Page 1 of 3

Pcp pellet/bb gun (closed,see new thread for build log)

Posted: Sat Feb 16, 2013 9:15 am
by sinister_shadows
Starting a new thread for build log.

If possible can this thread be deleted?

Posted: Sat Feb 16, 2013 11:55 am
by jakethebeast
If you want power, go for piston valve, that gives you alot of power :D

But i didnt quite get your idea from what your picture though..

Posted: Sat Feb 16, 2013 1:01 pm
by sinister_shadows
some power would be nice, but not needing heaps, trying to get as many shots out if a tank as i can.

to try and explain. The blue box at the back in the air tank with a input in the bottom. That then connects with a line to a second smaller air chamber, with a hammer valve in it (orange box) the hammer is connected to the trigger with a sear. When the triger is pulled it will release the hammer, causing air to flow past the valve, up the red tube, then into the barrel. To reset the hammer and chamer another round, you pull the charging handle at the back. The handle has a small bit on the bottom that pulls rod attached to the hammer to re-cock

if i can get the spring in the hammer right, i may be able to get it to re-cock the hammer with air. ive never made a gif before but ill see if i can figure it out so it gives you a better idea.\

Edit. here is that very first gif

Posted: Sat Feb 16, 2013 1:53 pm
by jakethebeast
Basically you would need some kind of a valve between reservoir->firing chamber, other than that i see no problem for it working, only some PITA o-rings :D

Posted: Sat Feb 16, 2013 1:56 pm
by wyz2285
jakethebeast wrote:Basically you would need some kind of a valve between reservoir->firing chamber, other than that i see no problem for it working, only some PITA o-rings :D
He is using a hammer valve.

Posted: Sat Feb 16, 2013 1:57 pm
by jackssmirkingrevenge

Posted: Sat Feb 16, 2013 2:12 pm
by sinister_shadows
thats pretty much it jsr, though the issue i had with that design is i want to use mags. If i have the valve like that i can see issues

This was my other idea with a blow back, it would waste air, but would mean semi auto, with only needing to chamber the first round (not after full auto)

i should have left the airtank in the back a lighter color because it woulent decrease much with the hammer valve in the firing chamber

excuse my gif quality


-EDIT. Off to bed for now, its 3:30am here in the land of aus. day off today so i may make a start if i have anything laying around i can use.
Just looked closer at the blowgun valve, can i drill a hole for a chamber anywhere? if i can put it underneath then it would probably work for me

Posted: Sat Feb 16, 2013 3:35 pm
by wyz2285
Unless you have a really tight bore and really heavy projectile, that probably won't work.

Posted: Sat Feb 16, 2013 10:03 pm
by sinister_shadows
Tight bore wouldent be a problem, but pellet weight would. Didnt think it would just work :P

went for a look round but sadly i dont have any parts to get started, so ill have to wait till wedneday. I may make the hammervalve, just to try and get a little more flow with it.

Posted: Sun Feb 17, 2013 1:54 am
by sinister_shadows
While doing more research today i saw your semi with a pneumatic cylinder Wyz. It seems to be a far simpler way of doing what i want to do, and auto feeding rounds. all i would need is a small detent to stop the rounds rolling out

id love to stuff it all in the body of a steyr but im insure it would fit. Anyway to trigger the 3way if i where to move it into the stock?

edit- Can i use a solenoid 3way valve? that way i can just trigger it with 12v. If yes, do i get limited with the pressure i could put thru it

Posted: Sun Feb 17, 2013 4:04 am
by POLAND_SPUD
Can i use a solenoid 3way valve? that way i can just trigger it with 12v. If yes, do i get limited with the pressure i could put thru it
Most valves are rated to 8-10 bar and you can usually use them at slightly higher pressures than that

but don't worry even 8 bar is more than enough for airsoft

Posted: Sun Feb 17, 2013 4:30 am
by sinister_shadows
i was looking at using one of these for the feeder

http://www.ebay.com.au/itm/360517335274 ... 983wt_1139

The listing says the ports are 4.5mm. im using these push to connects everywhere else
http://www.ebay.com.au/itm/251221046454 ... 1423.l2649

Is there a 4.mm to 1/4 adapter i can use? or 4.5mm to 1/4 push to connect? havent had much luck

Posted: Sun Feb 17, 2013 8:41 am
by wyz2285
Use a single action cylinder, a lot easier.
12 solenoid work, kind expensive comparing to manual ones through
The 4.5mm port is for a specific push to connect fitting for cylinders, you need to search for them. I donĀ“t know any adapters.

Posted: Mon Feb 18, 2013 8:45 am
by sinister_shadows
Alright all of my parts are ordered, other then a tube for the mag and the air tank the gets hooked up to the qev. The only question i have is does it matter what size airtank i use? i want to get a decent rof out of it, so if its to big it would take to long to fill, but if its to small it would rob power yes?

the barrel is 6mm and will be firing mostly steel bb's, barrel is 700mm long atm, may change in size when the steyr body rocks up so i can measure

the main tank will be a paintball tank in a back pack

Posted: Mon Feb 18, 2013 9:21 am
by jackssmirkingrevenge
A 13 cubic inch tank is a good balance between number of shots and bulk, you can easily mount it on your launcher:

Image

The Ninja tanks have shim adjustable regulators that can go down to 450 psi without the need for an additional reg, saving you bulk and money. At that pressure, you probably don't even need a firing chamber, just block off the QEV port.