1. CO2 DRAGSTERS
The Fast & the Furious

2. Forces Affecting Speed
Your CO2 dragster may be small, but it's going to be moving at incredible speeds when you race it. That means it will be subjected to a wide variety of forces that affect its motion and velocity. Here are some of the principal forces involved…

3. MASS
Obviously, this is how large and heavy the car is. Simply put, the less weight your dragster has, the faster it will go. This is the most important factor that will figure into your design. Keep it light!

4. THRUST
Thrust: The gas escaping from the CO2 cartridge in the car. Every cartridge has 8 oz. of CO2 and will be released the same way.

5. FRICTION
The second most important fact you'll face. Because the dragster has parts moving against one another, friction is created. You can help reduce it by making sure the axles are free to rotate, and that the wheels and tires are not rubbing on the car body.

6. DRAG
Here's where aerodynamics come into play. As an object moves through the air, it is met with air resistance as speeds increase. This air resistance pushes against your CO2 car and prevents it from going as fast as it could in a vacuum. You can't completely ever reduce drag, but you can help reduce it by building a more aerodynamic car, but those are more difficult to create.

7. In terms of physics, the rapidly escaping gas illustrates Newton's Third Law of Motion -- for every action there is an equal or opposite reaction. The rearward motion of the gas pushes the car forward in this case, overcoming inertia or the resistance to movement.

8. The Design Process
The Challenge: To design and build a CO2 dragster that will go as fast as possible.
Brainstorm Ideas: shapes? Cuts? Sanding? Wheels? Ways to eliminate friction?
Best Idea:
Build: weight/cut/weight/sand/weight/paint/weigh
Test : launch #1: How did yours compare to others?
Modify: make faster!
Launch #2: Did you improve?
Final launch: Did you make the top 16?

9. What Your Teacher Will Do:
Make one top cut and one side cut to your dragster body.
What YOU Will Do:
Trace the side and top view of your balsa blank onto paper.
Mark where the axle holes will be and where the CO2 hole is.
Use a different color to draw your dragster shape. Is it the right length?
Transfer your design to a dragster blank.
Drill axle holes in the body while the car is flat.
Have Mr. Johns cut the major cuts for you.
Use sandpaper to finish shaping and smoothing your dragster.
Paint your dragster.
Add axles, wheels, and screw islets.
Clearly paint or draw your ASSIGNED racing number on your dragster.

10. For Official Competitions
CO2 Car Specifications
For Official Competitions

11. Dragster Body
One (1)-piece, all-wood construction. Any type of lamination will result in disqualification. Two (2) or more like or unlike pieces of wood glued together are not considered one (1)-piece, all-wood construction. No add- ons such as body strengtheners, fenders, plastic canopy, exhausts, or air foils may be attached to or enclosed within the vehicle. Fiberglass and shrink wrap are considered body strengtheners and cannot be used on the car body for any reason. Decals may be used for decoration only. They may not be used to gain an aerodynamic advantage, i.e., decals cannot cover the exterior axle holes or be used to cover open areas of the body.

12. Dragster Body Length
Min. 230mm Max. 240mm

13. Dragster Body Height with Wheels
Max. 75mm

14. Dragster Body Mass (without Co2)
Min. 35g Max. 65g

15. Weights of Parts Standard back (large) wheel = 6g
Standard front (small) wheel = 2g
Standard axle = 4g
Four standards front wheels and two axles = 12g

16. Dragster Body Width at Axles Front & Back
Min. 35mm - Max. 42mm

17. Axle Hole Height
5-10mm

18. Wheelbase (Axle Distance at Farthest Points)
Min. 105mm Max. 222mm
105mm-222mm

19. Bearing, Bushing and Lubricants are Legal

20. Spacer Washer
Spacer Washer; Maximum: 10

21. Axle Clips Axle Clips; Maximum 4
(Used to hold axles in place for shell cars)

22. Power Plant Housing Thickness
Min. 3mm

23. Chamber Diameter to Race Surface (with wheels)
Lowest point of chamber diameter to race surface (with wheels)
26mm – 40mm
Min. 26 mm
Max. 40mm

24. Screw Eye Inside Diameter
Min. 3mm Max. 5mm
3-5mm

25. Screw Eye Distance Apart
200mm or more

26. Wheels Four 30mm-40mm wheels are required.
Wheels may be inside our outside of the dragster.
Total width of dragster must be 90mm or less.

27. Wheel Diameter
Min. 30mm Max. 40mm

28. Wheels Width
2mm-18mm
2mm-18mm
Min. 2mm Max. 18mm

29. CO2 CO2 canisters must be Pitsco 8 oz.
CO2 can be very dangerous or even deadly if treated improperly.
The most important measurement on your car is likely the “power plant housing thickness”.
The second most important safety detail is that both screw islets are secured. Use a drop of glue to secure them.

30. Strategic Ideas for Reducing Friction:
Put axles in a drill and use light grit sandpaper to clean and smooth them.
Put wheels in a wheel lathe.
Use a little graphic powder inside straw or bushings. Hand turn axles until the powder is as smooth as possible.
Use washers between wheels and body.

31. Strategic Ideas for Reducing Drag:
Put the wheels INSIDE the body.
To do this, you’ll need to hollow out the body. This is known as a SHELL CAR.
You will have to drill the wheels so that the axles go all the way through them.
Make your car as light as possible. (As close to 35 grams as possible).
Use an aerodynamic shape!

32. The Most Aerodynamic Shape?
The Teardrop

33. Real Cars Close to a Teardrop Shape:

34. Concept Car with Teardrop Shape

35. Making a Truck More Aero

36. Is a Teardrop Dragster Possible?
SIDE VIEW
TOP VIEW

37. National Junior High Champions!
10th PLACE

38. 9TH PLACE

39. 8TH PLACE

40. 7TH PLACE

41. 6TH PLACE

42. 5TH PLACE

43. 4TH PLACE

44. 3RD PLACE

45. 2ND PLACE

46. 1ST PLACE

47. National High School Champions!
10th Place

48. 9th Place

49. 8th Place

50. 7th Place

51. 6th Place

52. 5th Place

53. 4th Place

54. 3rd Place

55. 2nd Place

56. 1st Place

57. Shell Car?
Rail Car?
Hybrid?

58. Bottom of Shell Car
Use scraping or carving tools to hollow out room for the wheels.
You could also use a large drill bit and drill it out.
Use axle clips to prevent the axles from slipping out.

59. 2015 District CO2 Championship
Overall Points Winner: Les Bois
Fastest Car: Les Bois

60. The belly of the beast

61. What will YOU Build?