Pumpers: Air path makes 2 90 degree turns

dan_house · May 24th, 2012, 4:11 pm #1 2012-05-24T16:11

from thevalve to the red of the pellet

I think some gains could be had by straightening the air path. Inline from storage to the pellet skirt.....

But how?

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curt44319 · May 24th, 2012, 4:19 pm #2 2012-05-24T16:19

From Andy ( 2289 ) mentioning something about shaping the outside of the curve with JB Weld providing him his highest gains.
Unfortunately, the thread is 4 years old, and dies.

I'd like some details on that particular mod, myself.

For me, I did "funnel" the passage/port from the valve seal surface to the barrel port, so that it ( theoretically ) accelerates the air velocity all along that path, and it appears to have worked, but I don't have any "one step at a time" data for it.

Kinda sorta wish I still had my flow bench from my racing days....

TheOldBuzzard · May 24th, 2012, 4:22 pm #3 2012-05-24T16:22

from thevalve to the red of the pellet

I think some gains could be had by straightening the air path. Inline from storage to the pellet skirt.....

But how?

dr_subsonic's pneumatic research lab

the Lunatic Fringe of American Airgunning
Southwest Montana's headquarters for Airgunning Supremacy
Proud Sponsor of team_subsonic

Has to use a butt reservoir from my perspective----like a Girondoni or Air Force. Then it might as well be a PCP.
Scot mentioned an S path would be better. Perhaps he will elaborate for us. Tom

dan_house · May 24th, 2012, 4:29 pm #4 2012-05-24T16:29

From Andy ( 2289 ) mentioning something about shaping the outside of the curve with JB Weld providing him his highest gains.
Unfortunately, the thread is 4 years old, and dies.

I'd like some details on that particular mod, myself.

For me, I did "funnel" the passage/port from the valve seal surface to the barrel port, so that it ( theoretically ) accelerates the air velocity all along that path, and it appears to have worked, but I don't have any "one step at a time" data for it.

Kinda sorta wish I still had my flow bench from my racing days....

now we approach the edges of rocket science.....

dr_subsonic's pneumatic research lab

the Lunatic Fringe of American Airgunning
Southwest Montana's headquarters for Airgunning Supremacy
Proud Sponsor of team_subsonic

dan_house · May 24th, 2012, 4:43 pm #5 2012-05-24T16:43

from thevalve to the red of the pellet

I think some gains could be had by straightening the air path. Inline from storage to the pellet skirt.....

But how?

dr_subsonic's pneumatic research lab

the Lunatic Fringe of American Airgunning
Southwest Montana's headquarters for Airgunning Supremacy
Proud Sponsor of team_subsonic

eased the radius of the bends some you could mitigate some of the energy loss pusing it around those corners.

Which I'm guessing is what the JB weld was used for that Andy mentioned

dr_subsonic's pneumatic research lab

the Lunatic Fringe of American Airgunning
Southwest Montana's headquarters for Airgunning Supremacy
Proud Sponsor of team_subsonic

oo7fuzz · May 24th, 2012, 4:51 pm #6 2012-05-24T16:51

from thevalve to the red of the pellet

I think some gains could be had by straightening the air path. Inline from storage to the pellet skirt.....

But how?

dr_subsonic's pneumatic research lab

the Lunatic Fringe of American Airgunning
Southwest Montana's headquarters for Airgunning Supremacy
Proud Sponsor of team_subsonic

I have been using nothing but inline valves in all my scratch builds. This requires a whole bunch of tinkering and sealing.
Mostly they are blow open valves where the pellet actually lays against the valve.

Trueth be known, with all the tinkering with an inline valve which eliminates the topic 90 degree turns, I am beginning to believe the special sealing and tinkering to execute the inline valve just ain't worth the gain.

The greater problem is, that when the gun is built sporting the inline valve, one never really knows how the same gun would perform with the conventional knock open valve for comparison.

robnewyork · May 24th, 2012, 4:56 pm #7 2012-05-24T16:56

Has to use a butt reservoir from my perspective----like a Girondoni or Air Force. Then it might as well be a PCP.
Scot mentioned an S path would be better. Perhaps he will elaborate for us. Tom

dan_house · May 24th, 2012, 5:05 pm #8 2012-05-24T17:05

I have been using nothing but inline valves in all my scratch builds. This requires a whole bunch of tinkering and sealing.
Mostly they are blow open valves where the pellet actually lays against the valve.

Trueth be known, with all the tinkering with an inline valve which eliminates the topic 90 degree turns, I am beginning to believe the special sealing and tinkering to execute the inline valve just ain't worth the gain.

The greater problem is, that when the gun is built sporting the inline valve, one never really knows how the same gun would perform with the conventional knock open valve for comparison.

nt

dr_subsonic's pneumatic research lab

the Lunatic Fringe of American Airgunning
Southwest Montana's headquarters for Airgunning Supremacy
Proud Sponsor of team_subsonic

TheOldBuzzard · May 24th, 2012, 5:45 pm #9 2012-05-24T17:45

eased the radius of the bends some you could mitigate some of the energy loss pusing it around those corners.

Which I'm guessing is what the JB weld was used for that Andy mentioned

dr_subsonic's pneumatic research lab

the Lunatic Fringe of American Airgunning
Southwest Montana's headquarters for Airgunning Supremacy
Proud Sponsor of team_subsonic

"makes me wonder if you---eased the radius of the bends some you could mitigate some of the energy loss pusing it around those corners.

Which I'm guessing is what the JB weld was used for that Andy mentioned"
*********************************************************************
We all know how much it helps to soften the hard edge from valve body to transfer port---just knocking the sharp corner back a bit frees up flow rate.
I've long thought of doing the same thing by building up a gentle 'ramp' with JB Weld inside the flow-thru bolt opposite of the transfer port. Unfortunately thinking about it is all I've accomplished.
Perhaps that is what 'Andy' did or maybe someone here will try it and report back.
It seems reasonable to assume the same benefit as at the other end.
I seem to have more ideas than ambition these days.;o( Tom

Duane30 · May 24th, 2012, 6:09 pm #10 2012-05-24T18:09

from thevalve to the red of the pellet

I think some gains could be had by straightening the air path. Inline from storage to the pellet skirt.....

But how?

dr_subsonic's pneumatic research lab

the Lunatic Fringe of American Airgunning
Southwest Montana's headquarters for Airgunning Supremacy
Proud Sponsor of team_subsonic

Take, for example, the Air Force line of air systems. Direct path from valve pellet, no bends.

I do believe that Ron Burnett's bad-to-the-boen 'SSP' uses a direct line air passage:
http://www.network54.com/Forum/79537/me ... s+possible

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