TopBob goes for gold

With only milliseconds separating winners from losers in the Winter Olympics bobsled competition, a bobsled’s drag is critical. In short, the lower the bobsled’s air resistance, the higher the bobsled team’s podium position.
Nando Timmer, an assistant professor of aerodynamics at TU Delft’s faculty of Aerospace Engineering, is once again involved in helping Dutch Winter Olympians achieve glory. Timmer was a co-developer of the revolutionary ‘Nagano strips’, the performance-enhancing, aerodynamic strips of zigzag-shaped material added to Dutch speed-skating racing suits at the 1998 Winter Olympics in Nagano, Japan.

This past experience fuelled Timmer’s drive to help lower the aerodynamic drag of ‘TopBob’, the Dutch two-man Olympic bobsled.
TopBob’s aerodynamic development involved some ten days of three one-third scale models testing in TU Delft’s low-speed wind tunnel, followed by two days of full-scale testing at German-Dutch Wind Tunnels (DNW) LST-facility.

One of the solutions chosen by Timmer’s team was to build the bobsled front bumper as a wing with symmetrical airfoils, which Timmer says takes advantage of the “lower air resistance of symmetrical airfoils”.
Although international bobsled competition rules considerably
restrict a bobsled’s external shape and dimensions, leaving little room for aerodynamic innovation, Timmer is nonetheless satisfied with TopBob’s development, which, owing to the aerodynamic shaping, leaves TopBob looking like a hammer-head shark, but a shark that Timmer jokingly says “only eats gold, silver or bronze!”

The TopBob competing in Vancouver is the first bobsled in InnoSportNL’s long-term project aimed at producing world-class, all-Dutch bobsleds for the 2014 Winter Olympics in Sochi, Russia. The project brings together DSM, the supplier of the light-weight composite materials TopBob is made of; Eurotech, an international metal industry supplier that also supplies the TopBob race mechanics; Modesi, for engineering services and CFD calculations; and the three Dutch TUs: Delft, Eindhoven and Twente.

The original project plan was to have the bobsled ready for the 2014 Olympics, but thanks to the fantastic results achieved during development and testing, the project was fast-tracked and a sled built to race at the Vancouver games.
TopBob is a watershed project for the Dutch bobsled team: for the first time they have a sled capable of competing against the sport’s traditional giants: Germany, Switzerland, the United States and Canada. Remarkably, the Dutch two-man bobsled team finished in third place at last month’s World Cup event in St. Moritz, and that impressive finish has the Dutch bobsled team believing they can win an Olympic medal in Vancouver. Which would be quite a sporting coup for a country without mountains, and one in which TU Delft can rightly be proud.

With hordes of Oranje supporters cheering them on, Dutch Olympic skaters will race for glory at the Vancouver Olympics wearing advanced speed-skating suits developed by the KNSB (the Netherlands’ national skating association). And once again, in keeping with TU Delft’s history of developing low-drag speed-skating suits, TU Delft researchers have contributed to the aerodynamic design of the new KNSB suits.

Timmer, and dr. Leo Veldhuis, an associate professor of aerodynamics at the faculty of Aerospace Engineering, have lent their considerable aerodynamic expertise to the development of this new suit, after having helped cause a revolution at the 1998 Nagano Winter Olympics with the development of the then revolutionary, but now ubiquitous, ‘Nagano strips’.
This new KNSB racing suit replaces the Nike Swift skin suits that the Dutch team had worn for the past eight years. The Dutch skaters were unhappy with the fit of the Nike racing suits, but with Nike failing to promptly respond to the skaters’ complaints, the KNSB was forced to develop an alternative. The development of the new suit was an all-Dutch team effort: Sportconfex, a Dutch sport clothing manufacturer, tailored the suits; dr. Jos de Koning, of the Vrije Universiteit Amsterdam, supplied the biomechanics knowledge; and Veldhuis and Timmer provided the aerodynamics expertise.

“The end result is indeed a completely Dutch suit”, Veldhuis says, that “is sure to at least match the best Nike suits currently available to other nations.” Veldhuis does however add that the new Dutch racing suit will only have an “incremental” effect, compared to the revolutionary effects of the ‘Nagano strips’ in 1998. Nevertheless, in a sport where milliseconds matter, even incremental improvements can mean a lot.