This is the basic model we started out with. The steps we used to build it were by taking the card board and cutting out a strip in the back to put a skewer as the axle. Then you attach the cd's on with duct tape as well as a medium thickness rubber band for power. Then you attach a piece of tape to the axle to get the rubber band to "catch" to it so that you can wind back the rubber band and test the car.
Modification 1: Here is our second to last model. Before this, we made some modifications that were unsuccessful, so here are three of the four successful modifications we made that were on this particular model
One modification here is that we added a triangle to the front of the car with skewers. This helped to keep our car from flipping
A second modification we made was to roll the duct tape around the axle to keep the wheels extra sturdy
A third modification we made was that we cut out part of the cardboard in a parabola shape to minimize mass while stilling having a long cardboard structure. This helped keep our car from flipping as well as keeping the car balanced and straight
Our fourth modification was that we cut the rubber band so that we could roll it more. We also had a thicker rubber band. This helped to give more power to the car