2009 Pinewood Derby

1. 2009 Pinewood Derby Cubmaster Bob Stoneham Pack 551

2. 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.

3. “Look at my car go”

4. Message to Adults

5. 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.

6. 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.

7. Car Designs - Standard

8. Car Designs - Wacky

9. Car Designs - Wacky

10. Car Designs - Wacky

11. Car Designs - Wacky

12. Car Designs - Wacky

13. Car Designs - Wacky

14. Car Designs - Wacky

15. Car Designs - Wacky

16. Car Designs – Wacky

17. Car Designs – Fast but Ugly (Don’t let this happen to you!)

18. What forces affect the car • Gravity • Friction • Air Resistance

19. Gravity

20. Gravity - Good • Gravity pulls you (and everything else) to earth. • Gravity pulls the car downward –which causes it to go down the track.

21. Gravity Acting on the Car

22. Gravity Acting on Derby Car

23. Friction

24. Friction - Bad • Friction is caused when two surfaces rub together. • Rougher surfaces have more friction than smooth surfaces.

25. Friction Acting on the Car • As the car goes down the track. Friction slows the car down Cubmaster Bob Rules

26. Air Resistance

27. 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.

28. Air Resistance Acting on the Car

29. Which has less Air Resistance Note: This car has an illegal length (but it sure is cool looking!)

30. Derby Car Kit • Wood block • Four wheels • Four axles (nails)

31. 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.

32. Cutting the body (concluded) • Leave the front flat so it will work the starting gate

33. 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.

34. Weight • Drill holes and fill with weights

35. Weight Distribution

36. Whoops! - Weight too far back

37. Types of Weights • Zinc, Lead, Tungsten, Clay • Be careful with lead -- It is toxic.

38. Axles and Friction

39. Polishing Axles • Debur the axles with a file. • Sand the axles with sandpaper. • Can use a drill or Dremel tool. • Use the “spin test”.

40. Axles Before Polishing

41. Axles After Polishing

42. Polishing Axles with Drill

43. 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.

44. Smoothing the Wheels After Before

45. Wheel Mandrel

46. 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).

47. Align the wheels

48. Crooked Wheels

49. Decorate • Make it cool • Paint • Decals • Figures

50. Great Decorations