BIG M.A.C.C. Cannon

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BIG M.A.C.C.- Air Cannon Specifications.
Note that everything here is subject to change as construction problems arise and new design ideas come along.
Scroll down to UPDATES, to get the latest progress report on how construction is coming along.
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5-22-1999 Updated The first set of new pictures are in. I have put up a Thumbnail Gallery, there's now text and descriptions to go with them

5-27-2000 Phase 2
Well, I'm long past due for an update. So here it is.
Big MACC, Phase 2

Size Requirements
(1) It must fit in my garage in an upright position and not take up a space larger than 2ft X 2ft.X 8ft.
There is a high probability that the cannon will be longer than 8ft. 2-14-1999
(2) It must be light enough to two people to move without too much difficulty.
Well, Big M.A.C.C. has grown to a very large size. It will not be mounted on a small 4ft. X 8ft trailer.

Movement Requirements.
(1) It must be able to pivot Left, Right, Up, and Down, and shoot Strait Up.
I have acquired some hydraulic parts for the cannon. I have a very long 52" X 2" bore ram that will be used to elevate that front of the cannon up and down. Left and Right movement will most likely be accomplished using a 1" OD threaded rod assembly that I will make that will be turned with a hand crank, it could be hydraulic, but probably not.

Performance Requirements
(1) My goal it to build a Pneumatic Air Cannon that will be able to shoot a 2" dia. projectile over 1,000yds. and a Full 12oz. Coke can or Beer can filled with water over 500yds.
(2) The Cannon must be able to safely be pressurized 150psi. on a regular basis.

Structural Specifications
The cannon will have 8 air chambers surrounding the barrel.
The Cannon has been re designed to have 12 air chamber surrounding the barrel. 1-3-1999
The air chambers will connect to a combination "air manifold" and "firing chamber" on the back end of the gun and will be attached to a support ring at the front of the gun.
The cannon will be fired by having a seal pulled off the end of the barrel that is connected to the manifold. At first the air cannon will be fired by a "piston" assembly setup. To view a drawing of how I "plan" to build the first Firing Mechanism (note: page is almost 40k) that will be located inside the " Air Manifold "
Later,....The seal will be pulled by a pneumatic air cylinder located inside the manifold.
The air cylinder may have it's own small pressure chamber to store pressurized air for it's operation.
The cannon will have interchangeable barrels ranging from 6" dia Max. down to 1"dia.

Cannon Stand
The stand for this air cannon will be a tripod with a "double" pivot assembly. Click here for pictures and more details, when I get them up loaded.
Well, Big M.A.C.C. has grown to a very large size. It will not be mounted on a small 4ft. X 8ft trailer.

This Air Cannon was designed by me over the summer of 1998.
But I will claim it as officially designed , the day I started building this page.

Notes of Interest
Construction planed to start on Saturday
Construction started Sunday
The air manifold will be constructed in such a way as to allow me to open the back of it and change the firing mechanism to experiment with other means of firing the cannon and saving the wasted air pressure. I plan to try and put a "cuff" valve assembly on the cannon to seal the barrel as soon as the projectile leaves the end of the barrel. I also plan to experiment with a piston and spring assembly to also save on wasted pressurized air leaving the barrel

UpDates
Sunday 2-14-1999
Yesterday I went to the Scrap yard and bought a piece of 8" X 60" X 3/16" steel pipe to construct the new "Air Manifold" out of . I have decided to make it out of stronger pipe. I have spent over 15 hours of true labor fabricating parts of the cannon, But I have decided not to use them for safety reasons. I made the first air manifold, but decided that when finished that the thin metal it was constructed out of might not hold the 7,000 pounds of pressure pushing on the back end of the Air Manifold , I am concerned that the back may rip off the cannon with explosive force, and I may be standing behind it aiming the cannon to shoot when it might come off. So I upgraded to the thicker pipe. I will re drill new manifold. See a picture of the "First Air Manifold" .

Saturday 2-27-1999
Today I cut the 2" pipe for the air chambers. I have 12 pipes and I cut two 22 1/2deg. angle cuts on each end. This is 48 angled cuts. Six of the pipes I first shortened by 8". This is so that I can stager the connections to the air manifold. If I put all the openings to the manifold in one line it would cut the 8" pipe the manifold is made from in half.

Sunday 3-7-1999
This weekend I welded up the 12 Air Chambers ( all 48 joints) and plugged off one end of each air chamber. The next step will be to pressure check each air chamber and seal any leaks that may appear. Once the air chambers are welded in place on the manifold I will not be able to reach the side of the pipes facing inward to make any repairs with the welder, I will only get one chance to get it right! Check out how I made the 12 (ten foot long) AIR CHAMBERS.

I "dummied-up" the air chambers to the first manifold I built to get a feel for its size and how it would look.Until now it was all only on paper. To see a few pictures I took last night, of BIG MACC .

Sunday 4-3-1999
I am a bit behind on the updates. I have been able to cut two pieces of the 8" dia. pipe to a length of 10" long. I marked both pipes in 30 deg. increments around the outside of each pipe. I then marked 2 lines around the out side of each pipe, 3" from each end. Then I marked (with a punch) the pipe for drilling the 12 holes in each pipe section.

Saturday 5-1-1999
I have cut the first of the 8 1/4" OD disk from 1/4" steel plate that will be used in the construction of BIG MACC. I also made a circle cutting tool to help cut accurate circles.

Saturday 6-12-1999
I have made some "rings" that will be used to align the 8" pipe section that will be attached to the Air Manifold. They will also serve to keep an o-ring in place to help create an air tight seal between the pipes.

Sunday 1-21-2001
Hay Guys,
Well I finally got to the point of doing the first pressure test on it. I pumped it up to 150 lbs, (that's as high as the air compressor will go) and used soapy water to look for leaks. Well there where some expected and one unexpected. The unexpected leak is a very small pin hole at one of the 84 welds on the air tanks where it connects to the air manifold. There where no leaks at the welds on the air manifold ends. The other leaks where at the threads of the 24 bolts holding the front and rear of the air manifold on. As I will be taking it apart for installing the firing mechanism I did not seal the threads on the bolts. There where no leak at the 3 gasket areas or the at the large 8 inch OD oring I made that seals the two halves of the air manifold together with 12 large bolts. All in all, a good first run on the testing. Next I will hydra test the cannon with all leaks fixed and let it sit all day, venting the pressure and depressurizing it every hour or so.

I did notice something odd.
When I was venting the cannon, I did this through a 1/4 inch ID air hose that was 50 foot long so I could be in a safe distance from the cannon . When the pressure was vented it seamed to drop to zero then it would jump back up to around 60 psi and bleed down and jump back up to around 40 psi ect. ect. Well I thought that there was an obstruction in hose or the filling device I made with an air gauge and a ball valve, ( pic. soon to come ) Well I went and unplugged the hose from the cannon, It still did the same thing two more times.The hose hooked directly into the cannon through a male half of a quick coupler with a 1/4 inch ID.....Hmmm...... the outside temp was around 35 deg. F.