  Cross country skiing is an interplay between the active motion of the body of
the skier and the physical interaction between the surface of the skis and the
snow. Friction and glide between the ski base and the snow depend on the snow
temperature, ski surface chemistry and roughness, dry friction with the snow
crystals and liquid meltwater film flow properties. Although a great amount of
resources are being spent on understanding glide and friction, a basic physical
understanding of the phenomena at play is still at large and the methodology
used for assessing the gliding quality of different full scale configurations
is still coarse in real world applications, which limits novel development of
robust methods to control and optimize glide. Such understanding and full scale
testing is particularly important for designing new ski gliders. In the present
work, we develop a novel experimental setup and use it to investigate through
field experiments the basic mechanical phenomena that influence glide and
friction of full scale skis on snow. The field setup features a mobile, novel
linear tribometer allowing investigation with whole skis in realistic
cross-country conditions (speed and load). The coefficient of friction between
the skis and snow is obtained from a load cell, which reports the force
necessary to pull a ski sled along a flat track. Simultaneously, thermistors
measure the temperature at the ski-snow interface. In addition, a GPS measures
displacement and velocity. The results obtained are in good agreement with
several measurements reported from similar experiments, and provide a
real-world validation of results obtained in the laboratory. In addition, we
release the general tribometer setup as open source material in order to
provide a foundation on which other research teams as well as cross-country
teams can further iterate when designing later experiments.
