3D Printed CO2 Car - Part One Design

This is a project designing and building a 3D printed CO2 car. The car can be mostly printed with the only requirement for assembly being to purchase small steel rods that act as axles. This project is great way to introduce several skills that can easily be turned into lessons. I will be breaking this thing into 3 parts, each containing a separate lesson. The lessons will touch on skills like physics, math, spacial reasoning and design. My target population is 4th and 5th graders but this can easily be adopted for higher grades.
I found that getting my students excited about this project was simple. I taught them the basics of Tinkercad. Then I had them start with a template of a CO2 car and let them make it their own. The initial requirement is to go through the 'Basics" tutorial on Tinkercad.com at the very least.