A true cannon!

daveo · Thu May 10, 2007 1:47 pm

80 inches of 4inch tank a 72inch 2 1/2 inch barrel and a 2 inch ball valve. The valve works like a charm! It sounds like a shotgun going off and the recoil with just a tennis ball at 60 psi about broke my knee. The ball went over 900 ft with just 60 psi. Im going to take it to a 100 psi with a bottle of water shoved down the barrel later, maybe I will try and video it.

And I know I need to make a better support for the barrel/chambers.

spudthug · Thu May 10, 2007 1:52 pm

wow even though that is a ball valve i bet it has massive power

nice gun u should get into piston valves!

jjk92 · Thu May 10, 2007 2:26 pm

nice i always admired large ball valve users ...everyone always rags on them but there simple and durable not to mentoin the high pressures they can take

spanerman · Thu May 10, 2007 2:26 pm

you should spring load the ball valve

daveo · Thu May 10, 2007 2:40 pm

I am eventually going to spring load it.

When the ball valve is turned fast enough.....the gun makes a nice VERY LOUD pop and no air hissing out after the projectile has left. Im having a hard time believing a piston valve could do much better, as there are NO headaches with the ball valve, I have made some very nice piston valve guns and they all made that nice pop sound when shot. But there way too many problems with them, In my own opinion. All I have to do is unscrew the barrel and oil it every now and then. Multiple size barrels will be made too!!!

spudthug · Thu May 10, 2007 2:42 pm

ball valves un springed can only be openned at like 100ms minimum.. pistions open at about 4-5 ms if built properly. i have never had a probelm with any of my piston valves..

lukemc · Thu May 10, 2007 3:49 pm

thug you have never built a piston that didnt work right away? i find that hard to believe that you can just build a piston and on first test it seals perfect and fires perfect. aaaaannny way i like the gun very cool low frustration valve. as i said on the other your other topic i would have had a longer smaller diamiter barrel to make up for the slow ball valve speed but cool anyways

daveo · Thu May 10, 2007 4:22 pm

Yes...im thinking a longer 2 inch barrel, but water bottles fit right in a 2 1/2. I love it.

Hotwired · Thu May 10, 2007 4:26 pm

I've seen a pneumatic ram operated ballvalve on a cannon that opened in 90ms. So I kinda doubt the ability of a human to fully open a ballvalve only 10ms slower. -check the valve opening video clips on that one.

A ball valve gives full flow with little or no turbulence unlike every other common pneumatic valve.... Don't knock em.

The cannon looks like fun.

People say that a fixed angle on a cannon is wrong but in reality its no more fixed than any other large cannon

daveo · Thu May 10, 2007 5:19 pm

Hotwired wrote:I've seen a pneumatic ram operated ballvalve on a cannon that opened in 90ms. So I kinda doubt the ability of a human to fully open a ballvalve only 10ms slower. -check the valve opening video clips on that one.

Thanks for the tip....im going to look into that ram. Also the gun is heavy, I put the angle GGDT said was best for distance. Instead of propping it up all the time.

I shot it a few times straight up, the ball almost leaves your sight.

cb4289 · Thu May 10, 2007 6:49 pm

basic simple i like it

spudthug · Thu May 10, 2007 9:20 pm

thug you have never built a piston that didnt work right away? i find that hard to believe that you can just build a piston and on first test it seals perfect and fires perfect

of course not.. ive had many problems in the beginning..only on my first one though and after i fixed it it never ever failed again and i never take my gun apart any more..

joannaardway · Sat May 12, 2007 5:25 pm

I've seen lots of piston valves built, and have indeed done some of my own.
I have only ever seen one of those 12 valves (total) work absolutely flawlessly the first time (the most recent one of Ragnarok's, only finished today).

The rest sort of worked, but needed a fair whack of adjustment to get them sorted to the epitome of their operation.

Back to the start:
Ball valves can work very well for long barrels. I'd still look at ways to improve the opening time though.

Oh - whatever you do, don't be tempted to fill the barrel with water. The recoil (and potential failure) might well kill you.

TwitchTheAussie · Sat May 12, 2007 6:14 pm

Nice and simple matey. I dont think you should get a better chamber/barrel stock. This is deserving of my thumbsup because its a sweet and simple design for power :thumbright:

rna_duelers · Sat May 12, 2007 6:28 pm

Nice ball valve gun,get yourself a strong ass spring to help with the opening times but I have to admit some simple ball valve pneumatics are quite powerful.

As joan said-Wouldn't recomend filling the whole barrel with water and shooting,could see Newtons laws going against you and Darwins coming into light.

Get some damage pics up!Again nice gun and what type of band or clmap is that used to hold the barrel and chambers in suport of each other?