With great risk to my self and the neighbors I finally got up the nerve to test fire my Tennis ball Mortar. As you probably have read, most predicted (very nearly correct) that I would probably maim my self as well as likely kill my grandchildren with it. For those of you who have not read the original post, this is made from a Medical oxygen tank with a powder chamber meeting the standards listed in the Safe construction and loading sticky. The powder chamber has a volume of about .257 Cubic inch. I bedded all the joints and threads with JB weld. Being that the first shot would be the proof load, I loaded the powder chamber to the top plus a little, then dropped the tennis ball down to cover it all up. Then (just to make sure) I put another tennis ball on top of the first one, an overflowing powder charge and double projectile load! For a blast shield, I used two steel belted radial tires stacked on top of each other with the Mortar in the middle pointing straight up, I didn’t want to drop the balls on neighbors three blocks away, lucky it is close to the 4th Of July, so big bangs are mostly ignored around here. I cut an extra 6 inches of fuse so I could get to the Basement before the thing fired, I did set up a mirror so I could look at the event from a casement window while protected from any direct shrapnel path in the event of a total failure. Pictures below:
Well, I lit the fuse and ran really fast after first leaving a note telling my wife I loved her and hoped this would work out well but was sorry if I my math was a little off and I destroyed the south half of the house, but confidence was high! I watched carefully as the fuse burned close to the housing, it seemed to take forever for it to get to the powder chamber, I then started hoping that the gas meter reader would not choose this time to read the meter which was just around the corner of the house. I was in luck; no one opened the gate before the fuse entered the body of the powder chamber. It just hung there for a second, and then it happened! A tiny spurt of flame from the fuse hole, then a big puff of white smoke from the Mortar mouth, the two Tennis Balls rose nearly 9 feet, yes! Nine feet in the air, I was amazed, the house was still in one piece and I had all my fingers and both eyes!
The moral of the story is this: The design just doesn’t work, you can throw a tennis ball further than you can shoot one with this machine, and the noise it makes is not quite as loud as closing a bathroom door.
Larry
