yeah, we had to build self propelled vehicles once in high school....

mine was perfect.. i tested it all day long at home out on my DECK... it would go a pretty good distance...

race day comes.. i get a couple feet cause we were running it on tile.. i had no traction... (i used grip tape for the traction.. worked awesome on wood, turf, and carpet..) BUT what was great was when we put it on some wooden up ramps and another head to head... mine romped on this other guys... he made his outta balsa wood...