The U.S. team's two-man bobsled has gotten a high-tech makeover just in time for the Winter Olympics in Sochi, using lessons from race car technology to pick up speed in a quest for its first gold medal since 1936.
German automaker BMW joined the U.S. Bobsled federation in 2012 in a project to redesign the sled's aerodynamics. The idea was to find a way to shave off a few seconds by making the sled zip down the track more efficiently, according to Michael Scully, BMW's creative director for global design.
"It's been a complete ground-up project," Scully told Discovery News. "You need to take every opportunity to get on the bobsled track because it's such a changeable environment. The sled is going through so many different positions as it goes down the track, it's almost impossible to simulate."
Even so, Scully said computer simulations using the science of fluid dynamics played a huge role in understanding the drag forces acting on the sled from both the surrounding air and icy track surface.
Bobsled tracks are nearly a mile long, and the sleds -- four-man and two-man -- can reach speeds above 90 miles per hour. Heavier sleds ride faster, and while international rules limit the maximum weight to 390 kg (859.8 lbs) when loaded, the distribution of the weight can make a big difference, according to Scully.
The team replaced the existing Kevlar and fiberglas body of the sled with a special carbon fiber cooked in an auto-clave to several hundred degrees. The heating reduced the mass of the carbon fiber, while making it stronger. This in turn allowed the design team to make the entire sled lighter, and reposition weight where it was most needed.
"Aerodynamically, the reduction of frontal area, the silhouette it cast on the wall, was a big change," he said. "Also from a physics standpoint, we were trying to centralize the mass and reduce overhangs so that when the sled changes direction, the mass doesn't resist it."
With a sleeker front profile, Scully also looked to make more room for the driver inside and introduced a new steering mechanism.