What is the optimum amount of rubbing alcohol for explosions?
I am working on a mini-cannon based project. The cannon has a chamber with interior volume of 15.2 cubic inches. For propellant I am using rubbing alcohol (isopropyl alcohol) that is electronically ignited. The barrel on this gun is about 2 feet of 6mm tubing, designed to shoot Airsoft BBs. I was wondering if anyone knows what the ideal amount of rubbing alcohol to use was (I am using 70% alcohol now, but i can get at least 90% at the store). I could also possibly use butane or propane, if that is better. I went on the internet and looked up the stoichiometric ratio for isopropyl alcohol, but that just told me "1mol fuel to 4.5 mol oxygen at 100 percent concentration." I am not mathematically or scientifically capable of turning that bit of info into a usable amount.