SpudFiles

Ragnarok wrote:Nice one Pete - it looks better each time I see it.

You know, what you said might be right (I was suffering a brain-fart earlier) - is there a bigger piston valve than that?

brogdenlaxmiddie wrote:However, if you had a bigger pilot, your performance would increase exponentially.

Exponentially, eh? You mean to say the launcher's performance is directly linked by a function where the order of the function is the size of the pilot?
Damn, I never knew that.

Mind you, I do know lots of other things.

Well if you look at the cannon in my signature, the piston is bigger because its 4 inch. And possibly schmannman has the biggest one with his SWAT cannon.

Thats a very awesome cannon, reminds me of my cannon, except built a littler nicer and has supports (oh yea i gotta put supports on my cannon, eh ill do it tomorrow probably not.

Now launch other things besides tennis balls and you have a destructive cannon.

Amazing cannon. Your lucky to have access to a lathe. Hope to see some amazing work out of you.

Damn nice, i'd hate to think how much it cost, so will you tell us?

Well it was subsidiesed by the people that asked me to build it. The barrel pipe is currently on loan, and I was donated the chamber peice. The piston cost a fiver to make, and i spent about £50 on fittings. The base is made out of stuff i already had.

Also spent about 30 quid on airline parts

A load of stuff arrived today so I did some more work on the cannon. Nearly done now.


New piston bolts and firing system.


The out of focus safety relief valve. If the piston jams and wont fire, you open this to let the air out.


A shot down the barrel. It shows the piston at the end, and it shows how straight the aluminium makes the pipe.



The nearly finished base. Strapped down properly now...


The new remote control.

Looks great! You've added some really cool stuff to an already good cannon. I can honestly say, I look damn forward to your next builds! :salute:

That long hose in going to give a hell lot more pilot volume, this wil probaly result in a slower opening QEV-->piston valve. We will wait for the judgement of JSR .
G's from the Dutch, Tom

I just had a shootout in the garage. The projectile was an empty coke bottle (small 500ml kind). It was only half way down the barrel as it wont fit through the breech and I didn't have anything long enough to hand to poke it down further. I shot from about 5 feet (limited space in there) and the shooting pressure was ***80PSI***

I did set a camera up to film the action but unfortunately, the only time when ive ever had a dirty head, it just happens to cause a problem right when the gun fired, so I have no video of it

Oh well, I got some cool damage photos:

hoarp001 wrote:I did set a camera up to film the action but unfortunately, the only time when ive ever had a dirty head, it just happens to cause a problem right when the gun fired, so I have no video of it

I'm taking a guess here that you might be meaning a read/write head for your tape based camera?

*Edit: all that time building the cannon and now you don't have a ramrod long enough for it

Yeah all the best cameras are tapebased. DIgital storage for pro video production is a bad idea. I operated on a film recently shooting to solid state card, we lost a whole reel caus the camera crashed. Tapes are by far the most secure way of working... Until you get a dirty head.

It has a breech, as its designed mainly for tennis balls so i never thought about a ramrod for it...

That's an empty bottle? Blimey, you get the idea of the speed it must have been doing.

I'm impressed. It should be up to doing any job it's called on to do very nicely, unless the people decide they need a supersonic TB.

Great job machining all those parts.
EDIT: I forgot to add, this thing is freaking AWESOME.
EDIT 2: Hotwired - It's a breechload but I can't really tell where it is in comparison to the rest of the gun, I don't think he needs a ramrod though.

The piston is delrin. Its similar to nylon, its quite springy. its a plastic resin stuff. Its very cheap and turns down very well on the lathe. Infact the tool stripped off a continuous string of delrin which shot about 5 feet and landed in a heap on the floor, it was qutie spectacular.

The breech is right at teh base of the barrel. When its closed the breech cover sits flush with the base fitting that screws into the valve.

It was designed to shoot tennis balls so I never thought Id put anything else in the barrel so I never thought of making a ramrod. The breech fits other stuff too, but not a coke bottle.

hoarp001, very nice build.

One suggestion, you might want to add additional bracing between the chamber and barrel.

As your ammo gets heavier the recoil increases. With a gun that size there is going to be a heck of a lot of recoil in the barrel, but the bracing from barrel to chamber is pretty long. A small shift of the barrel backwards relative to the chamber is going to put a tremndous amount of stress on the elbows. The large distance the braces spans mean they won't be very effective at transfering the recoil to the chamber. The gun might be OK with tennis balls, but once you get tired of'm you probably try heavier ammo.