Hybrid: Semi-semi Auto Hybrid

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Jolly Roger
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Okay I've been through these designs over and over and I haven't fond any flaws in them yet. Basically it is an idea for a semi-semi-auto hybrid. No burst disk, no timely refiliing. And best of all efficient. I have posted the pictures below with a breif description of each stage.
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The beginning....
The beginning....
Boom. This is pretty straight forward. The chamber is ignited and the pressure pushes the piston back. (main piston is connected to smaller piston) The smaller piston then releases the pressure as it is pushed past the port. This is so the rear chamber doesn't blow out... As the piston goes back, in the split second it has to wait for the combustion to clear the barrel, it blocks off the air flow. (O-rings)
Boom. This is pretty straight forward. The chamber is ignited and the pressure pushes the piston back. (main piston is connected to smaller piston) The smaller piston then releases the pressure as it is pushed past the port. This is so the rear chamber doesn't blow out... As the piston goes back, in the split second it has to wait for the combustion to clear the barrel, it blocks off the air flow. (O-rings)
This is a notable stage in the firing/refilling of the gun. As stated the black lines indicate the o-rings on the piston (and rear piston, 3 in total) This is to stop the air flow while the gun is firing. If I placed it infront of the piston, it would not reseal. If behind it, the gun would not completely expel all of its energy from the chamber. Notice that the check valve will receive flow through this network. This is not bad as the inlet will provide more pressure than the check valve and therefore the piston will be able to reseal when pushed back again by the spring.
This is a notable stage in the firing/refilling of the gun. As stated the black lines indicate the o-rings on the piston (and rear piston, 3 in total) This is to stop the air flow while the gun is firing. If I placed it infront of the piston, it would not reseal. If behind it, the gun would not completely expel all of its energy from the chamber. Notice that the check valve will receive flow through this network. This is not bad as the inlet will provide more pressure than the check valve and therefore the piston will be able to reseal when pushed back again by the spring.
The oxidizer is filling the rear chamber faster than the front because of the slow flow of the check valve. This is good because if the check valve was too fast, the piston may not be able to reseal.
The oxidizer is filling the rear chamber faster than the front because of the slow flow of the check valve. This is good because if the check valve was too fast, the piston may not be able to reseal.
This is the where the chamber is fully pressurized with the oxidizer. The gas has not been added yet as it has to be done manually. (If done mechanically as part of a blowback system, the gun would not have time to accomodate for the other stages, such as refilling with the oxidizer.)
This is the where the chamber is fully pressurized with the oxidizer. The gas has not been added yet as it has to be done manually. (If done mechanically as part of a blowback system, the gun would not have time to accomodate for the other stages, such as refilling with the oxidizer.)
This is the final stage of the refill. The chamber and rear chamber are both charged with the oxidizer. The front chamber is now being charged with the gas source which will already be regulated at a certain pressure. Eg, if the ratio of oxygen and gas "y" was 3:1 respectively and I wanted a 2x mix (15psi), I would preset the oxygen to 10psi. The chamber will be at 10psi until I add gas "y" which is regulated at 15psi. That should provide the right conditions for a 3:1 ratio, 2x mix.. I hope, please correct me if I am wrong. The ball valve may be connected to an improvised bolt action system which would be pretty cool... :) So, bang, slide the bolt up and back, bang, slide the bolt.... semi-semi auto... :P
This is the final stage of the refill. The chamber and rear chamber are both charged with the oxidizer. The front chamber is now being charged with the gas source which will already be regulated at a certain pressure. Eg, if the ratio of oxygen and gas "y" was 3:1 respectively and I wanted a 2x mix (15psi), I would preset the oxygen to 10psi. The chamber will be at 10psi until I add gas "y" which is regulated at 15psi. That should provide the right conditions for a 3:1 ratio, 2x mix.. I hope, please correct me if I am wrong. The ball valve may be connected to an improvised bolt action system which would be pretty cool... :) So, bang, slide the bolt up and back, bang, slide the bolt.... semi-semi auto... :P
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potatoflinger
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That will certainly work, I think that it is a great idea.
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goose_man
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I like it alot. The piston idea is great!
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Jolly Roger
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Cheers guys, after a little mucking around with calculations and what not I plan on drawing up the details for it. I plan on using either stainless so at least I can weld wherever I may need to, or carbon steel although that may have to be machined alot for certain parts. Maybe even sculpted from rods.. :? Dunno.. I thought while I'm at it, may as well make it the best I can. Apart from that there shouldn't be too many hassles with it. Some guy's trying to make a homemade paintball gun from scratch on http://www.gizmology.net/pbm.htm and I hope to use his loading mechanism in mine. (With a couple of mods.) It's quite simple but thats what I like about it.
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Jolly Roger
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Anyone see any problems in the design?
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wannabie
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nope looks flawless to me. it would be really good if you could get it to work.
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TechnoMancer
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seems to waste an awful lot of oxidiser!!!!!
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wannabie
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dude from what i can see the oxidiser is the air and i dont think that we are going to run out of that anytime soon. please correct me if im wrong
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clide
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You have to make sure that the small disk that vents behind the piston is smaller than the barrel, otherwise it won't stay closed. Since adding fuel will raise the pressure on only one side of the piston, you will need to make the vent disk significantly smaller than the barrel, you would need to run the calculations with the actual pressure rise of adding fuel, and I would use an o-ring seal on the barrel to prevent leaking since you probably won't have a large force pushing the piston closed.
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Jolly Roger
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Yeah true, I havn't actually thought about about the added pressure of the gas. Maybe if I make it the same as the diagram with the addition of another inlet in the rear chamber. This has a ball valve between the reg and the inlet. This ball valve is connected to the gas ball valve so when I add the gas in the front chamber, it is equalized by adding air in the rear. I believe that should work. I'll put a diagram on. UPDATE: Either that or a piston equalization idea where it involves a piston connected before the check valve and after the ball valve along the gas line. This disperses pressure into the rear chamber without letting combustible gases in. (Top diagram - I tried to get the picture at the bottom but no go
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This is before adding the gas. Note: This is an example of a 15psi mix. (2x mix) Where the oxidizer and gas are a 3:1 ratio. The gas source is also set at 15psi. So when either ball valve is opened each chamber will be the same pressure, and technically, depending on flow, the rear should fill first as it is a smaller volume. This should eliminate the problem you mentioned clide, I hope anyway.
This is before adding the gas. Note: This is an example of a 15psi mix. (2x mix) Where the oxidizer and gas are a 3:1 ratio. The gas source is also set at 15psi. So when either ball valve is opened each chamber will be the same pressure, and technically, depending on flow, the rear should fill first as it is a smaller volume. This should eliminate the problem you mentioned clide, I hope anyway.
Should be self explanatory.
Should be self explanatory.
Hybrid idea- Pressure equalization Piston.JPG (38.79 KiB) Viewed 2985 times
Last edited by Jolly Roger on Wed Apr 22, 2009 7:00 am, edited 10 times in total.
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Jolly Roger
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TechnoMancer wrote:seems to waste an awful lot of oxidiser!!!!!
I dont see how it would, the combustion would be almost instantaneous so as soon as the piston hits the bumper, the oxidizer is shut off. And as the spring pushes the piston back foward again, it passes the inlet once again and the pressure will force it closed very quickly. There really should be a very minimal amount of air wasted, as much as a paintball marker 'wastes' in a shot.
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Jolly Roger
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