SpudFiles

I don't know if this counts as a "pneumatic cannon" but it's pretty darn close. I haven't seen any other bottle rocket launchers on spudfiles (although maybe there are some), so I figured I should post it.

I got the idea from http://www.sciencetoymaker.org. In fact its nearly an exact copy minus the length and male and female adapter.

Basically, the bottle is pressed against a rim (made by heating the pvc) and creates a seal. It is held there by having zip-ties lock around the neck of the bottle and a piece of 1.5" sch. 40 pvc is lid up preventing the zipties from pushing out. the zip-ties are held onto the 1/2" "barrel" with hose clamps. More detail and constructing instructions and videos can be found on the website. I have nothing to do with the website. I just thought it would be pretty fun to build and shoot.

[youtube][/youtube]

Nice work and pretty sweet website, I used to love those sort of things as a child and parents should encourage their offspring to partake in such projects.

Have a look at a slightly more sophisticated version by labtec using a commercially purchased quick connect:

Have a look at a slightly more sophisticated version by labtec using a commercially purchased quick connect:

Heh thanks, just wanted to link to that one


How high can you take the pressure before the zip-ties fail?
The design is pretty appealing to me, because there's no need to mod bottle caps to fit the quick-connect fitting.

Seems like a fun project for the summer hehe

Labtecpower wrote:Heh thanks, just wanted to link to that one

The brain chip I implanted in that piston I made for you is working well

Ah, that must be the cause.
It's still standing on a shelf above my bed, the honed steel pipe I wanted to use for the QDV was nicked at school.. I may use it for a future piston hybrid tough

I've pressurized it up to 150 psi and the only trouble I've ever had was that I needed another hose lamp because one wasn't enough. There's really too many zip ties for anything to go wrong.

Nice idea...a homemade zip-tie quick connect...hmm..

I immediately started fantasising about a 12gram CO2 bulb version...
With something to punch a hole bigger than the standard nail..

anyway...back in '87...when I made my handheld bottle-zooka..
I used a steel clamp made from a coathanger...
This is much better.

I could see some simple improvements like having the inner barrel touch the bottom of the bottle.
Another would be to use a pipesize that fits the inner bottleneck as close as possible.( if that isn't the case already)

Also...during my experiments I found that a smaller "jet" gives significantly longer flight time.

Perhaps a bottlecap with a smaller hole could be used with some adaptation to the QD...?

I know I'll have work to do this summer..

I used the quick-disconnect garden coupling as a nozzle for the water rockets, indeed gave a longer flight time

I used a ( heavy) steel QD for pneumatic use.
Worked fine dispite the added weight...

You can't use a bottle cap with this design because then you couldnt put it onto the PVC. And the 1/2" sch. 40 is probably the closest there is. If you put some soap, or even sunblock on it, there's practically no friction while shooting.

And the barrel should be longer. This gun was designed for smaller bottles. I had one for a 2 liter bottle (and boy did it have a recoil) but that one has since been thrown out due to a tragic accident involving a pickup truck in motion, hard tires, and a lot of Broken PVC

acs2997 wrote:I don't know if this counts as a "pneumatic cannon" but it's pretty darn close.

Make it combustion.

I was actually just drawing out a way to make it a hybrid
I was thinking I could add propane, pressurize it, then have an electric connection that set off a stun gun with wires going inside the barrel and out towards the muzzle at the same time I pulled back the release. Maybe a little risky, but if I could get it to work, I could get coke bottles into orbit