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2009 Pinewood Derby. Cubmaster Bob Stoneham Pack 551. Do your best. Do your best and have fun. Everyone who builds a car and races it is a winner Show good sportsmanship. No one “correct” way to make car. “Look at my car go”. Message to Adults. Message to Adults (concluded).
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2009 Pinewood Derby Cubmaster Bob Stoneham Pack 551
Do your best • Do your best and have fun. • Everyone who builds a car and races it is a winner • Show good sportsmanship. • No one “correct” way to make car.
Message to Adults (concluded) • Let the boys think up the design and do as much of the work as possible. • There is a Family Race for Dads/Moms/Sisters/Brothers/Etc for your creativity to shine. • Try to beat Cubmaster Bob in the Family Race.
What kind of car? • Use your imagination. • Be kind to the adults (pick something you can do yourself). • Scout shop has standard designs that come with templates and decals.
Car Designs – Fast but Ugly (Don’t let this happen to you!)
What forces affect the car • Gravity • Friction • Air Resistance
Gravity - Good • Gravity pulls you (and everything else) to earth. • Gravity pulls the car downward –which causes it to go down the track.
Friction - Bad • Friction is caused when two surfaces rub together. • Rougher surfaces have more friction than smooth surfaces.
Friction Acting on the Car • As the car goes down the track. Friction slows the car down Cubmaster Bob Rules
Air Resistance – Bad (a little) • Air resistance is friction between the air and the car. • The smoother the car shape the less air resistance. • Air resistance is not a major source of slowing the car down.
Which has less Air Resistance Note: This car has an illegal length (but it sure is cool looking!)
Derby Car Kit • Wood block • Four wheels • Four axles (nails)
Cutting the car body • Can use hack saw, jig saw, your teeth (just kidding) etc. • One area for adult to participate or supervise. • Scout should make a template (side view) of the car.
Cutting the body (concluded) • Leave the front flat so it will work the starting gate
Weight • Remove light weight wood and replace with heavier metal weights • Place weight towards the rear of the car. Higher on the track = more height for gravity to work on the track. • Max weight is 5 ounces. Build to slightly less than 5 ounces and add weight at weigh-in.
Weight • Drill holes and fill with weights
Types of Weights • Zinc, Lead, Tungsten, Clay • Be careful with lead -- It is toxic.
Polishing Axles • Debur the axles with a file. • Sand the axles with sandpaper. • Can use a drill or Dremel tool. • Use the “spin test”.
Wheels and Friction • Wherever wheels touch something there is friction. • Sanding your wheels can be tricky and error prone. • Smooth the tread and axle hole.
Smoothing the Wheels After Before
Attach the Wheels • Use the slots or make new holes using a drill press. Make sure they are straight with the car. • White glue or hot glue the axles in the slots. • Add dry lubrication (graphite).
Decorate • Make it cool • Paint • Decals • Figures