Local residents narrowly avoid cannonball.
- mark 12-07-2011 7:19 pm

oops! ryley wants to know how he can get a job for myth busters.
- linda 12-08-2011 2:28 am [add a comment]

Does he want my blueprints for a tennis ball cannon?
- mark 12-08-2011 7:17 am [add a comment]

Here's a career tip for Ryley: destructive testing is actually a real job.
- mark 12-08-2011 7:19 am [add a comment]

And for a smaller version, don't forget the marble cannon. Dangerous, fun, ill-advised, perfect for the kid in all of us.
- jimlouis 12-08-2011 2:26 pm [add a comment]

yes, mark, he does. for tree house intruders.
- linda 12-08-2011 3:20 pm [add a comment]

Let's see.

The barrel of the cannon is a tennis ball can. (I don't know if there is such a thing anymore.) Remove most of the bottom, but leave enough of a ring to support the tennis ball. The fit of the ball in the barrel should be snug to avoid allowing pressure to escape around the ball. The fit of the ball to the hole in the bottom should minimize gaps to allow pressure to build in the combustion chamber.

Graft a soda can to the bottom. That's the combustion chamber. The top should be open to the "barrel". A small hole in the side is for injecting the fuel and ignition. We used lighter fluid.

Insert tennis ball fully into barrel. It forms the top seal to the combustion chamber. Squirt a little fuel into the chamber via the ignition hole. Let it evaporate inside the chamber to create an air fuel mixture. Put a lighter or spark --- wait, wait, wait --- POINT THE CANNON IN A SAFE DIRECTION, ->then<- put a lighter or spark to the ignition hole.

Foom! Watch ball.

Typically we would aim at a 45 degree angle for maximum distance. I think we got 30 yards with a good shot. Bloopers were shorter. Repeat with different fuel loads to determine optimal amount of fuel to inject.

(Don't do this during fire season, as it's possible to send a flaming tennis ball through the air if the combustion chamber is running too rich. Aiming this at someone is a very bad idea, as the velocity can be pretty high.)
- mark 12-08-2011 10:53 pm [add a comment]

  • My imagining of Ryley reading this post:

    "blah blah blah blah blah blah it's possible to send a flaming tennis ball through the air blah blah blah"
    - jim 12-08-2011 11:20 pm [add a comment]

  • i didnt make it beyond "combustion chamber".
    - dave 12-08-2011 11:23 pm [add a comment]

jim, totally. weeeelllll, i think i'll leave this little project for big indian 2012 so that we don't get evicted from our happy little commune here. and what's the marble one, jim l?
- linda 12-09-2011 1:58 am [add a comment]

Same concept. But firecracker for charge. Secure 8 inch long section of galvanized pipe to block of wood, both ends extending out over block a bit. One end of pipe should be threaded and fit with threaded cap. Marble should fit inside pipe snugly. That will make it probably three quarter inch diameter pipe. The non threaded cut end should be sanded well along edges to de-burr it, that is remove rough edges. Some logical distance from threaded end, drill small hole. The hole is for the firecracker fuse to fit through and should be small as possible. You will then remove threaded cap, insert firecracker inside pipe and feed fuse through hole so it sticks out (not always easily accomplished). Screw cap back and gently roll marble into pipe so it rests against butt end of firecracker which if possible is facing towards open end of pipe. Light fuse. The marble will fairly easily go 200 feet or so, at what should be considered a dangerous velocity. Alternately, you can just put loose gunpowder in pipe, feed fuse from outside into drilled hole, stuff some wadding down pipe up against gunpowder, insert marble and light fuse, but this marble will go much farther, faster, and I highly don't recommend it. Anyway, this is what I've heard. I myself would never ever, and reading over this I think it sounds pretty stupid and no sane person should play with fire, fuses or gunpowder.
- jimlouis 12-09-2011 4:44 pm [add a comment]

  • carbon welded black seamless pipe is less toxic & holds up better than galvanized in the long run; black powder, muzzleload, no hole, long fuse, any fodder will do, the sky is the limit old well casing is perfect for bowling balls; the finger holes will emit the most lovely skirl you have ever heard, like some little round angel whistling through the Big Sky on the 4th of July
    - anonymous (guest) 12-15-2011 4:50 pm [add a comment] [edit]

hello nsa.
- dave 12-09-2011 4:50 pm [add a comment]

Jeez, is this what boys do? It's a wonder you all are still alive!
- linda 12-09-2011 6:37 pm [add a comment]

  • 'scuse me; but most of us aren't. Why the hell do you think smart parents choose MINECRAFT tm
    - anonymous (guest) 12-15-2011 4:53 pm [add a comment] [edit]

That's one baby step away from a pipe bomb. A co-worker has stories from growing up in Spokane playing with explosives. He got caught setting one off in an empty lot. It was treated as "boys will be boys, but don't let me catch you again." Nowadays, ATF, FBI, Gitmo.

I tried making old fashioned gunpowder as a kid. (Guns don't use that anymore. Modern "smokeless" is high explosives in small quantities.) I never got past sulfurous stinky smoke. But that was fun in it's own way.
- mark 12-10-2011 9:46 pm [add a comment]

We made smoke bombs by mixing saltpeter and sugar.
- alex 12-10-2011 10:06 pm [add a comment]

Beer can mortar here (PDF)
- bill 12-12-2011 1:20 pm [add a comment]

I'm not even gonna look.
- linda 12-12-2011 8:22 pm [add a comment]

Link not working.
- mark 12-13-2011 7:43 am [add a comment]

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