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2'' porting piston cannon. video. Built fot HPA

Built a pneumatic 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: MrCrowley » Fri Apr 06, 2012 5:32 pm

jhalek90 wrote:I have to laugh (evil laugh) at the idea of a 1000 cubic inch 1.9" porting hybrid... I may do ot in the future... I might be able to get another tank like this one...

There already is a burst disk hybrid using a similar sized SCUBA tank (one of my favourite hybrids on the site). Hopefully it will give you some incentive to leave Gun Freak and join the ever growing dark side.
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Unread postAuthor: High-PSI » Fri Apr 06, 2012 6:16 pm

You need to get the weight of the tank and all equipment behind the barrel to reduce the recoil without rotating (twisting) the whole cannon in your hands. A 2 inch slug produces HUGE recoil (as you have noticed).

You may have to brace it against a tree to fire at high pressure. :D

So, this May I will be in southern Michigan at a "Father/Son campout". I will have my HPA compressor there along with my big cannon and maybe a couple other cannons. We do 22 rifles, large bore handguns, and shotgun/skeet. I have been bringing air cannons for a couple years. The guys have been looking forward to what will be brought each year.

You should join us.

Matt
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Unread postAuthor: jsefcik » Fri Apr 06, 2012 6:27 pm

High-PSI wrote:You need to get the weight of the tank and all equipment behind the barrel to reduce the recoil without rotating (twisting) the whole cannon in your hands. A 2 inch slug produces HUGE recoil (as you have noticed).

You may have to brace it against a tree to fire at high pressure. :D

So, this May I will be in southern Michigan at a "Father/Son campout". I will have my HPA compressor there along with my big cannon and maybe a couple other cannons. We do 22 rifles, large bore handguns, and shotgun/skeet. I have been bringing air cannons for a couple years. The guys have been looking forward to what will be brought each year.

You should join us.


bring me bring me bring me!!!! lol
Matt
:D :D :D
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Unread postAuthor: jhalek90 » Fri Apr 06, 2012 8:04 pm

MrCrowley wrote:There already is a burst disk hybrid using a similar sized SCUBA tank


The second video in that topic says his tank is 353 cubic inches.
my take is labeled 1000 cubic inches.
It does not look like my tank is 3x the size though...

Either way, a burst disk hybrid should be easy.
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jackssmirkingrevenge wrote:I wonder... if you put flammable vapours inside a lady... could you get her to diesel?

POLAND_SPUD wrote:Anything is possible with the proper 3-way valve.
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Unread postAuthor: MrCrowley » Fri Apr 06, 2012 8:44 pm

jhalek90 wrote:
MrCrowley wrote:There already is a burst disk hybrid using a similar sized SCUBA tank


The second video in that topic says his tank is 353 cubic inches.
my take is labeled 1000 cubic inches.
It does not look like my tank is 3x the size though...

Either way, a burst disk hybrid should be easy.

I did think his was smaller but not that small in comparison to yours! :shock:

My 'big' piston hybrid is a measly ~120ci :(
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Unread postAuthor: jhalek90 » Sat Apr 07, 2012 7:10 am

The tank im using says on it 80 cubic feet!!!

Now, 80 cubic feet is 136,000 some odd cubic inches... there is no way that's right.

The part where it said 1000ci was on the neck, which has been replaced by a 2'' nipple.

I assume that 80 cubic feet, is how much air, when filled to the correct pressure for diving, it holds, After the air has expanded to 1atm. (hope that makes sense.) this is the only explanation for "80 cubic feet" i could come up with.

I am going to go find a tape measure, and check the volume of the tank, including the walls.

BRB

V = πr2h
The tank has a 3.5'' inch cross-sectional radius at the center of the tank.
r=3.5
The tank is 32'' in length.
h=32

V=3.14*3.5^2*32
V=3.14*12.25*32
V=38.46*32
V=1230 ci


the walls are pretty thick, but i think its safe to say, this is a 1000 ci tank. :-)
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Last edited by jhalek90 on Sat Apr 07, 2012 7:21 am, edited 1 time in total.
jackssmirkingrevenge wrote:I wonder... if you put flammable vapours inside a lady... could you get her to diesel?

POLAND_SPUD wrote:Anything is possible with the proper 3-way valve.
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Unread postAuthor: High-PSI » Sat Apr 07, 2012 7:13 am

Volume is calculated radius squared times pi times length.

1,000 ci is typical for a tank of that type. My scuba tank is 1,085 ci.

Matt
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Last edited by High-PSI on Sat Apr 07, 2012 7:56 am, edited 1 time in total.
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Unread postAuthor: jhalek90 » Sat Apr 07, 2012 7:22 am

High-PSI wrote:Volume is calculated as the length times radius squared.

1,000 ci is typical for a tank of that type. My scuba tank is 1,085 ci.

Matt


Ahh, ty. In my edited post above, i did the math. 1000 ci seems to be correct.
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jackssmirkingrevenge wrote:I wonder... if you put flammable vapours inside a lady... could you get her to diesel?

POLAND_SPUD wrote:Anything is possible with the proper 3-way valve.
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Unread postAuthor: High-PSI » Sat Apr 07, 2012 7:57 am

Sheesh, my math was off as well. I forgot pi.

It is too early............ :?

Matt
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Unread postAuthor: Technician1002 » Sat Apr 07, 2012 10:32 am

This is comparing apples to elephants. One measurement is the volume in cubic inches of space inside the tank. This is the number used here for GGDT and other math.

The other measurement is the volume of compressed gas the tank will hold at the rated pressure. So if you are using a Helium tank to blow up balloons and each balloon holds 1/4 cubic foot, you can tell how many it will fill.

The true volume of the inside the tank is stamped on it. In the US this is the WC number. Other countries use a metric equivalent. WC stands for Water Capacity and is given in Lbs. This is a measure of how much water in pounds it takes to fill the tank.

For air cannons, use the volume of the tank, not the compressed gas capacity in your measurements.

http://wiki.answers.com/Q/What_does_WC_mean_on_a_20_pound_propane_tank
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Unread postAuthor: jhalek90 » Mon Apr 09, 2012 1:12 pm

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jackssmirkingrevenge wrote:I wonder... if you put flammable vapours inside a lady... could you get her to diesel?

POLAND_SPUD wrote:Anything is possible with the proper 3-way valve.
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Unread postAuthor: jackssmirkingrevenge » Mon Apr 09, 2012 1:13 pm

Nice, I had missed this!

Needs some better projectiles though ;)
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Unread postAuthor: jhalek90 » Tue Apr 10, 2012 9:44 am

jackssmirkingrevenge wrote:Nice, I had missed this!

Needs some better projectiles though ;)


Any relatively cheap ideas? I would love to shoot something with more penetration power. (oh god.... here come the jokes.)

EDIT: in the second video, you can see the projectile i was shooting, in the first set of damage pics.

It is a full bore, UHDPE slug, with steel washers bolted to it for a nose.

The tail is hallow, and the nose slightly tapered. Imagine a 2'' pellet.

It flies very straight.
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jackssmirkingrevenge wrote:I wonder... if you put flammable vapours inside a lady... could you get her to diesel?

POLAND_SPUD wrote:Anything is possible with the proper 3-way valve.
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Unread postAuthor: jackssmirkingrevenge » Tue Apr 10, 2012 1:33 pm

If you can make a UHDPE slug, presumably you can make a UHDPE sabot ;)

With a drill press and 3/4" drill bit, you can make a good sabot for thiseasy and effective drag stabilised slug.

Image

You don't even need the sleeve, just chop the CO<sub>2</sub> capsule one inch from the pierced end.
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Unread postAuthor: shardbearer » Tue Apr 10, 2012 8:32 pm

I recommend newspaper pycrete. Take a piece of barrel with an endcap on it, roll up newspaper until it fits, fill with water, and throw it in the freezer. Has a tendency to fall apart when it hits the target, but it's cheap and the perfect size for your barrels.
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