Michael, Theissen get technical on the FW27 31 Jan 2005
At the launch of the Williams FW27 at Valencia on Monday, the teams technical director, Sam Michael, and BMW Motorsport director, Dr Mario Theissen, explained the thinking behind the new car and the effects of the 2005 rule changes on its design.
Sam Michael on the FW27: This car reflects a philosophy of concentrating on the fundamentals. Our focus throughout the design cycle has been built around simple variables that affect performance, such as reducing weight and friction while increasing stiffness. As a consequence of focusing on these fundamentals, we have reverted to a single keel configuration for the front suspension geometry. We have also been aggressive with our cooling, as witnessed by the extremely low engine bodywork and the large sidepod undercuts. Reliability is the final area we have been determined to pursue, and we have made significant progress, specifically with the gearbox which has been running on-track since November 2004 without problems.
Sam Michael on reduced downforce: The changes to the rules devised by the F1 Technical Working Group have fundamentally limited the expansion ratio of the air in the diffuser and reduced the ground effect of the front wing, the net result of which is a reduction of around 30% of downforce without reduction in drag. We have worked hard to recover as much lost downforce as possible, primarily via predictive means.
Prediction, using computational fluid dynamics (CFD) was our main tool to assess the implications of the new rules, and to consider a wide range of potential solutions. Together with our partners at HP, we have scaled up our computational resource by a factor of three times, which means we are operating with a facility that ranks in the top 500 globally, and in the top 40 in the UK. We augmented our in-house capability with the use of HPs Bristol Laboratories computer farm, which allows us to run computations using external resource at peak load times, such as during the new car design phase.
As a consequence of all of this additional capability, we ran almost 100% more aerodynamic models in CFD this year to investigate the optimal solutions under the new regs. Considering that each model contains around half a billion points of information, we have processed the equivalent of 70,000 volumes of the Encyclopaedia Britannicas simply to assess the aerodynamics of the FW27. We reduced our turnaround times, with post-processing times reduced to minutes as well as improving our accuracy. The CFD outcomes have allowed us to optimise solutions for front and rear wings, brake ducts and radiator ducts without fabrication or tunnel testing. It has been a major advantage in coping with the demands of the new rules.
The computational resource has also significantly enhanced our structural analysis process, which used to be highly reliant on manual calculations and testing validation. Now we can model these highly complex parameters and integrate the design of crash structures in the car with the aerodynamic demands.
The consequence of the application of advanced modelling together with a streamlining of tunnel experimentation has resulted in a distinctive profile to the FW27. As the front wing has been lifted by 50mm, it has become more important to utilise the drooped wing section in the centre of the car. Additionally, as the rear wing has moved forward relative to the lower diffuser, the other devices around the rear wing must be optimised to ensure they are all working in harmony.
Sam Michael on tyre restrictions: The BMW WilliamsF1 Team has won more races on Michelin tyres than any other team since their return to the sport, so we have worked closely on the implications of the new rules. Essentially, aerodynamics, weight transfer, mechanical balance and traction control are all slaves working to improve tyre performance. We have to find grip without destroying the tyres, and that challenge has become harder because of the new rules, but we are confident that we have made good headway over the winter.
Mario Theissen on one engine for two race weekends: Now there is a tactical need to save engine life as far as possible. We have two options, by running for fewer laps or decreasing engine speed. The first option is not desirable, so during free practice, when the team is undertaking setup work and selecting tyres, we will limit the maximum engine speed.
The penalty for an engine fault will be considerably tougher than for any other component. Replacing the engine before first qualifying will result in a ten place demotion on the grid, and after qualifying, it is demotion to the back of the grid. Only if the driver fails to finish the race can the engine be replaced without penalty, so the environment will be very demanding in 2005. There is also a question mark in the new rules, as a driver may deliberately fail to finish a race in order to have the advantage of a new engine for the next GP.
The critical (engine) components are the moving parts that endure a high mechanical and thermal load, particularly the crankshaft drive and valve gear. Each of these has been redesigned for a double life span, which normally means a bigger and heavier engine, costing speed and power. We have been meticulous to try and minimise these losses.