On our
t-shirt cannon, we are using a 1" NPT MAC Solenoid Valve at ~17.0 cV Flow Capacity with a 23 ms Response Time. The valve is connected to the barrel with a 1" NPT steel-braided hose. The high flow rate and reponse time is really what makes the cannon work great. We are actually able to vary the amount of time we open the valve from ~25ms to ~80ms to change the distance the shirt is launched.
http://team254.com/media/photos/imag...pe=img&id=4589
We store our air in a large scuba tank at ~3000 psi. This air is regulated down into a secondary scuba tank which holds air at about 150psi, our shooting pressure. Once pressurized at a dive shop, we can get more than 200 shots before the high-pressure tank needs refilling.