Road Bike, Cycling Forums banner
1 - 6 of 6 Posts

· Registered
Joined
·
78 Posts
Discussion Starter · #1 ·
please can i have any help for my school project. In my transportation class we are making CO2 cars and im looking for anyhelp to make it faster tonight :D so can anyone give me some ideas on how to make it more aerodynamic.

please any help ! thx

here are some pics of what i have now....





 

· Registered
Joined
·
21 Posts
It seems like you can't make it much lighter. The cars need practically 0 momentum as the CO2 blast usually lasts nearly as long as the time it takes to complete the track, so getting the car as light as possible is key.

Make sure the wheels turn freely - the times may be very, very close between the better cars and the friction of the axles may decide who wins. Aerodynamics have little to do with a project like this as long as you didn't make your car a single block of wood. Can't do much better then what you have right now.
 

· Banned
Joined
·
6,492 Posts
I'm a gravity-powered vehicle specialist, but...

I don't have much experience with CO2 power, but when my son was in Cub Scouts they defused the too-much-help-from-dad problem in the Pine Wood Derby by having a Parents' category, which I, uh, won several times. Some of the challenges are directly opposite yours--we wanted to be right on the maximum weight, and you want to be as light as possible.
The free-rolling wheels the other post mentioned, though, are common to both, and critical. We were using stock Pine Wood kits, which are pretty crude, and I used to clamp the axles in an electric drill, spin them up and polish them with steel wool, then rotate the wheels in a drill and hit them lightly with very fine sandpaper so they were smooth and round. You could sometimes hear and see the difference in the way a car went down the track before and after smoothing the wheels. If you use a lube (some events don't allow it), it should be as light as possible to reduce drag, some really fine, thin oil in minimal amounts, a fraction of a drop at each wheel.
I don't know if heating the cartridge would do anything. Never tried it, but it just occurred to me that if you could heat it up about one degree short of blowing up and killing everybody in the room, you might get a boost. If it ain't against the rules, it's legal....
 

· Registered
Joined
·
160 Posts
If you can get it, graphite is a superior lubricant for this application. Colloidal (that just means really small pieces) graphite is best and you can find it at most auto parts stores. From your pictures I would say you may want to check your wheel alignment. It looks like your front wheels are pointing away from each other and that causes drag. Try to get them parallel if you can, and the smoothing and balancing, mentioned above, is a great idea. You might want to try minimizing your contact patch (sharpen the tires so there is less tire in contact with the road) while you are at it. Make sure you have the basics, a car that runs perfectly straight will beat a car that doesn't, the more aligned you wheels are the better, friction is bad bad bad. I wouldn't worry about aerodynamics as much as I would friction.

Good luck and let us know how you do.
 

· Registered
Joined
·
78 Posts
Discussion Starter · #6 ·
well the class did that last races today and mine got first :thumbsup: :D . with a 12OZ co2 cartridge it went 50' in .783 of a second (i think) :eek: . I took it with me to work and weight it and it came out to 1.9 OZ . :thumbsup:

well here is the pics of it done :D :eek:
 
1 - 6 of 6 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top