Snowmobile testing in April?

May 1, 2009

The lack of snow did not deter the engineering students at Kettering University in their quest to improve the school's SAE Clean Snowmobile competition sled.

While the words “snowmobile” and “April” in the same sentence is unusual, Kettering students in Dr. Greg Davis’s Advanced Automotive Power Systems class made the combination almost seem plausible. They used a truck, some water and little wheels to run tests on the SAE Clean Snowmobile sled in the back parking lot April 23.

The students, including SAE Clean Snowmobile team captain Andrew Baker, of Lawton, Mich., were performing drag testing on the sled without the benefit of snow for two reasons: one, as a class project, and two, because “when there is snow, the team is usually working hard to get the snowmobile ready for competition, and there is rarely enough time to actually do much testing,” said Baker.

“This is obviously not ideal, but it is the way that things get done,” he explained.  And snow doesn’t necessarily mean better testing conditions, according to Baker. “From day-to-day snow conditions can change significantly and really affect the results of testing. Asphalt is always the same regardless of the weather conditions,” he said.

He convinced his classmates (see box), who were not part of the Clean Snowmobile team, to perform the tests on the snowmobile’s drivelines, which, in the past, have been extremely inefficient so the team had added idler wheels to the suspension system to make significant decreases in drag losses.  

The down-side to idler wheels is that they also add noise. Noise reduction is one goal of the Clean Snowmobile competition. “The point of the testing was to see if the idlers and Hyperfax slides that we added to the snowmobile for competition last March were really worth the added cost and potential noise,” Baker said.  

To test for noise, the groups hitched the snowmobile behind a pick up truck and dragged it around the parking lot at varying speeds. Testing consisted of varying system configurations to determine what products (idler wheels and/or Hyperfax) were the most beneficial to the snowmobile. Speeds were varied to see how the drag reductions were dependent on the speed of the machine.  

To keep the slides and “Hyperfax” from overheating during testing, the students rigged a water sprayer to keep them cool.  “When a snowmobile is running on snow like it’s supposed to, snow melts and keeps the slides cool and lubricated,” said Baker.  Because we are testing on asphalt, we needed a way to keep the slides cool and lubricated, otherwise, we could literally melt the slides onto the track and lock the whole system up. Doing this also helps simulate snow conditions so that our results are closer to what we would expect to see on snow,” he explained.

If testing proved that the drag was significantly reduced, the team would know that the idlers and Hyperfax are worth using, and may add even more wheels on future competition machines, according to Baker.  

The results are still pending, but after three days of testing, the group has a class project with real world application and the Clean Snowmobile team will get some invaluable insight about the work they did this year in preparation for next March.

Written by Dawn Hibbard