C02 Powered Pinewood Derby Motor.

Note: My car was featured in the September 2011 issue of Popular Mechanics
http://www.popularmechanics.com/home/how-to-plans/backyard-genius-2011-the-years-10-best-diy-creations-jet-propelled-pine-wood-derby-car

This is a 3D printable motor for an 'outlaw' class Pinewood derby car. My son's cub scout pack has run an outlaw class for the last couple years. I've made other cars (http://sliptonic.com/?p=113) but this year I wanted to make as much as possible 'printable'. The trigger was ins