Searching on Instructables, I found this tutorial from DotatDabbled. Very interesting, cool and well executed. But considering my objective, I have the following issues: So I created this easy-and-cheap-to-build car catapult (a "car-tapult"?). I made two prototypes and tested them with three different toy cars: a Hot Wheels "Batman Live! Batmobile", a Matchbox "MTN XT" and a generic bootleg car (suspiciously branded "Motor Wheels"). I'm in the process of improving the design, but until now, I'm happy with the results. Conversely, you don’t want to buy a set that will be too difficult if you are buying it for a younger sibling or relative. For those just getting into Hot Wheels, it is wise to buy them something that will spark their imagination, but not be over complicated enough to kill their enthusiasm.

My idea was to make a Hot Wheels launcher using simple materials, as a project for teaching kids in a funny way about mechanical engineering, specifically about the potential and kinetic energy concepts.