Introduction

The sport of skiing is known throughout the world as a test of human ingenuity, fortitude, and tenacity. Its technique was first developed in the icy hills of Scandinavia, where skiing was not just a sport but a necessity[1]. Incidentally, and most importantly in the case of this analysis, it is also one of the sports most affected by aerodynamic considerations[2]. These considerations namely include drag, the air resistance that saps away velocity on even the fastest slopes. While the field of aerodynamics extends beyond drag[3], these other factors are rarely practically applicable to the magnitudes of velocity experienced by skiers. Fortunately, modern innovations and high-performance materials have made it possible to reduce the effects of drag[4]. This investigation aims to analyze and minimize the effects of drag by testing the performance benefits of ski suits and tucking over naïve and unequipped skiing[5]. It is predicted that if a ski suit is used, greater performance will be obtained; additionally, if the skier remains in a tuck position, an even greater enhancement will be accomplished.

Background

The fundamental concept behind skiing relies on two long boards that are attached to the skier’s feet. These boards minimize friction, making it easier for the skier to cover snowy ground. In modern times the sport has developed into a competition for speed. On a given slope, speed can only be increased by reducing the forces resisting against the skier, specifically friction and drag (as opposed to forces that are beneficial to the skier, such as gravity). This analysis focuses on the control of drag, which can be reduced through materials and clothing designed with performance in mind. Static friction resultant from the contact of the skis with the snow is another resistive force not explored here in detail.

Hypothesis

It is predicted that if aerodynamic techniques, including tuck positions and streamlined clothing, are used when descending a ski slope, the skier’s average velocity will increase as a result of decreased drag.

Focus of analysis

This investigation aims to determine whether the position of the skier and the selection of clothing affect the speed attained on a given slope (with other factors held constant). The dependent variable of the study is average velocity, while clothing type and the skier’s position are both independent variables. The control value for the position variable is the normal, untucked position, while the control value for clothing type is typical ski attire. Controlled variables include, but are not limited to, the temperature of the air, the temperature of the snow, the length of the slope used, and the angle of declination of the slope used.

Experimental configuration

Anthony Juliana hits the slopes

An arbitrary slope near the Timberline ski area was selected for experimental data collection. Both skiers (Liverman and Juliana) each executed six runs across six aerodynamic scenarios:

This resulted in a total of twelve data points.

Each run was timed from top to bottom using a stopwatch. The length of the slope, determined to be 47 meters (154 feet), was obtained by measuring out a piece of string, then stretching it out across a football field.

Raw data

View as text (tab-delimited)

Aspect↘
Information collector→ Anthony Travis
Scenario↓ ∆t ∆s/∆t ∆t ∆s/∆t
Untucked/normal 7.87 s 5.96 ± 0.44 m/s 6.88 s 6.82 ± 0.57 m/s
High tuck/normal 8.06 s 5.82 ± 0.42 m/s 6.27 s 7.49 ± 0.68 m/s
Low tuck/normal 7.33 s 6.40 ± 0.51 m/s 5.76 s 8.15 ± 0.79 m/s
Untucked/speed suit 5.28 s 8.89 ± 0.94 m/s 5.79 s 8.11 ± 0.79 m/s
High tuck/speed suit 5.19 s 9.04 ± 0.97 m/s 5.87 s 8.00 ± 0.77 m/s
Low tuck/speed suit 5.00 s 9.39 ± 1.04 m/s 5.17 s 9.08 ± 0.97 m/s

Visualization of results

Graph of above raw data

Analysis of results

One thing is entirely clear: aerodynamic techniques for improving skiing performance are truly effective. The speed suit consistently offered a major gain in velocity, while the low tuck offered a modest advantage as well. The exception was the high tuck, which backfired in two out of four runs; this may explain why it is not commonly used in actual performance skiing.

Potential sources of error

A variety of factors may have contributed significantly to random and systematic error in the experiment. Sources of random error include temperature and humidity changes, unevenness of the snow, deviations in the ski path from a straight line, and others. Additionally, during each run the wax applied to the skis would have rubbed off onto the snow; this would result in a systematic increase in friction as more and more test runs were completed.

Mitigation of experimental error

While environmental factors are beyond anyone’s control, other sources of error are not. The ski path could have been made straighter by following a set line drawn in the snow, bringing the length of the actual path closer to that of the measured path. Furthermore, precisely reapplying wax between runs would avoid variation in friction as the experiment progresses. These positive changes have the potential to reduce error to a more manageable level.

Conclusion

While experimental error was significant, it was decisively shown that aerodynamic techniques, such as ski suits and tuck positions, offer a positive effect on skiing performance. In a sport like speed skiing, every single fraction of a second is critical, and not taking advantage of these techniques would be to doom one’s self to epic failure. Moreover, skiing is not the only sport affected by aerodynamics: many other extreme athletes can profit greatly by taking air resistance into account.

Works cited