Shooting the breeze Valley Arms Sponsors of UKAHFT  
Go Back   Shooting the breeze > The Chat > General Airgun Chat

General Airgun Chat Chat and banter that doesn't fit anywhere else...

Thread Tools Display Modes
Old 8th May 2014, 09:40 AM
sven's Avatar
sven sven is offline
Senior Member
Join Date: Dec 2009
Member of: FT Schalkhaar / SSV Ons Genoegen
Location: Arnhem, The Netherlands
Posts: 233

Thanks for the description of the test. Makes much more sense now.
So you found 2 to 3% of leak by the valve stem when the pressure difference over the valve stem is 100 psi or 7 bar. When actually shooting the pressure difference will be much larger (at it's maximum somewhat lower than 85 bar and decreasing rapidly) and so the leak will be larger as well. But because of the small space between valve stem and the hole it sits in the critical flow will be reached quite soon.
Nice to see how you proved and quantified there is quite some leak along the valve stem.
The volume of lost air will be small compared to the total amount of air used per shot because of the short time the valve is open.
The valve will probably open a few times (2 to 3) for each shot because of the hammer bouncing. (see this high speed movie: ). I think you can save much more air when you reduce the hammer bounce than when you would when sealing the valve stem.
Field Target Schalkhaar:
Airgun Accuracy weblog:
Reply With Quote

Thread Tools
Display Modes

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 On

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
EV2 Venting Toucan59 General Airgun Chat 3 26th September 2011 03:27 PM

All times are GMT. The time now is 04:17 PM.

Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2016, Jelsoft Enterprises Ltd. Skin design and concept by Attitude