Semi-automatic Coaxial

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.
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Mr.Tallahassee
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Fri Aug 05, 2011 3:01 am

I had a random thought :idea: to use a QDV to pilot a coaxial gun and it just kinda ran away from me. :D It's a little simplified but using paint to make really complicated pieces isn't easy at 3 am. :lol: Any thoughts?
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jackssmirkingrevenge
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Fri Aug 05, 2011 4:58 am

It would work as drawn but a slide valve pilot would be easier to put together and much more efficient too as the HPA feed is blocked off during firing.
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hectmarr wrote:You have to make many weapons, because this field is long and short life
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LovableAirGuns
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Fri Aug 05, 2011 8:20 am

What about a 3 way instead?
And then have a rod that comes from the trigger and pushes the button.
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jackssmirkingrevenge
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Fri Aug 05, 2011 8:36 am

LovableAirGuns wrote:And then have a rod that comes from the trigger and pushes the button.
A slide valve in this case is a three way valve ;)
hectmarr wrote:You have to make many weapons, because this field is long and short life
c9d
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Fri Aug 05, 2011 9:42 am

jackssmirkingrevenge wrote:It would work as drawn but a slide valve pilot would be easier to put together and much more efficient too as the HPA feed is blocked off during firing.
What are you using to block the flow of HPA through the slide valve? Its my understanding that the slide valve is just a pass through which has the ability to vent the pressure inside it to atmosphere. There would be nothing to stop the HPA from flowing out of the slide valve while firing from the HPA source unless a separate cut off valve was used... just trying to understand the drawings, sorry.
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Gun Freak
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Fri Aug 05, 2011 9:54 am

The slide valve is a three way valve, it shuts off the HPA when triggered.
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jackssmirkingrevenge
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Fri Aug 05, 2011 10:38 am

c9d wrote:What are you using to block the flow of HPA through the slide valve? Its my understanding that the slide valve is just a pass through which has the ability to vent the pressure inside it to atmosphere. There would be nothing to stop the HPA from flowing out of the slide valve while firing from the HPA source unless a separate cut off valve was used... just trying to understand the drawings, sorry.
Again:

Image

When the valve is in the forward position, it allows air to flow from the main supply to the QEV and fill the pilot and firing chamber.

When the valve is in the rear position, two things happen:

- main supply is cut off

- QEV pilot chamber is open to the atmosphere, emptying it and firing the launcher

The valve goes back to the forward position (you need to add a spring or do it manually) and the cycle can be repeated.
hectmarr wrote:You have to make many weapons, because this field is long and short life
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POLAND_SPUD
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Fri Aug 05, 2011 12:11 pm

@jsr
Again
you see what my life is like ?!
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Children are the future

unless we stop them now
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Mr.Tallahassee
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Fri Aug 05, 2011 1:00 pm

I think I'll try to build that slide valve. I figured with a restriction on the flow it would slow it down enough for the QDV piston to close. I never was one for finding the most efficient way to do things. :lol: I'll give it a go though.
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Gun Freak
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Fri Aug 05, 2011 1:04 pm

Just buy one, only 7 dollars on eBay.
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jackssmirkingrevenge
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Sat Aug 06, 2011 3:36 am

POLAND_SPUD wrote:you see what my life is like ?!
Fear not, I have similar experiences with a host of other topics, I have an 88% full PM inbox (even though I empty it regularly!) to prove it ;)
Mr.Tallahassee wrote:I never was one for finding the most efficient way to do things.
Americans... pffft!

;)
hectmarr wrote:You have to make many weapons, because this field is long and short life
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