Miniature load cell for measuring slipstream in speed skating

Heart rates at different positions 

In fast endurance sports such as road cycling, hand cycling and speed skating, riders usually ride in groups. In this case, the riders behind the leading person can take advantage of the slipstream and thus save power. A student at the Maximilian-von-Montgelas-Gymnasium in Vilsbiburg studied this effect in more detail. First, the heart rates that the riders have at different positions were examined in order to be able to conclude that they have a lower load and thus a lower effort. However, this way of determining the energy savings turned out to be difficult because recovery phases and individual ability play a major role, i.e. a human being does not function like a machine.

In order to look at the phenomenon from a physical point of view and to be able to determine differences quantitatively, the force effect on a model consisting of two cylinders, which were in different positions to each other on a plate, was tested in a wind tunnel. It was possible to see very clearly how the total force increases with increasing distance between the cylinders. In addition, it could be seen that the first rider also has to apply a slightly lower force if there is another rider directly behind him.

Diese Ergebnisse lassen sich mit dem Nachlauf, Verwirbelungen hinter dem umströmten Körper, begründen. Außerdem erhöht sich bei leicht schräger Positionierung des Zylinders die Kraft bei geringem vertikalem Abstand schneller als bei größerem. Zudem wurde ermittelt, dass der cW-Wert des verwendeten Zylinders etwa das Vierfache von dem eines Kleinwagens beträgt.