Unbalanced spool valve for coaxial hybrids

Harness the power of precision mixtures of pressurized flammable vapor. Safety first! These are advanced potato guns - not for the beginner.
User avatar
POLAND_SPUD
Captain
Captain
Posts: 5402
Joined: Sat Oct 13, 2007 4:43 pm
Been thanked: 1 time

Wed May 25, 2011 2:41 pm

So this is just a slightly modified version of the system I am going to use. However this one does not use a detent - instead it relies on an unbalanced spool valve acting as the main valve. The spool itself acts as a bolt too so the gun is loaded from the breech

The barrel and the tube housing the bolt/spool are not the same ID - that's the essence of this design. A spring keeps the bolt/spool in closed position prior to firing. When the mix is ignited high pressure shuts the valve open and cycles the action
(the exact size of all the parts is yet to be determined)

So what do you guys think ?
Attachments
unbalanced bolt.png
unbalanced bolt.png (11.26 KiB) Viewed 5018 times
gun2.png
gun1.png
gun1.png (27.47 KiB) Viewed 4669 times
Last edited by POLAND_SPUD on Tue Sep 20, 2011 4:14 pm, edited 1 time in total.
Children are the future

unless we stop them now
User avatar
wyz2285
First Sergeant 2
First Sergeant 2
Austria
Posts: 2385
Joined: Sat Mar 06, 2010 7:50 am
Location: Porto, Portugal
Has thanked: 1 time
Been thanked: 3 times
Contact:

Wed May 25, 2011 3:24 pm

So when it ignits the bolt will be bushed back right? But how are you going to be sure that it will open? it's for a hybrid or combustion?
User avatar
POLAND_SPUD
Captain
Captain
Posts: 5402
Joined: Sat Oct 13, 2007 4:43 pm
Been thanked: 1 time

Wed May 25, 2011 3:49 pm

yeah, the bolt will be pushed back.
how are you going to be sure that it will open
It's an unbalanced spool. There is a surface area differential there and that's what is going to shut the valve/spool open when the mix is ignited
Children are the future

unless we stop them now
User avatar
jrrdw
Moderator
Moderator
United States of America
Posts: 6572
Joined: Wed Nov 16, 2005 5:11 pm
Location: Maryland
Has thanked: 39 times
Been thanked: 22 times
Contact:

Donating Members

Wed May 25, 2011 4:45 pm

KABOOM, wheres the Earth shattering KABOOM? I think this will work, but how well is my question and, or, will the bolt/spool/valve tolerate the action???
User avatar
POLAND_SPUD
Captain
Captain
Posts: 5402
Joined: Sat Oct 13, 2007 4:43 pm
Been thanked: 1 time

Wed May 25, 2011 5:07 pm

but how well (...) will the bolt/spool/valve tolerate the action???
that's what I don't know. Obviously the oring that blocks the barrel will be exposed to high temperature.

I know that BUNA-N orings are good up to 250 F, Viton ones are good up to 450F. I also know that there are piston valve hybrids - if they can handle then why wouldn't this thing ?


The cool thing about this design is that you can use all sorts of ammo with it - both spherical non-spherical. Plus, it is a breech loaded coaxial, which is not something I've seen anywhere else.

It wouldn't be difficult to build a bolt action rifle around this system (and hopefully a true semiauto)
Children are the future

unless we stop them now
the unit
Private 3
Private 3
Posts: 51
Joined: Tue Jun 24, 2008 8:20 pm

Wed May 25, 2011 5:31 pm

POLAND_SPUD wrote:I also know that there are piston valve hybrids - if they can handle then why wouldn't this thing ?

It wouldn't be difficult to build a bolt action rifle around this system (and hopefully a true semiauto)
I have yet to see a piston valve hybrid that was fired as rapidly as bolt action or semi auto would likely be. I would utilize a teflon seal and mated sealing surface.
User avatar
POLAND_SPUD
Captain
Captain
Posts: 5402
Joined: Sat Oct 13, 2007 4:43 pm
Been thanked: 1 time

Wed May 25, 2011 5:55 pm

Well I am hoping that purging the chamber with propane or butane will help to some extend
I would utilize a teflon seal and mated sealing surface
Yeah I realize that's probably the best option

I have yet to see a piston valve hybrid that was fired as rapidly as bolt action or semi auto would likely be
The thing is that no one has ever built a hybrid that can achieve high ROF so it's not that there were 999 attempts that failed due to overheating

I don't recall anyone attempting that
Children are the future

unless we stop them now
User avatar
Zeus
Staff Sergeant
Staff Sergeant
Posts: 1505
Joined: Tue Oct 27, 2009 7:34 pm
Location: 'Straya, C*nt

Wed May 25, 2011 6:36 pm

Well first of all I'll suggest that you be rid of the spring and use compressed air instead. That'll make the opening pressure infinitly variable.

I hate to say this but this seems like a coaxial version of the rattlesnake valve. Good application though.
/sarcasm, /hyperbole
User avatar
saefroch
Staff Sergeant 2
Staff Sergeant 2
Posts: 1679
Joined: Mon Jun 08, 2009 8:47 am
Location: U.S.A.- See Map

Wed May 25, 2011 7:45 pm

Silicone o-rings are rated to 500F, and pretty cheap too.

The design has potential... but I'd like to see something work before I say too much.
User avatar
jrrdw
Moderator
Moderator
United States of America
Posts: 6572
Joined: Wed Nov 16, 2005 5:11 pm
Location: Maryland
Has thanked: 39 times
Been thanked: 22 times
Contact:

Donating Members

Wed May 25, 2011 8:12 pm

Do you have a ready made spool to use or are you building one from scratch?
User avatar
jhalek90
Specialist 4
Specialist 4
Posts: 498
Joined: Fri Aug 14, 2009 5:37 pm

Wed May 25, 2011 8:18 pm

where is the 3-way valve?

I assume it to be used for fule injection. haha.

The design, seems like it could work. the only problem i see is that in the event it does fail to open, the chamber will experience the full pressure of the combustion. (better make it strong!)
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
Gippeto
First Sergeant 3
First Sergeant 3
Venezuela
Posts: 2503
Joined: Sat Jan 19, 2008 10:14 am
Location: Soon to be socialist shit hole.
Has thanked: 2 times
Been thanked: 17 times

Donating Members

Wed May 25, 2011 10:37 pm

the unit wrote: I would utilize a teflon seal and mated sealing surface.
X2

As drawn, the o-ring will be blown off with the first quasi decent shot. Trust me on this.....happened with the hammer valve in my co-ax. :lol:

You COULD still use the o-ring, but you'll need to drill a series of holes from the spool face to the bottom of the o-ring groove. These passages will drain the pressure that builds in the groove, and keep the o-ring from blowing off. :) (cageless qdv anyone?:wink: )

THEN there's still the issue of temperature resistance. The gases in this case will bear more resemblance to a cutting torch....not o-ring friendly.

Sooooo.....What "he" said. :)
"It could be that the purpose of your life is to serve as a warning to others" – unknown

Liberalism is a mental disorder, reality is it's cure.
User avatar
Technician1002
Captain
Captain
Posts: 5189
Joined: Sat Apr 04, 2009 11:10 am

Wed May 25, 2011 11:06 pm

Even non combustion air cannons have the issue with o rings blowing off. One of my early piston valves suffered that fate. It lost the o ring when running above about 35 PSI.

An extended barrel with with QDV style ports can be used to retain the forward O ring. An early unbalanced spool valve design of mine used the extended barrel and ports. It worked but the early design used a row of holes in the breech of the barrel so the flow was poor.

This early valve has a nose that extends into the breech of the barrel to seal past ports in the breech.
Image
User avatar
jackssmirkingrevenge
Five Star General
Five Star General
Posts: 26203
Joined: Thu Mar 15, 2007 11:28 pm
Has thanked: 569 times
Been thanked: 343 times

Donating Members

Thu May 26, 2011 12:01 am

hmm... isn't it basically just like a piston valved hybrid though? There's a pressure differential but a spring keeps it shut until the ignition causes an overpressure. The only difference is that your piston seals inside the barrel as opposed to the face sealing against the breech end.

Let's not stand on ceremony mate, let's see this POLSKA_HYBRYDA happen!
hectmarr wrote:You have to make many weapons, because this field is long and short life
User avatar
POLAND_SPUD
Captain
Captain
Posts: 5402
Joined: Sat Oct 13, 2007 4:43 pm
Been thanked: 1 time

Thu May 26, 2011 12:08 am

The only difference is that your piston seals inside the barrel as opposed to the face sealing against the breech end.
naah, you can use both methods. The new thing is that it is breech loaded (not that there are any breech loaded coaxials that I know of)
I assume it is to be used for fuel injection. haha.
Yeah, I am predictable ;-)

EDIT
hmm I just realised that it might be possible to use metal to metal sealing alone (tapered spool/poppet). Even if it would be a bit tricky it is a viable option

EDIT no 2
Attachments
5.png
4.png
4.png (39.12 KiB) Viewed 4710 times
3.png
3.png (18.62 KiB) Viewed 4710 times
2,.png
2,.png (19.23 KiB) Viewed 4710 times
1.png
1.png (20.86 KiB) Viewed 4710 times
Children are the future

unless we stop them now
Post Reply