Coaxial Cannon Question.

[Mitchza89]

Hey guys hows it going.

I've made 6 or so cannons so I know a little about what I've worked with but I've never made a Coaxial. I've got the raw materials. I have a:

1m long 15mm barrel.
1m long 32mm chamber.
25mm modded sprinker valve.
Heavily modded blowgun.
Hot glue piston.

I just don't know what the power is gonna be like or what to expect....

If anyone can gimme' some info, it'll be greatly appreciated.

Thanks alot,

Mitch.

[jackssmirkingrevenge]

With those specs, performance can best be described as "fearsome" - keep the space between the back end of the piston and the inside of the chamber to 4mm (a piston only needs to move back 1/4th of the barrel diameter for maximum flow, anything more than that is simply wasted space) for maximum efficiency and you'll have a winner. If you manage to do the above I would say that the blowgun alone would be sufficient to pilot the valve - hell, even a schrader would do. I used the latter succesfully to pilot the 26mm piston in this project - the specs are vaguely similar so you have an indication of what performance will be like.

[Mitchza89]

Thank you so much for that Jack. Thats unreal. I'm only gonna use about 120psi though, I hope it should be enough. What psi are you using in yours? I'm drooling over your cannon's vids now haha.

All the best mate,

Mitcho.

[jackssmirkingrevenge]

All those vids were done at 110 psi, that's the best my compressor can manage. Glad to have been of help/inspiration

[Mitchza89]

Ah wow I should be able to expect some good results then haha. I've never seen a Coaxial like yours. It's like.....a T Valve crossed with a Coax It must have been a b1tch to get everything to seal up well. How did ya go about that?

Mitcho.

[jackssmirkingrevenge]

Lots of epoxy, patience, and hardcore anglo-saxon blasphemy. It would have been easier to make it a co-axial but I wanted to maximise chamber volume.

[Mitchza89]

Yeah thats what I was worried about. I'm thinking that I just don't have enough air. I'd love to think my new cannon will be "fearsome" but I just have a bad feeling.... I'll just have to wait and see. So what other cannons have ya made?

Mitcho.

[jackssmirkingrevenge]

Yeah thats what I was worried about. I'm thinking that I just don't have enough air.

Don't worry, punched in some numbers and since your chamber is longer, you actually have the same chamber volume with a coaxial design, slightly bigger actually

Some other designs of mine:

http://www.spudfiles.com/forums/vortex- ... -t166.html

http://www.spudfiles.com/forums/the-bea ... t7457.html

http://www.spudfiles.com/forums/cartrid ... t7176.html

http://www.spudfiles.com/forums/6mm-cro ... t7946.html

http://www.spudfiles.com/forums/pneumat ... t7858.html

http://www.spudfiles.com/forums/files/hvbb_681.jpg

http://www.spudfiles.com/forums/files/t ... ia_157.jpg

[super spuder]

jackssmirkingrevenge since you seem to know alot about co-axials, if i had a 3 inch diameter chamber, what size should the barrel be?i want the barrel to be just a bit longer than the chamber like 3 inches or so ,sorry Mitchza89 to be taking over your topic ,but i dont want to start a new one just to ask this question.

[jackssmirkingrevenge]

I'd say it can afford to be a 2 inch barrel, though 1.5 inches would probably be optimal.

[super spuder]

ok, thanks, 1.5 it is

[Mitchza89]

Haha no worries at all super spuder. So by the sounds of it, you need roughly a 2:1 ratio with the chamber n barrel. I was gonna go 25mm for the chamber but I just thought it would be a bit too small. so I went with for the 32mm. I reckon this will be my best cannon to date. I'm gonna put a decent stock of the back of the Sprinker Valve, paint it totally black and maybe make a Bi-pod but I'll see how I go with my money left over.

By the way Jack, those are some amazing cannons/air soft guns you have there. I'm amazed! haha.

Have either of you guys got any projects ahead?

Mitcho.

[noob of noobs]

About how long would you recomend making coaxials such as the 1.5" barell and 3" chamber?

P.S. By the way, Jackssmirkingrevenge, nice work! Those guns are amazing!