The new Sauber C29 design
New regulations force fresh thinking
At first glance the most important new technical and sporting changes for the 2010 season do not seem so major at all. Refuelling during the race is now banned and the cars’ front tyres must be around 25 millimetres slimmer. So far, so good. However, these apparently minor tweaks have extremely far-reaching consequences. The refuelling ban means each car’s fuel tank now needs to be almost twice as large as before, and the narrower front tyres require very different weight distribution.
Bearing this in mind, the designers had carried out initial calculations as early as February 2009 using computer-aided flow simulation. This involved examining the effects of the slimmer tyres and longer wheelbase before starting work on the concept for the car in April 2009.
The fuel tank of the 2009 car had a capacity of between 120 and 140 litres, and that has now had to be increased to around 200 litres. This has led to significant changes in the dimensions of the monocoque, making compromise unavoidable. The regulations limit the width of the car to 800mm, while space also has to be made for the radiators. These must be integrated to produce maximum aerodynamic effect and allow optimum airflow. Positioning the fuel tank any higher is not advisable, as this would also raise the car’s centre of gravity. This means that the tank’s length has been expanded chiefly to create the extra capacity required. The knock-on effect on the car’s total dimensions sees roughly 20 centimetres added to both its wheelbase and overall length.
Another important consideration is how the distribution of weight through the car will alter during the course of a race. The engineers’ aim is to ensure that weight distribution remains as constant as possible despite obvious changes in fuel load. The rise in the cars’ minimum weight – from 605 to 620 kilograms – and higher fuel loads at the start of a race mean that the overall grid weight of the cars will be around 80 to 90 kg higher than before. That will also lead to lap times falling by up to five seconds over the race distance.
Engine and gearbox
The adoption of a Ferrari engine and gearbox presented the engineers with another challenge. However, the linking with their counterparts in Maranello has run very smoothly from the start, allowing the switchover to pass off without any notable problems or delays. The standard engine electronics also slotted in well with the engineers’ designs and made a comparatively easy fit with the characteristics of the Ferrari powerplant.
Much more significant was the impact of the gearbox, which includes the inner mounting points for the rear suspension and therefore partially dictates the car’s kinematics.
Aerodynamics and form
The 25mm narrower front tyres require weight to be shifted further back in the car. And so, in order to guard against an excessive tendency to understeer, the car’s aero characteristics have to be adjusted accordingly.
When it came to the C29’s aerodynamics, the engineers have benefited from a development programme for the F1.09 which continued almost to the last race of 2009 – and underpinned a considerable increase in performance. Although the narrower front tyres and extended wheelbase gave the aerodynamics experts a different platform on which to work, they were still able to build on the knowledge gained with the 2009 car. With winter testing not permitted until 1st February, this provided them with a particularly significant edge. Indeed, for the engineers the final races of last season doubled up as opportunities for testing.
From the side view the highly intricate raised nose of the C29 is eye catching. Also clearly visible is the extremely long undercut at the transition from chassis into underbody. This solution, which turned out to be the most promising variant during the development phase, allows a particularly high quantity of air to be channelled to the underbody and therefore the double diffuser.
The front wing is a totally new construction, but is based in concept on the previous year’s design. Here again, the engineers had already successfully employed various technical solutions on race weekends in 2009.
Small, raised air intake apertures in the sidepods allow an extremely defined undercut. Their effect is complemented by the turning vanes positioned in front of them. These measures also help to optimise airflow to the underbody and lower rear wing.
The larger fuel tank also has an effect on the engine cover, of course. The length of this section, too, has been increased and it is heavily undercut at the rear. Extremely close-fitting exhaust pipes help to make this form possible. Here, slimmer design enables extremely effective airflow to the rear wing and upper section of the double diffuser.
It goes without saying that the design of the C29 focused squarely on the use of a double diffuser from the outset. The full spectrum of possibilities permitted by the regulations have been exploited to impressive effect, with the aerodynamic efficiency of the car as a whole significantly improved.
The rear wing represents a further development of last year’s version and retains the same central support construction.
Suspension and materials
Substantial changes have been made to the front suspension concept, the lower wishbones in particular being set a good deal higher than before. This arrangement was prompted by the modified monocoque. Another totally new feature of the front axle are the brake vents, which now have two air intake apertures each in response to the higher car weight and consequent increase in braking energy. Wheel rim shields are no longer permitted by the regulations.
The use of Ferrari’s carbon gearbox played a key role in the design of the rear suspension, as the inner pivot points were already decided by the architecture of the gearbox casing. The car’s overall weight (up to 90 kg greater than in 2009 with a full tank of fuel) was a factor in setting the kinematics. The aim is to make the car as easy as possible on the tyres, which will be placed under severe loads – especially when the car is heavily fuelled.
Of course, the C29 also incorporates the changes to the regulations aimed at cutting costs. For example, the wheel carriers are no longer made from the eye-wateringly expensive MMC (Metal Matrix Composite) widely used previously, and exotic alloys are no longer permitted for the wheel rims either. Their dimensions, furthermore, are precisely defined, removing any scope for the teams to experiment with marginal differences in rim widths.
BMW Sauber C29
Chassis: Carbon-fibre monocoque
Suspension: Upper and lower wishbones (front and rear), inboard springs and dampers, actuated by pushrods (Sachs Race Engineering)
Brakes: Six-piston brake callipers (Brembo), carbon pads and discs (Brembo, Carbon Industries)
Transmission: Ferrari 7-speed quick shift gearbox, carbon, longitudinally mounted, carbon-fibre clutch
Chassis electronics: MES
Steering wheel: BMW Sauber F1 Team
Tyres: Bridgestone Potenza
Dimensions: Length 4,940mm, Width 1,800mm, Height 1,000mm, Track width, front 1,495mm, Track width, rear 1,410mm
Weight: 620 kg (incl. driver, tank empty)
Ferrari 056 engine
Type: Naturally aspirated V8, cylinder angle 90 degrees
Cylinder block: Sand cast aluminium
Valves / valve train: 32 / pneumatic
Displacement: 2,398 cc
Weight: 95 kg
Electronic injection and ignition.