How to decrease HPA expent for Talon valve? The answer!
On the one of the best airgun forum in the web – guns.ru – once was a discussion about WERY big expent of HPA per shot on talon. And decision was found!
There http://www.sendspace.com/file/o6kzc0 is archve of that discussion.
Can somebody try to repeat?
If something is not understand – ask questions, I’ll try to explain.
Best regards – Gennady
All Replies
Put the valve on the bottle, and did “some” testing,
with the small hole in the valve stem of 3,3 mm you need more hammer tension, then a valvestem with a big hole.
With a bit off pressure on the bolt with your hand, you can shoot 290 m/s with JSB that’s, more then 30 ft/lbs.
One thing , the tophead leaks a lot 🙁 without a O-ring, so work to do.
But the best thing is here is all most no sound and the end of the barrel / ldc.
For a real string test , I must first work on the leak on the tophead valvestem, when there is no leaking may be I don’t need more spring pressue on the hammer.
My name is Ewoud, in the past I shot a lot of woodpigeons, so they give me the nickname ewoodie.
Looking good ewoodie I won’t ask how you got that name 😯 looking foward to see how it does on your gun!
Here a pic. of the parts.
Try to give it a try tomorrow, first go to the diving shop to fill some bottles.
Playing around with valves and bottles is very good for the airgun shop,
you need a lot of pellets and air. 😀
Some info:
Valve stem 4,7 mm
hole in valvestem 3,3 mm
hole valve seat 6 mm
valve diameter 7,6 mm
We call it a sissi cal. 🙂
As I know about PrOsT’s practice he woked only with “child” caliber – 4.5mm. I’ll ask him about “father’s” caliber – 5.5
PS – on russian talking forums we call calibers of airgun “child” (4.5), “father’s” (5.5), “grandfathers” (6.35) and “grandgrandfather’s” – 9 mm 🙂 Aesopian language 😉
Try to tell you, pressure works all ways, in front on the pellet, but also on the tophead, the normal tophad is 7,9 mm, with, say 100 Bar pressure on it , it get have a back force of around 30 kg ( 55 lbs ) on the tophead, ( calc. without the hole of 4 mm ).
so you get 3x less backforce on the valvestem, so it shut a lot faster,
I hope 😕
The valve head is normal 4,7 mm at the point of the “wings” , only at the end it’s 4 mm.
Try to get it finished in this weekend if I can find a good circlip 😕
When I have all the parts I show a expl. pic. of it.
CU.
very interesting….if your theory holds true you should be able to do the same by lighting the breech and use heavy springs….
could you do a video of the valve and how it works….
are you reducing the stems OD and or ID ?
what about travel…..
nothing lazy using brass….its just much easier to machine….especially the bearing brass that is self lubing 🙂
i am not sure i under stand why this should be more effecient….your power curve looks awesome no doubt…i jus dont get it…..
i miss machining….sigh
2 South, did PrOsT also try it at a 30 ft/lbs rifle?,
say .22 JSB @ 925 ft/sec?
It seems that I learned my English not in vain 🙂 I hope that info I give there are usefull for all talon owners.
2 Ewoodie: PrOsT looks at Your work and said that it exellent!
So, waiting for the test
Normal work for living is nice, but it takes to much time 😈
Did you get a chance to try you top hat you made looks interesting let us know thanks Eddie
Did a little thinking and made an other, fixed tophead.
every day a small part, hope to test it this weekend. 😛
( Just from brass, if it’works I make one in steel, yes I’m a lazy guy 😎 ).
hi,
just a day off, so playing in the workshop.
A bit different,
“I” think it’s to small for a normal Talon/ Stealth with a 7,9 mm Barrel.
The valvestem is only 4mm, with a 3 mm hole in it you have only 0,5 mm
wall thickness. 😕
You have more luck with a .25 barrel so you have a bit more space for the parts.
Thinking now of a srew on cap 💡 when I put plug in the valvehouse a bit deeper.
But it was fun to work on it. 😉
( Sorry for my bad writing )
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One thing at a time you will get it worked out on the air leak, several things there that need to be looked at but get the air leak fixed then you can experiment with the top hat and hole size and get it to where it is working well, keep at it as you have time I think you have something good going there just needs to be tinkered with 😯