Dual Camera System to enhance combustion weapons.

Miniature guns are novelty custom, unique, and sometime downright crude! Common construction materials often include pill bottles or pens. Show us your work!
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jackssmirkingrevenge
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Wed Jan 25, 2023 11:44 am

Technically if you've divided a chamber, you now have two chambers.
hectmarr wrote:You have to make many weapons, because this field is long and short life
Poyaa
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Sun Feb 26, 2023 6:11 pm

hello, please I need someone to help me create a system to load the mixture of alcohol and oxygen in the chamber as well as the one presented in this project 🙏🏼
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D_Hall
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Thu Mar 16, 2023 11:29 pm

What part about such do you find difficult?
Simulation geek (GGDT / HGDT) and designer of Vera.
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jackssmirkingrevenge
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Thu Dec 07, 2023 1:05 pm

pressurepiling.png
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Looking at this in more detail, the paper describes what is happening in a closed system, with a significant pressure peak happening in the secondary chamber much higher than what occurs in the first one.

In our case the dynamic is a little different as we want the second chamber to open to the barrel, so ideally that peak happens while the projectile is accelerating.

Looking at the preliminary data from these tests with two effective chambers of approximately equal size, and the orifice being the same diameter as the burst disk seat, it appears that peak pressure in the secondary chamber is less than what is achieved by having the separation removed, because in the latter case a certain level of disk will burst while it won't with the separation.


orificesize.png
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This graph suggests that with a smaller orifice the pressure spike will occur later and for longer, although with no significant change in peak pressure.


volumeratio.png
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This graph suggests that the bigger the volume ratio between the primary and secondary chamber, then the higher the peak pressure.

I think on that basis it would be worth experimenting with a significantly smaller separation with a smaller orifice.
hectmarr wrote:You have to make many weapons, because this field is long and short life
hectmarr
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Thu Dec 07, 2023 2:30 pm

It is clear what is happening, as far as I can understand. You can play with the size, shape and quantity of the hole. Also with the volumes of both chambers. Great that you can try all this. In my particular case, if 20 or 30% improvements can be obtained, I will apply it without hesitation to my weapons. It is simple to implement what is necessary in an already manufactured weapon. This is the most for me.
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jackssmirkingrevenge
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Thu Dec 07, 2023 10:25 pm

I made a second baffle that was both shorter and with a 1/8" orifice that looks something like this to scale:

baffling2.png
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I then did some more testing again at 16x and using photo paper disks and 0.25g airsoft BBs as projectiles:

1) 1 disk no baffle - 1136 fps / 21 J

2) 1 disk baffle - 1851 fps / 40 J

3) 2 disk no baffle - 2071 fps / 50 J

4) 2 disk baffle - 2133 fps / 53 J

The results are similar to the previous tests. If the burst pressure is low for a given mixture, then the energy gets a very significant boost from a divided chamber, virtually double the muzzle energy in this case.

This is still lower than a single chamber with double the disk layer, achieving 75% of the total power, all for the same pre-ignition pressure and amount of fuel.

It's worth noting that the baffle is not fixed in place and is just a tight fit, so I don't know if it's being moved around during the combustion cycle.

My conclusion based on this limited data would be that this setup might be useful with a simple combustion that wouldn't normally use a burst disk, but for hybrids there does not seem to be an advantage compared to using the optimal disk burst pressure.
hectmarr wrote:You have to make many weapons, because this field is long and short life
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Fri Dec 08, 2023 9:18 am

As seen in the tests, it could improve a combustion weapon. In a hybrid we could reach the same energies with more discs. Very interesting that we have proof of all this. As you think, maybe for a low pressure hybrid it can improve something.
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