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 64 users online :: 4 registered, 0 hidden and 60 guests


Most users ever online was 218 on Wed Dec 07, 2016 6:58 pm

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

The Team
Administrators
Global Moderators
global_moderators.png CS

Teaser pic of my 4inch piston cannon EDIT: cannon is done!

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

Teaser pic of my 4inch piston cannon EDIT: cannon is done!

Unread postAuthor: glass_05 » Mon Jul 13, 2009 11:39 pm

Here is just a teaser pic. Once the gun is tested tomorrow I will get some damage pics and a lot more pictures of the gun and some specs of it.

Be watching the showcase for me!

Image
  • 0

Last edited by glass_05 on Mon Jul 20, 2009 1:23 am, edited 2 times in total.
[url="http://www.airhardhq.com/"]Airhard HQ[/url]
User avatar
glass_05
Corporal
Corporal
 
Posts: 74
Joined: Sun Apr 27, 2008 7:08 pm
Location: Iowa
Reputation: 0

Unread postAuthor: Technician1002 » Mon Jul 13, 2009 11:48 pm

WOW. I like it. I'll wait for the showcase to find out what you are using for a bumper and piston. That should pack a punch.

:wav:
  • 0

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

Unread postAuthor: jackssmirkingrevenge » Tue Jul 14, 2009 1:10 am

Nice, whoever's napping in the background looks like he won't be resting for long :D
  • 0

User avatar
jackssmirkingrevenge
Donating Member
Donating Member
 
Posts: 24225
Joined: Thu Mar 15, 2007 11:28 pm
Country: Holy See (Vatican City State) (va)
Reputation: 66

Unread postAuthor: frozebyte » Tue Jul 14, 2009 4:37 am

Doesn't look like hes napping. Hes smiling in his sleep, scary... Hes probably just smiling til hes eyes look closed (Chinese proverb: 笑得见牙不见眼)
I may be wrong but is that messy line thing near the tee a decal or something similar?

Good luck!
  • 0

User avatar
frozebyte
Sergeant First Class
Sergeant First Class
 
Posts: 136
Joined: Wed Jun 24, 2009 7:22 am
Reputation: 0

Unread postAuthor: jackssmirkingrevenge » Tue Jul 14, 2009 4:55 am

frozebyte wrote:I may be wrong but is that messy line thing near the tee a decal or something similar?


Looks like spilt primer to me ;)
  • 0

User avatar
jackssmirkingrevenge
Donating Member
Donating Member
 
Posts: 24225
Joined: Thu Mar 15, 2007 11:28 pm
Country: Holy See (Vatican City State) (va)
Reputation: 66

Unread postAuthor: frozebyte » Tue Jul 14, 2009 5:24 am

I see, maybe he thought it looked nice so he didnt wipe it off?
  • 0

User avatar
frozebyte
Sergeant First Class
Sergeant First Class
 
Posts: 136
Joined: Wed Jun 24, 2009 7:22 am
Reputation: 0

Unread postAuthor: Technician1002 » Tue Jul 14, 2009 5:30 am

frozebyte wrote:I see, maybe he thought it looked nice so he didnt wipe it off?


Maybe it happened on the underside when it was being assembled and it wasn't noticed right away.
  • 0

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

Sponsored

Sponsor
 


Unread postAuthor: inonickname » Tue Jul 14, 2009 6:34 am

Once you've spilt primer it's too late

Looks excellent.
  • 0

PimpAssasinG wrote:no im strong but you are a fat gay mother sucker that gets raped by black man for fun
User avatar
inonickname
Lieutenant General
Lieutenant General
 
Posts: 2606
Joined: Sun Dec 07, 2008 3:27 am
Reputation: 0

Unread postAuthor: mobile chernobyl » Tue Jul 14, 2009 8:51 pm

m.e.k. takes care of "spilt" primer! get it at the Depot. just make sure you wipe it off right away or else it will just dry and you will have just spread the purpleness around.
  • 0

User avatar
mobile chernobyl
Colonel
Colonel
 
Posts: 732
Joined: Sun Dec 03, 2006 11:53 am
Reputation: 9

Unread postAuthor: glass_05 » Tue Jul 14, 2009 10:51 pm

yeah. that is primer. its not hurting anybody there

as for the test firing tonight... the piston seals wonderfully, but we couldnt get it to fire. we kept messing with the pitson and bumper and did get a couple of shots up, but they were VERY delayed and the power was horrible.

any ideas what the problem is?
  • 0

[url="http://www.airhardhq.com/"]Airhard HQ[/url]
User avatar
glass_05
Corporal
Corporal
 
Posts: 74
Joined: Sun Apr 27, 2008 7:08 pm
Location: Iowa
Reputation: 0

Unread postAuthor: THUNDERLORD » Tue Jul 14, 2009 11:14 pm

...any ideas what the problem is?


It's too late for me to be an @ss.
I got to work early.
....eat some steaks and p*ssy and figure it out later(?)
Beverage is not essential...

Judging by your avatar you like big women.
also in the pic it is easy to spot a wet -dreamer.

Anyhow hope you fix your cannon.
it will be simple.
I like your style. 8)
  • 0

-----SPEED,STRENGTH, AND ACCURACY.-----
"Procrastination" is five syllables for "Sloth".
Theopia 8)
Born To Be Alive!

THUNDERLORD
Major General
Major General
 
Posts: 1264
Joined: Fri Mar 28, 2008 1:42 pm
Reputation: 0

Unread postAuthor: LikimysCrotchus5 » Tue Jul 14, 2009 11:20 pm

Decrease pilot volume and use a valve that opens quicker to release the pilot volume.

The cannon reminds me of my cannon, which still need a support system and a barrel support, man in lazy. :(
  • 0

4SPC, My 4" piston 3" porting cannon
Memo:
Fix up copper cannon
Fix up 4SPC
Start Stirrup pump
Start Toolies piston bazooka
User avatar
LikimysCrotchus5
Brigadier General
Brigadier General
 
Posts: 1100
Joined: Tue Sep 04, 2007 10:16 pm
Reputation: 0

Unread postAuthor: glass_05 » Tue Jul 14, 2009 11:40 pm

I will try messing with the pilot volume and piston some more, as of right now I have it very small by the time I get the bumper in there.

And to trigger it I have a 1inch modded rainbird
  • 0

[url="http://www.airhardhq.com/"]Airhard HQ[/url]
User avatar
glass_05
Corporal
Corporal
 
Posts: 74
Joined: Sun Apr 27, 2008 7:08 pm
Location: Iowa
Reputation: 0

Unread postAuthor: Technician1002 » Wed Jul 15, 2009 1:03 am

glass_05 wrote:yeah. that is primer. its not hurting anybody there

as for the test firing tonight... the piston seals wonderfully, but we couldnt get it to fire. we kept messing with the pitson and bumper and did get a couple of shots up, but they were VERY delayed and the power was horrible.

any ideas what the problem is?


I have edited this wiki page to cover some of the math and theory that makes piston valves work and it includes some details that make some tempermental.

http://www.spudfiles.com/spud_wiki/index.php/Piston_valve
See the Small Ratio or QEV section for common problems with pistons and their causes.

To troubleshoot the valve, some of the parameters will need to be known.

These are;
1 Piston outside diameter to the valve seat seal diameter.

This is used to calculate the area ratio of the valve and identify the balance pressure needed to open the valve.

2 The pilot volume

3 The pilot EQ port size

These 2 item are used to find the rate the chamber bleeds into the pilot and if the valve lifts, the rate the pilot pressure jumps as the piston reduces the volume in the pilot.

4 The piston friction. A stuck piston doesn't work well. How is it sealed and how well does it move.

5 The pilot valve parameters. Can the pilot valve drop the pilot low enough to open the main valve?

6 Position of the piston in relation to the air inlet. When the piston pops, the chamber air needs to hit the face of the piston and valve seat area without the piston still blocking the flow.

7 Is there a spring? High spring tension can exceed the opening force of some close ratio piston valves and prevent opening. Same if the bumper is acting as a spring.

If you have questions, PM me. I'll be on the road for a couple days with a major league baseball game and an Amature Radio Operator gathering, so don't worry if an answer is slow getting back.
  • 0

Last edited by Technician1002 on Wed Jul 15, 2009 1:55 am, edited 2 times in total.
User avatar
Technician1002
Chief of Staff
Chief of Staff
 
Posts: 5190
Joined: Sat Apr 04, 2009 11:10 am
Reputation: 14

Unread postAuthor: Gippeto » Wed Jul 15, 2009 1:03 am

any ideas what the problem is?



I suspect that most of the chamber air comes out through the pilot valve, and then it "pops" ??

Dollars to doughnuts, you've replicated the most common problem with first time piston valves. ie. The piston is too loose in the housing, and blow by can keep up with the pilot valve flow.

To check and see, give the piston a wrap or two of tape, grease it up, and try it again.

If it seems like the world might be coming to an end, you've found the problem. :D

If not, post in detail what DOES happen.
  • 0

"It could be that the purpose of your life is to serve as a warning to others" – unknown

Liberalism is a mental disorder, reality is it's cure.
User avatar
Gippeto
Donating Member
Donating Member
 
Posts: 2394
Joined: Sat Jan 19, 2008 10:14 am
Location: The Great White North...Canada eh!
Reputation: 11

Next

Return to Pneumatic Cannon Discussion

Who is online

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

Reputation System ©'