3" porting artillery( i call her jane)

[spudtyrrant]

well i was in the neighborhood and decided to make a 75mm beast of an air cannon here are the specs

barrel: 10ft 3" sch 40 approx: 850 ci

chamber:11ft 4" sch 40 approx: 1659 ci

valve: 4"tee 3" full porting piston valve 1 1/2" travel

pilot: 3/4 inch modded sprinkler valve with popoff(with string attached so it can be fired from a distance)

bumper: a plunger with holes cut in it for air flow

stand: made from an old wheelchair( will be replacing wheels) and dolly welded together well without further ado here she is:

http://www.seehere.com/spudtyrrant/artillery (lots of picture so i made a webpage)

and here are some dry fire vids @ 60psi:
from the back:
http://img531.imageshack.us/my.php?imag ... 203kf4.flv
from the side:
http://img531.imageshack.us/my.php?imag ... 033ez5.flv
tell me what you think constuctive criticism appreciated

[elitesniper]

SON OF A BEAST!
Now THAT deserves to be called a howitzer !
NICE :cheers:

[spudtyrrant]

SON OF A BEAST!
Now THAT deserves to be called a howitzer !
NICE :cheers:

ty i was going for the howitzer look IT SOUNDS LIKE ONE TOO the videos do not do it justice

[LCTChamp]

Looks good. I was going to make something similar, but didn't have enough cash. I can't wait to see some damage pics/vids!

[spudtyrrant]

Looks good. I was going to make something similar, but didn't have enough cash. I can't wait to see some damage pics/vids!

i should have damage pics and vids up next week when i get somewhere to test it and then it will be unleashed at 100psi
ggdt predicts 460fps and 4103FT/LBS @ 100PSI a 20 ounce soda bottle

[theBOOM]

Good job spudt! you got it finished!!
Can't wait to see this beastly cannon's damage

Good job

[glass_05]

BEAUTIFUL! i am just finishing my 4inch tee piston. My gun's length is about half of yours. Very good job!

interesting piston design. i like it. i be the shape of it helps triggering it alot

[spudtyrrant]

ty for you comment yeah i made the piston out of red oak so its nice and sturdy its very light only about 12 ounces i was trying to give the piston the largest amount of area possible for faster actuation i can put a soccer ball in front of the barrel @ 80 psi and dry fire and it will send the soccer ball a good 100feet

[c11man]

nice cannon, wait scratch that very nice big cannon. i wish i could talk about my big cannon on this site.... but that will have to wait for a while.

[thedeathofall]

Great job! Thats one HUGE cannon.

I would think with all that chamber, you could use a bigger barrel.

Great job with this though!

[spudmanb3]

awesome, I'd go with a longer barrel though, you know chamber to barrel ratios yada yada yada...... :blah5:

[spudtyrrant]

i would add a longer barrel but 2:1 is always what i have heard concerning pneumatic cannons and i just checked ggdt and i only get a 10fps for every foot i add so i don't think i will be making the barrel longer plus i don't feel like adding a coupling and still making it look good

[King_TaTer]

Well the video links are broken for me. They send me to the home page. The pictures look great. I Hope to see that thing at 100 psi.

[thedeathofall]

Actually ive heard several ratios, but never have I heard 2:1. Between 1 and 1.5 to 1 is the norm.

Although its only 10 fps per foot, by making the barrel longer you can increase accuracy, and decrease noise as well. A gun as big as yours will be pretty loud with a 2:1 ratio.

[mark.f]

Is that a toilet plunger cut up into a bumper?