No burst disk hybrid

Insomniac · Wed Dec 20, 2006 5:46 pm

Well I didn't sleep well last night and while I was awake I thought this idea up. The diagram is ultra simple, it's just to illustrate my idea.
I've seen few designs for burst disk free hybrids, but they all tried to prevent the flame travelling backwards through the valve. My idea is to deliberatly let the flame backwards into the main chamber. This probably wouldnt work, but I'd like to see what you all think anyway.

benstern · Wed Dec 20, 2006 5:49 pm

all that would do is create a big flamethrower.

Insomniac · Wed Dec 20, 2006 6:14 pm

Why? It would still go boom, as there is air and fuel in the chamber.
If the chamber was just propane then it would be a flamethrower.

judgment_arms · Wed Dec 20, 2006 6:56 pm

My theory is you’d get a big fireball, and not much else what I see is a ball valve pneumatic with propane in the chamber and a sparker in the barrel…it may improve performance, but the increase would not be much. You’d get a fireball and a loud boom, which would still be cool, but not a high-performance hybrid cannon. Although it would, by definition, be a hybrid. What I see happen is, the ball valve opens allowing the compressed air/propane mix into the barrel the propane hits the spark (I would suggest a taser) the propane goes and adds an extra 60-90psi and by the time that happens the projectile is already three quarters the way out the barrel. Now IF you hade the barrel long enough, like ten feet or more, then, yeah, you’d have a very interesting hybrid.
But that just my two cents. I just kind of contradicted my self didn’t I?

Insomniac · Wed Dec 20, 2006 7:25 pm

Hehe yeah you did contradict yourself a bit. What if you ran it at a low mix, like 2x, and used a tight fitting projectile that 28 (I think thats the pressure in a 2x mix) psi couldnt move? I think there was a hybrid, might of been reapers, that just had a barb in the barrel that held the potato in and sealed the compressed air in the barrel. This would be just like that, but a bit more reliable as the potato only has to hold the pressuere for a split second. This desighn would probably work best with a small diameter ammo, as its got less surface area exposed to that 28 psi. One problem is that the gas is ignited from the front of the chamber, when its better to have it near ther rear. Still, even it it only had the power of a good pnumatic, It would be a lot more satisfying to shoot, because you would still get a nice BOOM!

judgment_arms · Wed Dec 20, 2006 10:35 pm

I’m in just a little over my head here but I’m going to make an educated guess.
Search for the cased ammo thread, in it, can’t for the life o’ me tell you he’s name, had a case made of 1 ¼inch PVC and an weighted end cap for ammo fired out of a 2inch barrel, the principle being the same as when you forget to glue a cap on. (I hope your following me, and that I’m making sense.) use that idea and pressurize it to just bellow the point were the end cap goes and add propane (I know precious little about combustions and even less about hybrids, I’m a pneumatics guy.) basically I’m saying have the ammo fit as tightly as possible with out glue. I hope I ain’t lost you, if I have tell my and I’ll explain it better when I’m not asleep.

Insomniac · Wed Dec 20, 2006 10:44 pm

What, you mean somthing like this (or am I just not understanding?)
The problem would be that replacing endcaps is like replacing burstdisks, but caps are more expensieve.

judgment_arms · Wed Dec 20, 2006 11:00 pm

No that’s not quite what I meant here’s the link I was talking about:
http://www.spudfiles.com/forums/viewtopic.php?t=3692&
I’m tired so I’ll explain it more tomorrow ifin ya want me to.

Insomniac · Wed Dec 20, 2006 11:41 pm

Oh yeah, now I get it. You have the ammo tightly held in the case, and firing dislodges it.

judgment_arms · Thu Dec 21, 2006 12:53 am

Can’t sleep.
What if you just had the propane/air in the case (without the hole in the back as in the picture) with electrodes (spark gap thingy) in the case, on the outside of the case you have two bands of copper attached to the electrodes, in the breach of the gun you have to corresponding bands of copper…crap I think somebody already suggested this never mind…time for bed…

Insomniac · Thu Dec 21, 2006 1:24 am

I've got it! Throw the no burst disk idea out the window, and make a cartrige fed hybrid! The problem with cartrige fed combustions is that the cartrige has to be huge because of the combustion chamber, but a hybrid can get around that problem by using a small chamber with a higher mix to get the same (or higher) power! The cartrige would be a chamber at 3x mix with a pre installed burstdisk and ammo jammed in front, and with copper strips on the outside wired to a spark gap. The gun would simply be a barrel with a breech to insert a cartrige, and a stungun wired to copper strips that corrospond to the ones on the cartrige. This could be semi auto or even FULL AUTO! Imagine that, a full auto hybrid cannon!

judgment_arms · Thu Dec 21, 2006 4:47 pm

Your welcome, good luck with that.
I would suggest you make single shot breach loader first then once you get that right then make a full/semi-auto. Also do some research on machine guns, in particular the Thompson sub machine gun, it’s recoil operated and fires from an open bolt. I think it would be you best bet for full-auto spud gun. One problem I see is, now I may be wrong as I’ve never fired a combustion/hybrid, is that the may not be enough recoil to cycle the action. It’ll takes some work but it would be vary interesting to say the least.
I’m willin’ to help if you need it, actually I’d love to help this sounds cool,

Insomniac · Thu Dec 21, 2006 5:10 pm

Well unfortunatly I have neither the money or the machining skills or the experience to make this. Your right though, start with a single shot then semi auto etc. I wish somone with the nessicary resources would try this, It would be an incredible gun. I think the best design would be a single shot gun with a magazine that you manually 'pump' to load the next shot. Kind of like a lever or pump action rifle with a magazine. I only have a ball valve pnumatic, not even a simple combustion, so theres no way I'll be making a hybrid. Damn

judgment_arms · Thu Dec 21, 2006 5:52 pm

It’s not rocket surgery. I think it would be easier than you think. Remember the K.I.S.S. principle (keep it simple, stupid). Fallow thrasmussen's instructions for the cased ammo (in the link I already posted) and the gun to shoot them. This would be easy and cool, make something that looks like a 105mm howitzer or a flak 88.
As for an automatic look for diagrams, etc. on the Sten, Thompson, and the Kalashnikov. All of which have vary simple mechanisms. Once you fully understand how they work then it would be simple to make an automatic spud cannon. You shouldn’t need milling machines, lathes, etc. just basic tools like a drill press/electric drill(the later being more desirable but not necessary), files, a sharp knife, and maybe, but I doubt it, a tap and dye set. I’ll work on some plans, if I get time, but like I said it’s not rocket sugery.

Insomniac · Thu Dec 21, 2006 6:14 pm

Well even if I come up with a design, pressure rated pvc is expensieve in Australia, I live in a residential area, spudguns are illegal and hybrids are LOUD, and I'm 13 and get $10 a week, theres no way i could fund it. Fittings in non pressure rated conduit are 5 dollars each! I don't want to know what sch 80 parts cost! I don't have ANY experience glueing pvc and my dad is scared enough of my ballvalve pnumatic! I also can't get stunguns or tazers here. If I built it I would be able to shoot it once every few months. Its not just a matter of me decideng not to make one, Its just that it would be a stupid waste of money in my situation. If I lived on a farm, maybe. But I don't, so theres no way I would, or could, make one.

No burst disk hybrid

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