BMW Sauber F1 Team
The BMW Sauber F1.09 and BMW P86/9

Winds of Change

2009 sees arguably the most significant rewrite of the F1 technical rulebook in the history of the sport. Where the engineers had in the past always been able to use the previous year’s car as a basis for the design of their new machine, they now have been asked to start with a clean slate - more accurately, a blank computer screen.  Completely redefined aerodynamics, the return of treadless tyres (slicks) and the option of fitting KERS (Kinetic Energy Recovery System) technology have literally brought the teams back to the drawing board.

In identifying areas where change was needed to make overtaking easier, the primary problems of modern Formula One cars is the massive amount of downforce lost once the distance to the car ahead dipped below 2 seconds. The “dirty air” whipped up by the preceding car significantly diminished the effect of the front wing, which revealed itself in pronounced understeer. The result: changes in position often relied on pit strategies rather than overtaking manoeuvres out on track.

The solution: reducing aerodynamic downforce by some 40% combined with more mechanical grip. This led to radical changes, especially as far as aerodynamics is concerned. The front wing of the F1.09, for example, has grown in width making it as broad as the car as a whole. It is also fixed lower down than before. Added to which, spectators will find the significantly narrower, higher-mounted rear wing takes some getting used to. The regulations have also limited the use of air deflectors and cooling apertures to a minimum. Basically, there is a new look for the F1 cars.



Factbox: BMW Sauber F1.09

Powertrain – Three-race engine, improved driveability and KERS
Building something new requires solid foundations. And here, the powertrain of the basic BMW V8 engine, quick shift gearbox, hydraulics and electrics/electronics – all developed in Munich – fits the bill perfectly. Each of these components showed maximum reliability in every round of the 2008 season.

In line with the regulations, the team has only been allowed to develop peripheral aspects of the engine since 2006. As such, the engine will need to demonstrate its reliability over three successive GPs – as opposed to two in 2008. The reliability demonstrated over the 2008 season provided a strong basis to focus on the quality of the parts to ensure that the engine can perform longer. In addition to durability, there is a high priority on further optimization of its driveability, addressing the torque band through measures applied to the peripheral components.

BMW G1.09 quick shift gearbox
The BMW Sauber F1.09 is equipped with a quick shift gearbox, developed and built in Munich, which shifts the gears without interrupting the power flow. First used in 2007, it was then adapted for the 2008 season to take account of the standard electronics unit and the required lifetime of four GP race weekends with additional refinements in 2009.

The quick shift gearbox maintains a constant power flow through an ingenious interplay between mechanical, hydraulic and electronic components. In a conventional F1 gearbox, power delivery was interrupted for approximately 50 milliseconds during gearshifts, which means that for this length of time the vehicle is coasting without power. At Formula One speeds, aerodynamic drag during each such time lapse can decelerate the vehicle by up to 1g. In a road car, this would come across as powerful braking. Eliminating this power loss every time the driver changes up – which he will do some 2,000 times over the race distance of the Monaco Grand Prix – adds up to significant time savings, and a gain of several hundred metres by the end of the race.

KERS (Kinetic Energy Recovery System)
From 2009, teams have the option to employ KERS to boost the car’s performance. In essence KERS recovers the (typically wasted) kinetic energy generated by the braking process. The energy is stored and put on tap as an extra source of power under acceleration to complement the output of the V8 engine. The engineers at BMW have broken new ground with the development of KERS.

The regulations allow the developers creative room for manoeuvre, only setting out guidelines for certain performance parameters. The Formula One energy conservation law, as it could be termed, allows for a total of 400 kJ of energy – generating 60 kW of mechanical output – to be supplied to the driven axle under acceleration during the course of a race lap with the energy storage unit restocked only under braking.

As such, 2009 will see the introduction of a Boost button for the drivers. When pressed, this will provide them with an extra 60 kW of output for 6.5 seconds per lap to aid overtaking manoeuvres. But this advantage should be set against the system’s adverse effects in terms of weight and weight distribution.

Factbox BMW P86/9 – technical data

Related:
- F1 Feature: Season 2009 - What's hot and what's not
- F1 Feature: The 2009 FIA Formula One World Championship Calendar
- The men behind the wheel - Robert Kubica  /  Nick Heidfeld  /  Christian Klien