Interview with the Force behind Team USA’s Bobsled, NASCAR’s Geoff Bodine

His inspiration began in 1992 when he found that Team USA was struggling with their European bought sleds. “You never sell your best equipment. You leave that for your own team. I don’t like to have our team taking out a mortgage to buy a second rate sled,” said Bodine. “In 92’, I had the chance to try one of Bruce Rosselli’s sleds in Lake Placid. I crashed it and said, ‘Bruce I will have to build you a bobsled.’ We built a fleet of them.”

It turns out that NASCAR had prepared Bodine and his engineer Bob Cuneo well for their new career building the Night Train bobsleds. “The rules are very similar. They check everything, length or runners, weight of sled, steering. They even check the temperature of your runners. If they are too warm, you don’t go down! They want a level playing field,” expressed Bodine.

You might think that such strict rules wouldn’t make for a lot of innovation. However, the Olympic committee didn’t count on Bodine, the man that brought power steering to NASCAR.

Aerodynamics and Chassis

With Night Train, the first incarnation of their sled, Bodine and his team worked on the aerodynamics. This assisted in their gold win in the 2010 Vancouver Olympics. “We tested Night Train one and really optimized it. At Vancouver we had our athletes sitting lower. Before, with their heads bobbing out it was like a spoiler. Now you can’t even see the last two athletes in our sled. It looks like they fell out! Everyone saw it and others are trying the same now. Some better than others.”

“We applied the same aerodynamic tech to Night Train 2. It has the same body shape. But with simulation, we were able to make the chassis 50lbs lighter and about 50% stronger,” said Bodine.

Now to a trained engineer, this comment may seem a little counterproductive. Why would one want to reduce the weight and potential energy of the sled? It turns out that the IOC limits the weight of the sled and the total weight once all competitors are in it. By reducing the weight of the chassis, Bodine and his team are able to place ballasts in order to tweak the weight of the sled exactly where they want it. And thanks to the simulation, they knew exactly where the weight is needed.

Steering

The major aerodynamics task was solved with Night Train 1, and was key in Vancouver where they have one of the fastest tracks in the world. However, with the three uphill sections of Sochi, the biggest hurdle for Night Train 2 was the steering. Luckily, this was Bodine’s specialty.

“Bringing power steering to NASCAR allowed for the caster and camber to be optimized for a better front end of the car. This allowed for better handling. I wanted to bring something similar to bobsled with Night Train 2 but the rules still called for ropes, grips and bungee cords. We therefore decided to improve the linkages, leverage, ratios, and usability of the steering. We replaced metal brushings with ball bearings to make the steering easier. Simulation helped a lot to design the new steering mechanism. The ratios can also be adjusted for the preference of the driver. We trained the maintenance team to use the simulation so they can analyze and change it in real time,” said Bodine.

The ratio adjustments were key to the team’s win at the World Cup. Due to an eye condition, driver Steven Holcomb tends to pilot based on the feel of the runners on the track and less on his actual sight. Bodine explains that “this was similar to the drivers in NASCAR that didn’t like the power steering. But they can get used to it. As for Steve this is more complicated. We had to find the right settings to allow him to feel the track and steer the sled easier. We seem to have found the sweet spot for the World Cup, just in time for Sochi.”

“Suspension” and Articulation

It seems that the rules in bobsled don’t allow for customary shock absorbers such as springs and suspension. The bobsled is therefore built to flex and bend itself. This will naturally lead to added maintenance.

However, there is one leaf spring in the sled used to control articulation. Bodine adds that “we use a torsion bar to control our spring. Most other teams don’t do this. We want to dampen the vibrations as this is wasted energy. Some of our other tech to do this have been blocked but not all. The audience says that our sled is the quietest down the track. This gives us just a little bit of speed.”

In the end, many of these designs will account for improvements on the scale of hundredths of a second. However, in the sport of bobsled, that much time can mean the difference between a medal and a lonely ride home. This is why the real time testing and adjustments in the simulation are so important to the team. It can give them this edge.

However, none of this is a secret, when teams place high in the rankings the judges will actually take apart the sled to ensure it meets spec. Every team can see it and replicate it. To this Bodine says, “they can copy but they may not understand the theory of why we do things a particular way. You can copy it all day long and it won’t work as well if you don’t know what is going on. So far no one understands why we use the torsion bar. Same thing happens in NASCAR when you park next to your competitors.”

“It is amazing how technical the sport has become. It would now be impossible to produce the improvements we have without a tool like SolidWorks. Long gone are the days where I drew something on paper and built the model with cardboard,” adds Bodine.

In the end it seems that Bodine is just proud to help his American team. Humbly he said, “God saved me from a horrific crash in Daytona and he led me to help out the Bobsled team. This has been very special in my life. But the athletes did all the big work they made all the sacrifices. We are just the support in the background. I’m glad to be a part of it.”

Images and videos courtesy of 3DS.