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Pilot valve??

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sb327:
I had this idea awhile back and thought I’d throw one together to check function. I have heard mention of a ‘pilot valve’ and this is kinda what pops in my mind.

I made the test valve to fit my 7/8” tube on my sidelever breech. I know, I know, this type of valve is more for easy opening, power situations but I wanted to test it.

I’ve shot it several times. It resets perfectly in spite of no springs. Matter of fact, when I put it together, I had to make sure I held tube upright to keep the poppet assembly from falling into tube until I aired it up.

It has a declining shot string (of course).

What is surprising is I have it set to blow open just a smidge and it kicks out 50fpe avg for 10 shots with 45grainers. 3100psi down to 2400. Not the best efficiency but not just a pig. 24ish inch barrel, I’d have to measure for sure.

Cocking effort…..verrry little. Especially with the side lever. My arthritis fingers love it.

Anyway, just sharing an experiment here. I don’t think it’s some great revelation. Just a different valve to tinker with for me.

Dave

The last photo is just to show function, I kinda messed up on some ‘it doesn’t matter’ aspects. It’s NTS

MJP:
Nice work David,
I have used pilot valve on first 20mm experiment. Works but I had some issues on hydro testing it and it exploded around 500 bar. So I went woth a different design.
Have something very similar designs somewhere but never got to make and test so thanks for beating me to it!
My version was inverted and pull type hammer and rear opening valve. But concept is the same.

Edit: oh yeah, put some sort of a buffer inside the main valve very stiff spring or rubber to stop it from cracking at the corner. POM is not as shock resistant as needed on opening. At least on bigger power it shatters. Don't as how I know.
Marko

sb327:
It worked surprisingly well first time out. Thanks for checking it out and commenting.

I was looking last night at the Leishy 2 patent and it appears he does pretty much the same thing but vents to atmosphere. I think. I have a hard time understanding patent lingo sometimes.

I’ll be testing more on this in a couple weeks. I’ve decided to bottle/reg feed my test (ugly) sidelever mule.

Dave

Rob M:
very cool.. whats the total travel on the shuttle  part thats slams open ??

sb327:
Right now I have it set about a 1/16”. But…what inertia it has on full open MAY carry the adjustable cylinder forward some and allow for more than 1/16” full open. Like I do with my bv’s, I don’t leave a solid surface to hit, it can float.

I only adjust hammer to crack the pilot and start the cycle. I also left a pocket in front of the pilot poppet to keep it from hitting anything.

Dave

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