Solid targets for the Sauber C30
"It is important for us to go into winter testing with a car we understand"
“Our aim in the development of the Sauber C30-Ferrari has been to build on the strengths of the C29 and to eliminate its weak points,” says Technical Director, James Key, previewing the Sauber F1 Team’s new car for 2011. Heading the list of improvements are aerodynamic efficiency, performance through low-speed corners and the car’s mechanical grip. The Sauber engineers began to address these aspects during the course of the 2010 season and achieved measurable progress. However, their options were limited by the boundaries of an existing concept. By contrast, the C30 gives them considerably greater room for manoeuvre here. “In addition, it is also important for us to go into winter testing with a car we understand, and we have worked hard on ensuring the characteristics of the car are heading in a direction we believe in. There will be much to learn about the new Pirelli tyres and in this respect we want to ensure there are no surprises with the way the car is handling,” adds Key.
New technical regulations have once again presented the designers with a major challenge. Double diffusers are now banned and the height of the underbody at the rear has been further limited. That may not sound like much, but presented a major challenge to the aerodynamicists since the architecture of the diffuser affects the overall concept of the car.
The second major change lies in the switch to Pirelli tyres. This was a particularly exacting undertaking as the engineers had to make decisions in the concept phase before the teams had even been able to test the tyres out on the track. However, here they were aided significantly by the regulations, which stipulate the weight distribution range of the cars.
Another feature of 2010 no longer permitted is the F-duct, which last year enabled the drivers to cause the air flow to the rear wing to stall – and in so doing significantly reduce drag. Instead, the new regulations allow adjustable rear wings, which have a similar effect.
The minimum weight of the cars has been raised by 20 kg to 640 kg for this season, which helps the teams to integrate the KERS (Kinetic Energy Recovery System) technology with a reduced weight penalty.
“We began work on the concept for the car in early May,” says Key, “and set about drawing up its architecture – the exact position of the engine and transmission, the wheelbase, the chassis and fuel tank, and the arrangement of the radiators. This allowed us to make maximum use of our limited resources and invest a lot of time in autumn 2010 in areas which have a bigger impact on the car’s performance.”
The nose and the front section of the monocoque have a significantly elevated position on the C30, which optimises the flow of air to the underbody. In addition, the upper side of the monocoque around the front suspension is more contoured. The front wing is mounted to pylons which drop vertically downwards. The wing itself is based on the final specification from the C29, but a host of details have been modified.
The layout of the front suspension is entirely new. It has been designed to give the engineers maximum flexibility in the set-up of the car. James Key elaborates: “With Pirelli not confirmed as the F1 tyre supplier until a late stage, we only had a limited amount of information available. What we wanted to avoid was a situation where we would be limited in the mechanical set-up of the car.”
Another area playing an important role this year is what we refer to as “packaging”, i.e. the arrangement of many small components such as electronics boxes, chassis-based engine systems, the fire extinguishers, etc. in and around the cockpit and side pods. The reason for this is KERS, whose major components – such as the electric motor/generator, batteries, electronics box and cooling – all take up additional space. The aim of the engineers was to integrate KERS without adversely affecting the car’s aerodynamics, weight and centre of gravity. The benefits of the technology are well known; for 6.7 seconds per lap the drivers can summon up an extra 60 kW of power. The entire system was developed by Ferrari.
The cooling inlets have a small cross-sectional area and are positioned high up, which allows a prominent side undercut in the lower section of the sidepods. This helps to generate optimum airflow to the diffuser and rear wing. The arrangement of the radiators is also totally new: they are now mounted more vertically allowing for a strongly tapered rear. The volume of the car’s rear section as a whole has been significantly reduced to optimise the aero effectiveness of the rear end. Instead of extending straight back towards the rear, the engine cover is now angled downwards and contains rearward cooling exits.
A familiar element of the car is the Ferrari engine, onto which has been bolted an all-new carbon transmission – also supplied by Ferrari. The design of the longitudinally mounted transmission has been significantly affected by the new diffuser regulations in 2011 which require a different approach to 2010.
The transmission picks up the inner pivot points of the rear suspension and so largely determines their geometry, which has been configured to exploit the potential of the Pirelli tyres to the maximum. As Key explains: “We were in constant communication with Ferrari, and enjoyed very constructive discussions. As with the front axle, it was important the design of the rear allowed a high level of flexibility in the mechanical set-up of the car.”
Although the technical regulations for the diffuser are far tighter than in 2010, it still makes sense to use a blown diffuser, and the exhaust pipes are positioned low as a result. This is a new development for the team as it was not introduced in 2010. “This is an area where there’s a lot of potential for further development. I expect we’ll see some interesting solutions as the season unfolds,” says Key. Channelling the hot exhaust gases to the rear of the car without damaging the suspension components presented the engineers with a particularly tough challenge.
The rear wing of the C30 now has a single support mount in place of the twin arrangement of last season’s car. The F-duct is banned in 2011, but the regulations do allow the upper flap on the rear wing to be adjusted. The driver adjusts the wing electro-hydraulically at the touch of a button in the cockpit to reduce drag on the straights and make it easier to overtake. While the drivers are free to use this rear wing adjustment at any time during practice sessions and qualifying, in races it may only be activated if the driver is close enough to the car in front.
“Putting all the changes into action was a fascinating exercise,” says Key, “and the development of the Sauber C30-Ferrari will continue almost to the end of the season. We’re looking to take a clear step forward in 2011.”