The Pinewood Derby is a racing event for unpowered, unmanned miniature cars. Pinewood derbies are often run by Packs of the Cub Scouts program of Boy Scouts of America. With the help of adults, Scouts build their own cars from wood, usually from kits containing a block of pine wood, plastic wheels, and metal axles. With the popularity of the pinewood derby, other organizations have developed similar events, and a small industry has developed to provide organizer equipment (e.g. tracks, timers, and scales) and awards (e.g. trophies and ribbons). Similar Cub Scouting events include the raingutter regatta (a race for miniature boats) and the space derby (a race for rubber band-driven propeller shuttles)
Frankie Hinson, Cubmaster of Pack 323-Bastrop along with his wife, Debra Hinson, Committee Chair of Pack 323, hosted 8 Cub Scouts and their parents in their shop at their home.
"It takes planning and committment to make sure every Cub Scout that needs help, gets the help they need to be able to participate. My husband and I have done this for the last 7 years and we wouldn't have it any other way. We enjoy seeing the parents work along side their Cub Scouts achieving a common goal like building a fast car! After all, all the kids want a fast car verses a slow car. My husband gets a kick out of me always asking the Cubs, when its time to pick a pattern for the car," Well, do you want a fast car or a slow car?"
At first, most of the Cubs want a real fancy car but those tend to be "complicated to build" or much to fancy to be a "speedster". Once you go with the fast or slow comparison, it's relatively easy..."F A S T" wins out every time," explains, Debra Hinson.
The Hinsons incorporate fun with learning and hope they "make learning FUN" at the same time. So while Mr. Hinson works with the Scout and Parent team, during down time, Mrs. Hinson brings in the Science behind event. The force accelerating a pinewood derby car is gravity; the opposing forces are friction and air drag. Therefore, car modifications are aimed at maximizing the potential energy in the car design and minimizing the air drag and the friction that occurs when the wheel spins on the axle, contacts the axle head or car body, or contacts the track guide rail. Friction due to air drag is a minor, although not insignificant, factor. The wheel tread can be sanded or turned on a lathe and the inner surface of the hub can be tapered to minimize the contact area between the hub and body. Polishing the wheel, especially the inner hub, with a plastic polish can also reduce friction. Often one front wheel is raised slightly so that it does not contact the track and add to the rolling resistance. Axles are filed or turned on a lathe to remove the burr and crimp marks and polished smooth. More extensive modifications involve tapering the axle head and cutting a notch to minimize the wheel-to-axle contact area. Packs can establish additional rules for what, if any, modifications are allowed. In some areas, no changes can be made to the axles or wheels.
A second consideration is the rotational energy stored in the wheels. The pinewood derby car converts gravitational potential energy into translational kinetic energy (speed) plus rotational energy. Heavier wheels have a greater moment of inertia and their spinning takes away energy that would otherwise contribute to the speed of the car. A standard wheel has a mass of 2.6 g, but this can be reduced to as little as 1 g by removing material from the inside of the wheel. A raised wheel can reduce the rotational energy up to one-quarter, but this advantage is less with a bumpy track.
Another consideration is the track itself. A track that is mostly sloping, with little flat at the end, can allow cars with minimal mass in their wheels to shine. However, a track with a steep slope and then a long flat section can penalize such cars due to the quick loss of energy they experience once they have reached the bottom, when all potential energy has been transferred to kinetic and rotational energy. Such cars will take a lead on the downslope, but may be passed by cars with more energy "stored" away as rotational energy on the flat.
A proper lubricant, typically graphite powder, is essential. Wheel alignment is important both to minimize wheel contact with the axle head and body as well as to limit the contact between the wheels and guide rail as the car travels down the track. There are 32 friction causing surfaces on a pinewood derby car. These include the surfaces of all four wheels which touch either the axle, the body or the track and the surfaces of all four axles which touch the wheel. Neglecting to polish and lubricate any of these 32 surfaces will result in degraded performance. The center of mass of a typical car is low and slightly ahead of the rear axle, which helps the car track straight as well as providing a slight advantage due to the additional gravitational potential energy.
The entire Cub Scout Pack 323-Bastrop showed up and showed out racing their cars this year. With 20 racers and each racer running on each lane on the wooden 6 lane track the race took about an hour. The Troop 56 Bastrop sold concessions to everyone that was in attendance. The racers were as follows:
Lion Den:Cash Hogan, Colton Thompson, Tanner Wood, and Ryder Broadway.
Tiger Den:Travis Jones and Amethyst Middlebrooks.
Wolf Den:Grady Allred, Gabriel Thomas, and James Viereck.
Bear Den:Samantha Jones, Olivia Bautista, Branson Blissett, Woody Viereck, Aiden Ogden, and Russell Ogden.
Webelos Den:Isaiah Baustista, Riley Belin, Zakary Wood, and Javion Grant. (First Image)
The Cub Scout Pack 323-Bastrop recognizes the Best of Show out of each Den. The judges never know who is going to be asked and the parents are never a judge of the den their Scout is in. Imparial judging is paramount in order for this phase of the race to be fair. This years winners were:Lion Den-Tanner Wood, Tiger Den-Amethyst Middlebrooks, Wolf Den-Gabriel Thomas, Bear Den-Branson Blissett, and Webelos Den-Isaiah Bautista.(Second Image)
Cub Scout Pack 323-Bastrop recognizes and awards the first top 6 time speedracers. This year our first place winner was Javion Grant, a Webelos AOL recepient. Second place went to Woody Viereck from the Bear Den. Third place went to Isaiah Bautista from the Webelos I Den. Fourth place going to James Viereck out of the Wolf Den. Fifth place was taken by Amethyst Middlebrooks in the Tiger Den and sixth place went to Gabriel Thomas out of the Wolf Den. (Third image)
Should you have any questions about your child joining Cub Scouts in Bastrop feel free to give Debra Hinson, Committee Chair at call at 318-282-1225. Open registration is every September and your child will bring home a flyer from school with information on it.