Pinewood Derby Car Designs
Don Murphy started his race with some basic design considerations still adhered to within the competition -- all Pinewood Derby cars must meet the same weight, size and configuration standards:
- No car must weigh more than 5 ounces (141.7 grams)
- Cars must be no longer than 7 inches (17.78 centimeters) from front to rear bumpers
- Cars cannot be more than 2 3/4 inch (6.99 centimeters) wide
- The clearance between the car and the track must be no more than 3/8 of an inch (0.95 centimeters)
- The cars must be freewheeling and have no starting devices
Other than these rules, how a car is made is open to the builder's interpretation. While artistic inspiration strikes more than a few Scouts and parents -- some have made moving replicas of the Iwo Jima Memorial as well as exact replicas of classic muscle cars and NASCAR favorites -- the more traditional races draw in more traditional materials. The body is often crafted of pine or balsa, both materials are easy to work and rather forgiving, with an egalitarian acceptance of an unsteady 10-year-old hand. These woods are also light and if necessary, weight can be added to bring them up to race standard. More importantly, the weight can be distributed where it is deemed to be the most effective -- but more on this later.
Bodies are shaped using a variety of methods ranging from the Scout classic of whittling with a pocketknife to more advanced techniques involving sanding, wood files and rasps and high-speed wood-shaping equipment like a Dremel tool. Some racers opt for a simple block as aerodynamics don't really play a role. Others go for the ever-popular "wedge-on-wheels" look.
With the body shaped, next come wheels and axles. The Boy Scouts of America (BSA) offers standard kits providing wood blocks, simple axles and plastic wheels. Most racers advocate buffing the axles with an emery cloth to shave off any burrs that could slow the cars. They also recommend "truing" the wheels, or making sure they're perfectly round and spin cleanly on the axle.
While the basics will provide a serviceable racer, today's Scouts, as well as the other groups involved in the sport, have learned a few high-tech tips and tricks that would make a NASCAR pit crew chief envious.