Making a pcp valve that has a greater than 50% "theory" max power.
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Making a pcp valve that has a greater than 50% "theory" max power.
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Topic: Making a pcp valve that has a greater than 50% "theory" max power. (Read 7750 times))
shorty
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Posts: 1936
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Real Name: Tim
Making a pcp valve that has a greater than 50% "theory" max power.
«
on:
October 05, 2018, 09:59:25 AM »
Starting a thread here for some R&D and stemming from here:
https://www.gatewaytoairguns.org/GTA/index.php?topic=148850.0
Please add your own thoughts and ideas freely as this could get pretty interesting.
I truly hate the fact that even our best tuned pcp's can not achieve 50% of the theory max fpe (except for only like 2 or 3 guys that has accomplished this).
Since the thread above and a lot of trying to think out of the box, I think ( on paper and in my head ) that maybe we can do this and possibly have a completely new valve design/system that would exceed ( in hopes ) anything you have ever seen.
Basically what I did was list everything ( what i thought ) would be the ideal condition for max theory PFE. Things such as full pore porting, ultra fast opening valve, shortest porting possible ect.
From there I made a scratch drawing of the ideal thing.
My drawing stinks and is not complete so I will try to describe it. It is also a single shot gun that loads like a airforce gun.
So,
Just like our crosman guns, the barrel sits above the HPA tube and has an upper receiver. Darn, this is too hard to describe. Here's the dumb drawing.
The valve stem that connects the main poppet (at barrel side) is hollow (even at barrel opening) and uses secondary poppet at the back of it for closing while the hammer and spring sit on the stem (cocks forward not backwards).
The system is a combination of all our greatest valve designs ( I think ) and eliminates nearly every obstacle that the pellet or projectile typically see's to allow for instant HPA delivery without loss.
I have today off to get a head start on the honey do list but, I have a feeling that I have an old rusted .357 barrel in the garage around 20 inches long and a shop compressor to do some SAFE testing at low pressures.
Let me hear your thoughts and ideas.
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Palm Coast, FL
PCPhack
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Real Name: David
Re: Making a pcp valve that has a greater than 50% "theory" max power.
«
Reply #1 on:
October 05, 2018, 10:14:24 AM »
I would think that a valve that is nothing more than a laminar flow optimized poppet, and fully open otherwise, would render the absolute highest power. So no thimble, no return spring, full bore port, any edges where the air must change directions rounded, and no sharp edges anywhere.
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Texas, USA
shorty
Expert
Posts: 1936
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Real Name: Tim
Re: Making a pcp valve that has a greater than 50% "theory" max power.
«
Reply #2 on:
October 05, 2018, 10:40:36 AM »
Exactly....
That is what the concept drawing shows. The poppet seals to the barrel. When the poppet opens, it is full bore porting straight from the HPA reservoir to the back of the pellet (nothing in the way ). It also uses the back pressure from the barrel to close the valve for higher efficiency.
I ran your numbers with your bulldog a fews days ago before the post went south. Believe it or not, with under .3 porting and your 300 fpe shot, your gun was only operating in the low to mid 40 percentile even at higher pressures. Those are great numbers seriously but it's aggravating to know that at full bore porting, you would have hit just over 350FPE at 3000 psi with the theory max FPE hovering in the mid 50 percentile.
This is why I am so interested. Just a 10% to 20% increase is HUGE.
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Palm Coast, FL
rsterne
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Bob and Lloyd
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Real Name: Bob
Re: Making a pcp valve that has a greater than 50% "theory" max power.
«
Reply #3 on:
October 05, 2018, 04:26:44 PM »
I don't follow your drawing or description.... but I wish you luck in your venture....
Bob
Logged
Coalmont, BC, Canada
🇺🇦
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since! 🇺🇦
Airsenal:
1750 CO2 Carbine, .177 Uber-Pumper, .22 Uber-Carbine, .25 Discovery, 2260 PCP 8-shot Carbine, 2260 HPA (37 FPE), 2560 HPA (52 FPE), XS-60c HPA in .30 cal (90 FPE), .22 cal QB79 HPA, Disco Doubles in .22, .25 & .30 cal, "Hayabusa" Custom PCP Project (Mk.I is .22 & .25 cal regulated; Mk.II is .224, .257, 7mm, .308 & .357; Mk.III is .410 shotgun and .458 cal), .257 "Monocoque" Benchrest PCP, .172/6mm Regulated PCP and .224/.257 Unregulated, Three regulated BRods in .25 cal (70 FPE), .30 cal (100 FPE) & .35 cal (145 FPE), .257 Condor (180 FPE).
shorty
Expert
Posts: 1936
yes
Real Name: Tim
Re: Making a pcp valve that has a greater than 50% "theory" max power.
«
Reply #4 on:
October 06, 2018, 03:35:41 PM »
That's Ok Bob. I kind of knew I couldn't explain it good enough.
But,
I did print some parts out on the 3d printer last night just to "feel" some of the ideas before turning some metal.
While the parts were printing, it looked more and more like a piloted QEV valve. And, after putting one and one together, that's nearly what I ended up with after watching some youtube vids and google searches.
So, same ole same ole.
I tell you though,
Using a piloted QEV valve looks like the ticket for high flow/high pressure for easy full bore porting of a single loader though.
Why don't we see piloted QEV valves in PCP's ?
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Palm Coast, FL
rsterne
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Bob and Lloyd
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Real Name: Bob
Re: Making a pcp valve that has a greater than 50% "theory" max power.
«
Reply #5 on:
October 06, 2018, 06:31:43 PM »
Simple, they waste a huge amount of air.... Whatever the reservoir size, that is what gets dumped with every shot....
bob
Logged
Coalmont, BC, Canada
🇺🇦
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since! 🇺🇦
Airsenal:
1750 CO2 Carbine, .177 Uber-Pumper, .22 Uber-Carbine, .25 Discovery, 2260 PCP 8-shot Carbine, 2260 HPA (37 FPE), 2560 HPA (52 FPE), XS-60c HPA in .30 cal (90 FPE), .22 cal QB79 HPA, Disco Doubles in .22, .25 & .30 cal, "Hayabusa" Custom PCP Project (Mk.I is .22 & .25 cal regulated; Mk.II is .224, .257, 7mm, .308 & .357; Mk.III is .410 shotgun and .458 cal), .257 "Monocoque" Benchrest PCP, .172/6mm Regulated PCP and .224/.257 Unregulated, Three regulated BRods in .25 cal (70 FPE), .30 cal (100 FPE) & .35 cal (145 FPE), .257 Condor (180 FPE).
MJP
Member 4400+Fpe Club
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Posts: 2136
I'll make it real. For me.
Real Name: Marko
Re: Making a pcp valve that has a greater than 50% "theory" max power.
«
Reply #6 on:
October 07, 2018, 03:58:39 PM »
If you want good power, you need high pressure throughout the shot cycle. With QEV you have high starting pressure but low volume and the further the projectile gets the lower the pressure.
What you have sketched looks like Lloyd Sikes valve. He has a patent on similar valve.
What you need is getting out of the box first, your box is bound by the rules you read and think.
I have no boundaries on what I search, it is not limited in airguns you need to see beyond that.
Fluid dynamics, pulsating flow, steam turbines, retro rockets... see past the airgun.
Marko
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Finland
Impossible just takes a little bit longer to achieve.
If an engineer is not presented with a suitable problem, they will create their own!
shorty
Expert
Posts: 1936
yes
Real Name: Tim
Re: Making a pcp valve that has a greater than 50% "theory" max power.
«
Reply #7 on:
October 07, 2018, 05:29:02 PM »
I am trying Marko....
Thanks for posting. Please come and visit this post frequently to keep me on the correct path. I am sure I will have more "wrong" ideas then right one's.
Fast "full" valve opening with controlled dwell. Got it
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Palm Coast, FL
rsterne
Member 2000+fps Club
Bob and Lloyd
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Real Name: Bob
Re: Making a pcp valve that has a greater than 50% "theory" max power.
«
Reply #8 on:
October 07, 2018, 06:58:20 PM »
You aren't going to get to 50% of the theoretical maximum FPE with "controlled dwell".... You need to keep the valve open until the pellet exits the muzzle to get that last bit of power to approach the 50% level.... That will result in about 0.5 FPE/CI or maybe less....
As I said, you are confusing FPE/CI efficiency with the ability to extract more than 50% of the "input" energy.... As Marco said....
Quote
If you want good power, you need high pressure throughout the shot cycle
Bob
Logged
Coalmont, BC, Canada
🇺🇦
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since! 🇺🇦
Airsenal:
1750 CO2 Carbine, .177 Uber-Pumper, .22 Uber-Carbine, .25 Discovery, 2260 PCP 8-shot Carbine, 2260 HPA (37 FPE), 2560 HPA (52 FPE), XS-60c HPA in .30 cal (90 FPE), .22 cal QB79 HPA, Disco Doubles in .22, .25 & .30 cal, "Hayabusa" Custom PCP Project (Mk.I is .22 & .25 cal regulated; Mk.II is .224, .257, 7mm, .308 & .357; Mk.III is .410 shotgun and .458 cal), .257 "Monocoque" Benchrest PCP, .172/6mm Regulated PCP and .224/.257 Unregulated, Three regulated BRods in .25 cal (70 FPE), .30 cal (100 FPE) & .35 cal (145 FPE), .257 Condor (180 FPE).
shorty
Expert
Posts: 1936
yes
Real Name: Tim
Re: Making a pcp valve that has a greater than 50% "theory" max power.
«
Reply #9 on:
October 07, 2018, 07:11:25 PM »
Bob, I may not be explaining good enough to you.
I don't care about FPE/CI efficiency..... for the very last time...
Iam not confused....
It's all about achieving the fpe level according to only a very few select has done.
Please provide positive posts...
if you have more bread crumbs to follow then please post them.
Thank you again.
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Palm Coast, FL
rsterne
Member 2000+fps Club
Bob and Lloyd
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Posts: 26958
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Real Name: Bob
Re: Making a pcp valve that has a greater than 50% "theory" max power.
«
Reply #10 on:
October 07, 2018, 07:16:10 PM »
Tim, "controlled dwell" does not compute.... If you are not confused, why say that?....
Perhaps it would be better if I stay out of this thread....
Bob
«
Last Edit: October 07, 2018, 07:22:02 PM by rsterne
»
Logged
Coalmont, BC, Canada
🇺🇦
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since! 🇺🇦
Airsenal:
1750 CO2 Carbine, .177 Uber-Pumper, .22 Uber-Carbine, .25 Discovery, 2260 PCP 8-shot Carbine, 2260 HPA (37 FPE), 2560 HPA (52 FPE), XS-60c HPA in .30 cal (90 FPE), .22 cal QB79 HPA, Disco Doubles in .22, .25 & .30 cal, "Hayabusa" Custom PCP Project (Mk.I is .22 & .25 cal regulated; Mk.II is .224, .257, 7mm, .308 & .357; Mk.III is .410 shotgun and .458 cal), .257 "Monocoque" Benchrest PCP, .172/6mm Regulated PCP and .224/.257 Unregulated, Three regulated BRods in .25 cal (70 FPE), .30 cal (100 FPE) & .35 cal (145 FPE), .257 Condor (180 FPE).
shorty
Expert
Posts: 1936
yes
Real Name: Tim
Re: Making a pcp valve that has a greater than 50% "theory" max power.
«
Reply #11 on:
October 07, 2018, 07:46:06 PM »
Its up to you to stay out of a post. You don't need to share that.
What I meant about controlled dwell was a valve that opens at it's max for a controlled (adjustable) amount of time to either close at 10" down the barrel or 20" down the barrel or 28" down the barrel ect.
Please be positive and entertain "out of the box" ideas. We are all too old for not learning new tricks chief.
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Palm Coast, FL
shorty
Expert
Posts: 1936
yes
Real Name: Tim
Re: Making a pcp valve that has a greater than 50% "theory" max power.
«
Reply #12 on:
October 09, 2018, 05:57:07 PM »
I am trying..
How about this one ?
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Palm Coast, FL
MJP
Member 4400+Fpe Club
GTA Senior Contributor
Posts: 2136
I'll make it real. For me.
Real Name: Marko
Re: Making a pcp valve that has a greater than 50% "theory" max power.
«
Reply #13 on:
October 10, 2018, 02:18:11 AM »
Been there done that!
Made one for the 20mm without the TP passage.
Pain to get it seal, and it blew out of the transfer port on hydro testing around 450bar.
It functions but you will need to make it tough enough as it tends to bind up towards the tp with flow.
Marko
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Finland
Impossible just takes a little bit longer to achieve.
If an engineer is not presented with a suitable problem, they will create their own!
rsterne
Member 2000+fps Club
Bob and Lloyd
GTA Senior Contributor
Posts: 26958
GTA Forums Person of the Year 2017
Real Name: Bob
Re: Making a pcp valve that has a greater than 50% "theory" max power.
«
Reply #14 on:
October 10, 2018, 01:21:08 PM »
Isn't that just a piloted sleeve valve?.... As such, it would tend to dump the entire reservoir, unless the spring is strong enough to close it during the shot cycle.... Once open, the pressure on both sides of the O-rings is the same, so no closing force except the spring....
Bob
Logged
Coalmont, BC, Canada
🇺🇦
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since! 🇺🇦
Airsenal:
1750 CO2 Carbine, .177 Uber-Pumper, .22 Uber-Carbine, .25 Discovery, 2260 PCP 8-shot Carbine, 2260 HPA (37 FPE), 2560 HPA (52 FPE), XS-60c HPA in .30 cal (90 FPE), .22 cal QB79 HPA, Disco Doubles in .22, .25 & .30 cal, "Hayabusa" Custom PCP Project (Mk.I is .22 & .25 cal regulated; Mk.II is .224, .257, 7mm, .308 & .357; Mk.III is .410 shotgun and .458 cal), .257 "Monocoque" Benchrest PCP, .172/6mm Regulated PCP and .224/.257 Unregulated, Three regulated BRods in .25 cal (70 FPE), .30 cal (100 FPE) & .35 cal (145 FPE), .257 Condor (180 FPE).
shorty
Expert
Posts: 1936
yes
Real Name: Tim
Re: Making a pcp valve that has a greater than 50% "theory" max power.
«
Reply #15 on:
October 10, 2018, 05:31:19 PM »
Now we are cooking. Ideas and design flaws. For some reason I am hooked on this one.
V7 here to try and solve dwell / lift / sealing / balancing / piston deflection.
Piston is the same except small in the front and large in the back for closing balance.
2 screws added:
1) Tp on pilot poppet now has a metering screw to block off "some" HPA for closing speed (dwell adjustment)
2) Pilot chamber now has piloted sleeve travel screw (lift adjustment).
Of course the valve would need to be made in 2 pieces with a mating oring but, who cares.
Am I getting closer ? Keep the ideas flowing.
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Palm Coast, FL
rsterne
Member 2000+fps Club
Bob and Lloyd
GTA Senior Contributor
Posts: 26958
GTA Forums Person of the Year 2017
Real Name: Bob
Re: Making a pcp valve that has a greater than 50% "theory" max power.
«
Reply #16 on:
October 10, 2018, 05:59:41 PM »
Diameter of vent hole through piston would be critical.... also proportions of front to rear poppet diameter.... Build it, try it, rebuild it once you understand what works and what doesn't.... I still don't see the advantage, however, compared to a balanced valve....
Bob
Logged
Coalmont, BC, Canada
🇺🇦
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since! 🇺🇦
Airsenal:
1750 CO2 Carbine, .177 Uber-Pumper, .22 Uber-Carbine, .25 Discovery, 2260 PCP 8-shot Carbine, 2260 HPA (37 FPE), 2560 HPA (52 FPE), XS-60c HPA in .30 cal (90 FPE), .22 cal QB79 HPA, Disco Doubles in .22, .25 & .30 cal, "Hayabusa" Custom PCP Project (Mk.I is .22 & .25 cal regulated; Mk.II is .224, .257, 7mm, .308 & .357; Mk.III is .410 shotgun and .458 cal), .257 "Monocoque" Benchrest PCP, .172/6mm Regulated PCP and .224/.257 Unregulated, Three regulated BRods in .25 cal (70 FPE), .30 cal (100 FPE) & .35 cal (145 FPE), .257 Condor (180 FPE).
Gippeto
Sharp Shooter
Posts: 864
Re: Making a pcp valve that has a greater than 50% "theory" max power.
«
Reply #17 on:
October 11, 2018, 11:38:18 AM »
Several examples out there of fellows with qev type valves that reset...they don't "have to" dump the entire reservoir.
Ditch the passage from the transfer port, and fill from behind the spool through a small orifice. The direction you're heading is not new. On the spudgun forums, it's referred to as a chamber sealing piston valve, LD (if you know who that is) made one he called his "assisted" valve.
Notice the fill from behind the spool here; If you manage poppet dwell and bounce, you can manage the pressure drop in the "firing reservoir"...pressure differential can and will reset the spool. If a fellow was so inclined, he might re configure slightly to allow filling from a regulated source. I have this one drawn and online, so it's convenient to re post it...apologies if you've seen it more than you care to...it's useful to get points across.
Or set it up to dump the entire reservoir...choice is good.
JM .02....pick
your
goals, pick
your
compromises, build it, tweak it, shoot the sh1t out of it and above all....have fun.
Al
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Alberta, Canada
MJP
Member 4400+Fpe Club
GTA Senior Contributor
Posts: 2136
I'll make it real. For me.
Real Name: Marko
Re: Making a pcp valve that has a greater than 50% "theory" max power.
«
Reply #18 on:
October 12, 2018, 04:25:15 AM »
Now that you have good examples on how to make different valves and more ideas I can tell you one funny fact, I can get the same power vs barrel length on both of my valves, balanced or conventional.
Its not the valve that is holding you back, you just need to make it big enough to flow enough fast enough.
Marko
Logged
Finland
Impossible just takes a little bit longer to achieve.
If an engineer is not presented with a suitable problem, they will create their own!
rsterne
Member 2000+fps Club
Bob and Lloyd
GTA Senior Contributor
Posts: 26958
GTA Forums Person of the Year 2017
Real Name: Bob
Re: Making a pcp valve that has a greater than 50% "theory" max power.
«
Reply #19 on:
October 12, 2018, 12:51:22 PM »
Exactly my experience, Marco, and I have said that several times before, in many threads.... Balanced and conventional valves produce the same power with the same port size.... Balanced valves just do it with less hammer strike.... I do think that your experiments with valves larger than required "in theory".... ie using a valve designed for a .45 cal in your .224 and then coning the transfer port down to the barrel port (which is full bore area)…. may provide the ultimate in power by oversupplying air and letting the barrel be the absolute limiting factor....
In the Korean gate, Hobbyman2007 has a thread on converting a Winchester / Blizzard .357 down to .257 cal.... Instead of increasing the caliber, and having to make all the ports larger, it makes sense to go the other way.... Start with a PCP designed to deliver a ton of air, and then only use what you can cram into the barrel....
One of the problems with that approach in the past has been that large valve were too hard to knock open.... Now that balanced valves are becoming more common, I think the idea of "downsizing" PCPs may become much more popular.... It only makes sense.... Sometimes ideas which in hindsight seem so obvious require a few pieces of technology to come together to make them possible.... Synergy at its best....
Bob
Logged
Coalmont, BC, Canada
🇺🇦
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since! 🇺🇦
Airsenal:
1750 CO2 Carbine, .177 Uber-Pumper, .22 Uber-Carbine, .25 Discovery, 2260 PCP 8-shot Carbine, 2260 HPA (37 FPE), 2560 HPA (52 FPE), XS-60c HPA in .30 cal (90 FPE), .22 cal QB79 HPA, Disco Doubles in .22, .25 & .30 cal, "Hayabusa" Custom PCP Project (Mk.I is .22 & .25 cal regulated; Mk.II is .224, .257, 7mm, .308 & .357; Mk.III is .410 shotgun and .458 cal), .257 "Monocoque" Benchrest PCP, .172/6mm Regulated PCP and .224/.257 Unregulated, Three regulated BRods in .25 cal (70 FPE), .30 cal (100 FPE) & .35 cal (145 FPE), .257 Condor (180 FPE).
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Making a pcp valve that has a greater than 50% "theory" max power.