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 78 users online :: 5 registered, 0 hidden and 73 guests


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

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

The Team
Administrators
Global Moderators
global_moderators.png CS

double pilot vertical piston

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

double pilot vertical piston

Unread postAuthor: kydavies » Sat May 29, 2010 12:52 pm

a while ago i was trying to wrap my head around the idea of modding my super cannon from a ball valve to a piston valve but because its already built it's kind of hard. so hears what i came up with a cross between a ball valve and a piston
  • 0

Attachments
piston mod kit.png
piston mod kit.png (16.98 KiB) Viewed 287 times
mikemurph wrote:yea, the ammo has been changed to a more aero dynamic projectile. it consists of the back half of a dart, and a hot glue ball
AHahahahah!!
User avatar
kydavies
1st Lieutenant
1st Lieutenant
 
Posts: 258
Joined: Thu Apr 22, 2010 9:09 pm
Location: Comox BC
Reputation: 0

Unread postAuthor: irisher » Sat May 29, 2010 12:54 pm

Wouldn't that just be a chamber sealing piston valve?
  • 0

User avatar
irisher
Lieutenant Colonel
Lieutenant Colonel
 
Posts: 420
Joined: Mon Dec 29, 2008 2:53 am
Reputation: 0

Unread postAuthor: kydavies » Sat May 29, 2010 12:56 pm

i have no idea what it is cause i really dont have any experience with piston valves
  • 0

mikemurph wrote:yea, the ammo has been changed to a more aero dynamic projectile. it consists of the back half of a dart, and a hot glue ball
AHahahahah!!
User avatar
kydavies
1st Lieutenant
1st Lieutenant
 
Posts: 258
Joined: Thu Apr 22, 2010 9:09 pm
Location: Comox BC
Reputation: 0

Unread postAuthor: Gun Freak » Sat May 29, 2010 1:14 pm

That would be very hard to make functional, how would you make it seal? O-rings wouldn't work here.
  • 0

OG Anti-Hybrid
One man's trash is a true Spudder's treasure!
Golf Ball Cannon "Superna"M16 BBMGPengunHammer Valve Airsoft SniperHigh Pressure .22 Coax
Holy Shat!
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: Technician1002 » Sat May 29, 2010 1:55 pm

For that type of valve to function, the piston must be much larger in diameter than the valve porting to provide a seal area to the cross flow much like a ball in a ball valve is larger than the port.

The chamber pressure will provide a side thrust on the piston causing increased friction (even ball valves do this some).

The worst problem with the design is the chamber pressure provides no pressure boost once the valve begins to open. This valve slowly opens as the pressure in the pilot drops and the gas spring slowly expands slowly opening the valve. Remember as the piston moves the gas spring as the volume increases, drops in pressure. You will have little need for much of a bumper.

These sliding valves are sometimes used in motorcycle carburetors where a full closed seal is not needed and the pressure is less than one Atm. They are not used as a high speed cannon valve and for good reason.

In your drawing, the 40 PSI area is way too small. In absolute pressure that is only (40 + 1 atm) 55 PSI. If it doubles volume (moves the same distance as it's volume) the pressure plummets to 27.5 PSI absolute or (27.5- 15) 11.5 PSI on the gauge. The pressure will be below atmospheric before it opens. (it won't open)

The idea shows you are thinking of options which is good. It was posted here for everyone to evaluate before you built it which is good. I would recommend learning the gas laws and become your own best critic to critique your own ideas.

Many of my wild ideas are proven to not work and are never built. Some of my ideas that work on paper are sometimes posted here and tossed around and something I missed gets identified. From there I build the best ideas. I have several plans on the drawing board. One is a full auto combustion design and another is a 2 stage air piston springer for supersonic launches.
  • 0

User avatar
Technician1002
Chief of Staff
Chief of Staff
 
Posts: 5190
Joined: Sat Apr 04, 2009 11:10 am
Reputation: 14

Unread postAuthor: kydavies » Sat May 29, 2010 3:57 pm

k thanks, looks like im back to the drawing board
  • 0

mikemurph wrote:yea, the ammo has been changed to a more aero dynamic projectile. it consists of the back half of a dart, and a hot glue ball
AHahahahah!!
User avatar
kydavies
1st Lieutenant
1st Lieutenant
 
Posts: 258
Joined: Thu Apr 22, 2010 9:09 pm
Location: Comox BC
Reputation: 0

Unread postAuthor: Crna Legija » Sat May 29, 2010 8:22 pm

have you read this
  • 0

'' To alcohol... The cause of, and solution to, all of life's problems.”
--Homer Simpson

Add me on ps3: wannafuk, 8/11/11 cant wait
User avatar
Crna Legija
Major General
Major General
 
Posts: 2333
Joined: Sun Jul 20, 2008 5:14 am
Location: australia
Reputation: 0

Sponsored

Sponsor
 


Return to Pneumatic Cannon Discussion

Who is online

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

Reputation System ©'