Pinewood Derby Principles

Use Science to Build a Fast Pinewood Derby Car

Build a fast Pinewood Derby car!*Make sure to consult your local race rules before using these tips.*

Posted by Boy Scouts of America on Thursday, January 8, 2015

Cub Scout Pack 3512  Pinewood Derby - Principals

Principle 1: Have Fun!

The sole purpose of this event is for the Scouts and families to have FUN. This is the first and most important principal. Spend some time with your Scouts and build something together that will REALLY last...great memories!

Principle 2: Cub Scouts - Do your best

Designing, constructing, and racing a car is a joint effort between a young person and a mentor. Obviously, there are some jobs that some young people can not perform adequately or, more important, safely. But if the young person has the skill or can learn the skill, then let the young person exercise the skill. You'll both probably learn more that way.

For younger scouts be sure to keep the "core" shape of the car simple. Let your scout personalize the car by adding balsa wood - which they can cut and shape easily. In addition, they can personalize the car with paint, stickers and other decorations (e.g., LEGOTM parts, pieces from broken toys, craft store adornments).

Coaching Hints for Parents

Help your son plan a schedule to prevent a last?minute project and allow time for him to do his best.

  • Help your son understand the Pack rules and specification requirements.
  • As your son chooses his favorite design, help him trace it on the block of wood from the kit. Guide him in the use of tools in the shaping of the model and encourage him to sandpaper the model to a smooth finish.
  • Help your son feel that this is a joint project, with him doing much of the work.
  • Help your son understand that "doing your best" is more important then having the fastest car.
  • Feel a sense of pride and satisfaction when the model and race are finished. Share it with your son. You have both earned it.
  • Understand that the leaders may need your help. If you have the interest and the time, you might contact the leaders and volunteers to help.
  • Spending time with your son, helping him "do his best" will be remembered by both of you long after the race is finished.
  • Talk to your son about the race and the importance of good sportsmanship.


Principle 3: Performance and beauty are often opposites.

Everyone would like to simultaneously optimize for both speed and beauty. Historically the simplest cars always appear to be the quickest. So, it is important to consider whether you want a fast car or to win a design award. Very few cars have won both.

Principle 4: Maximum weight enables maximum speed.

Get the car's weight as close to five ounces as possible. The easiest way to address this is to drill holes or mill out space to add weight to the car at the registration weigh-in.

Most folks agree that having the weight shifted to the back is best. However, if too much is shifted to the back the car tends to do a wheelie. This leads to a car that is directionally unstable. You cannot win a race if your car cannot stay on the track.

Principle 5: Little things DO matter.

Taking time to polish the axles and to smooth the wheels can make a significant difference in how fast the car is on the track. Wheels with high spots produce a bumpy ride, causing loss of time and might cause the car to leave the track, possibly resulting in major damage.

In addition, getting the wheels and axles on the car straight is absolutely critical. Some people recommend using a drill press to push a sacrificial axle in place and others suggest using pieces of wax paper (or regular paper) to carefully shim the wheel straight. All of the various approaches can work given that you take your time.

Set enough time aside to get the wheels straight.

Consider a few practice runs at the local hobby shop test tracks.

Lastly, be certain to set aside time for the paint to thoroughly dry. Paints can remain gummy and tacky for days.

Principle 6: Remember the rules.

Follow your the rules. If you can't pass inspection, you can't race. No one wants anyone to spend hours building a car that cannot race. In addition, last minute "fixes" can lead to big problems and should be avoided as much as possible.

Assure that you have adequate ground clearance. You can do this by rolling your car over five stacked nickels (the car straddles the center rail as it runs down the track). Failure results in either grinding to a stop part way down the track or flipping off the track as a high spot is passed. If you can't get to the finish line, you can't win!

Assure that the car will "run" on the track. A narrow or pointed nose may not stage correctly on the starting mechanism and may not trip the finish line sensor correctly (might lose a race you may have otherwise won).

When is your Pinewood Derby race day?

Posted by Boy Scouts of America on Sunday, January 11, 2015

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