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Every corner of human endeavor has its researchers, and that includes activities that we might think are just supposed to be fun for kids, like pinewood derbies. In case you don't know, a pinewood derby where kids build a car out of a block of wood, add some nails for axles and plastic wheels and then race them head-to-head on a length of track with an elevated starting line. It's all about kids having fun with gravity and little chunks of timber.

Except it isn't at all, because dads are involved, and that means that winning pinewood derby cars use the kind of science and technology real car enthusiasts are familiar with: center-of-mass studies, polished axles, lightweight wheels and copious use of graphite.

YouTube regular Mark Rober gives an excellent explanation of what goes into a champion derby run, with science help from Dr. Scott Acton, a physicist with spacecraft and defense component maker Ball Aerospace. But Rober mostly uses children's blocks to lay it all out, and then he wins, which are things we can all understand. You'll find an education in the video below.



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    • 1 Second Ago
  • 14 Comments
      BipDBo
      • 9 Months Ago
      That's a fancy track. When I was in cub scouts, the track was homemade out of wood. Unless one car was really slow, the winner was always the one on the "fast lane." Also lubricants such as graphite were prohibited. My dad however found a loophole. Any part of the car could be decorated, so we heavily decorated our axels with pencil.
        Gorgenapper
        • 9 Months Ago
        @BipDBo
        Luckily for us it didn't achieve warp speed and attract the attention of the Space Police.
        Egon
        • 9 Months Ago
        @BipDBo
        Yes, that is a really nice track setup. My son's Pack had the same track and the accompanying timing software. I ended up as the 'derby commissioner' for a few years and got a chance to check out some of the stat reports that came with the software. After running all cars on all 4 lanes, we had a few derbies where the lane variance was measured in hundredths of a second. Science, indeed.
      rcavaretti
      • 9 Months Ago
      Unless it's an open class, Cub Scouts don't allow lightened wheels. You must use the parts provided in the issued by the pack box, no mods. And yes, the adults have more fun.
        stbham
        • 9 Months Ago
        @rcavaretti
        Ditto here, they also check (but not real hard) if all 4 wheels are on the ground. Bent axles are also a no no. You are talking about 0.15 sec between fastest and slowest of all comers
        JayP
        • 9 Months Ago
        @rcavaretti
        My son spotted a kid using non-BSA wheels and started to get bent. I calmed him down since it it just a dang race with wood blocks. The kid's car was painfully slow. But it was obvious 100% of the work was done by the boy. Good for him. That is the exception.
      churchmotor
      • 9 Months Ago
      Finally an article where carguy1701 can contribute.
      Yeah yeah
      • 9 Months Ago
      Great, but where was this video in 1972 when I needed it?
      Sissyfoot
      • 9 Months Ago
      When I was in high school, I had to build a 'gravity' car like these for a class I took. Instead of wheels, I put a plastic model car body with little guide wheels onto a block of dry ice. The track was just a ramp placed in the gym, so I swept the floor real well. I don't remember at all how it fared in our 'competition.' I just remember that thing kept going and going. Also, dry ice being cut on a band saw makes a *terrible* noise.
      b.rn
      • 9 Months Ago
      Why are we listening to this guy instead of Dr Acton? It's certainly not for the background music. Seriously, it's not a bad video. It's just that the Dr deserves most of the credit. Mark links to Acton. Autoblog should too.
      Exit
      • 9 Months Ago
      When I was in cub scouts, I spent hours and hours carving, sanding, and polishing my car, sanding the wheels and using graphite lubricant on the axles. I tested it against my two previous cars that I had entered. Those were "theme cars" that were more about looks than speed but they did fairly well when they competed. This new car beat them easily, I couldn't wait to see how it stacked up! The day of the competition, my car barely passed the finish line. I was crushed. When I got it back it was apparent why; one of the wood-tack front axles were badly bent. The race was won by the kid of the man that set the cars on the track. The next year we were given more tamper proof axles, but I was too apathetic to put as much effort into the build again, I just chopped off enough to get the car to the right weight.
        JayP
        • 9 Months Ago
        @Exit
        Use google to find that dad and kick his ass. No jury would convict.
      supr2nr1
      • 9 Months Ago
      I remember building my state winning derby car. It was a cylindrical, rocket shaped body with aerofoil shaped axles. Heavily painted in Red white and blue. We had to drill the back half to add lead to meet minimum weight. It looked so good that the tech inspector chipped the paint to make sure it was still pinewood. Wish I still had that car. I might build another just for the beck of it.
      JayP
      • 9 Months Ago
      My son crossed over to Boy Scouts last year so this was the first time we've missed building a car. He sanded, primed, painted, sanded, painted... until it looked like plastic. Spent an hour polishing the axles and wheels but was underweight, but not by much. He won the den and pack championship. I won the dad's class. The kid's car was just a little faster than mine in the head to head race. He was so happy, he coulda popped. I took a 30+ yr old car my dad and I made and entered it in the catchall siblings class under the dog's name. The wheels were flats spotted from sitting for decades. Still managed to come in second. Yea- I need to make another one.
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