Super sleds - in search of vital milliseconds.

Oberhof / Munich. With speeds on international sliding tracks rising year on
year, optimum aerodynamics are becoming a decisive success factor for
competitors in Bobsleigh and Luge events. Which explains why German athletes
have been coming to the BMW Group wind tunnel to test their sports equipment
for over 20 years now. In a sport where victories are often decided by
thousandths of a second, it can fairly be claimed that the precision data
provided by the BMW Group wind tunnel may literally be worth gold.

Cars are tested at the BMW Group wind tunnel on a daily basis to optimise
aerodynamic drag, lift and flow profile. The findings play a part in reducing
fuel consumption and increasing dynamic performance. The wind tunnel is also
used to test acoustics, comfort, cooling and dirt build-up. Tests involving the
athletes, on the other hand, serve mainly to determine drag, which should be as
low as possible - even with speeds approaching 150 km/h.

The 2007/2008 season proved outstandingly successful for the Bobsleigh and Luge
Federation for Germany (BSD). Seven out of a possible eight World Cup gold
medals for Bobsleigh and Luge were won by German sliders. In addition, the
German team scooped all the titles at the World Championship in Altenberg. But
success like this does not come by accident. Just last June the new prototype
four-man bobsleigh was put through its paces for the forthcoming season at the
BMW Group wind tunnel to measure aerodynamic drag, lift and downforce. The Luge
team was also able to use the wind tunnel to optimise body positions, materials
and equipment. A crucial element of testing is the accuracy with which data is
measured, as well as the ability to test equipment at high speeds. The BMW wind
tunnel is just such a facility. And it was an honour for the BMW Group
aerodynamics engineers to lend the athletes a hand in their quest for Olympic
gold.

Cars and bobsleighs are actually not that dissimilar. "The main difference is
that our vehicles have wheels, whereas the bobsleighs have runners. Otherwise
the principles are the same," explains Hans Kerschbaum, Head of Aerodynamics at
the BMW Group. Of course, the bobsleigh's frontal area is much smaller - more
akin to that of a motorcycle than a car; but the Cd figure, or drag
coefficient, is higher than for many current car designs. For example, the
latest BMW 3 Series has a Cd value of 0.26, compared with between 0.32 and 0.35
for a bobsleigh.

Tensing muscles at over 140 kilometres per hour.

Aerodynamics are particularly critical for luge racers. Even more so than for
bobsleigh racers, equipment set-up and body position are crucial. Which is why
in September, Germany's luge specialists were invited to visit the BMW Group
wind tunnel. Patric Leitner and Alexander Resch, the highly successful veteran
doubles team, have their sights set on the 2010 Winter Olympics: "We still have
a score to settle as far as the Olympic Games are concerned, because sixth
place in Turin was not what we had hoped for. That's why we're determined to
make the start in Vancouver and fight for a medal. This will be our last race -
and we would love to crown it with a place on the podium."

To achieve this they honing what might appear to be minor details such as foot
position. Norbert Loch, the Luge team's chief coach, gives an insight into wind
tunnel testing: "We evaluate the best foot position for each individual
athlete; then they go away and train so as to reproduce this optimum position
under competitive conditions." Measurements in the wind tunnel show up even the
slightest variations. Weight sensors under the sled also record minute
differences in lift or downforce, i.e. values measured in grams. And smoke
plumes allow the experts to observe any turbulence - with a luge racer this is
usually around the feet, in cars behind the wing mirrors, for example. In
either case, what matters are position and angle.

The doubles team of Tobias Wendl and Tobias Arlt describe the sensation of
lying down in hurricane-force wind speeds: "Sure, your muscles tighten up. It
forces you to keep your body taut. After three minutes in the wind tunnel you
realise you are starting to lose concentration." Reigning singles champion
Felix Loch and runner-up David Möller also placed themselves at the mercy of
the wind forces. Testing for the women's team was undertaken by Tatjana Hüfner
and Natalie Geisenberger.

The medal hopefuls were also eager to see the results with the new sled, since
these are made-to-measure. Thomas Schwab explains the detail: "We modified the
trim on the underside of the sled and adapted it to fit each competitor more
closely. Here in the wind tunnel our aim is to optimise the racing position of
individual competitors for their specific sled." Schwab knows what he's talking
about. As a practitioner of the luge, he too has spent time lying in the BMW
wind tunnel.

High-speed testing for the four-man bobsleigh.

Last season got off to a problematic start for the four-man bobsleigh crew. So
chief coach Raimund Bethge has accorded this sled top priority. This year the
new prototype was sent for testing in the BMW Group wind tunnel back in June in
preparation for the forthcoming season.

Comparative tests between last season's sled and the prototype have so far
proved promising. Figures for aerodynamic drag and lift were much improved,
despite the athletes benefiting from extra space. But this did not stop the
engineers from immediately trying out a range of modelled front ends to gauge
the effects these had on the sled's front-end lift.

Bethge is already looking further ahead - to the 2010 Winter Olympics in
Vancouver: "Whistler is a high-speed sliding track, so aerodynamics will play a
very important role - which is why our preparations are already in full swing."
Triple Olympic champion Kevin Kuske explains the importance of wind tunnel
testing: "Many people may not realise it, but like cars we operate at
relatively high speeds - up to 160 km/h and in Vancouver maybe even in excess
of 160 km/h."

At the end of the day's testing there are contented faces. Even the secretary
general of the BSD, Thomas Schwab, is smiling: "We were looking for an
improvement in overall aerodynamics and today's results suggest this may be
achievable - linked, of course, to improvements on the track." Having seen the
results for himself, B-team pilot Karl Angerer needed no further convincing of
the potential of the new bobsleigh: "I think we can expect it to be faster - it
might be a tenth of a second or just a few hundredths. But in bobsleigh every
hundredth counts. If we've sliced off a couple of hundredths, then that's a
real result for us."

Sound partners for efficient dynamics.

The BMW Group is delighted that its wind tunnel test facilities have been
playing a part in the success of Germany's Luge and Bobsleigh teams for over 20
years. A cooperative venture between the BMW Group's Heat Treatment Centre and
the Luge team has been ongoing since the 1990s. This is where luge runners have
been optimised for the past few years.

Precision measurements even at high speeds are the basis of vehicle
development. And it is this precision, made possible by the BMW Group wind
tunnel, that gives a decisive competitive edge to athletes for whom victory is
often measured in milliseconds.