Published data relevant to snowmobile crash reconstruction is comparatively limited, especially pertaining to mountain snowmobiling and riding in deep snow. Snowmobiling is a unique motorsport activity as it requires substantial rider input and physical interaction to properly control the vehicle. The added complexities of varying slope angle and snow depth in mountain terrain make application of test data from testing done on flat surfaces less useful when applied to sloped terrain analysis.
New data from testing performed in deep snow conditions on various slopes is presented in this paper. Acceleration tests were performed using two late model mountain snowmobiles from a stop on various slope angles. Additional related factors such as snow density, trenching, and snow mass momentum exchange are also discussed. Comparison of these test results to previously published snowmobile testing data advances the understanding of snowmobile acceleration parameters into mountain terrain.
Significant changes in acceleration performance can result from small changes in slope. Even for the most advanced mountain snowmobiles in loose snow, acceleration becomes more limited as slope increases. Acceleration results are comparable to earlier data, irrespective of snowmobile horsepower and snow conditions. In earlier published data, flat terrain accelerations on packed snow in the range of 0.60g were recorded. In this testing, 0.65 was at the low end of the data, with average full-throttle accelerations of between 0.65g and 0.75g being achieved by both snowmobiles on flat undisturbed powder snow. Keeping in mind that these are different machines, the findings show that traction and horsepower are as significant as snow characteristics when analyzing snowmobile performance.