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!
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

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
Recruit
Recruit
Australia
Posts: 1
Joined: Sun Feb 26, 2023 6:07 pm

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 🙏🏼
User avatar
D_Hall
Staff Sergeant 5
Staff Sergeant 5
United States of America
Posts: 1920
Joined: Thu Feb 07, 2008 7:37 pm
Location: SoCal
Has thanked: 7 times
Been thanked: 42 times

Donating Members

Thu Mar 16, 2023 11:29 pm

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

pressurepiling.png
pressurepiling.png (20.17 KiB) Viewed 32074 times


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
orificesize.png (32.55 KiB) Viewed 32074 times
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
volumeratio.png (23.45 KiB) Viewed 32074 times
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
Sergeant
Sergeant
Argentina
Posts: 1064
Joined: Sat May 07, 2016 3:49 pm
Location: Argentina
Has thanked: 273 times
Been thanked: 276 times
Contact:

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.
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 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
baffling2.png (10.27 KiB) Viewed 32037 times

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
hectmarr
Sergeant
Sergeant
Argentina
Posts: 1064
Joined: Sat May 07, 2016 3:49 pm
Location: Argentina
Has thanked: 273 times
Been thanked: 276 times
Contact:

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.
quinn whitsitt
Specialist 2
Specialist 2
United States of America
Posts: 234
Joined: Fri Feb 09, 2024 1:58 pm
Location: central city arkansas
Has thanked: 55 times
Been thanked: 7 times
Contact:

Fri Mar 01, 2024 10:46 am

nice gun!!
i might use parts from that for a new gun
Post Reply