Kässbohrer PistenBully 400 4F, Руководство по эксплуатации

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Operation
Bumpy runs
The friction of skis over the surface causes some of the crystals
to melt and form a film of water, and this produces sheets of
ice and the softer spots beside them.
Over a period of time skiers break down the topmost layer –
humps and hollows form and the run becomes bumpy.
Preparing slopes like this is a process in which old snow is mixed
with relatively fresh-fallen snow (snow crystals) and this
produces a durable surface.
If outdoor temperatures are correspondingly low, the snow
freezes and forms lumps
. When this happens, the only way
of making a ski run look good is to work with a tiller
mounted on the rear of the vehicle.
The teeth of the tiller break the lumps down into gritty snow,
which fills the hollows in the surface of the run; the finisher
shapes the surface and a water film forms to hold the grains
of gritty snow together. Breaking down the lumpy snow also
damages the ice crystals, so they lose a considerable proportion
of their ability to cohere. This is the reason why only gritty snow,
not powdery snow, can be produced from ice.
A durable ski slope can be formed only by mixing this mate-
rial with fresh-fallen snow or with unused old snow from
deeper levels.
Iced slopes/sheets of ice
Do not break up an iced slope unless the ice is of adequate
thickness or fresh snow falls. The gritty snow produced by
breaking up the ice needs fresh-fallen snow to cohere, or else
it will cohere with water - and this will again cause ice to form.
Consequently, it is advisable only to roughen the surface of the
ice to make the slope skiable. Sheets of ice on slopes that are
otherwise in good condition can be broken up and mixed with
crystals from deeper in the snow.
The more frequently the ice is turned and the crystals dam-
aged, the less will be their ability to cohere.
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RIVING TIPS AND INFORMATION