Physics of Snowmachining :: physics snowmobile snowmachine

Whether zipping along a winding trail, flying through the open flats, or powering up a steep hill snowmachines and the rider need to use physics to stay in control of the machine and themselves. The main compenents are the track, engine, skis and riding. Snowmachine tracks are essential to making a snowmachine move. Ever since snowmachines first originated in the late 50's designers have been finding ways to improve traction in a variety of conditions. Some of these conditions are driving on groomed trails, not groomed trails, overflow, and deep snow. The very first snowmachines had tracks with very bad traction. But you must realize that they weren't driving in the same conditions snowmachines of today can handle. Old machines were limited to readily used trails and very little powder. The tracks used on the old machines looked like the one shown in the picture below. The traction, the little raised bits of rubber, was minimal and the tracks weren't very economical either. The first attempts at making a track was using steel, which was too heavy, and rubber, which was to flexible and brittle at cold temperatures. Eventually manufacturers found the key ingredients. Kevlar tracks with imbedded nylon strands to reinforce and improve strength. A kevlar track is now the standard in today's snowmachines. Another key ingredient to the track is the paddles. Paddles are the pieces coming off of the track itself, a picture these paddles is shown below. This is what provides the traction for the snowmachine to move. In today's market these paddles come in sizes ranging from 1 inch to 3 inches. The saying "bigger is better" does not hold true for these paddles though. When the paddles get to big the rotating mass actually bogs the machine down and reduces performance. Polaris Industries have found, through the use of physics and other tests, that the most efficient paddle length is 2.4 inches. This length gives the most grip in deep snow while still being semi-economical on trails. Snowmachine engines come in two types, two-stroke and four-stroke. Two stroke engines are simpler, lighter, and cheaper to manufacture then four-stroke engines, "plus two-stroke engines also have the potential to pack about twice the power into the same space because there are twice as many power strokes per revolution than in four-strokes". There are other advantages two-stroke engines have which include not having valves which lowers weight and eases construction.