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mini hybrid win!

Post questions and info about hybrid (compressed gas with fuel) powered cannons here. This includes discussion about fuels, ratios, ignition systems, build types, safety, and anything else relevant.
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Unread postAuthor: POLAND_SPUD » Tue Sep 14, 2010 10:46 am

yeah but the SOS is just for showing off... you can always use heavier ammo to get more KE and penetration
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Unread postAuthor: CpTn_lAw » Tue Sep 14, 2010 11:10 am

POLAND_SPUD wrote:don't forget that a larger cal. and longer barrel can act as a suppressor


I don't want to sound bad or anything, but it is exactly the opposite on my hybrid. The 6mm 15cm long barrel is noisy, but the 16mm - 45 cm barrel is deafening, let alone the 20 mm-50 cm long one...concussion is also out of comparison.
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Unread postAuthor: Ragnarok » Tue Sep 14, 2010 11:20 am

I have to agree with CpTn_lAw here.

It's the sudden displacement of air caused by the muzzle blast that's the source of the "report". Thus, a barrel that allows greater flow can well be louder.
So, a longer barrel will probably be quieter, but a higher calibre barrel - despite having a greater volume - does not necessarily (although it can) have the same effect.

It'll probably be the case here that it is quieter as a result, but it's not a hard and fast rule.
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Unread postAuthor: SpudFarm » Tue Sep 14, 2010 11:40 am

I don't think hybrids are loud, they make noise but is not deafening IMO.
I have just fired outside though, something completely else is to be expected inside.

The best way to reduce noise should be larger volume and lower mix, my hybrid at 7x isn't loud at all..

Perhaps I should check my hearing?
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Unread postAuthor: jakethebeast » Tue Sep 14, 2010 1:41 pm

hah, yeah, hybrids are loud but not that loud when compared to .50BMG :D
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Unread postAuthor: Ragnarok » Tue Sep 14, 2010 1:49 pm

SpudFarm wrote:I don't think hybrids are loud, they make noise but is not deafening IMO.

Loud is subjective.

Deafening is not, however. By distinct majority, the spudguns on this site are capable of causing permanent hearing loss.
Lost hearing cannot be replaced, so any macho "I don't need hearing protection" posing will be regretted in later life.
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Unread postAuthor: jackssmirkingrevenge » Tue Sep 14, 2010 1:53 pm

Hate to butt in the discussion, but extra barrel length or not, this thing is LOUD! (subjectively)

It's too dark for chrony data, but did some damage shots and the performance increase is very evident.

Here it is firing a flared out 0.22" pellet fired at 1mm thick steel plate, punched right through and as it disintegrated against the hard surface behind it, made a mess of the "witness" paper:

[youtube]http://www.youtube.com/watch?v=pwx-Kh7xPi8[/youtube]

Long suffering UPS case, as you can tell from the paper background this time the pellet made it clean through both sides :D

[youtube]http://www.youtube.com/watch?v=UCRXzVNw1u4[/youtube]

0.25g airsoft BB fired at a 5 euro cent coin, no penetration but it printed the coin on the metal cap support and left a pretty deep dent

[youtube]http://www.youtube.com/watch?v=j1e7Q-p9pmw[/youtube]

0.22" pellet vs a 10p coin, again no penetration but the pellet fused with the coin and dented it quite deeply, to the extent that if you look at it from the other side, the queen looks like she's got a mouth full of sweets :D

[youtube]http://www.youtube.com/watch?v=dhEXJg3eXQE[/youtube]

Here's the targets:
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Unread postAuthor: jakethebeast » Tue Sep 14, 2010 2:08 pm

thats pretty impressive damage wtih airsoft bb :D
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Unread postAuthor: jackssmirkingrevenge » Tue Sep 14, 2010 11:59 pm

jakethebeast wrote:thats pretty impressive damage wtih airsoft bb :D


Not as impressive as I hoped, however when fired at the UPS case, a 0.25g BB made a dent deeper than its 6mm diameter which was quite significant.

Now I just want some chrony results with a range of projectiles in the long barrel, but I have to wait for the weekend to be at home at a reasonable hour for the correct amount of light.
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Unread postAuthor: POLAND_SPUD » Wed Sep 15, 2010 12:09 am

:twisted:
nice

do you still have that 3/8" BBs and 3/8" ID barrel?? :)

@cptn_law
what HGDT tells you about the temperature and pressure in the barrel when the projectile leaves it ?

I am hoping that with a small chamber + long barrel (90cm or longer) it is possible to reduce both temperature and pressure to minimum. Even if that won't be enough a suppressor would have easier job. Well that's just a theory
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Unread postAuthor: jackssmirkingrevenge » Wed Sep 15, 2010 12:29 am

POLAND_SPUD wrote:you can always use heavier ammo to get more KE and penetration


Fair point, at 1100 feet per second a 16 grain 0.22" pellet would have around 43 ft/lbs of muzzle energy, using heavyweight 31 grain pellets at the same velocity will give you almost double that, so if you wanted to make an "anti-material rifle" type launcher (that really would have less energy than a 22 rimfire :roll:) it would be perfectly feasible. Still, I'm not really interested in making a long finished launcher aside from for velocity test purposes

do you still have that 3/8" BBs and 3/8" ID barrel?


Indeed :D and that would be ideal for the "suppressed pistol" type project I'd like to make. A 3.5 gram BB at just 500 feet per second will already match the Monsoon in terms of muzzle energy, and that sounds like a realistic velocity target from a high mix and short barrel, though I would want to make the chamber volume smaller to aid with sound suppression.

On another note, considering that to some extent you instigated this whole "pneumatics are an evolutionary dead end, lets burn some pressurised gas instead" thing, when are we going to see a POLSKA_HYBRYDA?
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Unread postAuthor: SpudBlaster15 » Wed Sep 15, 2010 4:35 am

SpudFarm wrote:I don't think hybrids are loud, they make noise but is not deafening IMO.


It depends entirely on the pressure and flow rate of the propellant gas at the muzzle.

In general, most hybrids have large and relatively inefficient C:B ratios, and are loud enough to necessitate hearing protection at close range. I've built hybrids with barrel diameters ranging from 1/2" - 1.5", and only the smallest could be shoulder fired without causing discomfort to unprotected ears.

I have to agree with Rag with regard to the relationship between noise output and barrel diameter. Using a larger barrel diameter will typically increase the magnitude of the sound wave produced, even if it brings the launcher volume ratio closer to optimum.
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Unread postAuthor: jackssmirkingrevenge » Wed Sep 15, 2010 8:32 am

SpudBlaster15 wrote:In general, most hybrids have large and relatively inefficient C:B ratios, and are loud enough to necessitate hearing protection at close range.


Even though it's just over 18mL in volume, the subject of this thread has quite a large chamber for a mini, which is a bit much for the suppressor to cope with. I'll probably make a smaller chamber to go with it as certainly with the current C:B ratio it isn't going to give me the noise levels I was aiming for. It will also give me an idea of the power levels I can expect from my planned cartridges as to date I have never evaluated this potential.
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Unread postAuthor: SpudFarm » Wed Sep 15, 2010 11:05 am

so any macho "I don't need hearing protection" posing will be regretted in later life.


That was not what I meant at all. I mean that I don't think they are loud like one would expect.
As long as you use a heavy subsonic projectile they are just like a pneumatic at moderate pressure (unless your name is Larda).

I do understand that they can cause hearing damage/loss, belive it or not. But once again, I just meant that they are not as loud as one would expect.

(Spellcheck don't work in Google Chrome)
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Unread postAuthor: jackssmirkingrevenge » Wed Sep 15, 2010 1:02 pm

I was sifting through the debris littering the testing area, and noticed something about the walkman - it seems that the "auto stop mechanism" doesn't stop near supersonic lead pellets, someone should tell Aiwa :D
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