Building Faster & Safer Bobsleds

Bobsled is one of the fastest and most exciting sports at the 2014 Olympic Winter Games. Michael Scully from BMW DesignWorks USA is the designer behind the new two-man Team USA bobsled, which he hopes will be one of the fastest sleds ever build. Meantime, engineers like Mont Hubbard are working to make tracks safer for the athletes. "Science and Engineering of the 2014 Olympic Winter Games” is produced in partnership with the National Science Foundation.

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LIAM McHUGH, reporting: Bobsled is one of the fastest, most exciting, and most dangerous sports in the Olympic Winter Games. Reaching speeds close to 100 miles per hour, these two and four person sleds roar down an icy track complete with sharp turns and spectacular straightaways.

STEVE LANGTON (U.S. Bobsled Team): I just couldn’t believe that that sport was that rough and that loud. It’s controlled violence.

McHUGH: What may seem to be just a chaotic joyride, is actually the product of meticulous research and design from top engineers who strive to make sleds faster and tracks safer.

MICHAEL SCULLY: Let’s take a look at the top bumper radius.

McHUGH: Michael Scully is the Creative Director of Global Design at BMW DesignWorks USA in Newbury Park, California, and the lead designer of team USA's new 2-man bobsled. His goal-- to help the U.S. win gold in the 2-man event for the first time since 1936. Using a sleek, innovative design and cutting edge technology, this new sled reduces drag, the force that resists the sled's movement down the track, optimizing aerodynamics to create the next step in bobsled engineering.

MICHAEL SCULLY (BMW DesignWorks USA): We hope that this is the best tool available to them. People have invested their lives in these careers and making these achievements hopefully in the form of an Olympic medal is something that we take very seriously.

McHUGH: One of the biggest challenges for designers is the rules regarding the weight of the bobsled. The International Bobsleigh & Skeleton Federation requires that a 2-man bobsled weigh no less than 374 pounds when empty and 860 pounds with crew and equipment. To make a faster sled, but stay within the weight restrictions, Scully utilized his prior experience as a race car designer, incorporating lightweight materials such as carbon fiber and Kevlar, and fashioning them into a sleeker and more aerodynamic sled.

SCULLY: The overall approach is a bit different. Absolutely minimized frontal area as well as cross-sectional throughout the form. That’s something that we put a large emphasis on.

LANGTON: What makes the BMW sled so much different aesthetically is the carbon giver cowling. It’s very, very sleek and every measurement, every detail is Michael Scully’s brain child.

McHUGH: Once the sled is pushed from the starting line, gravity is the only force causing it to accelerate down the track, therefore it is crucial that any force that might slow down the sled be minimized.

SCULLY: You need to consider all of the different contacts that the sled will encounter down the run, which are a lot of them.

McHUGH: A bobsled does not travel in a straight line. Instead, it bounces and bobs. Any contact that the sled has with the side of the track will cause it to slow down. By distributing the weight in strategic parts of the sled Scully was able to keep it more stable.

SCULLY: The ability to tune the weight balance either forward to back or sideways is something that is a new capability for the U.S. team.

LAURENZ SCHAFFE: This is really interesting conceptually…

McHUGH: Once Scully and his team decided on the final design, a three-dimensional model was created for further testing. Tweaked and perfected through both virtual and physical wind tunnel tests, a prototype was then constructed and tested on a track with the athletes.

STEVE HOLCOMB (Bobsled Gold Medalist): We took it down and it was a pretty good sled. It came out of the box pretty fast, and I think it was pretty motivating.

McHUGH: With sleds like the BMW 2-man bobsled getting faster, another concern for designers and engineers is the safety of the track itself. Dr. Mont Hubbard is professor emeritus in mechanical engineering at the University of California- Davis and has been funded by the National Science Foundation.

MONT HUBBARD (University of California-Davis, Professor Emeritus): I think what contributes to them being so treacherous is a lack of understanding of this motion on a surface, and how the surface can interact with the object to eject the object from the track.

McHUGH: On every bobsled track, there is a section of the surface called a fillet, a small circular rounding at the point where the vertical wall and horizontal wall of the track connect. The fillet works to keep sleds in line on the straightaways, but in the curves of the track, Hubbard believes it can cause a problem.

HUBBARD: If you’re going that direction, the track can go away from you, and all of a sudden, there’s no track there to support you anymore. And then, if at that moment when you leave the track, you have enough velocity to fly past the rest of the track, then you’ve been ejected.

McHUGH: Hubbard proposes that removing the fillet from the curves of the track could help prevent athletes from being ejected or thrown from the sled when it goes too fast around the curvature

HUBBARD: If the fillets are gone, then I don’t think ejection from the track can happen.

McHUGH: Though Hubbard's research won't influence the track design for the Sochi games, new engineering endeavors like his represent increasing advances in bobsled track safety... which may be necessary if designers like Scully continue to push the sport of bobsled down the fast track.