CO2 Dragster... HELP

[blondiechick]

I am in an Auto Cad Class and our current project is to build a CO2 Dragster out of ballsa wood(sp?) . I was wondering which would be the best type of design to win =) ... if anyone has any pointers it'd be greatly appruciated

THANX

[white97ex]

give us some specs. what weight limits, material restrictions. just post all the rules.

[gasman03]

ahh, CO2 cars, that takes me back,

first off, make it sturdy, and strong, I was able to finish third in my class becouse everyone's car I ran against broke before the finish. and your also gonna want to put alot of weight near the C02 bottle, helps the rear wheels with traction, becouse odds are the front wheels will never touch the ground

[DSM-Mark]

Originally Posted by gasman03

ahh, CO2 cars, that takes me back,

first off, make it sturdy, and strong, I was able to finish third in my class becouse everyone's car I ran against broke before the finish. and your also gonna want to put alot of weight near the C02 bottle, helps the rear wheels with traction, becouse odds are the front wheels will never touch the ground

Actually, since the rear wheels really provide no motivation force for the car, you really don't need any weight over them.

These cars are a balance of weight vs. aerodynamics vs. strength. And skill in crafting them is also important.

When I built mine, the rules specified a height, a minimum thickness and width and also various specs for other things. Mine was an arrowhead design in the front, which rapidly became a 1 cm diameter neck after the front axle that was about 4" long (for length requirements) then bubbled out to accommodate a CO2 cartridge. A single fin on the top brought my total height to the requirement.

A couple of tips to score better:
1: make sure your axles are well lubed. The C02 runs out halfway down the track, and it's a coast from there. Besides, friction = bad.
2: Think very carefully about paint. Your instructor might tell you to paint the car, but it really adds a lot of weight. Haha, funny right? Nope. Consider that the balsa you use is incredibly light. Paint is not so light. I remember we coated ours with a primer sealer, then a body colour (sometimes 2 or 3). As i recall, some people ended up with about a 25% increase in weight. Just go au naturel. no paint. You'll probably do better without it.

[SLAYTANIC_1134]

I think dsm - mark has hit it right on the nose. Friction is going to be a big factor along w/ reliability. I think if you concentrate on those two things you will have a real winner. Make sure you let us know how it goes! Good Luck!!

[JDM Wagon]

i just did an internet search for CO2 dragsters and there is a lot of info out there. it appears that the rail design is the best. that is where the wheels are tucked under the body of the car.

as far as axles go, i see a lot of these so called nitro axles for pinewood derby cars that will probably work with a co2 dragster.

[blondiechick]

We are given a kit. So the balsa wood is mandatory.
Body length -
min=200mm max=305

Body height w/ wheels -
Max=75mm

Body mass (completes car w/o CO2)-
min = 60g

Body width at axles, from and back -
min=35mm max=42mm

Vehicle total width(including wheels)
max=90mm

Thanks for your help. If you want any other restrictions let me know

[parts]

It's been 20+ years since I built one.

A few tips:
Place the wheels on an axle and chuck it up in the drill press. Then use sandpaper or a file to make the wheels round. Most of the kit wheels will have a high spot.

Then chuck the axles up and use very fine sandpaper and later steel wool to polish the axles to almost a mirror finish.

As for the body, a teacher in college had a computer designed body. It was just a rail design except for where the rear axle was placed. The axle was placed forward enough that when an full CO2 bottle is place in it the tail would go down (do a wheelie). Place an empty CO2 bottle in and it would set level. His car took state that year.

[blondiechick]

Thanks for the tips