SpudFiles

Hi guys, I dont know how many of you are familiar with co2 cars, but I will explain how they work. A small 8g co2 cartridge goes in the hole in the back, and they are set side by side on a race track. A small needle electronically punctures the back of the cartridge, and they race down the 65 ft. track at around 1 sec. My car isnt finished, but I thought I would show it to you anyway. It obviously needs wheels and paint, expect to see them within a week. This is for a Power and Transportation Tech class. I also plan to install brass bushings and axles.

Very cool. What are you using to open the cartridge? Your car has a "cool futuristic" look to it.

Very slick, i'm guessing the final result will be sealed, painted and wax polished for that few extra feet per second what wheels will you be using?

By "opening" the cartridge, you mean to propel the car in a race? That is described in my first post, it is some sort of electronic puncturing needle.

EDIT: Jack slipped in a post as I was typing. Yes the car will be sanded with 600 grit, painted, and clear coated. The front wheels are going to be standard PITSCO wheels and the back wheels will be PITSCO GT-R wheels, I dont know if you are familiar with them, you will see them in about a week anyway.

Sweet, but they look a bit wide for speed...

They ar actually the minimum allowed by the regulations in width, and the lip on the rear of the car covers about half of them to reduce drag.

right, I didn't realised width was limited by regulations.

Yeah i got a whole packet of 'em, these things arent as easy as they look.

i made a few of these. mine looked nothing like this though. i went for as light as possible and barely passed regulations.

ive actually made one or two of those the best design is the tear shape design. and another tip after you paint it give it a rub down with steel wool it makes it faster.

I sagest NOT useing brass as a bushing, a steel axle will cut into it and bind up slowing it down. Bronze would work better, steel would be best. A lite coat of WD-40 on the axle and it will roll freely! Are you allowed a wing? Looking good so far!

Here's a few tips I can give you, having made these cars myself:
1.The lightest car will usually win. This is something that almost always happens.
You should drill out as much of the bottom as you possibly can.

2.If your launching platform has a "tree" setup, practice improving your reaction time in the days before the race.

3. Graphite may work better than oil/grease as a lubricant. Figure out which works better for you.

4.Get the co2 cartidge as hot as possible.
Rub it on your jeans, put it in your mouth, do anything you can. Just heat the sucker up!

Thanks for the tips everyone!

jrrdw: As stated in the top post I am using brass bushings and axles. A component of brass is lead, which means that it is self lubricating, or at least that is what I have read:

When used together, brass axles and bushings provide ultralow rolling friction for faster runs.

From the Pitsco site. I was wondering, should I still use graphite?

_Fnord: I realized your first tip last year, and I will make sure my car weighs exactly 60 grams, the minimum.

Also, I never thought of making the cartridge hotter, I assume this increases the pressure? Thanks again for the tips.

Gee, this contest has a lot of regulations...

In our tech class contest, we didn't have any at all. We could even use different sizes of CO2 cylinders. I came in second by using a 12 gram cartridge and a car that looked quite a bit like a dragster. Nowhere near as good as your's though.

I have no idea of the burst pressure of one of those 8 gram cartridges, but if you could insulate the compartment on the car that holds it, and then quickly heat up the cartridge with a lighter or something, you could probably gain a noticeable advantage.

How long is the course that you're using?

Im not sure of the exact distance, but I know it is around 65 feet. Your insulation idea is a good one, but unfortunately not legal. The regulations are crazy, I think they are the official TSA* regulations. Every single dimension, down to the 1/64" of an inch in some cases. Mess one thing up, and your disqualified.

*TSA = Technology Student Association, of which I am a proud member!
http://www.tsaweb.org/

Also, I have been asked 3 questions so far about things that I answered in my first post. I dont know if people arent seeing it or what, but there is a small paragraph above the pictures.