I am in the process of helping my son design a sort of model of the Bloodhound SSC car for his school project, using balsa wood, model aircraft wheels, etc... It doesn't have to a like of like, but vaguely resemblant so that you can tell what it is just by looking at it. It would also be nice if the car could move and I was thinking of using on this small CO2 gas canisters as a means of propulsion:
You can get some which are threaded, as above, or some which are just plain. What I haven't been able to find is a way to quickly release the pressure from the canister to propel the car. Are there any small on/off manual valves that would fit this type of gas canister? I haven't been able to find any, the only ones apparently in existence are for fitting onto bike tyres to (re)inflate them.
The only method I have come across is people using some sort of puncturing device (e.g. with a nail) that is generally sprung-loaded to pierce the gas canister when launching the model car. This puncturing device can be made part of the car, but more generally tends to be part of the "launching pad" as it adds weight and unnecessary complexity to the car. I would like to avoid this if I can.