It's that time of year again. In schools and churches and community centers around the globe, Cub Scouts are gathering to put their building skills to the test in the annual Pinewood Derby race.
Thankfully, our Cub Scout pack has a category just for dads, so I can build my own car. My son -- although I help with the more difficult and dangerous tasks -- is largely on his own. I believe it's important that his car be his own. That's not to say I haven't searched long and hard to find the best performance tips for making my car as fast as possible.
It's my understanding that there are as many different rule sets as there are packs, so what I've tried to do is keep these tips as universal and broad-based as possible. Be sure to double-check your pack's rules before your first cut into your pine block.
Put all of your weight in the back. Much has been written about the physics of pinewood derby cars, and this is one rare case in racing where heavy = fast. Aerodynamics have little effect in such a short race, but weight does and putting the weight at the back of the car will make your car faster on the flat of the track. Tungsten weights, in most cases, are best because of their high density.
Lube the car at the body/wheel friction point. Do not paint the car on the small semicircle point where the wheels meet up with the body (where the wheel well is on the car in your driveway). Rather, sand this point to a smooth finish with a very fine sandpaper. Next, after masking off the body's paint, gently massage some dry graphite into the wood. This will reduce friction and increase wheel speed.
Spend a fair amount of time on axle prep. Using a file and fine sandpaper, make sure you remove any burrs and defects from the axles, near the head of the nail. Some people will put a number of axles in a power drill and spin them to find the axles that are most straight (and eliminate any with noticeable wobble).
Make sure your wheels are ready. Depending on your pack rules, polishing (or sanding) the business side of the wheel can improve rolling resistance. You can also massage powdered graphite into the wheel edge to further reduce friction. There are plenty of vendors who sell improved wheels, but if your group is like ours, these are outlawed. You can also polish (with graphite again) the wheel's bore. Once your axles and wheels are finished, a good rule of thumb is that, with a flick of a finger, they should be able to freely spin for 20 seconds.
Finally, once your wheels are mounted, check their alignment. Find a long board and mark off a racing lane, about 6 inches across. Put the board on a very slight incline and allow your car to roll a few feet. If, at the end of this test run, your car has moved significantly to one side or the other (or the wheels have moved in or out), move the axle up or down to adjust your alignment.
That's it! These are my quick tips for improving your pinewood derby car's speed. Do you have a speed secret that you can share with us for making your car move? Let us know in the comments.
The following parameters made pinewood derby cars faster: using graphite on the axles and wheels, using lightweight wheels and polished axles, lifting the left front wheel and bending rear axles also raised speed.
The following parameters made pinewood derby cars faster: using graphite on the axles and wheels, using lightweight wheels and polished axles, lifting the left front wheel and bending rear axles also raised speed.
To go fast, it's all about aerodynamics, and the best shape is a simple wedge. Just like a spoiler on the rear of a sports car, the wedge shape allows as much air to flow over the top of the car without hinderance while keeping the car pinned to the track.
Assuming all other factors are equal, a heavier car will be faster than a lighter car. The Pinewood Derby rules limit the weight of each car to 5 ounces.
The wheels are a significant source of potential energy drain on a Pinewood Derby® car. Raising the non-steer wheel (typically the front left) so it does not contact the track reduces the amount of energy used to start the wheels spinning.
Bake the wooden block, usually at 250 degrees for two hours. This removes moisture, which allows you to apply weights when the block is finished. A heavier car is a faster car, but you can't go over that 5-ounce mark.
Applying too much lubricant will slow your car down. How to use: Put one drop of lubricant on an axle. Tip the axle so down and let the lube flow to the end of the axle.
Science says the heaviest part of your car should be about 1 inch in front of the rear axle. The idea is that the farther back the weight is, the more potential energy you have because your center of mass is higher up on the track.
Your pine wood derby car moves from the force of gravity and is slowed down from friction. Friction acts like brakes. Reduce friction and your car goes faster. Increase friction and your car slows down.
While just about any graphite will work as a lubricant, some versions are specially formulated and work best for Pinewood Derby®. Liquid - There are different liquid lubricants as well. Nyoil™ has been a popular option in years past, as well as Krytox™, produced by DuPont®.
To conclude it is clear that sitting as low as possible and placing as much of the ballast weight in the rear, will give a driver the best chance at crossing the finish line of a race quicker than a racer who is sitting higher in their car or who has placed their ballast weight in the front of the car.
Introduction: My name is Duane Harber, I am a modern, clever, handsome, fair, agreeable, inexpensive, beautiful person who loves writing and wants to share my knowledge and understanding with you.
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