SpudFiles

psycix wrote:Surface of flow: 2*pi*r*r

There's no factor of 2 in area of a circle.
It's 2*pi*r for circumference, pi*r² for area - you have a blend of both. However, the ratio is fine.

The problem with dual valves is that the extra pipe work adds a lot of dead space.

I still have plans I drew up a while ago for a 30 bar four piston valve cannon with a 2 metre barrel (appropriately called Leviathan). GGDT tells me it would get 262m/s or 860 fps (2434 J/1795 ft-lbs) with a potato.
I was suffering from visions of kickass because the A-Team theme had come up on my music player though - I find that cannons change depending on the music I was listening to when I came up with them.

I'm almost tempted to try it, simply to see what that much power is like.

The problem with dual valves is that the extra pipe work adds a lot of dead space.

I still have plans I drew up a while ago for a 30 bar four piston valve cannon with a 2 metre barrel (appropriately called Leviathan). GGDT tells me it would get 262m/s or 860 fps (2434 J/1795 ft-lbs) with a potato.
I was suffering from visions of kickass because the A-Team theme had come up on my music player though - I find that cannons change depending on the music I was listening to when I came up with them.

I'm almost tempted to try it, simply to see what that much power is like.

that sounds awesome although wouldn't it be hard finding a 4 into 1 socket? the pilot would also have a large(ish) volume and as you said the dead space is a limitation but it could be done, although i wouldn't like the job of making four identical piston valves i haven't even made one work yet

ALIHISGREAT wrote:that sounds awesome although wouldn't it be hard finding a 4 into 1 socket? the pilot would also have a large(ish) volume and as you said the dead space is a limitation but it could be done, although i wouldn't like the job of making four identical piston valves i haven't even made one work yet

4 valves is easy work, it's just a repetition of a basic concept. Also, 4 into 1 isn't that hard either - Two valves feeding into the arms of a tee on each side, and those tees feeding into a third. Remaining tee arm goes to barrel.

Those would be minor issues. A high volume of 30 bar air dumping through 4 valves... would be loud.
I might make it in a smaller size, for somewhere between a thousand joules/thousand foot pounds.

Those would be minor issues. A high volume of 30 bar air dumping through 4 valves... would be loud.
I might make it in a smaller size, for somewhere between a thousand joules/thousand foot pounds.

maybe a marble cannon with a 2m barrel working at those pressures would have good power although the barrel would be expensive or you could use four 1/4" qevs on a 6-10mm cannon...

on an unrelated note how were you planning to get to 30bar? i'm guessing an air rifle pump or a homemade pump?

The modified compressor I'm planning to make should get to just over 30 bar.
I was thinking more like a 4 foot long 28mm or 35mm barrel.

Ragnarok wrote:The modified compressor I'm planning to make should get to just over 30 bar.
I was thinking more like a 4 foot long 28mm or 35mm barrel.

i think i may try and find a freezer pump and make a compressor out of that which should be a challenge (for me) at some point when i have decided whether i really want a paintball marker or not... damn my indecisiveness

I don't know whether I want to build a gas booster or modify a fridge compressor, but I'm sure prices will make the decision for me.

And I have a similar thing going on. Right now, I'm telling myself I don't need things, and then want them, then realise there's a way round it, then...

Ragnarok wrote:

psycix wrote:Surface of flow: 2*pi*r*r

There's no factor of 2 in area of a circle.
It's 2*pi*r for circumference, pi*r² for area - you have a blend of both. However, the ratio is fine.

The problem with dual valves is that the extra pipe work adds a lot of dead space.

OMG your right.....
I should look up formulas before posting them argh....
Feeling stupid lol...

But indeed the ratio stays the same. So its not a worse mistake... only stupid.

octane89 wrote:Ions...paintballs low point. I have seen a 1inch qev, and will see if I can find it in my history online.

I read about some here.
http://www.globalmanufacturing.com/prod ... ccessories

Could this be used as a ready made chamber and valve package on a marble gun say?

sorry for hijacking ill get back on topic now. if you were to have those four qevs would the added 10 turns make a difference to the power or will it be overshadowed by the sheer flow of those valves

Carlman wrote:sorry for hijacking ill get back on topic now. if you were to have those four qevs would the added 10 turns make a difference to the power or will it be overshadowed by the sheer flow of those valves

Well, I would probably make piston valves... but the flow from the valves would be a much larger deciding factor than the losses from the turns.

Per valve, I've built launchers with a similar number of turns which worked just fine.

I found a 3/4" QEV for you on eBay that is $9.99 + shipping, ending at 10 pm (1.5 hours from the time of this post) Eastern Time (I think ). Not only is it a quality QEV, it can be filled from the chamber side, a quality which the McMaster ones do not have.

Send me a PM if you want it.

Edit: Found a big 1.5" for the same price

Are those QEV's gone ?

You better not buy all of them! When I come home tommarow I expect to see at least two there!

Ok I just bought a 3/2 inch QEV and I was wondering, it has two pilot intakes on the back of it. Whats the deal with that? Oh and btw there are now 29 left.

I have 2x 3/4 deltrols ill sell for $30 Shipped.