Conclusion

Conclusion:

1. Using Graphite makes the biggest difference (about 44 inches).

2. The second most important thing is to make sure the wheels are aligned. (About 8 inches faster on my test car.)

3. Sanding and waxing the wheels made the car about 7 inches faster.

4. Having the graphite "worn in" was about 6 inches faster than a freshly graphited car.

5. Having an aerodynamic shape made the car about 5 inches faster.

6. Having the weight towards the back and the back wheels closer to the back was 2 to 4 inches faster than having them in other locations.

FasterPinewoodDerbyCars.pdf

Using the results of these tests, my Dad helped me build two cars. We made the shape flat and pointed to be aerodynamic. We put the weight and wheels toward the back. We sanded, polished and waxed the wheels. We also filed the bumps off the inside of the heads of the axle nails. When we put on the wheels, we rolled the cars on a table to make sure they rolled straight and made adjustments as needed. Then we put graphite on the axles and spun the wheels a lot to work in the graphite.

New car Results:

Using all these modification, one of my new test cars was faster than my fastest Cub Scout car. The other one was close but only beat one out of 10 races.

My fastest car from when I was in Cub Scouts averaged 2.845 seconds in 10 runs. The fastest time was 2.812.

My new blue test car averaged 2.825 seconds. The fastest time was 2.797 seconds. 2 inches faster than my fastest Cub Scout car. (0.015 Seconds faster)

My new red test car averaged 2.873 seconds. The fastest time was 2.854 seconds. 5 inches slower than my fastest Cub Scout car. (0.042 seconds slower)

The results were a little different each time ran them and one of the cars we made using these tips was slower than the other.  But both were fast.  There's always the element of chance that could make the difference between winning and losing.  But using these tips can give you a better chance.

Next, I'd like to test the two new cars to find out why the red one is a little slower. And I'd like to test more tips we've found on the Internet. Then maybe I can put my results on the Internet so other kids can make fast cars.

1st Place Butterfield Elementary Science Fair 6th Grade 2-12-2002
1st Place SARSEF Engineering Middle School  3-28-2002