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 81 users online :: 5 registered, 0 hidden and 76 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

Bumper Piloting Issues

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

Bumper Piloting Issues

Unread postAuthor: clemsonguy1125 » Mon May 10, 2010 4:10 pm

On my rocket launcher launcher the piston works fine if the bumpers attached to the piston but when I add the second part of the bumper to the back of the adapter, the piston wont move. The bumpers part of a pool noodle.
  • 0

Attachments
100510-170358.jpg
Bumper Part 1
100510-170423.jpg
Bumper Part 2
100510-170436.jpg
Wont Work
100510-170446.jpg
Will Work
That is all.
User avatar
clemsonguy1125
Major General
Major General
 
Posts: 1485
Joined: Tue Jul 21, 2009 4:00 pm
Location: East Coast
Reputation: 1

Unread postAuthor: Gun Freak » Mon May 10, 2010 4:14 pm

Try using some softer foam for the back bumper (th one not on the piston). The noodle may be too hard for the piston to push against.
  • 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: clemsonguy1125 » Mon May 10, 2010 4:17 pm

But ai just slowly comes out the pilot valve , not only when the bumpers are touching.
  • 0

That is all.
User avatar
clemsonguy1125
Major General
Major General
 
Posts: 1485
Joined: Tue Jul 21, 2009 4:00 pm
Location: East Coast
Reputation: 1

Unread postAuthor: Gun Freak » Mon May 10, 2010 4:19 pm

did you put some lube in?
  • 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: clemsonguy1125 » Mon May 10, 2010 4:22 pm

yeah piston seals and pilots fine without bumper part 2, it has to be there since without it bumper part 1 slide into the adapter and the piston slams into the adapter
  • 0

That is all.
User avatar
clemsonguy1125
Major General
Major General
 
Posts: 1485
Joined: Tue Jul 21, 2009 4:00 pm
Location: East Coast
Reputation: 1

Unread postAuthor: Gun Freak » Mon May 10, 2010 4:26 pm

ok then take the bumper off the piston and just use one on the back or just cut the bumpers down a bit
  • 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: mark.f » Mon May 10, 2010 4:29 pm

Are pool noodles closed or open cell foam?

I think you need to use a different approach for constructing a bumper. They're designed to absorb the impact of the piston, not push on it the entire time it's traveling backwards.

For 2" piston valves, a good bumper can be made from a section of a tennis ball. Cut the ball roughly in half, cut a 1/4"-1/2" hole in the center of the cone, then cut a slit from the edge of the cone through the hole in the center. This can then be "rolled" to fit in the piston track.
  • 0

User avatar
mark.f
Donating Member
Donating Member
 
Posts: 3464
Joined: Sat May 06, 2006 11:18 am
Country: United States (us)
Reputation: 21

Sponsored

Sponsor
 


Unread postAuthor: clemsonguy1125 » Mon May 10, 2010 4:35 pm

Thanks, I think the problem was the bumper was getting sucked into the pilot and clogging it up
  • 0

That is all.
User avatar
clemsonguy1125
Major General
Major General
 
Posts: 1485
Joined: Tue Jul 21, 2009 4:00 pm
Location: East Coast
Reputation: 1

Unread postAuthor: cannon monkey » Mon May 10, 2010 5:04 pm

im going to try the tennis ball bumper idea im working right now on a bumper so far i put a 1-1/4 inch slip to 1/2 inch thread bushing inisde my 2 inch slip to 1 inch thread bushing and stuffing rubber in the space between the two bushing walls
  • 0

most big random like i ever seen

cannon monkey
Major
Major
 
Posts: 399
Joined: Sun Sep 07, 2008 10:50 am
Location: usa FL
Reputation: 0

Unread postAuthor: Technician1002 » Mon May 10, 2010 6:28 pm

The bumper should not "Fill" the entire pilot area. If it does, then the bumper can provide enough pressure by itself to hold the piston closed. Be sure there is some freedom for the piston to move before it hits the bumper. In my cannons, both QDV and conventional, I try to allow about 1/2 the piston travel to be free before reaching the bumper and then the 2nd half is the deceleration zone. This permits the piston to open with air pressure and open 1/2 way at least before it starts to slow down due to hitting the bumper.

Does your pilot have any pilot space? If not, then all you have is the bumper to vent out the trigger valve.

I make all my bumpers with a hole through the center, both for QDV with a rod and conventional without a rod. This permits rapid venting of the pilot area from the back of the piston out the pilot vent without blowing the bumper out the hole.
  • 0

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

Unread postAuthor: clemsonguy1125 » Mon May 10, 2010 7:32 pm

Yes it did, Ive confirmed that the issue was the pool noodle getting sucked into the valve, I tried the tennis ball bumper and it worked ok but I need to order the threaded bushing to get it to work up to its potential.
  • 0

That is all.
User avatar
clemsonguy1125
Major General
Major General
 
Posts: 1485
Joined: Tue Jul 21, 2009 4:00 pm
Location: East Coast
Reputation: 1

Unread postAuthor: mark.f » Mon May 10, 2010 7:39 pm

Glad it worked out for you. Make sure to check the shape of the bumper after a few firings and periodically to ensure it retains it's shape.
  • 0

User avatar
mark.f
Donating Member
Donating Member
 
Posts: 3464
Joined: Sat May 06, 2006 11:18 am
Country: United States (us)
Reputation: 21

Unread postAuthor: clemsonguy1125 » Mon May 10, 2010 7:41 pm

Ok, I took your suggestion and shortened the piston length, I will post updated pictures as soon as I find a shorter bolt
  • 0

That is all.
User avatar
clemsonguy1125
Major General
Major General
 
Posts: 1485
Joined: Tue Jul 21, 2009 4:00 pm
Location: East Coast
Reputation: 1

Unread postAuthor: mark.f » Mon May 10, 2010 7:46 pm

My suggestion was to shorten the overall valve length by replacing the male adapter and bushing combination at the rear with a 2" threaded plug, which might require a shorter piston if it is sliding into the male adapter...

Just shortening the piston will create more pilot volume (although greater opening distance).

Ideally, your piston should be just long enough to leave your opening space (~ 1/2 the port diameter if you've got space to spare) plus room for a bumper behind it when contacting the barrel port.

What length is your new piston and what is the distance between the barrel port and the front of the bumper (when compressed)?
  • 0

User avatar
mark.f
Donating Member
Donating Member
 
Posts: 3464
Joined: Sat May 06, 2006 11:18 am
Country: United States (us)
Reputation: 21

Unread postAuthor: Gun Freak » Mon May 10, 2010 7:59 pm

I took apart my valve to paint my gun today, my raquet ball bumper was destroyed. I'll have to try the tennis ball.
  • 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

Next

Return to Pneumatic Cannon Discussion

Who is online

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

Reputation System ©'