Rubber Band Car

With thanks to Scott Gilliland who created the first version of this project.

Requirements and constraints

You are to design and build a rubber-band powered car that can safely transport an egg. It must meet the following constraints:

• It must include a laser-cut wood part.
• It must include a 3d printed part that is involved in the functioning of the car.
• It must be powered by a rubber-band.
• It must fit within one cubic foot.
• It must include an openable hatch to enable inserting and removing an egg.
• It must be able to travel 10 feet on a hard surface floor while carrying an egg under its own rubber-band power.
• It must be able to travel 10 feet when rolled down a ramp, (with rubber band disengaged).
• The egg must survive when the cart is rolled down the same ramp, then colliding with a concrete block 2 feet away.

Hints: Because laser­ cutable materials are cheap, and 3D printing is expensive, you’ll likely want to save your 3D printing allotment for the wheels of your car or other small parts, so you car will likely be mostly laser­cut wood.

Materials

All of the following materials will be available to each student:

• 1x 12"x24"x 2mm Craft Plywood
• 2x 3" #8­32 threaded rod
• 2x 4” #8-32 threaded rod
• 4x #8­32 hex lock nuts*
• 4x #8­32 hex nuts*
• 4x #8 flat washers*
• 4x O­Rings AS568A Dash Number 119
• 4x O­Rings AS568A Dash Number 125
• 1x #8­32 threaded hook
• Glue, including wood glue and CA with hardener
• 4x 7”x1/16” Rubber Bands
• 4x 1/2” x 1/4” Rubber Bands
• Cushioning foam TBD.
• 1 inch^3 of plastic on the 3D printer in the GVU Prototyping Lab (more may be available if 
requested)
• Use of the laser cutter in the GVU Prototyping Lab (or alternatively, the laser cutter in the 
ME Invention Studio)
• Any additional resources you decide to use.

Many parts above have CAD models available from McMaster Carr

Process

We will have at least the following milestones, which will be confirmed with “skill-demos”:

• Example hardcopy of something output from CAD software – confirming that you have successfully accessed some CAD platform.
• Initial 3D design of your car (not perfect, but initial).
• File suitable for lasercutting wood. And cut wood.
• File suitable for 3D printing, and a 3D part.

Details on these skill demos will be provided and refined via the course wiki and t-square.