Drafting is a tactic employed in many sports. This technique allows competitors to conserve energy by using the wake created by other athletes to pull them along. The wake provides a favorable pressure gradient to the trailing athlete. Since the pressure is low in the wake, the athlete is pushed along by the atmospheric pressure behind them. While drafting is frequently used in high-speed sports, such auto racing or bicycling, it is also an effective technique in low-speed sports, such as marathon running.
In order to study this phenomenon, scale models of runners were constructed and the drag on the trailing runner measured. This allows for the determination of the optimal position for the trailing runner. By varying the velocity in the wind tunnel, the effect of headwinds and tailwinds on this technique can be studied. A one-sixth scale model will be used as it allows for the optimization of the wind tunnel conditions.
High quality marathon runners run at an average pace of 5 minutes per mile. A 4 mile per hour headwind and tailwind are to be tested in order to determine the effect that each condition has on a runner's ability to draft.
Plastic action figure models with one sixth of the height of an actual six foot tall marathon runners were used in the equipment. One model was threaded so that it would fit directly onto the sting mount. The mounting block will be constructed to allow appropriate but variable spacing between the leading and trailing runner models. The mounting block will be of a height that allows the lead runner to be at the same height as the trail runner model that will be mounted to the sting to insure the accuracy of the data that will be gathered.
Diagrams and results of the objects may be found below.