How Are CO2 Cars Made?

CO2 Car Basics

A CO2 car is a car powered by a pressurized cartridge filled with carbon dioxide. CO2 cars are designed to drag race on a straight course. Racers try to vary the size, shape and cartridge placement of their cars to get the quickest car possible. The cars are made out of lightweight balsa and basswood to maximize efficiency, and use manufactured plastic wheels.

The Kit

Most CO2 cars start with a kit. The kit comes with a body blank--a wedge shaped piece of balsa or basswood about the right length for a car--along with wheels, bearings, washers, axles and screw eyes. Some kits come pre-drilled with holes cut out for the CO2 cartridge and sometimes the axles as well. Other kits need to be drilled once the car is finished.

Designing the Car

Racers first sketch out a design for the car. The design should include a profile of the car and a top-down view. Ideally, the car should be lightweight and streamlined to minimize wind resistance and maximize thrust-to-weight ratio. Once a racer decides on the perfect design, he traces it onto the wood block. The side view goes on one side and any vertical designs go on top.

Drilling and Cutting

The racer uses a drill press to make two small holes for the axles. A drill press is the best way to go, since the holes have to be perpendicular to the car's axis. He also makes a hole for the CO2 cartridge, if necessary. Then, he uses a band saw to cut the basic shape of the car. If the car has any rounded edges, the racer can use a table sander to round them.

Finishing and Painting

The car is sanded. First, the racer uses coarse sandpaper to remove any bumps and even out any asymmetries in the car's design. Then, the racer uses finer and finer sandpaper until the body of the car is perfectly smooth. Next, he spray paints the car. Then, he puts the wheel axle assembly together, installs it and tests the car to make sure it roles. Finally, he attaches two screw eyes under the car. These screw eyes will keep the car driving straight along a guide wire when it races.