By Chris Deziel
Updated Aug 30, 2022
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Building an electric car for a science project involves four essential components: a chassis, wheels and axles, an electric motor, and a power source such as a battery. A drivetrain—whether a gear, pulley, or fan—translates motor torque into motion. While every mini‑car must include these parts, the materials and design choices offer plenty of creative freedom.
The Woody is built on a flat, rectangular chassis made from balsa wood or another lightweight hardwood. A thickness of about 1/4 inch allows you to drill four screw‑eye holes on the underside, through which you can insert wooden skewers to form the axles. Fender washers (≈1 in. diameter) make excellent wheels; they fit the skewers and can be secured with hot‑melt glue. Test the assembly on a flat surface to confirm that all wheels rotate freely.
Locate a small DC motor—available at most hobby stores—or salvage one from an old personal fan. Attach the motor to the chassis so that its shaft protrudes approximately 1/2 inch beyond the vehicle’s side. Mount a 9‑V battery or a set of AA batteries on the opposite side of the chassis to supply power. Use a rubber band to connect the motor shaft to one of the rear axles; the tension drives the wheels.
Before installing a switch, briefly connect the motor leads to the battery terminals to confirm operation. Create a simple toggle by wrapping one motor wire around a metal screw and driving the screw into the chassis. Wrap the second wire around a bare metal paperclip, secure the clip to the chassis with a screw and washer, and adjust the clip so it makes contact when pressed. This completes a basic on/off switch.
The Fantom Flyer’s chassis, wheels, and drive mechanism are constructed from recycled plastic items. Only wooden skewers are needed for the axles.
Cut the top off a 1‑quart plastic soda bottle about 3 inches from the mouth. Preserve the cap and top for later use. Drill two holes on the side of the bottle and insert plastic drinking straws; these will serve as axles, spaced roughly 8 inches apart. Glue the straws to the bottle and trim them so they extend about an inch beyond each side.
Insert a wooden skewer into each straw and push it through to the opposite end. Take four plastic pill bottle caps, punch a central hole in each, and glue a cap to the end of each skewer. Ensure all caps are identical in size for balanced wheel motion. Test the vehicle by rolling it on a flat surface; the wheels should spin smoothly.
Attach the motor and battery on the opposite side of the bottle using hot‑melt glue. Mount the motor on the rear of the vehicle—whether the open or closed end of the bottle—so the shaft projects about one inch. Construct a fan by cutting slits on the bottle top that extend downward from the cap, spaced roughly an inch apart. After cutting, press down on the cap to flare the sections into a fan shape. Drill a hole in the cap and glue the fan to the motor shaft. When the battery is connected, the fan spins, propelling the car forward.
