Judging Sail Car Event at MN Renewable Energy Challenge

For the second time I had the opportunity to volunteer as a judge for the Minnesota Renewable Energy Challenge at the School of Environmental Studies in Apple Valley Minnesota. This event is collaboration between High Tech Kids and the Kid Wind Project.

 On the previous tournament I was one of the judges for documentation, this year I was a judge for the Sail Car event.  There were two teams running at the same time but it was not a race, Asia Ward was the judge for the A team and I for the B.

Materials to Build Sail Cars

This event which might appear very simple but there is so much opportunity for creative thinking, working as a team, and applying principles of physics. With a time limit, it is important to think about how to divide the tasks during the time limit. If too much time is spent in discussion of a design idea and construction, there might be little time left for testing and tweaking the car to get the longest possible distance.

Hitting the Wall

The rules for the event went something like this: car chassis made from coroplast that has two axles made from bamboo skewers with four wheels made from wood balls are available in sufficient number that team members can make their own cars or more than one car can be attached together. There was no limit on how many runs of the cars, only the overall time limit 20 minutes. The furthest distance obtained by placing cars in front of two fans was the score for the team along with some judged construction points.

Asia at left was the Other Judge

Fans Provided the Wind

Construction was in building of the sail structure from bamboo skewers and construction paper. Many ideas were tried and it became fairly obvious what was not working but less obvious what the optimum design might be.  The car had to go straight without turning into a wall or tipping over which was not easy for some designs.  Early distances were in the 6 meter range but by afternoon an amazing distance of almost 9 meters was made by one happy young man.

Side by Side Design

Long and Narrow Design

What was rather amazing was that a car might stop but if you let it set for several seconds it might start moving again. This really added to the drama of the event.  I had measured the wind speed before the event started at a couple of distances and had noticed it was varying. If anyone has theories on this, please comment below.

Bill Kuhl
http://www.ideas-inspire.com

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