(2x) Gold, silver and bronze for ‘Delft’ sit-ski

At the Winter Paralympics in Cortina, Italy, Dutch sit-skiers Jeroen Kampschreur and Niels de Langen have won multiple medals in recent days, partly thanks to an invention developed in collaboration with researchers from Delft: a teardrop-shaped aerodynamic hood.

On Saturday, Niels de Langen won silver in the downhill event. Favourite Jeroen Kampschreur crashed out and missed out on a medal. Kampschreur did win gold in the super-G on Monday (while De Langen finished fifth). On Tuesday, both athletes stood on the podium: Kampschreur won gold again in the combined event and De Langen took bronze.

Kampschreur and De Langen ski on a sit-ski with an aerodynamic, custom-made hood made of flexible, 3D-printed plastic attached to the back. This hood is detachable, making it easy to take with you on the ski lift and mount on the mountain. The hood reduces air resistance by 8 per cent, resulting in a 2 per cent increase in speed during downhill sections.

The hood is the product of collaboration between TU Delft, TeamNL Sport Science Centre, the Dutch Ski Association, consultancy Actiflow and Roel van der Hooft Engineering.

The sit-ski project was led by Wouter Terra, researcher in sports aerodynamics at TU Delft. “As a skier, you experience a small amount of friction from the snow, but the vast majority of the resistance you face – around 80 per cent – is air resistance,” Terra explains. “In able-bodied skiing, strict regulations governing skis and clothing mean there is very little you can change, aside from posture, to influence aerodynamics. In sit-skiing, by contrast, an aerodynamics expert has far more opportunities to reduce drag.”