SpudFiles

Id like to put together a cannon to shoot nerf vertex rockets. primarily used to entertain the kids but id like to use it as a law rocket in paintball. 2" barrel ID iirc. I think ive got this figured out but i could use some help finding a qev and 3 way to fire this. Could someone point me in the right direction?

http://www.ebay.com/

Find as big a QEV as you can if you want good performance without resorting to high pressures.

im considering a 1/8" unit simply because its the right size fitting to make things super easier for me. would the pressure requirements be too great for the qev? would i have a hard time making 140fps?

heavyengineering wrote:im considering a 1/8" unit simply because its the right size fitting to make things super easier for me. would the pressure requirements be too great for the qev? would i have a hard time making 140fps?

Yes. An 1/8" QEV will be woefully inadequate. Size up and purchase bushings to connect with your other parts. Good luck

He's right you know. You would need an insane amount of pressure to get 140 fps from such a small valve, and having that jet of air from a tiny nozzle would probably shred the projectile anyway.

You should be looking into something like a 1.5" or 2" sprinkler valve, they can still be filled and piloted by three way valves.

heavyengineering wrote:Id like to put together a cannon to shoot nerf vertex rockets.

Here is one design you are welcome to use;
http://www.spudfiles.com/forums/asco-ne ... 17764.html

Here is another;
http://www.spudfiles.com/forums/comfy-c ... 11219.html

the sprinkler valves seem too big for a compact carryable design. is 1.5" the smallest practical size?

i can find 1/2" qev's easily enough, will that still be too small?

Here is a real nice one!

http://www.spudfiles.com/forums/my-m72a ... 19228.html

i like that one, unfortunately it runs off propane. ill be using regulated air from a paintball tank.

ive see rigs using 12 gram co2, some pipe and a ball valve work. is that because the pressure is so high?

my alternative is to buy something purpose built like this http://www.metadyneindustries.com/produ ... -launcher/

heavyengineering wrote:my alternative is to buy something purpose built like this http://www.metadyneindustries.com/produ ... -launcher/

Don't waste your money. You can achieve the same thing for much less by building one yourself. If you want the HPA paintball tank feature, just buy a secondary regulator and use it in conjunction with a QEV.

It's been I while since I've played paintball, but I believe HPA tanks output either 400 or 800 psi. You'll want to lower that closer to 100 and then have the ability to make smaller adjustments to keep your velocity safe.

so my local menards has rainbird 1" sprinkler valves on the shelf. i think im going to make something similar to this (thanks dewey)

what can i use to adapt 1/2" x14 bsp to npt? is there something on the shelf i missed?

1/2" bsp happens to be ..just about the same as the NPT-paintball size.

I can thread an aluminum 12gram quick change adapter into 1/2" bsp that is.
Tight fit, but it works.


I wouldn't recomment forking up the threads on your tank, but if you could find a male-female socket in npt you could sacrifice it and just thread it in.

That is, if you can't find a factory made adapter ofcourse...