Have you ever dropped a bear can on a rock or something? Well if not it shreds open, and thats with a fraction of the power in it(as liquids don't compress). Now if i can tell you one thing about you bottle for sure its that if it blows while in your hand it won't be a pretty sight, do you REALLY wa...

I think you guys are missing the boat. I never used the word perfect at all. And Sigg bottles are clearly not created to serve the purpose of launching a potato. But then again neither is ANY other material used in ANY potato cannon that ANY person on this forum has ever built. Soooo, o think it's ...

Well it would be the simplest semi automatic valve ever designed...

Do you think the inside of the spool housing could be built similar to a BV interior for sealing?

Well you can modify a BV to do that, making is one of the most efficient valves, but why simple if it can be hard too?

Think a BV sealing mech could be incorporated into a rotary valve?

Well, i don't know you, but nice to have you back on board. I'm trying my hand at semi mechanisms, have a look here

Well I was thinking that putting grease inbetween the gap between spool and spool housing would make it leak proof, this has apparently been confirmed by psycix. @poland spud; if I have a confined space for the grease to be in then if any air escapes the pressure of the grease rises, I would hope th...

machined to a millionth of an inch...thats out of question. Also what about the barrel port?

I wonder, if I had a closed mechanism up top, and an O-ring at the bottom of the spool, inside the casing, wouldn't that prevent the air from leaking out, and the grease from seaping out?

Would you mind elaborationg on your rotary valve idea?

Personally I would prefer to use an up-down valve, like poland_spud.

Anyone have opinions on the grease and tight parts idea?

A heavy cloth, with one loose side should do the tricky really...

I'd like to see someone film toilet paper being shot with a strong rubber band. If you do it hard enough you can get it to flare up and tear to tiny bits that go all over the place, much like confetti, fairly cool acctually.

From what I see here the only real constraint in using this type of valve is the sealing. It would be great if anyone here could supply numbers on how much pressure different types of lubricants can withstand in different gaps. (so weather thick grease can contain 200psi on a 0.05mm gap that is 1cm ...

Its a pitty the original desin would not work, but it seemed just a little too simple... I assume that with a VERY tight fitting spool and heavy grease i can surely get it to work. The question until what pressure is one left to be answered. Perhaps with very high pressure applications the entire sy...

I did not notice that, but it can be avoided, thoguh it makes the design more complex , which I wish to avoid. As for the speed, please consider the O-ring inside the ammunition compartment within the spool. The O-ring here prevents air to flow before the projectile clears the compartment fully, whi...

Its nice to know I'm not alone with my concept, as they say "great minds..." I'll spare you the rest. Now the sealing problem is a large one, though I assume the problem could some how be solved. Insomniac suggested I use a concept similar to that used in boats for sealing around the propellor shaft...