"I've made some nice home-made cannons myself. Propane and a coleman lantern lighter plus an ability to clear out all the gasses from the last shot and get fresh air in for a proper stoichiometric mix are key."
Absolutely... noting that the young test pilots here, being the geeks that they are, as well as being firearms nuts, built up a tennis ball cannon with one each of the disposable oxygen cylinders and disposable mapp gas cylinders used for the cheap two-gas welding kit strapped to the bottom of the barrel, with a homebuild PIC microprocesser controller opening and closing miniature solenoid valves to get the correct purge and fill cycle for the fuel/oxygen mix. They rammed the projectile, then hit the "arm" button. That opened a vent solenoid to atmosphere and then opened the oxygen solenoid for a purge and fill with 02, then the oxygen and vent solenoids closed and the propellent gas solenoid opened for a short period, then a red light came on marked "ready to fire". It was a remarkable accurate thing.
Anything worth doing is worth doing well.. ;-)
I probobly ought to note that this was an ajunct to their electric RC airplane "combat rules" air to air combat hobby, and formed the anti-aircraft ground defense network for the noonday sport of full contact air to air RC airplane clombat flying.
Nice tip on using ice as the projectile though. Low coefficient of friction, cheap, and repeatable. Well done! I'll pass it on.
Willie
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