mcarterbrown.com  

General Chat MCB's Coffee House: Pull up a seat, and grab your favorite caffeinated beverage. Non-paintball related chat within.

Reply
 
Thread Tools
Old 11-06-2017, 05:58 PM   #1 (permalink)
MCB Member
 
LT72884's Avatar
 
Join Date: Jun 2016

Velocity screw

When one adjusts the velocity screw, where does the excess gas go? Adjusting said screw does not adjust the gas at the tank side, it just prevents all of the gas hitting the round. So where does the excess go then?

Thanks

Sent from my SM-S920L using Tapatalk
LT72884 is offline   Reply With Quote
Old 11-06-2017, 06:03 PM   #2 (permalink)
(V) (o,,,o) (V) WOOP WOOP
 
foughtwolf's Avatar
 
Join Date: Apr 2007
Location: Springfield, MO

It’s still there. That’s why a clearing shot is required between each test shot when lowering velocity/pressure.
__________________
Know me by name; Shepherd of Fire!
foughtwolf is offline   Reply With Quote
Old 11-06-2017, 06:04 PM   #3 (permalink)
Voted most ball-fondliest
 
freedummy's Avatar
 
Join Date: Aug 2012
Location: Calgary, Alberta

Velocity screw, like on a Tippmann?

I think it's a little two-fold - the screw acts like a choke between valve and ball, so it would result in more back-pressure (higher pressure in the valve) which slows the flow out of the tank. That restricted pressure in the valve would bleed down the barrel more slowly as well, longer after the paintball has exited the barrel (relatively, compared to a wide open choke)

/armchair fluid dynamics
__________________
Quote:
Originally Posted by The Flounder View Post
We don't do easy here! Here we do different and not done before!
My feedback: MCB / eBay

Last edited by freedummy; 11-06-2017 at 06:07 PM.
freedummy is offline   Reply With Quote
Old 11-06-2017, 11:41 PM   #4 (permalink)
MCB Member
 
Deus Machina's Avatar
 
Join Date: May 2006
Location: Brandon, Florida

Yup. It's just a choke. Depending on the valve, it either lets the same amount out more slowly, and thus at a lower pressure post-screw, or prevents as much coming through before the spring and gas pressure inside the valve closes the valve again.
I personally prefer designs that adjust the spring pressure instead (it lends itself toward better efficiency IMO) but if it works... there's still a reason Tippmanns sell like AKs.
__________________
Quote:
HurtCow:Sure, plastic is pretty innocuous. Beef maxi-pads won't hurt you.
russc:Yeah, mcdonalds hamburgers haven't killed me yet!
My MCB Feedback
My eBay Feedback
Moriearty Hobby Supply on eBay and Facebook.
Deus Machina is offline   Reply With Quote
Old 11-07-2017, 01:33 AM   #5 (permalink)
MCB Member
 
LT72884's Avatar
 
Join Date: Jun 2016

Interesting. I like learnimg all of this stuff. Thanks for the input. On a tippmann cannyou adjust the spring or is it just the screw

Sent from my SM-S920L using Tapatalk
LT72884 is offline   Reply With Quote
Old 11-07-2017, 01:48 AM   #6 (permalink)
MCB Member
 
Fubarius's Avatar
 
Join Date: Apr 2006
Location: New Richmond, WI
Send a message via AIM to Fubarius Send a message via Yahoo to Fubarius

Brass and Wood Fan
PPS Fan
If you add an aftermarket rear velocity adjuster, or pick up a spring kit you can adjust the spring.

On my mag converted A5...



...if you look where the choke screw normally is you instead see gold anodized aluminum, that's because I replaced the stock powertube with a metal one that does not have the front velocity adjuster. It was a version that JCS made for a while, but it was only for heavily modified guns that had another way to adjust velocity. Mine can adjust both the rear spring tension with the added rear velocity adjuster, and can also adjust the input pressure by the regulator on the bottom of the grip.

This particular setup has a very, very high flow valve so I can run it with the rear velocity adjuster backed all the way out, running the lightest main spring from a spring kit, have the regulator turned down to below 500 psi, and still get 300 fps.
__________________
David Johnson
aka Fubarius

Nunquam emere quid potes facere
Fubarius is online now   Reply With Quote
Old 11-07-2017, 01:52 AM   #7 (permalink)
FNG
 
Soolio's Avatar
 
Join Date: Oct 2015
Location: San Diego

I just bought an aluminum powertube and the velocity screw port was sealed off with JB weld. I hear it’s an efficiency mod. Haven’t had a chance to get real world numbers on it yet, but I’m down
Soolio is offline   Reply With Quote
Old 11-07-2017, 02:00 AM   #8 (permalink)
Voted most ball-fondliest
 
freedummy's Avatar
 
Join Date: Aug 2012
Location: Calgary, Alberta

Yeah, supposedly consistency too. The easy way is to back the velocity screw out so it's flush with the inside of the powertube. The theory goes that using a choke screw introduces turbulence to the airflow, and is less efficient than using RVA/spring tension to meter the air released by the valve.
__________________
Quote:
Originally Posted by The Flounder View Post
We don't do easy here! Here we do different and not done before!
My feedback: MCB / eBay
freedummy is offline   Reply With Quote
Old 11-07-2017, 02:13 AM   #9 (permalink)
MCB Member
 
LT72884's Avatar
 
Join Date: Jun 2016

@ Fubarius. Is that a tacamo mag fed conversion kit?

Thanks for the info on that. Is it worth it to use a spring rather than a screw

Sent from my SM-S920L using Tapatalk
LT72884 is offline   Reply With Quote
Reply

  mcarterbrown.com » General » General Chat

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

Forum Jump


All times are GMT -4. The time now is 08:40 AM.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO
© MCB Network LLC