When I was “younger” I saw a tennis ball cannon that had a 4’ piece of pipe with legs holding one end up off the ground about a foot. That end was also pinched so that the tennis ball couldn’t fit through it. Underneath this an M-80 was lit sending the tennis ball flying. However, I decided that it was very inefficient, so I set out to improve the design. I worked at a muffler shop and I took an 18” piece of 2.5” pipe, opened one end up so that a tennis ball would fit snuggly in it, welded legs on the other end and made a plug-in breach that would hold the M-80. The breach was sealed with a large rubber O-ring, held in with a pin and had a small hole for the fuse. In short nearly all the explosive force from the M-80 went up and out where the tennis ball was. The first time I fired it I was at my old elementary school’s open field and I thought the tennis ball disintegrated because long after the thing went off there was no sign of it. However, a little over 15 seconds later the tennis ball finally came back down. I was planning on making a golf ball version knowing that golf balls store much more energy than a tennis ball does and it’s much more aerodynamic, so it should travel much further. But first, we decided to see what would happen if we tilted the cannon on its side and pointed it at the brick wall of the school. Ok, side note, I was younger and a lot dumber back then. The field was 50 yards wide, we were at the center with the cannon pointed at the wall (25 yards away). In the opposite direction was an undeveloped property with a bunch of trees. When the shot went off we could hear the tennis ball ricocheting off the trees across the street which means the tennis ball travelled approximately 85 yards in less than a second (or over 170mph) and when we went and looked at the brick wall there was a 3” wide 1” deep divot in it. At that moment I decided that I didn’t want to accidently shoot down an airplane, so the golf ball version was out.
Yes, the stupid **** we did, I’m lucky to still be here.
P.S. My rough math (and I mean very rough math) tells me that the Tennis ball went as high as 1000’