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Built a hybrid cannon? Then post it here! This section is for completed, finished cannons that you have built. Please include pictures and information.
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Unread postAuthor: Killjoy » Wed Jan 23, 2008 4:17 am

I do believe we must test this theory haha.
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Unread postAuthor: Solar » Wed Jan 23, 2008 5:28 am

Killjoy wrote:haha I have always wondered what golfballs at 1900 fps would do to flesh...
But yes I see no way this wouldn't kill you if you stood in front of the barrel unless it was a blank shot.


Whoa! bad idea anyways. Compressed air, even at shop pressures can kill you by being injected(injested?) through the skin which is very porous like a sponge. I will look for some info to back that up.
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Unread postAuthor: Novacastrian » Wed Jan 23, 2008 5:44 am

Solar wrote:
Killjoy wrote:haha I have always wondered what golfballs at 1900 fps would do to flesh...
But yes I see no way this wouldn't kill you if you stood in front of the barrel unless it was a blank shot.


Whoa! bad idea anyways. Compressed air, even at shop pressures can kill you by being injected(injested?) through the skin which is very porous like a sponge. I will look for some info to back that up.


I think you are right to a certain degree, however my understanding is that one must have a cut fairly close to an artery to enable death by air injection, by blowgun or otherwise. Your heart can only be stopped by a substantially large "plug" of air.
If this were to happen otherwise it would have to involve air pressures above normal "shop" pressures. (Like 1400psi).
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Unread postAuthor: jackssmirkingrevenge » Wed Jan 23, 2008 5:59 am

in any case, a facefull of hot supersonic gas isn't going to be too healthy. The following refers to firearms but is just as relevant to hybrids:

Q. Is blank ammunition really dangerous?

A. Absolutely! First, let's reiterate the second rule of firearm safety. Never point a firearm at anything you are not willing to destroy. Now say it again: Never point a firearm at anything you are not willing to destroy. Blank ammunition, while it contains no bullet in the usual sense does project bits of wadding material (some of which are fairly thick) and powder, as well as a blast of high pressure and very hot gases which can penetrate skin at a fairly great distance. Common smokeless powders have an energy potential of around 180 ft lb per grain weight of powder.

Using GI .30-06 blanks I was able to punch holes in a cardboard target at 7 feet quite regularly and at near contact distances I could easily break a 1" board with the muzzle blast. Using .38SPL blanks I could shatter a watermelon at 2 feet and pepper its skin at 5 feet. Note that some military ammunition sold as blank ammunition and which is totally made of plastic with a metallic base is actually short range practice ammunition that fires a hollow plastic "bullet" at very high velocity. Nuff said! Remember, Never point a firearm at anything you are not willing to destroy.

Also, keep in mind that the muzzle blast from a blank (just as with live ammunition) can damage your hearing.
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Unread postAuthor: Killjoy » Wed Jan 23, 2008 3:21 pm

maybe I should have added "perhaps" before the blank shot part. Sure there's a chance it would kill you, but even if you lived you would be pretty messed up from the hot gases, so bad idea all around.
And solar I wasn't saying that would be a good idea, standing in front of this thing when you fire would be incredibly stupid, actually standing directly or relatively close and in front of the muzzle of almost any hybrid, pneumatic, or combustion would be a bad idea, ammo or not.
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Unread postAuthor: SpudFarm » Wed Jan 23, 2008 4:36 pm

i would be really exited if you can do a blank with no barrel at some plywood from like 2 feet you should be able to crack it from the blast of gasses BTW is your spark strip working again?
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Unread postAuthor: Killjoy » Fri Jan 25, 2008 1:49 am

that would be pretty cool. i shot at a two by six with a 3x mix and that blew it back with a good amount of force.

And no I haven't gotten around to rebuilding the spark strip, been snowy and old here so to much of a pain to drag it out and test it. Maybe when it gets a little warmer.
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Unread postAuthor: SpudFarm » Mon Jan 28, 2008 9:57 am

do you got a peak pressure gauge on it? sorry i am late was down by the flu.
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Unread postAuthor: Killjoy » Mon Jan 28, 2008 2:49 pm

Yeah, just a check valve gauge deal. But when I was moving it over the summer the gauge got crushed so for now I just have the hole plugged where the guage was.
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Unread postAuthor: sniper hero » Sat Apr 19, 2008 6:03 pm

monster is the only word to describe this cannon

that's a good piece of work
and the damage is just unbelievable
the vids are awesome :D
I love this cannon
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coming: semi auto pellet sniper:D
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Unread postAuthor: willarddaniels » Thu May 22, 2008 6:36 pm

bump

I don't usually kick up old threads- but this is beautiful! One question, KJ: did your improvised peak gauge work well?

One word to describe this cannon: Inspiring.
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Unread postAuthor: Killjoy » Sat May 24, 2008 1:26 am

Thanks willard, glad to make something to inspire.

The improvised peak gauge worked very well, the only problem was my burst disks failed to early so it gave a low reading but I fixed that and now the readings tend to be close to the estimated pressures.
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Unread postAuthor: SpudFarm » Sat May 24, 2008 9:36 am

can you share your readings?
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Unread postAuthor: Killjoy » Thu Jun 19, 2008 3:03 pm

Wow I just realized I never replied to your post, my bad.
I have a sheet with all this written down, but the current state of my room forbids my location of it, so I'll try and give you the ones I remember.

I tried several 4X mixes with poor burst disks that were giving at around 270 psi (gauge reading). I switched to 1/4" particle board and 4x mixes were resulting in gauge readings between 350 and 370 psi roughly.
I also tried a couple 3x mixes and was getting readings around 275 psi.

I wanted to test higher mixes but when I was moving the cannon I dropped it by accident and the gauge got crushed and I haven't replaced it yet. I have gone up to 6x mixes but their was no gauge.

Now these readings are no means accurate, but they're at least in the same ball park as the estimated pressures gaseq coughed up for me and also these show more at what pressure my burst disks were giving then the combustion pressures, but oh well.



And to update ya'll on the status of the cannon, heres a list of new developments:
> I received my new 2" 3000psi forged steel union yesterday

> I also got a 300psi digital gauge with a pressure resolution of 0.1psi and =-1% accuracy (I am pursuing making a universal fueling/ignition box based on the design of DYI's fueling meter).

>The 2" barrel has been scraped and will be replaced with a 4" bore, 50 foot long barrel. I also received all the stuff for reinforcing the barrel yesterday as well (fiberglass, epoxy, steel wire, and dense expanding foam).

>A new fully portable platform as been designed and everything acquired to build it. Will be constructed out of steel.

So things are finally coming together.
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Unread postAuthor: SpudFarm » Thu Jun 19, 2008 3:08 pm

souns like stuff!

can't wait and i have no more to say :D
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