Hammer pilot valve with QEV

Show us your pneumatic spud gun! Discuss pneumatic (compressed gas) powered potato guns and related accessories. Valve types, actuation, pipe, materials, fittings, compressors, safety, gas choices, and more.
KAspud
Recruit
Recruit
Posts: 1
Joined: Fri May 11, 2012 1:51 pm

Fri May 11, 2012 2:19 pm

Hi, i'm new relatively new to this but I'm planning to build a QEV or pistonvalve airgun with a hammer valve as the pilot, allowing semi-auto firing. Any suggestions on chamber volume ( i'll use 1/2 inch copper barrel) or general help will be greatly appreciated :)
User avatar
Gun Freak
Lieutenant 5
Lieutenant 5
Posts: 4971
Joined: Mon Jan 25, 2010 4:38 pm
Location: Florida
Been thanked: 7 times

Fri May 11, 2012 5:10 pm

I'd say about 67.634 liters will be sufficient.
OG Anti-Hybrid
One man's trash is a true Spudder's treasure!
Golf Ball Cannon "Superna"M16 BBMGPengunHammer Valve Airsoft SniperHigh Pressure .22 Coax
Holy Shat!
User avatar
DYI
First Sergeant 5
First Sergeant 5
Posts: 2862
Joined: Sat Jul 07, 2007 8:18 pm
Location: The People's Republic of Canuckistan

Fri May 11, 2012 5:23 pm

You'll want 12.38 times the volume of a piece of string ±0.5% for optimal k3wlness...
Spudfiles' resident expert on all things that sail through the air at improbable speeds, trailing an incandescent wake of ionized air, dissociated polymers and metal oxides.
User avatar
mark.f
Sergeant Major 3
Sergeant Major 3
Eritrea
Posts: 3570
Joined: Sat May 06, 2006 11:18 am
Location: The Big Steezy
Has thanked: 15 times
Been thanked: 10 times
Contact:

Donating Members

Fri May 11, 2012 6:22 pm

Don't forget that chamber condensation (being a liquid) is virtually incompressible and it's average volume should be subtracted from total chamber volume during design.
User avatar
mattyzip77
Sergeant 3
Sergeant 3
Posts: 1249
Joined: Tue Jun 28, 2011 12:22 pm
Location: Taxachusetts

Donating Members

Fri May 11, 2012 8:14 pm

I would say multiply your barrel width by the length and then divide that number by the size of your q e v!!
Go Bruins!!!!
User avatar
Crna Legija
First Sergeant 2
First Sergeant 2
Posts: 2333
Joined: Sun Jul 20, 2008 5:14 am
Location: australia

Fri May 11, 2012 8:35 pm

umm tough one but, if you have a spare fuel tanker on hand it should work out as the tank.



or maybe give use more info
'' To alcohol... The cause of, and solution to, all of life's problems.”
--Homer Simpson

Add me on ps3: wannafuk, 8/11/11 cant wait
User avatar
jhalek90
Specialist 4
Specialist 4
Posts: 498
Joined: Fri Aug 14, 2009 5:37 pm

Wed May 16, 2012 1:18 pm

Image
jackssmirkingrevenge wrote:I wonder... if you put flammable vapours inside a lady... could you get her to diesel?
POLAND_SPUD wrote:Anything is possible with the proper 3-way valve.
User avatar
Brian the brain
Moderator
Moderator
Posts: 3495
Joined: Mon Dec 05, 2005 2:06 am
Location: Holland

Wed May 16, 2012 3:37 pm

Forum rule nr 1.
Not nr.2...

1!
Don't be a jerk.
Keep the flaming to a minimum. Remember, you were a noob once too. Also, keep in mind that this is a text-based medium, and as such, sarcasm does not always translate well.
:shock:
Boys!
Behave yourselves.


now..
Hi, i'm new relatively new to this but I'm planning to build a QEV or pistonvalve airgun with a hammer valve as the pilot, allowing semi-auto firing. Any suggestions on chamber volume ( i'll use 1/2 inch copper barrel) or general help will be greatly appreciated
Small chamber volume would give you very few shots and pressuredrop between shots is drastic.
No matter what pressure you intend to use a basic principle is that for multishot you want as much volume as possible.
Only you can decide how much is too much.
I like both performance and looks so I generally go as big as possible without making it look bulky.

Using high pressure allows you to get powerful multishots from a relatively small package.
But size still matters at high pressure.
The bigger, the better.
Big means better power and less dramatic pressuredrop.

Now another thing that comes into play with a hammered QEV:
The pilot can be used to tune the powerlevel.
A strong hammerspring and heavy hammer give what I like to call "deep"shots, the reverse will give you "shallow"shots.
The amount of gas expelled by the QEV is closely related to the pilotvalve settings in this kind of setup.
The very size of the hammervalve also makes a difference.

All this makes it very hard to give an exact answer to your question.
Leaving out the information on pressure, barrellength, ammo, personal taste and last but not least your expectations on performance makes it downright impossible.

Hope this helps.
welcome to the forum!
Gun Freak wrote:
Oh my friggin god stop being so awesome, that thing is pure kick ass. Most innovative and creative pneumatic that the files have ever come by!

Can't ask for a better compliment!!
Post Reply