Login    Register
User Information
Username:
Password:
We are a free and open
community, all are welcome.
Click here to Register
Sponsored
Who is online

In total there are 74 users online :: 4 registered, 0 hidden and 70 guests


Most users ever online was 155 on Mon Aug 15, 2016 1:40 am

Registered users: Bing [Bot], Google [Bot], Google Adsense [Bot], Yahoo [Bot] based on users active over the past 5 minutes

The Team
Administrators
Global Moderators
global_moderators.png CS

First Piston Valve Pneumatic

Post questions and info about pneumatic (compressed gas) powered cannons here. This includes discussion about valves, pipe types, compressors, alternate gas setups, and anything else relevant.
Sponsored 
  • Author
    Message

First Piston Valve Pneumatic

Unread postAuthor: Gun Freak » Mon Jan 25, 2010 4:49 pm

Hey guys, this is my fist piston valve attempt, and after about 20 different designs (lol), i came up with this.

Image

i wanted to know if this would be an effective and powerful design. i shoot my current gun at about 120 psi[/img]
  • 0

User avatar
Gun Freak
Lieutenant General
Lieutenant General
 
Posts: 4969
Joined: Mon Jan 25, 2010 4:38 pm
Location: Florida
Country: United States (us)
Reputation: 11

Unread postAuthor: deathbyDWV » Mon Jan 25, 2010 5:06 pm

Looks like you've got it.

It should work.

What size of barrel will you use?
  • 0

Life's too short to mark off the items on your wish list...
User avatar
deathbyDWV
Colonel
Colonel
 
Posts: 576
Joined: Sat May 16, 2009 4:02 pm
Location: Owasso, OK
Reputation: 2

Unread postAuthor: Gun Freak » Mon Jan 25, 2010 5:10 pm

i will be using a 1/2" barrel, that extends into the 3/4" T so that the piston can seal it.

thanks so much for the reply :D
  • 0

User avatar
Gun Freak
Lieutenant General
Lieutenant General
 
Posts: 4969
Joined: Mon Jan 25, 2010 4:38 pm
Location: Florida
Country: United States (us)
Reputation: 11

Unread postAuthor: MrCrowley » Mon Jan 25, 2010 5:21 pm

Your pilot volume looks a bit big, it's even worse that it is using PVC fittings as they seem to have more volume than same sized metal fittings.
Just try to keep it as small as you can, and if you can't make it any smaller, up the pilot valve. :)
  • 0

User avatar
MrCrowley
Moderator
Moderator
 
Posts: 10207
Joined: Fri Jun 23, 2006 10:42 pm
Location: Auckland, New Zealand
Country: New Zealand (nz)
Reputation: 4

Unread postAuthor: Gun Freak » Mon Jan 25, 2010 5:25 pm

it may seem big because the diagram is all dissasembled... but does the pilot volume make a difference?
  • 0

User avatar
Gun Freak
Lieutenant General
Lieutenant General
 
Posts: 4969
Joined: Mon Jan 25, 2010 4:38 pm
Location: Florida
Country: United States (us)
Reputation: 11

Unread postAuthor: deathbyDWV » Mon Jan 25, 2010 5:27 pm

Oh yeah... I forgot to mention that crowley...

If you didn't know already, a smaller pilot volume leads to faster piston opening time and more power.
  • 0

Life's too short to mark off the items on your wish list...
User avatar
deathbyDWV
Colonel
Colonel
 
Posts: 576
Joined: Sat May 16, 2009 4:02 pm
Location: Owasso, OK
Reputation: 2

Unread postAuthor: Gun Freak » Mon Jan 25, 2010 5:29 pm

ohh. thanks. maybe i wont put the whole stock deal, just the ball valve right after the Tee that houses the schrader?
  • 0

User avatar
Gun Freak
Lieutenant General
Lieutenant General
 
Posts: 4969
Joined: Mon Jan 25, 2010 4:38 pm
Location: Florida
Country: United States (us)
Reputation: 11

Sponsored

Sponsor
 


Unread postAuthor: MrCrowley » Mon Jan 25, 2010 5:30 pm

You'll notice not every fitting will fit together perfectly, so if a fitting can only fit halfway in to another fitting, this creates more volume. Yes, the pilot volume is quite essential to making a good valve. If you have a big enough pilot valve, it doesn't matter so much. Just remember the smaller pilot volume you have, the faster your valve will open.

If your pilot volume is too big, your pilot valve too small and your piston isn't sealed with o-rings, your piston might not even open at all.
Just something to keep in mind. :)
  • 0

User avatar
MrCrowley
Moderator
Moderator
 
Posts: 10207
Joined: Fri Jun 23, 2006 10:42 pm
Location: Auckland, New Zealand
Country: New Zealand (nz)
Reputation: 4

Unread postAuthor: deathbyDWV » Mon Jan 25, 2010 5:34 pm

The stock is fine.

Your pilot volume is what is between the back of the piston and the front of your pilot valve. That is what you want to make smaller.
  • 0

Life's too short to mark off the items on your wish list...
User avatar
deathbyDWV
Colonel
Colonel
 
Posts: 576
Joined: Sat May 16, 2009 4:02 pm
Location: Owasso, OK
Reputation: 2

Unread postAuthor: Gun Freak » Mon Jan 25, 2010 5:35 pm

this is my first day on spudfiles... sorry for being stupid :D
the pilot volume is to the left of the ball valve right? so if i put nothing behind it it will open quicker?
  • 0

User avatar
Gun Freak
Lieutenant General
Lieutenant General
 
Posts: 4969
Joined: Mon Jan 25, 2010 4:38 pm
Location: Florida
Country: United States (us)
Reputation: 11

Unread postAuthor: MrCrowley » Mon Jan 25, 2010 5:39 pm

No worries, we don't mind helping everynow and then :P

The pilot volume is between the piston and the pilot valve. The pilot valve in this case is that 1/2" ball valve you have. Anything on the left side of that ball valve doesn't matter as long as it can allow air to escape in to the atmosphere.

Just remember that the faster you can get the air pressure in the pilot volume out in to the atmosphere, the faster your valve will open. Ways to do this are; you need to minimize the pilot volume and maximize the pilot valve. Or you can do one or the other, big pilot valve means you can have a big pilot volume. Small piot volume means you can have a smaller pilot valve.

Just build your cannon how you think is right, and then if you have troubles with the piston later we can sort that out.
  • 0

User avatar
MrCrowley
Moderator
Moderator
 
Posts: 10207
Joined: Fri Jun 23, 2006 10:42 pm
Location: Auckland, New Zealand
Country: New Zealand (nz)
Reputation: 4

Unread postAuthor: deathbyDWV » Mon Jan 25, 2010 5:40 pm

No, your pilot volume is to the right of the ball valve.

And don't call yourself stupid. You are just new and un-informed. Not stupid.

Edit... Beat me to it crowley.
  • 0

Life's too short to mark off the items on your wish list...
User avatar
deathbyDWV
Colonel
Colonel
 
Posts: 576
Joined: Sat May 16, 2009 4:02 pm
Location: Owasso, OK
Reputation: 2

Unread postAuthor: Gun Freak » Mon Jan 25, 2010 5:44 pm

Alright. I just wanted to make the gun the best it could be. Thanks so much for your help :D

i will take your comments into consideration. how about i redesign it then you can tell me if its better?

for now i got to go

thanks again
  • 0

User avatar
Gun Freak
Lieutenant General
Lieutenant General
 
Posts: 4969
Joined: Mon Jan 25, 2010 4:38 pm
Location: Florida
Country: United States (us)
Reputation: 11

Unread postAuthor: Gun Freak » Mon Jan 25, 2010 6:12 pm

i've been thinking... i cant think of any ways to get less pilot volume... because i have to pump it up through a schrader that has to be to the left of the piston so it can push it into the barrel, right? so how am i supposed to lower the pilot volume? i may use metal fittings, which may help... but will that be enough?
  • 0

User avatar
Gun Freak
Lieutenant General
Lieutenant General
 
Posts: 4969
Joined: Mon Jan 25, 2010 4:38 pm
Location: Florida
Country: United States (us)
Reputation: 11

Unread postAuthor: deathbyDWV » Mon Jan 25, 2010 6:28 pm

You could just screw the schrader straight into the side of the PVC male adapter on the right of the ballvalve. As long as it is through two layers of PVC, it will be plenty strong.
  • 0

Life's too short to mark off the items on your wish list...
User avatar
deathbyDWV
Colonel
Colonel
 
Posts: 576
Joined: Sat May 16, 2009 4:02 pm
Location: Owasso, OK
Reputation: 2

Next

Return to Pneumatic Cannon Discussion

Who is online

Registered users: Bing [Bot], Google [Bot], Google Adsense [Bot], Yahoo [Bot]

Reputation System ©'