My one and only experience with a "potato cannon" came when I was living in the dorm. At the time we were allowed to take fruit out of the cafeteria (only thing allowed) for snacks later. One time when the fruit-du-jour was pears my roommate happened to have just completed his soda-can cannon. It was about 10 cans long. All but the first had their ends cut-out and they were held together axially with duct tape (or whatever the equivament was in those days). The first can was intact except for a small hole bored into the side near its bottom and taped into the series with the opening where the removable pull tab (remember those?) was facing inward. We'd put a few drops of ligher fluid into the small hole, drop the projectile in (aforementioned pear), aim it out the window, touch a match to that small hole, and >>ka-BOOOOOM !!! << the pear was launched with quite some force. From the 5th floor window and a 45 deg. trajectory we could cover the distance back to the dining hall which seemed to be a convenient target. Several shots were made until we finally managed to drop one through a skylight into the building. Good thing it was closed at the time! Last time they served pears, BTW...
