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| nabsnoabs |
 Posted: 09/24/2006 13:02 PM Post subject: no burst disc hybrid |
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Private
Joined: 24 Sep 2006
Posts: 13
46.25 Spud Bux
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I was thinkin of this design for my first hybrid:
The gun would basically be a pneumatic and a cumbustion gun joined together with a sprinkler valve
In the rear, a chamber would be pressurized with air
the front chamber, which is connected to the barrel, would be injected with the right amount of propane to reach the resired fuel to air ratio
an igniter connedted to a spark strip would have a spark constantly running through this chamber, which would not ignite the gas because the concentrations would be too high
this eleminates the need to synchronize the opening of the valve with the sparking of the igniter
once the solenoid is activated, the valve is opened, the pressurized air hits the gas, and it immediately ignites
an alternative to this design would be another sprinkler valve between the gas chamber and the barrel to prevent any potential gas leaks prior to firing
its solenoid would be the same trigger as the first sprinler valve so they open at the same time and there is no need to worry about synchronizing
think of bein in a room and holding a lighter and sprayin aerosol over it
the room is full of air and ur sprayin fuel into it
now just imagine the opposite
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| Torch |
| Posted: 09/24/2006 13:15 PM Post subject: |
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Sergeant Major
Joined: 27 Jun 2006
Posts: 179
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| Hmm this seems like a great idea. But you would need to dump the air fast enough so the air part wont ignite. Or is that impossible? *goes off thinking*
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| nabsnoabs |
| Posted: 09/24/2006 13:27 PM Post subject: |
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Joined: 24 Sep 2006
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i figured that the air chamber wouldnt ignite because the pressure of the air rushing in would hold the propane in its respective chamber
once it ignites, the sprinkle rvalve would close to prevent backflow
i may have to rig multiple valves however to get a fast enough dump
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| Velocity |
| Posted: 09/24/2006 13:31 PM Post subject: |
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Brigadier General
Joined: 07 Feb 2006
Posts: 1011
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May work... I would NEVER use a sprinkler valve in a hybrid, no matter what it is for; maybe actuated ball valves would be another option?
Would the air rushing in mix well with the propane?
Anyways, considering that using a sprinkler valve between the gas chamber and barrel is an idea that should not be used, how would it actuate? Maybe some high-pressure asco valve perhaps... even then, the flow would suck.
If you didnt have a valve between the gas chamber and barrel, and kept a constant spark, it would be unpredictable, because say some fuel leaked out the barrel, then you have 8% propane in the chamber and BAM it fires (propane ignites between like 2% and 9% right? Or am I way off?)
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| nabsnoabs |
| Posted: 09/24/2006 13:47 PM Post subject: |
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Joined: 24 Sep 2006
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ive been searching around online all weekend for solenoid activaited valves and most of them are way over my head when it comes to pricing
also its hard to find valves that can handle the potential pressures of a hybrid unless they are industrial grade
any ideas???
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| boilingleadbath |
| Posted: 09/24/2006 20:20 PM Post subject: |
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Moderator
Joined: 12 Mar 2005
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Protecting a cheap valve is simple: just put a check-valve in the air-inlet stream.
...but I don't think this will preform very well, considering how long you have for the fuel/air mixture to mix.
If you want to shoot 1 kg projectiles from a 2" bore (or simmilar), though, it might work out fairly well with the proper air-inlet geometry.
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| experament_u2 |
| Posted: 09/25/2006 0:32 AM Post subject: |
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1st Lieutenant
Joined: 06 Aug 2006
Posts: 268
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but think about if u time the activating wrong then everything could go horibly wrong and no more nabsnoabs (btw nice name  )
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| GalFisk |
| Posted: 09/25/2006 8:52 AM Post subject: |
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Corporal
Joined: 28 Feb 2005
Posts: 77
276.52 Spud Bux
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| I remember posting a similar idea long ago, when the hybrid as it is was not yet invented. It could work if you get the air and propane to mix well as blb mentions. Injection through a capped coaxial piece of pipe drilled full of holes may work.
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| jrrdw |
| Posted: 09/25/2006 17:00 PM Post subject: |
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Donating Moderator
Joined: 16 Nov 2005
Posts: 3284
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| To many moveing parts in this idea for my taste, i'm interested in knowing how this would turn out. So if you build it, post it.
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| drac |
| Posted: 09/25/2006 20:25 PM Post subject: |
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Metalhead Moderator
Joined: 24 Apr 2005
Posts: 894
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| DR already tried this and scrapped it. Not to shoot ya down, just saying it's been done before and the results weren't very satisfactory.
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| Jolly Roger |
| Posted: 09/26/2006 0:36 AM Post subject: |
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Master Sergeant
Joined: 25 Aug 2006
Posts: 156
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I posted a reply a while ago about non busrt disk hyrbids. I was thinking about having everything the same as a piston exhaust pneumatic. It would work the same althought the only difference is, instead of releasing the pressure from the rear behind the piston, you could place multiple safety valves set to a certain releif pressure (eg. 100psi) and simply ignite the mixture with a spark strip in the primary chamber in front of the piston.. Heres a diagram, it should be pretty straighfoward. The trick would be to dispose of the pressure quickly enough so it wouldn't explode.
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| killagorrila99 |
| Posted: 09/26/2006 1:00 AM Post subject: |
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Captain Obvious
Joined: 25 Jul 2006
Posts: 1103
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| Thats an interesting concept.
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| GalFisk |
| Posted: 09/26/2006 2:42 AM Post subject: |
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Corporal
Joined: 28 Feb 2005
Posts: 77
276.52 Spud Bux
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| And it works, too. See my piston valved hybrid (which is not posted here because it's not yet finished). I've dry-fired it a few times, it also works well in pure pneumatic mode. The valve design is based on the DFTV by AKB.
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| Jolly Roger |
| Posted: 09/26/2006 7:26 AM Post subject: |
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Master Sergeant
Joined: 25 Aug 2006
Posts: 156
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DUDE THAT IS AWESOME!!!! That is exactly what I planned on doing! What type of valve is the one at the rear? I'm using Rhino as well, just trying to figure it all out though thats all. Man thats mad, so the exhaust piston works by slightly pressurizing the air/fuel mixture in the area behind the piston upon ignition and then vents the air out of outlets just behind the small piston as it moves back a couple of centimetres?
Last edited by Jolly Roger on 07/02/2007 6:33 AM; edited 1 time in total |
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| GalFisk |
| Posted: 09/27/2006 4:26 AM Post subject: |
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Corporal
Joined: 28 Feb 2005
Posts: 77
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The exhaust piston is connected directly to the main piston, so when the mix is ignited in the chamber, the pressure begins to move the main piston, which moves the exhaust piston and vents the pilot. When the piston is fully open, the vent is blocked off again which lessens the strain on the main piston.
The valve is a three way ball valve, which is modded so that it can point in any direction for fueling, pressurization or firing. It's also used as the trigger when firing in pneumatic mode.
I have a detailed (though somewhat obsolete) Rhino3D model of the gun if you're interested.
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