Rocket Dragster - The World's Fastest 3D Printed Car (for ants)

The Rocket Dragster is designed to use standard Estes model B and C rocket engines set into the rear of the craft. Print off 4 wheel hubs and press fit them into standard 608 bearings (https://a.co/d/d0hcxeg) to giving it less frictional contact with the ground….or don't and just watch it slide nearly as far; the rocket motor doesn't care. 

Model rockets are typically 10x lighter than this design, so don't worry about this traveling much more than a city block, assuming it maintains a straight trajectory on your surface. All the same, don't have anyone or anything you care about standing anywhere in front of it when you set it off. Stand back and wear safety glasses.  

The overall design arrangement was inspired by the Bloodhound Super-Sonic Car. 

This started as a project to create a way to easily press-fit 608 bearings for any type of toy car wheels. Once I did that I thought that I should probably include a car…and as an engineer I got a little carried away. I've included a model file of the axel and put everything under a creative commons license, so you may all easily and freely duplicate the use of press-fitting 608 bearings into your own projects. Enjoy! 

Printed this with 0.2mm layers, support everywhere, 3 layer wall thickness, 2-layer 5% infill (1-layer 20% infill also works). Prints best in vertical orientation to provide optimal strength in the rocket engine holder. Be careful when attempting to separate the supports in the front wheel wells, the nose likes to break off if you snip the support because of the forward pressure. I super glued the nose back on with no issue after I accidentally broke it off, by filling the infill cavities on one side with baking soda and applying super glue to the mating surface of the other side before mating them together, which then cures almost instantaneously.

The rocket motor cavity is designed to fit a little loose around the rocket motor, to accommodate any heat expansion of the motor. However if you prefer a tighter fit just apply a strip of masking tape around the engine.