SpudFiles

I soon will start on my latest cannon, my third. I've been thinking about it for a few days and have figured it out. It will consist of a 15 foot piece of 8inch Schedule 40 PVC cut in to three 5 foot lengths. They will be placed side by side in a roller cart. Each will be capped on one end with a schrater valve. On the other end will be a automatic modded sprinkler valve. After the valve on each the pipes will connect and form something like a _ _|_ _
so one pipe on one side, 2 connect on the other, and they go to a T pipe that is not glued in, so the barell that goes into it can move at a free 180 degrees.
It will have multiple barrel attachments ( not quite sure how to do that yet) and the 3 inch barelle will be 15-20ft long.
The reason for 3 pieces of the 8 inch pipe instead of one long piece is to allow me to either fire 1 shot withall the power, or 3 seperate shots at a 1/3 of the power.

The total chamber size will be about 8000cu in
Luckily i found a great irigation store that sells all this for real cheap, plus they give me the contractors discount which is 30% off!

I've included a drawing to give an idea of what it will look like.

Sorry how bad it is, im no artist
Suggestions and comments

Your ratio wont be that bad.
8x15=120
3x20=60
2:1 ratio
When you said your going to attach schrader valve to the ends I assume that you plan on pumping it up with a bike pump (manual/ electric) If so thats not going to work very well when you have to fill up that much area so I would suggest a air compressor if you planned other wise. If you end up building it you defintly need to post videos and pictures. If I may suggest I would recomend that you arrange the air tanks like in the picture below and then have the barrel a straight shot out of the top tank with a tee to connect it to the bottom two tanks. I think it would just look cooler arranged this way (no practical use behind design besides that it might be more compact)

Hi, thanks for replying with some feedback. Yah that design works good to, ill have to try both once i get the parts and see which is easier to make, im trying to be as cheap as possible but still having a great cannon.
And no i wont be using a bicycle pump, im using a compressor that does 100psi at like 2.8cfm probably will still take like 5-7min to fill to 100psi since the cfm measures are usually overrated. The cool thing is though this gives meaning to Cannon :p it will look like one with it on a rolling cart , should be enormous =]

Ya im not quite sure on barel length, if you use the pneumatic calc it usually says something like 400ft long lol
I wonder if its possible to make some type of tellescoping barel, since 2-25ft is quite long =]

Also, the largest cannon ive seen on line is a 3000cu in one that can shoot tennis balls at mach2 (1300mph)with a 10ft barel mine will be 8000cu inches and have a 20ft barel so i probably will be able to improve on that speed ( id hope

Thanks, and of course ill be taking LOTS of pics and videos once its done =]

wee i just calculated my specs from http://www.bavetta.com/aircannon.html

im supposed to have a 350ft barel, and exit velocity of 564m/s
and max height of 53375ft

Of course theres no way id ever reach those estimates hehe but its still fun to imagine =p

The <a href="http://www1.iwvisp.com/thehalls/GGDT/in ... l">GGDT</a>... accept no substitutions.

Assuming you are planning on using a sprinkler valve, a tenis ball gets a top velocity of 350 feet/sec at 120", and a 150 g projectile gets a top speed of 335 feet/sec at a bit over 200"

hmm thats it?

I was hoping for much better results, I really don't want to have to play for 3 supah valves jeeze thats like 300+ bucks =\

And ggdt doesnt work on my computer, it gives me an error7 out of memory error =(

Well, you could have 1 supah, an auxilary chamber, and a few 2" ball valves (PVC ones go for like 12$); use the auxilary chamber to seat the supah (by oppening and then closing a small ball valve that lets the air into the pilot volume), then open the ball valve connected to the chamber you wish to fire.
Like this (the periods are placeholders):

(chamber)-(2"bv)-|
(chamber)-(2"bv)-|--(supah[pilot])=========
(chamber)-(2"bv)-| . . . . . . . .|
(aux chamber)-(bv)------------/

On second thought, your aux chamber might have to be fairly big ... it'd probably be better to have the seating air come from the chamber to be used - have 3 small ball valves placed chamber-side of the 2 inchers.
(this works if you have 2 supas too, although you may want to use 3" ballvalves.)

With 2 (estimates of) supahs at 100 psi (max recomended operating pressure: 120 psi), you get 600 feet/sec with a 300 g projectile and 120"x3" of barrel (one chamber), and 1 supah gets you 500 feet/sec. 240"x3" of barrel get you 700 feet/sec with 2, and 570 with one.