Two years ago, my son William won the annual pinewood derby. Last year he placed second. This year we had to take it up a notch.
We did all the same tricks as previous years: extending the wheelbase, squaring the axles, reducing friction by polishing the axles.
This year we worked on weight distribution. We've always tried to have the center of mass as far back as possible, but this year we went to more extremes. We hollowed out most of the car. This allowed us to move more of the mass to the back of the car. We also weighted the car with tungsten this year, instead of lead.
The standard rules state that the maximum length of the car is 7 inches. For some reason, our local rules allow for a length of 7 3/8 inches. The rules that they hand out each year look like a 20th generation photocopy, so perhaps the pine blocks were longer in the past. Thus far it appears that I'm the only one who has noticed this anomaly, so our wheelbase is a bit longer than even the others who drill their own axle holes instead of using the standard axle slots. We place our axles right at the back corner of the car, so the rear wheels actually protrude beyond the back of the car. This allows us to put the center of mass even farther to the rear of the car without destabilizing the car.
