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Unread postPosted: Thu Jun 26, 2008 8:30 pm
Author: SEAKING9006
It doesn't need one. Almost the entire assembly is inside the main tank. When it's open, the pilot vent takes the place of the sprinkler valve. The way it's set up, the sprinkler valve is hooked up directly to the primary tank. The barrel inlet doesn't open the same time the pilot vent does. Once the pilot vent opens, the sprinkler valve closes. Because the pilot vent is pushing directly on the piston, the piston continues to move forward. The pilot vent, once the barrel inlet is open, will continue to vent until just before the piston re-seats itself. At that point, there will still be approx 10-20psi in the pilot valve. However, this will be countered by the spring. The whole thing with this cannon is that without the roller switch, the design might not work, or at least would be far less efficient.

Unread postPosted: Fri Jun 27, 2008 5:56 pm
Author: iknowmy3tables
so your tying fully automatic, but you know with the piston filling as fast as the chamber you better have a high flow input or small system

Unread postPosted: Fri Jun 27, 2008 5:58 pm
Author: SEAKING9006
No, it won't. I'm not looking for MG42 performance here. Just auto that fires. Besides, I'm going for as small a chamber volume as possible to minimize that effect enough so it doesn't effect muzzle velocity.

Unread postPosted: Fri Jun 27, 2008 6:02 pm
Author: MaxuS the 2nd
Ooops, it was I who did not understand...Ignore this post.

Unread postPosted: Sat Jun 28, 2008 1:30 pm
Author: iknowmy3tables
okay whats your projectile, and what is your air source? that's going to determine the practicality

Unread postPosted: Sat Jun 28, 2008 3:57 pm
Author: SEAKING9006
The projectile is still debatable. Might use golf balls if I could find some 1 1/2"SDR21 and 2" Sch-80. Air source will be a compressor, feeding into a secondary tank (not shown in graphic), which is connected to the primary tank, which surrounds the piston, by a regulator and a sprinkler valve. The regulator is to reduce air pressure and ensure faster filling and more consistency. For now, the project has been put on hold. I can't seem to find any pressure rated fittings above 2", and I have other projects which I could much more readily finish (My dad locked his tool drawers shut again :x ).

Unread postPosted: Sun Jun 29, 2008 3:25 am
Author: psycix
Why don't you first make a smaller prototype with BB or marble caliber?

Unread postPosted: Sun Jun 29, 2008 5:01 pm
Author: SEAKING9006
Well, the reason is, 1" is the smallest pipe I know that will fit inside another with a fairly decent fit.

Unread postPosted: Mon Jun 30, 2008 2:01 pm
Author: iknowmy3tables
I can't seem to find any pressure rated fittings above 2"
I don't think you need any, except for accumulation chamber(the one after the regulator. but I think its still too big, unless you had some insane quad regulator setup, I know my compressor couldn't do it, cause unless your compressor can fill your other spud guns from 0 to 90 psi in fractions of a second it won't fill fast enough, however I think the system is very practical for bbs

Unread postPosted: Tue Jul 01, 2008 1:29 pm
Author: SEAKING9006
I have done quite a bit of research lately pertaining to the action. I've calculated force levels at different pressures and selected a return spring. I should have higher-quality diagrams up by Thursday. But after Thursday, I'll be out for a week on vacation.

Unread postPosted: Tue Jul 01, 2008 1:31 pm
Author: SEAKING9006
iknowmy3tables wrote:unless your compressor can fill your other spud guns from 0 to 90 psi in fractions of a second it won't fill fast enough, however I think the system is very practical for bbs


Mine can't, but my dad's can. :wink: It's a 33 gallon 135psi max shop compressor. Mines a 3 gallon 120psi max comp.

Unread postPosted: Tue Jul 01, 2008 1:52 pm
Author: Sticky_Tape
he he I got 6 gallon 120 max compressor. you really should make a sistem for a smaller cal.

Unread postPosted: Tue Jul 01, 2008 2:47 pm
Author: SEAKING9006
I have added a new full-scale diagram, minus controls. Control diagram will be added soon, in the form of a schematic layout.

Unread postPosted: Tue Jul 01, 2008 4:02 pm
Author: SEAKING9006
Schematics uploaded.

Unread postPosted: Tue Jul 01, 2008 4:06 pm
Author: Sticky_Tape
Well that is cool why is there such a short barrel duhhhhh just kidding I know not to scale I like how the PILOT chambers air is put back into the secondary chamber.