MATCHETT: The Rise & Rise of BMW (Part 2)

Formula 1

MATCHETT: The Rise & Rise of BMW (Part 2)

SPEED'S F1 analyst Steve Matchett continues the story of how BMW returned to grand prix racing on its own terms, and is now poised to reap the benefits.

Steve Matchett | Posted October 02, 2007 Charlotte, N.C.

CLICK HERE FOR PART 1.

BMW Sauber began to sketch initial concepts for their 2007 chassis in April, 2006. At this point the team was operating without a chief designer. After quitting Williams, Jorg Zander had been hired to fulfil that role but he would be required to serve a period of gardening leave before joining his new employers in July.

When Zander finally arrived at Hinwil, he joined forces with the team's technical director, Willy Ramph, and their super-talented aerodynamicist, Willem Toet, not to scrap all that had gone before and start afresh but rather to carefully hone the design concepts of the already proven F1.06. The fruit of that Ramph/Toet/Zander collaboration would be the F1.07, the chassis destined to become BMW's first race car designed and built specifically to meet the FIA's Formula 1 technical regulations.

Following Michelin's withdrawal from the sport at the end of 2006, Bridgestone are now F1's sole tire supplier. In BMW's case, the switch from custom Michelin rubber to the control Bridgestones has placed greater emphasis on aerodynamic performance; today's cars need to generate ever more downforce to compensate for the reduction in grip from these harder tires.

In response to this, Toet has raised the nose of the F1.07 significantly higher that its predecessor. The idea is to increase the flow and quality of the air moving across the front wing's mainplane. The underside of the monocoque, the area beneath the driver's legs has been raised too, helping to channel the airflow rearward.

This raised, sculptured profile requires there be no keel or suspension mounting on the underside, blocking the airflow. The absence of a keel requires the lower wishbones to be mounted directly to the flanks of the chassis. This results is the inner mounting clevises of the lower wishbones sitting relatively high on the chassis, and in order to maintain a workable suspension geometry the mounting clevises for the top wishbones must be raised too. All of which lends the front suspension its aggressive drooping look.

Not so long ago this zero-keel layout was considered a radical alternative; now it is all but universal throughout the pit lane. Only Renault continue to hold out, the Enstone-based team continue to use their tried and tested V-keel, allowing the suspension points to be mounted lower, their wishbones to sit horizontally and the pushrods to work in a more vertical plane. The pushrods are still angled, naturally, but the more vertical a pushrod is mounted, the better it can cope with suspension loadings.

Pushrod location is one of the downsides of the zero-keel layout. The high-mounted wishbones require that the pushrods are positioned at a less oblique angle: less vertical, more horizontal. This means that the suspension loads are trying more to bend the pushrod, rather than compress it, reducing it's strength. A simple analogy of this phenomenon is to consider the legs of a chair: when sitting on a chair with vertical legs your weight is transmitted vertically through the legs directly to the ground. But sit on a chair with splayed legs and your weight will only splay the legs further or, worse still, break the legs, leaving you slumped on the ground.

Designer Willem Toet has raised the nose of the F1.07 significantly higher that its predecessor. The idea is to increase the flow and quality of the air moving across the front wing�s mainplane. (LAT photo) MORE PHOTO

The F1 solution to this conundrum is to make the pushrod stronger, increasing its mass and size. This, however, is far from popular with the mechanical engineers. F1 engineers like words such as smaller and lighter; heavier and bigger are poisonous concepts. When designing the front suspension, therefore, the trick is find and maintain a hold of that fine line that exists between performance and reliability. Front suspension geometry, moreover, pushrod reliability, may well have contributed to Toyota's problems in Montreal, where, while riding the curbs at turn eight, Trulli broke the suspension of his TF107 on two separate occasions.

At the rear of the F1.07, the team have chosen to mount the mainplane of the rear wing via the car's end-plates. There are no central mounting pylons attaching the wing to the rear crash structure. Only BMW and Toyota have adopted this method of securing the wing. The load is transmitted from the mainplane to the endplates to the lower element. The downside to this method is that the wing end-plates must act as load-bearing members, making them heavier. The upside, however, is that there are no mounting pylons blocking the airflow around the central section of the rear wing. Again, just as with the zero-keel suspension, the advantage is one of aerodynamics over mechanics.

With the F1.07 the Munich-based automotive giant have finally achieved its goal of becoming a full-fledged Formula 1 constructor. With each passing race the team and the car appears to grow stronger. There will always be problems, of course, a Formula 1 car will always present is team with problems, but as the season has progressed, so has the overall performance of the F1.07, proving itself at both high- and low-speed tracks.

At the January launch of the F1.07 Mario Theissen said, "It is not just another launch, another car, it is the first car developed by our new team� it really is a very, very special day for us."

Theissen was visibly proud back in January. Now, as we approach the final two races of the year, he has every reason to remain proud too: Throughout 2007 his team continually outpaced Renault, the reigning World Champions. And with McLaren's banishment from the constructors' championship, BMW are now assured a second-place finish.

That said, however, I'm sure that BMW would have been more than delighted to have finished the year in third place, behind Ferrari and McLaren. A dusty Parisian courtroom, with its scratching quills and hissing, tired radiators is no fitting place to decide the outcome of such a prestigious world-class contest of engineering excellence. A few accountants may be relieved by the outcome but I feel confident that the multitude of BMW mechanics, engineers, designers, machinists, electricians, and composite specialists will take no additional pleasure at finishing ahead of McLaren by virtue of the FIA's intervention in the industry's inter-team battle.

Still, Theissen and his team have every reason to be pleased with a job well done. And there's always next year: with Renault now behind them, McLaren and Ferrari are next on BMW's list.

SPEED's Formula 1 technical analyst Steve Matchett presently resides in the south of France. In addition to his duties on SPEED'S F1 broadcasts alongside Bob Varsha and David Hobbs, Steve will be providing insight into the high-tech world of Formula One through regular video features and commentary on SPEEDtv.com.

The opinions reflected herein are solely those of the above commentator and are not necessarily those of SpeedTV.com, FOX, NewsCorp, Speed Channel, or Haymarket Worldwide.

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Steve Matchett

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