SpudFiles

i got an idea to make some projectiles from a bottle that you will pump with air (80 psi) and put it in a cannon (tube with on end closed) and then open a litle hole a the end of the projectile and the bottle will get out of the cannon. its juste a idea like that... i didint try it yet...

kinda like a pneumatic missle? Sounds like an interesting concept, but maybe if you could make it release the air somehow besides releasing it manually. Like if you could fire it out of a combustion gun, and have the heat make it release?
hint hint, nudge nudge

It's certainly a possibility, but preformance is rather limited by the low chamber volume/projectile mass ratio and the large amount of dead space you'd get around the neck of a standard bottle.

In other words, the bottle is heavy, small, won't give you very much pressure initialy. Such leads to low velocities.
(Ok, I was thinking glass bottels here for some reason. Plastic pottles arn't so heavy, and will get you much better velocities - although power will still be fairly low.)

Not to mention flow choking caused by the narrow mouth of said container, althoug that's not a big concern at the velocities we are expecting.

It might have some sort of nich application, though, where some aspect of that system would overcome the described disadvantages.
What did you have in mind?

There must be ways to combine water rockets with pneumatic cannons you know....

A bottle in the barrel, help back by a catch or something

Or maybe better... a waterfilled bottle over the barrel!! sealed against a rubber plug and held in place with one of those couplers that they use to change barrels quickly.( dunno the name right now)

I thought of this idea a few days ago, this always seems to happen to me. Those water rockets normally only work when pinted straight up, air alone won't shoot it very far.

they are called banjo cam lock couplings

You might be able to shoot a water rocket out of a cannon at any angle if you put a light weight piston between the water and the compresses air, therefor the air cannot pass the water and reduce thrust. With a barrel of around 2" or something like that you may be able to find some high strength material (Being a small diamiter) and may be able to pump to fairly high pressures to acheive some reasonable results. I was also thinking that you could attach some fins that could be bent to the side and then when the leave the barrel the will snap out and add some stability.

I know this topic is old but i made a projectile like this and it was pretty interesting. i got a coke bottle and i filled it 3/4 with water then caped it with a rubber stoper that had a small hole in the middle then pumped it to 60 psi and tied a string around the cork and put it in a rather large barrel that i had to make for my pneumatic cannon at the end of the barrel i put a scrw and tied the string that was attached to the cork so when it shot the pressure made the coke bottle detach from the stopper shooting it extremely fast and splashing, swirving all over the place. hope this answers your questions.

In the US, you aren't allowed to have pre-charged pneumatic ammunition.

And the problem is? Just kiding thanks for the info.

BC Pneumatics wrote:In the US, you aren't allowed to have pre-charged pneumatic ammunition.

since when? what about the 12 gram co2 cartriges?

co2 rocket?