Monster tennis ball gun

[hoarp001]

Hi,

I built this gun to fire tennis balls, its all PVC, with a 3.5inch piston valve. Heres the specs:

1.5m of 110mm 16bar pipe (thats 5 feet of 4inch 200psi) chamber
2.5m of 75mm 16bar barrel (= 8.2 fee of 3inch 200psi)

The valve was custom made by me and a friend, the piston is turned out of a solid delrin rod. It is length adjustable to obtain the best opening distance, as space is quite limited inside the tee. Its piloted with a 1/4in QEV.

It sits on a sliding base which is so far uncompleted. Needs more straps and structural supports, and it also needs its shock absorbing bits.

The white stuff on the chamber joint is epoxy putty. Im not sure how but I ended up with a tiny leak in that joint, and I thought i might as well do the whole joint all the way round.

The aluminium on the barrel is to stop it drooping and it also helps support it and stop it wobbling after its fired.

Also I need to replace the ratchet straps for hose clips.





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Let me know what you think....

Pete
UKSGC.co.uk

[SpudFarm]

OMG that is HUUUGE!

i really love it! beast to say the least!

[brother361]

wow thats insane i guess you guys know exactly what you where doin good job it looks great

[brogdenlaxmiddie]

GOD THATS A BIG TENNIS BALL GUN! Wow, good job! However, if you had a bigger pilot, your performance would increase exponentially.

[magnum9987]

Howitzer!Yippee Hurray!

[hoarp001]

Mm well I can very easily screw a 3/4in qev on the back... i got one lying around in my garage...

[brogdenlaxmiddie]

Thats what I would do. The bigger the pilot, the faster the piston will move back. The faster the piston moves back , the faster the air will get to the ammo. I'm sure you know all of this but a 3/4" QEV would be awsome!

[Ragnarok]

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?

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.

[hoarp001]

Yeah il do it in the morning.

Oh also some other stuff i forgot to mention.

I work in the film industry and through my various contacts I have managed to borrow myself a Phantom HD Highspeed camera, shooting at rediculous frame rates. does 1000FPS at 2k HD (thats two times the resolution of normal, full HD) and will do up to 250,000fps at reduced rez and frame size.

Its worth a fortune, the lenses are £25,000 each, (we have four) and the whole system is £350,000 ($700,000).

Im really looking forward to getting some amazing footage with this, we are going to a feild to shoot stuff for afew hours. Hopefuly get some footage of the balls exiting the barrel and some nice impacts and super-slomo.

[psycix]

Surely looks awesome with that shiny barrel.
It would indeed be very cool if you can record this massive thing with a hi-speed cam.

[starman]

Nice work. That's sweet that you are able to machine out custom parts. Have you shot the thing yet? With that long barrel it can't help but be a pretty fair performer.

[hoarp001]

My compressor only does 8bar (110ish PSI) and it currently has a leaky valve. I got a whole box of stuff arriving tomorrow to get it working. Ive fired lots of dry fires at 7 bar, and I have stuck lots of stuff in the barrel (but no tennis balls yet).

I have fired things like tea towels and rubber gloves, (anything fairly soft that fits in the breech as I have been making it indoors). I put a foot long paper tube, like a toilet roll tube) and shot it at the wall at 5bar (60ish psi) and it turned to dust, which i think is quite interesting considering its hollow.

I was asked to build this thing for a specific job. I cant say what yet, but it should be pretty cool. When we do it we are actually running on nitrogen, as its easier to reg nitrogen down to 10bar from a tank than it is to hire and drag along a massive compressor.

[brogdenlaxmiddie]

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?

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.

Ok, not exponentially, but it improves it HUGELY!!

[socoj2]

Christ 3.5" delrin rod that was cheap.

[hoarp001]

The rod was 4inch in diameter.

Its dirt cheap, two rods a foot long and 4inches in diameter was £5 off ebay