144" barrel combustion

[jagerbond]

Recently assembled, giant coaxial breech loader. 144" barrel, 2", 450 cubic inches and 700 cubic inch 6" chamber. 18" long x 1" diameter metering tube (2 squirts to fill at 45PSI of MAPP gas) battery BBQ ignition with 2 gaps (one top, one bottom).

Fired twice over the weekend and 2nd shot blew through 5/8" plywood and 1 1/2" hardwood solid core door. This was a little unexpected and I have decided continue testing somewhere less populated.

Anybody got ideas on distance I can expect? of FPS for the matter.

[SpudFarm]

that is a beast! speeds of up to 800fps should go pretty good.


DAMAGE PICS

[ramses]

HGDT is estimating around 750fps with an 80g potato. At at 28 degree angle, you are looking at just over 1000 ft. kinetic energy is over 15x that of a .22 lr. Nice cannon.

EDIT: linkey

[starman]

That's one colossus of a combustion gun there. It was kind of hard to grasp the scale of this gun until I saw the mapp gas canister.

Looks good. Some more detailed pics and a shot video would be much appreciated.

[drex]

lol when i first read the title i thought you ment 144"diameter barrel :happy8:
nice gun, i would like to see a video of this thing in action.

[jagerbond]

Thanks for all of the responses. I reversed engineered this to fit in my Vanagon (rear hatch to dash... flash suppressor sits on dash). I hope to get some testing in this weekend and I will document and take some photos/video.

Anybody have ideas on how you can record spike chamber pressure? At first thought I was thinking about an automotive compression tester...
What pressures are estimated for this?

What's the largest combustion you guys have seen?

Is it dangerous territory to add some oxygen, say increase to 40% total content and double the MAPP gas?

Damn spud guns are keeping me up at night.

[TwitchTheAussie]

This is probably the biggest inline I've seen but their have been some colossus sized combustions. Great work mate :thumbright:

[jackssmirkingrevenge]

Turns out size does matter

[Killjoy]

Ah a fellow spudder who builds huge. Thank god, It was starting to get lonely around here.

Great work, that beauty is huge. I can't wait to see how it performs and what it does to its targets. Keep up the good work.

To answer your questions.
This is the biggest inline I've seen, there are some huge bore combustions though. Somewhere around here is a 8" bore one I think.

I wouldn't try it with oxygen, it's really pushing it. You'd probably be fine but that's still pretty iffy.

I check valve and gauge would work, but by know means would be accurate. One of the pop out pressure gauges for tires might work too. But overall it's unnecessary. And I don't know what kind of pressure's you're getting, (hgdt doesn't work with vista), but I'm sure someone else can answer it.

Haha you got the same problem huh? I go to bed at 4am cause I can't stop thinking about spudguns.

[psycix]

Wow that gun must be huge.
I cant get a good image of how large it is (looking at the picture I guessed it was a 3/4th" or smaller barrel) could you post it along with something for size comparison. Like a person holding it?

Turns out size does matter

Sais the guy who invented the pen gun.

[jackssmirkingrevenge]

I can't get a good image of how large it is (looking at the picture I guessed it was a 3/4" or smaller barrel) could you post it along with something for size comparison. Like a person holding it?

At 12 feet it would about as tall as two tall people standing on top of eachother

Says the guy who invented the pen gun.

Well, I don't feel the need to compensate

What pressures are estimated for this?

Less than 50psi at best.

What's the largest combustion you guys have seen?

I don't know about length but in terms of calibre, this one.

I wouldn't mess with oxygen in a PVC cannon if I were you.

[Mr.Sandman]

What's the largest combustion you guys have seen?

probably that cannon .......... brobdingnagian bertha. that was huge

Edit: crap i hate that quote button

[jackssmirkingrevenge]

What's the largest combustion you guys have seen?

probably that cannon .......... brobdingnagian bertha. that was huge

You mean this one? I think it's shorter than DRs but no contest in terms of calibre

[Mr.Sandman]

or maybe the cannons at punkin chunkin those are collassol