Tripple Barrel launcher

[n2extreme1]

Hello everyone. This is my 1st post. I have been trolling for a bit and trying to get a better understanding on launchers. I plan on making a 3 barrel cart mounted launcher. I want to use 2in barrels. I will be using 1in sprinkler valves electronicaly fired. The cannon will be firing nerf vortex rockets and I want to be able to get about 250fps out of it. My questions are can I use 1 chamber to power all 3 barrels? What size and diameter chamber do I need. The chamber will be feed by a compressed paintball tank regulated of course. Also are 3ft barrels long enough or should I gl larger? Thanks everyone for your help in advance.

[jackssmirkingrevenge]

Do you want to fire the barrel at once or sequentially?

[n2extreme1]

I want to fire them 1 at a time.

[cannon monkey]

if your firing them one at a time just make one chamber for each barrel make it easyer

[n2extreme1]

Ok thanks. I thought so but wanted to double check. Now as for barrel length and chamber diameter and size. What is needed in order to get roughly 250 fps from a nerf vortex rocket?

[jackssmirkingrevenge]

I suggest you download Gas Gun Design Tool and play around with the parameters to get your ideal performance.

[n2extreme1]

Great thanks. Now if only there wasn't a block at work and I could view the site

[n2extreme1]

Im unable to view the file for whatever reason. Would someone be willing to input the information and see what they come up with for me? Im not sure what information you need. 1in unmodified sprinkler valve. Max pressure 125 psi. Firing nerf vortex rocket from a 2in pipe. Looking to see what size chamber and barrel length I need. Thanks for the help guys!

[dewey-1]

Using a 2 inch diameter chamber at 12 inches long and 30 inch barrel at 2 inch diameter with 100 psi and 30 gram Nerf Pocket Vortex will give about 252 fps muzzle velocity and 285 foot range at 32 degree elevation.

Hope this helps. This is based on pneumatic piloting.

Using the solenoid for operation is not recommend due to very poor performance. Do the valve modification, you will notice a great performance increase over stock/unmodified!

[Brian the brain]

As this is supposed to be cart mounted, I say get quick exhaust valves or modified sprinkler valves and pilot them using unmodified sprinklers.
This would be easiest to fire while driving.

Not only would it be simpler to use a seperate chamber for each barrel, it would be a stronger design when it comes to shaking about on a go-kart.

[n2extreme1]

Thanks for the input guys. I was hoping to get a better range than 285 ft. Somewhere around double that actually. Will a longer barrel or larger chamber help with the desired range and still keep it under 250 fps? Or am I going to have to go another route such as modify the sprinkler valve and or use a qev? Im trying to build this on a budget and am trying to figure out my best options.
Thanks.

[jackssmirkingrevenge]

Will a longer barrel or larger chamber help with the desired range and still keep it under 250 fps?

Range is directly related to velocity. If you're firing at a certain speed, the projectile is only going to go so far. A longer barrel or larger chamber will increase range, but only because it will increase velocity. This means that if you're limited to the same projectile, with 250 fps you're stuck at that range.

It can be argued that if you're only firing at a high angle and not directly at people, the muzzle velocity can be much higher because if you're going for long range by the time the projectile eventually reaches the target it wouldn't be travelling very fast anyway.