M107 project

[JDP12]

hmm.. So basically the bolt head slides over the barrel, and when it is pulled back, the barrel is exposed?

Interesting concept, personally I like POLAND_SPUDs, but yours probably works just as well

[POLAND_SPUD]

If it has to look like M107 then yours is probably better
Mine would make more sense for a Barrett M95 replica, since it is loaded from the back

[Technician1002]

I think the valve design looks more like a toolie valve than a short piston QDV. The operation is similar. The big differences is piston length and diameter. The OD of a QDV is the same as the barrel I'D. The seal is on the piston OD, not piston face like a toolie. In a QDV, the barrel goes through the entire length of the chamber and the spool shaped piston fits inside that.

http://www.spudfiles.com/spud_wiki/inde ... ston_Valve

[qwerty]

After finishing my 2meters wingspan rc airplane and not being able to fly it because of the goddamn wind

Got picks? I make RC planes too

[Demon]

Got picks? I make RC planes too

The reason why i want to build this M107 replica is because my RC plane (completly all homemade that waits its maiden flight) is out of access for two weeks

Q.D. fittings can't be disconnected under pressure, can they ?

[the unit]

I think the valve design looks more like a toolie valve than a short piston QDV. The operation is similar. The big differences is piston length and diameter. The OD of a QDV is the same as the barrel I'D. The seal is on the piston OD, not piston face like a toolie. In a QDV, the barrel goes through the entire length of the chamber and the spool shaped piston fits inside that.

http://www.spudfiles.com/spud_wiki/inde ... ston_Valve

I also thought from what I could gather this is a toolies valve, with mechanical actuaction as oppose to pneumatic.

[Demon]

But can a Quick Disconnect be disconnected under pressure ?
Knowing that will modify my plans, so i need to know.

My guess is that i can't, since the two mating parts want to expel each other but are kept together by 4 steel balls. So the friction will make it impossible to take off under pressure.
Amiright ?

[Crna Legija]

yes they can but at 250+psi its near impossible. and only the female park will hold pressure back.

[Demon]

So higher the air pressure, the harder it gets ?
At 150 PSI, is it possible to disconnect the two without ripping the gun appart ?

[Gun Freak]

So higher the air pressure, the harder it gets ?
At 150 PSI, is it possible to disconnect the two without ripping the gun appart ?

It will be very difficult...

[warhead052]

It may not suit your needs, but add a ball valve inbetween the QD and the air chamber. When you shut the valve, it releases the pressure on the QD and makes it easy to pop off.

[ramses]

Not really, depending on your quick connect. I use ball bearing quick connects and they are still almost one handed at 150 PSI.

[Demon]

It will be fine i will put a ball valve on the pump to depressurize the system.

Here is some progress :
The yellopw thingy is the no-return valve and Q.D.
The CPVC pipe is the air chamber, barrel to the left, trigger to the right (the trigger will be rigged to be installed to the left).
The pump is the only thing left to do. The seal right now is total at lung pressure, so everything is alright !

[Demon]

Hello again

The pump works perfectly, but I can say as much of the QDV ...
The piston head won't seal, and the o-ring slide lets air slip trough. It should not be hard to repair tough, it will only take time.

Here's Teh pump :

[warhead052]

Nice job. It looks awesome, does the ball valve help?