Sprinkler valve rifle

[devilman]

I havent been here for a long time, but i have re-found my interest in building another sniper.

I just have a few questions. If i use a un-modded sprinkler valve with the electric actuation, is it going to give me enough flow/power to shoot cans in the back-yard, as thats all i really want to do. Also how small can i make my chamber if i want to operate the gun at 150psi or so? My barrels roughly 6mm id

See im trying to keep all parts as small as possible, so it can build it into a neat casing to make it look "more real"

Heres just a quick drawing of the operating parts

[blind909]

Your image tag is messed up, here you go-http://img159.imageshack.us/my.php?image=aall5.png, And you should do a 1/2 inch or 1/4 inch QEV instead, because that sprinkler is restricting flow waayyy to much, and a 3/4 inch by 6 inch chamber should be good, with a say 2 foot barrel, but I would go against using the sprinkler valve. And if you do go with the sprinkler valve, an unmodded one will still put holes through cans BTW.

[devilman]

if i remember correctly from doing research when i first became interested in building a pnuematic, was that i couldent easily obtain a QEV in australia?

I have some steel 3/4 pipe here thats left over from what i didnt use in my combustion rifle, its threaded both ends. would a quick release valve be fine to fill?

Also my barrel has a male 3/4 threaded end on it, is the sprinkler or qev valve female both ends?

*thanks for the image thing also

[jook13]

for the purposes you are talking about, an unmodded sprinkler valve should be fine. But why not mod it? you could get a blow-gun and whatever else is needed to mod it for roughly the same price as the electronics needed to actuate the solenoid. plus you get the perk of having a blow-gun trigger setup and better performance.

And you should do a 1/2 inch or 1/4 inch QEV instead, because that sprinkler is restricting flow waayyy to much

how much flow do you think is needed for a bb or pellet shooter? I would bet money the barrel constricts flow more than any sprinkler valve.

Just in case you did decide to consider a QEV, a good one would be the fastenal one for a few bucks more than the sprinkler valve. Linked---> http://www.fastenal.com/web/products/de ... ku=0443028 I have used this one a few times (in varying sizes) and it is always awesome.

as for the chamber and barrel size, Blind909 had the right idea. I don't feel like doing the math but try to keep the barrel and chamber volumes close to the same. the longer the barrel, the more power you get generally.

I hope that any of this was helpful.

[devilman]

Yes info is always helpful

heres just a quick sketch of what the gun will roughly look like when its finished. I opted for this design because all the internals can be house in a straight line and have the caseing built around it.

How is the QEV actuated?

http://img137.imageshack.us/my.php?image=ideacj7.png

[jook13]

a qev is basically a premade and commercially available piston valve. so it is actuated pnuematically, usually with a blowgun. if you do a search for QEV guns, you could see a few examples.

[Davidvaini]

That is the image the thread starter wished to post. ^

[jackssmirkingrevenge]

For a 6mm launcher, even using a blowgun directly as a valve will suffice, without needing fiddly electronics and the result will be much more compact and "realistic". Something like this:



Hooked up to a 150 psi chamber of say half a litre, you'll still have more than enough power to punch through a soup tin assuming you have a long enough barrel (20 inches+). This is the above setup at 100 psi using a 0.22 airgun pellet as ammunition:

[youtube][/youtube]

[devilman]

with the sniper i would like something with a little more power then just a blow gun, thats why i was thinking sprinkler valve. After a little looking round ive decided to go modded sprinkler, as i cannot get a QEV easily here in aus

the vortex bbmg im also making will use the blower tho, now its just a matter of getting the time and waiting to get paid

ill keep a build log when i start and keep u guys updated, hopefully when im done ill have a nice neat looking gun ^-^



*EDIT- i was just thinking, is it possibe to have a rifle that can be set to 1 powerfull shot when sniping, then switch to full auto when needed? SO far the only way i could think of was building a sprinkler valve system and a vortex into the one gun, which means i would have 2 triggers and 2 air inlets, plus all the bulkyness which would be hard to hide. justan idea i would like to look into further.

[Lentamentalisk]

ya, that is how everyone does it. That is the point of an under the barrel shotgun/grenade launcher etc. You use two different cannons

[jackssmirkingrevenge]

For 6mm calibre you're not going to get much difference between a sprinkler valve and a blowgun. With small calibres, the secret to decent power is upping the pressure to the 300-400 psi range.

Have a look at this data for a virtual launcher modelled in GGDT - in each case, we're talking about the same quantity of air, but in a reduced volume and therefore at higher pressure.

20 inch chamber at 50 psi - 406 feet per second

10 inch chamber at 100 psi - 537 feet per second

5 inch chamber at 200 psi - 684 feet per second

2.5 inch chamber at 400 psi - 830 feet per second

1.25 inch chamber at 800 psi - 958 feet per second

0.625 inch chamber at 1600 psi - 1006 feet per second

As to combining a BBMG with a single shot rifle, here's a possible compromise - burst fire with less shots than a BBMG, but with velocity and power closer to a single shot launcher.

[devilman]

hmm its a good concept but not quite what i want to do. The idea with the sniper was to use a small chamber under high pressure. The chamber i have is 3/4 gal steel.

What i want to build is something that can be operated in either a single fire mode or fully automatic. Im trying to figure a way to mix a single shot sprinkler valve system with a vortex system, then have a way to toggel which fireing mode that i wish to use. Its going to be very complex but would be a awsom tool once finished

[Davidvaini]

Problem with the blowgun design is you have nothing from stopping the bbs from falling out the barrel.. the other problem is that after every time you fire you have to stick bbs down the end of your barrel. This will work in non skirmish situations but if you are into Airsoft (skirmishes) then I would actually suggest doing this...


Co2 Inflator hooked up to a tire valve stem(without valve screwed in.)... attach the tire valve stem directly into the back of an Airsoft hopup.. Stick magazine in to the hopup and press the co2 trigger to fire. This has the high pressure, the skirmish able functionality, and the magazine capacity. It also has a hopup for good range and If you choose a wind up high cap it acts as a burst fire until you wind up the mag.

The only problem is that you have to wait between each burst shot or your 12gram co2 cartridges will get too cold too fast and you wont get many shots.

Here is my thread on the subject...
http://www.spudfiles.com/forums/viewtop ... tml#211004

[devilman]

Well im in aus so i carnt get my hands on any airsoft gear

I gotta wait till payday so i can start this project, but ill keep u guys updated, hopefully i can come up with something awsom

[ckman]

I made a rifle out of 3/4 pvc and a modded sprink i could stick it through half inch piec of wood with a pellet