Search found 45 matches

by Jabingo19
Wed Jul 13, 2011 5:25 pm
Forum: Pneumatic Cannons
Topic: Critique: Changeable Barrel Coaxial 2" Piston Cannon
Replies: 2
Views: 359

Critique: Changeable Barrel Coaxial 2" Piston Cannon

Please critique any problems you see, already had it told to me that I'm missing a ball valve before the quick connect.

Thanks!
Jabingo19
by Jabingo19
Wed Jul 13, 2011 2:53 pm
Forum: Pneumatic Cannons
Topic: .1835 C:B Ratio Acceptable for Pneumatics?
Replies: 23
Views: 2177

You have to take into account that the OD of the 2.5 inch barrel is 2.875. But thanks for checking my math! So yeah you don't use 1.25 as the radius for the 2.5 inch, you use 1.4375. But yeah I actually did my math wrong anyways, since the chamber volume actually ended up at 27.69 cubic inches. Glad...
by Jabingo19
Wed Jul 13, 2011 1:36 pm
Forum: Pneumatic Cannons
Topic: .1835 C:B Ratio Acceptable for Pneumatics?
Replies: 23
Views: 2177

Yeah I missed the ball valve too, thanks for the catch. But yes Mr Vortex, I just plan on threading smaller barrels within the larger 2.5 inch barrel, not too elegant but it will work. Also, thanks for the reassurances Technitian, I was beginning to worry a little that flow would be a problem. But t...
by Jabingo19
Wed Jul 13, 2011 1:03 pm
Forum: Pneumatic Cannons
Topic: .1835 C:B Ratio Acceptable for Pneumatics?
Replies: 23
Views: 2177

Alright, so here are the plans for the back half of this cannon. Includes everything important I guess. The idea for changeable barrels is due to the 1.5 inch female adapter that will be sitting at the bottom of the 2.5 inch barrel, should allow anything 1.5 inch or smaller to get in (all i really w...
by Jabingo19
Wed Jul 13, 2011 12:14 pm
Forum: Pneumatic Cannons
Topic: .1835 C:B Ratio Acceptable for Pneumatics?
Replies: 23
Views: 2177

Alright thanks Jack. Rough plans to come up soon.
by Jabingo19
Wed Jul 13, 2011 11:59 am
Forum: Pneumatic Cannons
Topic: .1835 C:B Ratio Acceptable for Pneumatics?
Replies: 23
Views: 2177

Barrel will be about 4 ft in a piece of 4" PVC (3" just wasn't giving me enough room for my liking), 2.5 inch sch 40 (so fairly rigid) it will be piloted by a sprinkler, so no higher than 125-150 psi

Hope that helps
Thanks
by Jabingo19
Wed Jul 13, 2011 11:51 am
Forum: Pneumatic Cannons
Topic: .1835 C:B Ratio Acceptable for Pneumatics?
Replies: 23
Views: 2177

Also, I don't know if you have any experience or whatnot, but is some sort of barrel support at the bottom of the coax necessary? At the end of the barrel is it necessary to have that supported so it doesn't wobble when sealing against the piston?
by Jabingo19
Wed Jul 13, 2011 11:07 am
Forum: Pneumatic Cannons
Topic: .1835 C:B Ratio Acceptable for Pneumatics?
Replies: 23
Views: 2177

Thanks Jack, I would play with GGDT but I have no idea how to... And Gun Freak I am capable of reading, and it said "Suggestively, the optimal C:B ratio for pneumatic guns, as predicted by GGDT are in the vicinity of 0.2~0.3" Also Jack, once I get some rough plans drawn up I'll post a pic.
by Jabingo19
Wed Jul 13, 2011 10:23 am
Forum: Pneumatic Cannons
Topic: .1835 C:B Ratio Acceptable for Pneumatics?
Replies: 23
Views: 2177

Haha yeah... Thanks Technician, sorry 43.25 and 235.6 cubic inches. As far as performance, I'm looking for, well, good performance. I certainly don't want to be limited by the lack of air to push it. I was looking on spudwiki and it said that according to GGDT the ideal was between .2 and .3, with c...
by Jabingo19
Wed Jul 13, 2011 9:53 am
Forum: Pneumatic Cannons
Topic: .1835 C:B Ratio Acceptable for Pneumatics?
Replies: 23
Views: 2177

.1835 C:B Ratio Acceptable for Pneumatics?

I'm working on a coaxial piston cannon with a 2.5 inch barrel and 3 inch chamber, at 48 inches long I calculated the volume of the chamber to be 43.25 square inches and the barrel to be 235.6, giving a B:C ratio of .1835. Is this within acceptable range? The reason I'm using 2.5 inch for the barrel ...
by Jabingo19
Tue Jul 12, 2011 1:44 pm
Forum: Ammo & Parts
Topic: 2" Ammo Ideas?
Replies: 8
Views: 1427

2" Ammo Ideas?

Just looking for a few ideas to put in my 2" barrel for my 2" piston valve cannon (showcase coming as soon as I get it painted)

Thanks
Jabingo19
by Jabingo19
Fri Jul 01, 2011 10:04 am
Forum: Pneumatic Cannons
Topic: Blowgun-Triggered Piston Valve
Replies: 7
Views: 862

Gippeto the design you linked is almost exactly what I'm doing... Which is weird. Anyways, I do have a lathe, on my older piston gun I bought two flat endcaps and turned them down, problem is that the ID of one of the pipes in my tee housing was actually bigger than the other, so it fit pretty loose...
by Jabingo19
Thu Jun 30, 2011 11:39 pm
Forum: Pneumatic Cannons
Topic: Blowgun-Triggered Piston Valve
Replies: 7
Views: 862

Blowgun-Triggered Piston Valve

I'm coming up with the basic concept of my next build, a more or less rifle-shaped golf ball gun, and I'm curious if with an efficient enough pilot area I can trigger the piston using just a blowgun and cutting out the unnecessary (in my opinion) cost of a sprinkler valve? Is it possible and I so ho...
by Jabingo19
Sun Jun 26, 2011 10:55 am
Forum: General How-To & Discussion
Topic: Male quick connect that holds pressure?
Replies: 4
Views: 562

Wow, yeah. I didn't even think of the ball valve. Duh. Thanks Crna.
by Jabingo19
Sun Jun 26, 2011 10:21 am
Forum: General How-To & Discussion
Topic: Male quick connect that holds pressure?
Replies: 4
Views: 562

Male quick connect that holds pressure?

Anybody heard of one? I am building a golf ball gun and I found out the hard way that quick connects do not hold pressure when detached from the compressor. Are there any that do and if so, where can I find them?

Thanks in advance.