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BLD 3 hammervalve project

Built a pneumatic cannon? Then post it here! This section is for completed, finished cannons that you have built. Please include pictures and information.
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BLD 3 hammervalve project

Unread postAuthor: bladeul2006 » Sun Feb 23, 2014 2:06 am

So I decided to post a new topic with this project because I am planning to "make it happen".
I was hoping to use the barrel exit gas to pull back the hammer like on the FX Revolution (no semi though).Hope it works ;)
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Re: BLD 3 hammervalve project

Unread postAuthor: jackssmirkingrevenge » Sun Feb 23, 2014 2:48 am

A diagram of sorts to let us know what is going on would be helpful :)
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Re: BLD 3 hammervalve project

Unread postAuthor: bladeul2006 » Sun Feb 23, 2014 3:02 am

edited first post. hope it helps
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Re: BLD 3 hammervalve project

Unread postAuthor: jackssmirkingrevenge » Sun Feb 23, 2014 3:07 am

Two small notes:

- as drawn, your plan to recock the hammer using barrel pressure seems a little ambitious... my FX Monsoon used to stop cycling once chamber pressure dropped below 100 bar. Still, not impossible.

- Why do this at all if you're not going for semi auto? Why not make the pressure cock the hammer and reload the ammunition?
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Re: BLD 3 hammervalve project

Unread postAuthor: bladeul2006 » Sun Feb 23, 2014 3:16 am

I'm still working on a plan for the ammunition reloading.
I'm not planning to make the self cocking just yet, fist I want to see how it performs without the gas collector.
I already manufactured the hammervalve still need to make the bolt and the barrel assembly (hopefully this week), before the testing
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Re: BLD 3 hammervalve project

Unread postAuthor: Gippeto » Sun Feb 23, 2014 10:27 am

O-ring seal for the poppet is not needed, and will blow out in any case. Make the poppet head from delrin, keep things concentric and it'll seal fine. Tone down the big wedge shape, wedges jam into the seat under pressure. BTW....undercut a delrin head with a ball end mill and face off to leave ~.020" flat on the perimeter and it'll seal super easy on a flat faced valve body. :)

Image

If the striker is to scale, it'll be far heavier than required. Would suggest cutting the mass in half at least for co2 operation.

O-ring on either end of the valve body is not needed, only the pressure end of it. You're going to secure the valve body with screws, and it'll leak there....which is why you don't need the second o-ring. Need to seal the transfer port though.

Please use high quality socket head cap screws to secure the valve, and do the calculations for screw shear and bearing stress on the tube. Ask for help if you don't know how...it's easy and in your best interests to do it. :) I stick to a minimum safety factor of 3x MWP at yield strength. For co2, that's 5400psi.


BTw.....do you actually have the Lonestar Gambler in your avatar pic??? Haven't seen those in years, but they sure were FUN!! 8)
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Re: BLD 3 hammervalve project

Unread postAuthor: Dig_Gil » Sun Feb 23, 2014 11:17 am

I think that the recocking really should be mechanically interlocked with the lever/whatever makes the reloading. Firearms have a lot of recoil and gasses and heavy projectiles, so collecting gases is feasible unlike with airguns. It's possible, but I don't see why do it that way.
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Re: BLD 3 hammervalve project

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Re: BLD 3 hammervalve project

Unread postAuthor: bladeul2006 » Sun Feb 23, 2014 12:39 pm

to "Gippeto":
Thank you very much for your help, like I said I already made the hammervalve, I had problems with the seal of the poppet, that's why I put the o-ring there (wich by the way is on the valve body and is more than 3/4 embedded in it - it does not get blown up - I tested it) . I know the O-ring on the other side is unnecessary. The striker/hammer has a hollow core (basicaly a cup) wich I plan to fill with an amount of lead that I would find necessary(I noticed that the poppet is fairly difficult to push under pressure - tried with an actual hammer)

to "Dig_Gil" :
I'm not realy confident that it will work but "a man's gotta try " :P
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Re: BLD 3 hammervalve project

Unread postAuthor: Brian the brain » Sun Feb 23, 2014 1:16 pm

It's all a matter of surface area.

With pressure, a bigger surface area means more force.
Use the full diameter of the hammer and use a one-way valve to keep the pressure on the hammer as much as you can.

Works in my "Caselman" attempt.

I am using a high flow ( balanced) hammervalve, but without a checkvalve.
You could use a two-part hammer to get rid of the airresistance the hammer has to fight.
The front would seal against the tube walls, the rear is able to move fast as it isn't artight.
When the front is forced against the back , the two seal.
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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!!
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Re: BLD 3 hammervalve project

Unread postAuthor: bladeul2006 » Mon Feb 24, 2014 2:27 pm

Brian the brain : put those toughts on a piece of paper please
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Re: BLD 3 hammervalve project

Unread postAuthor: Brian the brain » Mon Feb 24, 2014 2:39 pm

Okay...and now what?

:D
Edit:

Something like this:
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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!!
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Re: BLD 3 hammervalve project

Unread postAuthor: Dig_Gil » Tue Feb 25, 2014 12:59 pm

I wonder if the recocking could be made with the reservoir's pressure instead of costing the shot's air volume...
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Re: BLD 3 hammervalve project

Unread postAuthor: cammyd32 » Tue Feb 25, 2014 4:08 pm

Dig_Gil wrote:I wonder if the recocking could be made with the reservoir's pressure instead of costing the shot's air volume...

I have thought about that before, but the difficulty is then emptying a recock cylinder which would be essentially directly linked to the reservoir, at the end of its stroke, without losing pressure.
And anyway, It really doesn't matter in the long run, its all work done at somepoint, and energy you use to recock it will always detract from the potential power of the gun unless you have a seemingly limitless source of constant pressure compressed gas.
In fact, tapping out the excess at the muzzle of the gun is a lot more efficient than any type of system which recocks the gun either simultaneously, or before the point at which the pellet is fired, as it only uses energy after, (or as close to) the point at which the pellet has achieved it's peak velocity.
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Re: BLD 3 hammervalve project

Unread postAuthor: Brian the brain » Thu Feb 27, 2014 2:56 pm

In my diagram I powered blowback directly from the hammervalve.
It would be quite easy to hook up an airline to the muzzle instead.
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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!!
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Re: BLD 3 hammervalve project

Unread postAuthor: bladeul2006 » Fri Feb 28, 2014 1:01 pm

my latest work

P.S.
no auto recocking , my hammer spring needs to be quite tough to open the valve, so I think that the muzzle air will not be able to push the hammer back.
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