum downforce but enhanced efficiency as well. The construction, arrangement and design of all sub-assemblies and components followed this premise.

The front section of the new car came in for some striking treatment. The chassis has been significantly lowered at the front, which means the lower wishbones are no longer attached below the monocoque but directly to the side of the chassis. The nose of the car has also been lowered further to the ground and features an underside that curves slightly upwards. The front wing has been adjusted to the other changes through numerous optimisation measures. The aim of all these measures has been to improve the air flow to the underbody and the sidepods.

The reduced cooling requirement of the V8 engine allows not only for more compact radiators but for smaller apertures in the sidepods as well, which also benefits the car’s aerodynamics. The same goes for the rollover bar with its integral air intake, which has been reduced in size as a result of the engine’s lower air throughput. Complex finite-element calculations, furthermore, have enabled a significant reduction in the weight of the rollover bar while at the same time complying with stringent safety requirements.

A completely new feature on the BMW Sauber F1.06 is the design of the front and rear suspension. On the front axle, the layout is significantly determined by the higher attachement points of the lower wishbones, as dictated by efficient aerodynamics. The rear axle is similarly a new construction. At the heart of the deliberations here, however, were modified kinematics to match the demands of the Michelin tyres. Lowering the front section, moreover, has made for a corresponding drop in the position of the pedals and the inboard front-axle components, along with a lower position for the driver’s legs. All these factors help to bring down the car’s centre of gravity.

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