Co2 Car help.

[rap129]

Hey guys, in my school we just started a new semester and I now have Technology Education (wood shop) Right now we are getting ready to make Co2 cars and I need some help. I was hoping you guys could give me some tips on how the car should be shaped for the best aero dynamics. My teacher said to search the internet for information and tips to help us with the design process. Couldn't think of a better place to ask! Basically we get a Bass wood blank and make the car out of it. Heres some information and rules for the project. Thanks guys!

-The track is 20 meters long
-Car must have a mass between 70 and 170 grams
-Must have a length between 180mm and 250mm
-Cant be taller then 90mm
-No wider then 80mm
-8mm of clearance off the track
-Must have 4 wheels and 2 axles
-Axles must go through the body of the car
-Co2 cartridge must be encased in 3mm of solid wood and hole depth must be 51mm+/- 1mm
-Height of Co2 cartridge must be from 33mm and 43 mm (floor to center of the hole)
-Must be able to withstand several races.

The tires will be provided and if I have any questions about tire choice ill be sure to ask. If any additional information is given ill post it and let everyone know. Thanks everyone and hope to get some good ideas!!

 

[Beeblebrox237]

I made one of these a few years ago. Bottom line: aerodynamics really don't matter, just make it as light as possible.

 

[rap129]

I made one of these a few years ago. Bottom line: aerodynamics really don't matter, just make it as light as possible.

Thanks! He said that a few times and ill try to get it as light as possible. 👍

 

[Durp13579]

I made one of these a few years ago. Bottom line: aerodynamics really don't matter, just make it as light as possible.

Don't use balsa wood! It has way to many problems withe the co2 tank in it. Unless you can use a 3d printer. Then it will be simple to do. Also, make sure you keep the edges alike. Don't do it in a cast . Ummm... Use a saw, and make sure you align everything.

 

[Grayfox]

It is about thrust, weight and aerodynamics.

A block of wood will still travel but the larger surface area of the face will slow to down quickly as well as add air resistance.

More weight means more energy to move vehicle with X amount of fuel-this car wont travel far but will have better stability.

Less weight means less energy to move vehicle with X amount of fuel-this car will travel farther but will have less stability.

Look at some solar car designs if you want to add aerodynamics

 

[rap129]

Awesome!! Thanks so much for the tips guys!

 

[Slash]

I did this a few years ago as well. Make it as light as you can. That's the key.

 

[Durp13579]

I did this a few years ago as well. Make it as light as you can. That's the key.

Put some weight in the front though, or else it will wheelie down the track.

 

[Slash]

Put some weight in the front though, or else it will wheelie down the track.

Yeah but over all you don't want it to weigh a lot. If I still had some of the ones I did years ago I'd do a test with these requirements and see just how fast I could get it.

 

[cgg]

I would get a really cheap 1/24 slot car, and use that body, wheels etc. Chassis should literally be like this. Light yet strong. Forget the motor and guide though.

 

[Durp13579]

I would get a really cheap 1/24 slot car, and use that body, wheels etc. Chassis should literally be like this. Light yet strong. Forget the motor and guide though.

Wood cars though.

 

[Slash]

Wheelie bar is definitely a must

 

[Beeblebrox237]

...Basically we get a Bass wood blank and make the car out of it.

-Co2 cartridge must be encased in 3mm of solid wood and hole depth must be 51mm+/- 1mm

I would get a really cheap 1/24 slot car, and use that body, wheels etc. Chassis should literally be like this. Light yet strong. Forget the motor and guide though.

 

[cgg]

Wooden Dowel. It's the same principle, just a different material. If you need to just reinforce the beams, just put cross beams on.

 

[Slash]

It doesn't say the entire car has to be made of wood. You could take that chassis and put a wood block on the rear with the C02 cartride in it.

You get a blank, and technically, you did use the amount of wood it asked. I see nowhere in the regulations that the entire vehicle has to be made of wood. They just provide something for you to start with.


That said, are you only allowed one blank? I would take it home and get the measurements and make more for you to perform trial and error tests and pick up tires/axles at a store somewhere. That way you are pretty much guaranteed to win.

 

[cgg]

That's what I initially thought Slash that's why I picked that design. It is made out of piano wire 0063" I think. It's strong stuff. If it needs to be stronger, put two beams soldered together on each side, before you do anything else.

 

[Beeblebrox237]

It doesn't say the entire car has to be made of wood. You could take that chassis and put a wood block on the rear with the C02 cartride in it.

You get a blank, and technically, you did use the amount of wood it asked. I see nowhere in the regulations that the entire vehicle has to be made of wood. They just provide something for you to start with.


That said, are you only allowed one blank? I would take it home and get the measurements and make more for you to perform trial and error tests and pick up tires/axles at a store somewhere. That way you are pretty much guaranteed to win.

Sounds like more trouble than it's worth, especially if you can just build the lightest car possible.

 

[cgg]

Just do what I said and you'll be bound to win. Can you use bearings or do you just have to put the axles straight through a drilled hole? If you can, these will be the best things for you. Only cost around $1 for a pair.

 

[Slash]

Sounds like more trouble than it's worth, especially if you can just build the lightest car possible.

It depends on how bad he really wants to win this. If its just for fun, go for your objective. If he really wants to win, well follow our instruction haha.

Just do what I said and you'll be bound to win. Can you use bearings or do you just have to put the axles straight through a drilled hole? If you can, these will be the best things for you. Only cost around $1 for a pair.

This combined with what I said will really help.

 

[cgg]

Slot car parts will be your best friend for this semester. Cheap parts that will really benefit your car.

 

[Slash]

How much time do you actually have to work on this?

 

[rap129]

I have the option to buy another wood block if needed and were getting ready to design it on the computer. Then we make a Styrofoam model and put it in a wind tunnel. Id like to win, but overall its for fun. He said several times lighter is better but I had a feeling there is a point where not enough weight could be a problem. He never said theres a rule of adding different parts. Thanks again guys for all the tips

 

[Beeblebrox237]

So you are aware, when I did mine, the top three cars were the three lightest, in that order, and the winner wieghed 60-some grams IIRC, so your minimum weight of 70 grams would be a good target. Sounds like great fun to put a syrofoam model in a wind tunnel! Good luck, and most of all, have fun!

 

[cgg]

Long thin and pointy. Make it like a land speed recondvcar, with the CO2 bottle where the jet engine would be.

 

[Slash]

I have the option to buy another wood block if needed and were getting ready to design it on the computer. Then we make a Styrofoam model and put it in a wind tunnel. Id like to win, but overall its for fun. He said several times lighter is better but I had a feeling there is a point where not enough weight could be a problem. He never said theres a rule of adding different parts. Thanks again guys for all the tips

Well I hope you keep us updated and I hope you win. Good luck.

 

[Bopop4]

You won't need a wheelie bar, it's pushing from the back, so it can't wheelie unless you put the CO2 cartridge on an angle.

 

[Durp13579]

You won't need a wheelie bar, it's pushing from the back, so it can't wheelie unless you put the CO2 cartridge on an angle.

If it is super light on the front, the co2 tank will weight the car down, and at the speeds they get, it will wheelie.

 

[Bopop4]

If it stays down when it's stopped, then it will stay down at speed.
Especially since they are guided on a wire.

 

[Slash]

Who said they were on a guided wire?

 

[Beeblebrox237]

Typically there are two eyehooks that go on the bottom of the car and go on a fishing line to keep the car from veering off the track and hitting somebody. Schools tend to avoid hitting people with rocket powered cars .