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will this work?? piston valve
Posted: Tue Jul 29, 2008 5:35 pm
by The_Kangsta
Will this idea work? its not really a *proper* barrel sealing valve, but it should work.
Posted: Tue Jul 29, 2008 5:45 pm
by Coodude26
Whats with the arrows at the end of the chamber?
And no one can tell you for sure if something will work or not because you haven't even built it yet.
Posted: Tue Jul 29, 2008 5:48 pm
by jrrdw
It might. I'de move the sealing face to the center of the tee. More flow that way.
Posted: Tue Jul 29, 2008 7:19 pm
by Gippeto
If it was a straight pipe, it would be a co-ax. Which is just fine!
Comments;
If that is anywhere near scale, you should reduce the pilot volume.
Otherwise, jrrdw gives good advice, as always.
Posted: Tue Jul 29, 2008 7:22 pm
by potatoflinger
It will work, it is pretty much just a coaxial piston valve with a tee and another air chamber coming out of it.
Posted: Tue Jul 29, 2008 7:32 pm
by mobile chernobyl
What size Tee is that you plan on using? If its a 2" I have a way better design thats just as easy to make that I use on my "1 gallon" launcher.
Posted: Tue Jul 29, 2008 7:39 pm
by Mr.Sandman
pretty good but why this design? also what do you plan on using as your piston? wait nevermind i was looking at it wrong.
Posted: Tue Jul 29, 2008 10:32 pm
by the unit
Gippeto wrote:If it was a straight pipe, it would be a co-ax. Which is just fine!
Comments;
If that is anywhere near scale, you should reduce the pilot volume.
Otherwise, jrrdw gives good advice, as always.
while your talking about pilot volume, what would be a good pilot volume for a 1.5" chamber co-ax
Posted: Tue Jul 29, 2008 11:16 pm
by MrCrowley
Coodude26 wrote:Whats with the arrows at the end of the chamber?
And no one can tell you for sure if something will work or not because you haven't even built it yet.
The arrows show that the chamber is not to scale and will be longer i'm guessing.
He is wondering if the concept will work, if you understand physics you can tell if something will work before building it...idiot.
Posted: Tue Jul 29, 2008 11:27 pm
by Gippeto
You didn't say what your barrel id was so I'll just give an example.
If your barrel id is other than .750" you can adjust things accordingly.
Just remember that TOTAL PISTON TRAVEL should (ideally) be equal to id/4 minimum. A little bit more is okay, a little bit less will hurt performance.
Theoretical canon as follows:
Barrel inside diameter of .750inches
Chamber inside diameter of 1.50inches
Ideal piston travel is barrel id divided by 4.
So your piston should move .750"/4 or 0.1875" (3/16") before hitting your bumper. (Mouse pad, camping mat, etc.)
This would make your theoretical "ideal pilot volume" roughly
pi*r*r * .1875" or 3.14*.750*.750*.1875 = 0.3312cu.in.
Hint: Use this number in ggdt to size your pilot valve. Increase/decrease the pilot diameter until you eliminate piston bounce.
Okay, that's in an ideal world. In "our world", call it 1/4" of total piston travel, and a pilot volume of 0.44 cu.in.
Posted: Wed Jul 30, 2008 12:52 pm
by Coodude26
MrCrowley wrote:Coodude26 wrote:Whats with the arrows at the end of the chamber?
And no one can tell you for sure if something will work or not because you haven't even built it yet.
The arrows show that the chamber is not to scale and will be longer i'm guessing.
He is wondering if the concept will work, if you understand physics you can tell if something will work before building it...idiot.
No need to insult me. I just didn't want him to get over-excited when a couple people tell him it would work, and then be careless with the construction.