SpudFiles

I'm really, really curious about how you get more than one shot per tank. That method would pretty much enable an amateur to build something like a pcp rifle. The trick has to be with your triggering method, because it's not like a qev is anything special. I've observed multi-shotting from two different barrel-sealers, though, so I can see that it might be possible. Perhaps a qev is easier to reseat than a piston valve?

Mmm it is kinda curious

I'd like to keep it under wraps though until I get round to making the semi-auto design I've got in the design process.

mm yer i am interested when you finally do tell us how make sure ya have diagrams to explain it, thnx. man that must be so kool to have semi auto.

You can't really get consistent triggering just by pulling a blowgun trigger or ballvalve. You might arrange a hammer valve, which is what I was thinking of, or you might have a pseudo-hammer valve, where your hammer hits the little button on the blowgun valve. A direct hammer with a schrader valve would be cheaper. I considered using a blowgun valve emptying into a small chamber, to limit the pressure loss. This small volume could be then emptied by a bleed hole of appropriate size. The problem with this being that the hole size would be critical: too big, and holding the trigger down longer would result in a longer shot; too small and you'd have to wait several seconds to a minute between rounds, maybe.

Hmm! Perhaps with the bleed-hole adjusted just right, you could just hold the trigger down and get full auto fire. The piston would bounce closed after a shot, and then the pilot chamber pressure would drop some more, and trigger the piston again. An auto-piston with only pneumatic action would be really sick!

is the piston in the qev the same as the airlines ones ie black plastic? cant wait to see the semi auto

love the colour of it. Nice valve use too.

leeeeshad wrote:is the piston in the qev the same as the airlines ones ie black plastic? cant wait to see the semi auto

I didn't even open up my QEV when I got it (wish I had) and it was from airlines so theres nothing different between it and a new one.

oh, thought you got it from technobots and didnt know if it was rated higher as i think airlines only said 145 psi, thanks 260psi track pump here i come

The QEV is manumactured by Mead Fluid Dynamics, link here: http://www.mead-usa.com/products/detail.aspx?id=46
check for their distributors which are in every US state, link here: http://www.mead-usa.com/distribution/index.aspx
There just happens to be two distributors of this item in my town, they are not retailers, but I can get the parts through my uncle who has an air conditioning installation business.

Hmm... so they won't deal with the public?

Thats a shame, quite a few people have asked about getting those in the US.

how much did this cost all up? could you plz PM me?

It cost about £100 to buy all the parts online and get them shipped to me.

I didn't pay for it though, I won a competition on the UKSGC forums where I designed a cannon and the competiton sponsor paid for me to build it

If you want to pm me about it feel free but I don't see anything I need to pm.

what is the biggest size of copper pipe you can get. I once saw 3'' but that was on a old copper still for mountain dew. ps. cool cannon i like the design and the bullpup idea.

Thankyou

You'd need to get out a loan from the bank to build something with the largest copper pipe I know of.

76mm is as high as I've heard of in the UK. Just over 2.99 inches.

You'd need to be in the business to even know where to buy it though, I've looked at the professional plumbers suppliers and the largest they do is 54mm at £55.22 for 3m.

I do know someone that does know where to get 76mm though, but thats only because he is a plumber.

I think that you can find it on ebay ya know you can find any thing on ebay. But really i almost had a chance to get one once from a friend but he moved away before i could.