USA manufactured PCP Regulator ( testing and discussion ) * RESULTS POSTED

[Motorhead]

Please everyone... allow me to ask a really "dumb" question here without getting flamed :-)

Will there still be a need for a De-pinger or can the regulator also act as one, thus killing two birds with one stone?  Please forgive my ignorance.

Lol .... No problem.
NO depinger required once a regulator is within air tube.
* The sound signature of the popping valve no longer pings the air tube because the regulator isolates valve from primary air tube 

Savvy

[Pellgunfun]

Awesome!!!  Thanks for such a smooth reply... without taking my head off :-)

I'll test my luck with one more seemingly dumb question.  Can I get one for my BAM B 50?  I mean is the guy only making them for certain pellguns?

I suppose that's two questions :-)

P

[Motorhead]

Awesome!!!  Thanks for such a smooth reply... without taking my head off :-)

I'll test my luck with one more seemingly dumb question.  Can I get one for my BAM B 50?  I mean is the guy only making them for certain pellguns?

I suppose that's two questions :-)

P

Of which should be directly asked: http://www.gatewaytoairguns.org/GTA/index.php?action=profile;u=9821

[Pellgunfun]

Thanks again Motorhead.

I shot him a PM...   (Pun intended)  :-)

[MichaelM]

ugh... all this regulator talk makes me want to get one for my disco double!!!!!!!

[Pellgunfun]

Milo asked me a very good question.  The only problem is, I don't know how to answer the question.  On my BAM B 50, how would I go about determining the set pressure for a regulator?  Milo asked what set pressure I was looking for.  All I could provide is the current MV with my pellet weights.  His regulator maxes out at 2000 psi.  My BAM B 50 fill pressure is 200 bar max (2900 psi).  Is that a problem?

[Motorhead]

Milo asked me a very good question.  The only problem is, I don't know how to answer the question.  On my BAM B 50, how would I go about determining the set pressure for a regulator?  Milo asked what set pressure I was looking for.  All I could provide is the current MV with my pellet weights.  His regulator maxes out at 2000 psi.  My BAM B 50 fill pressure is 200 bar max (2900 psi).  Is that a problem?

IMO ... in .177 cal @ 1600# in .22 1800# is what i find to be good average to start with.

[vigilandy]

Milo asked me a very good question.  The only problem is, I don't know how to answer the question.  On my BAM B 50, how would I go about determining the set pressure for a regulator?  Milo asked what set pressure I was looking for.  All I could provide is the current MV with my pellet weights.  His regulator maxes out at 2000 psi.  My BAM B 50 fill pressure is 200 bar max (2900 psi).  Is that a problem?

Once you determine the fill pressure you want,  how are you going to set it without a gauge on the B50? 

[AmBraCol]

Milo asked me a very good question.  The only problem is, I don't know how to answer the question.  On my BAM B 50, how would I go about determining the set pressure for a regulator?  Milo asked what set pressure I was looking for.  All I could provide is the current MV with my pellet weights.  His regulator maxes out at 2000 psi.  My BAM B 50 fill pressure is 200 bar max (2900 psi).  Is that a problem?

The "set pressure" you're looking for is the point in the curve where you're getting the best velocity, lowest deviation.  You need to run a few strings from your top pressure to your bottom pressure and study the curve.  When you determine where the "knee" of the curve is (as rsterne calls it) then you shoot a string from the regular fill pressure to that point.  Let's say, for illustration sake, that you've determined that shot number 12 is the beginning of the "sweet spot" and it carries through to shot 24.  You can then stop a string at 12, find the pressure (ie: pump or fill from your tank until you hear the valve click open and determine at what pressure that happened). Fill it back up, shoot to the other end of the string - shot 24 - and then determine the pressure.  You now know that your "sweet spot" is between H psi and L psi of pressure. (H = high pressure  L = low pressure).  You can then choose what point to set your regulator at. 

So, in your experiments you find that your original 2900 PSI fill yields you a nice almost flat curve from 2,500 to 1,600 PSI.  You could set your regulator at any point in that pressure range and have it work.  But if you set it towards the lower end of the pressure range you'll end up with a greater number of regulated shots until it "drops off" the regulator.  If you set it at the lower end of the fill pressure you'll have your valve working in the range that it works best at and will have a greater number of shots "on tap" in the higher pressure end of the fill tube.  You can keep filling it to the max of 2900 psi instead of lowering the fill pressure to get only the shots contained in the "sweet spot".

[rsterne]

Determining the setpoint pressure in that way will often result too high a pressure.... I think you are confused between the "sweet spot" in an unregulated gun WHERE THE PRESSURE IS DROPPING and the "knee" when you plot velocity vs. hammer strike AT CONSTANT PRESSURE.... The width of the sweet spot will depend on what you decide is an acceptable extreme spread (ES).... If, for example, you choose 4%, you may get a pressure range of (using the numbers above) of 2,500 down to 1,600 psi that peaks at maybe 2000 psi.... If you choose 2000 psi for your setpoint you are attempting to regulate the gun at it's highest power, and that is likely too high a value to use as it will limit your shot count.... Selecting a higher pressure really has no value at all, as you are getting less velocity and even fewer shots.... I would be looking at using 1600 psi as the setpoint because you are only 4% down from the peak velocity and have much more "headroom" in the tank, which means the difference between the tank fill pressure and the setpoint is greater, giving more shots.... In other words, in the above example, I would tune to pressure "L psi" (1600)....

The term "knee" is something I coined (at least I never heard it before I started using it) to describe the relationship between hammer strike and velocity AT CONSTANT PRESSURE, regardless of what that pressure is.... Some people are using it to describe the sweet spot in an unregulated gun, but that is incorrect.... When you have a PCP running at constant pressure (ie regulated) and you try increasing the hammer strike (usually by increasing the preload) you will find a point at which you no longer get an increase in velocity, but the increased valve dwell just keeps using more air.... If you graph that, you get something like this....



What I call the "knee" of the curve would be between 4-5 turns out from coil bind on that graph.... Above that is the "plateau" where you get little or no velocity increase with increased preload, but the efficiency tanks.... Below that is the "downslope" where reducing the preload decreases the velocity.... The "knee" is the transition point between the two, and tuning to that point will give you the highest efficiency at nearly full power.... This point corresponds to approximately tuning as if the gun was unregulated with the peak of the velocity curve slightly below the regulator setpoint you have.... Tuning on the "downslope" is tuning on what in an unregulated gun would be the first part of the "sweet spot", ie before the velocity peak....

If you look at what your regulated shot string looks like at different points on the above curve, this is what you will find....

1. If the gun is running on the "plateau", it will be using a lot of air, be very loud, and once you hit the setpoint the velocity will tank quickly....
2. If the gun is running on the "knee", it will be more efficient and quieter, and the velocity will rise a few fps for a short distance below the setpoint before declining....
3. If the gun is running on the "downslope", it will have less power, be very quiet (and efficient), but once the tank pressure drops below the setpoint the velocity will begin to increase, eventually peaking (exactly like in an unregulated gun) before declining....

I hope that helps people understand the difference between what I call the "knee" in a constant pressure situation, and the "sweet spot" in an unregulated gun....

Bob

[AmBraCol]

Thank you for clearing that up, Bob. 

[Pellgunfun]

Thank you gentleman, for that information.  I actually understood all of it :-)

Still one question.  How will all of that help me determine what the set pressure will be to maintain approx 900 fps.  How can I know (for example) if 1600 psi will allow me to get a consistent 900 fps before I install any regulator in it?  Don't I have to provide a "set pressure" for the initial setting?  Seems like there would be a way to determine the initial setting that would get me close, then fine tune from there.  Is there just no way other than trial and error?

[rsterne]

Providing you have a plenum (volume between the regulator and valve) of about 1 cc per FPE the gun is intended to produce.... then you should be able to run a setpoint that produces the velocity you want in the unregulated gun, or only slightly above.... If your gun shoots 900 fps at 1600 psi, you should be able to accomplish that if you regulate to 1600-1700.... However, getting that much volume downstream of an in-tube regulator may cost you too many shots because of the volume you have to take away from the (upstream) reservoir.... If you drop the plenum down to 1/2 cc per FPE, you will likely have to increase the setpoint roughly another 10% to get back to where you were because the small volume will cause the pressure DURING THE SHOT to fall too much.... Going even smaller will severely restrict both the power output and the efficiency....

Bob

[Motorhead]

Thank you gentleman, for that information.  I actually understood all of it :-)

Still one question.  How will all of that help me determine what the set pressure will be to maintain approx 900 fps.  How can I know (for example) if 1600 psi will allow me to get a consistent 900 fps before I install any regulator in it?  Don't I have to provide a "set pressure" for the initial setting?  Seems like there would be a way to determine the initial setting that would get me close, then fine tune from there.  Is there just no way other than trial and error?

In your case ... We really need some info on WHAT CALIBER your working with, WEIGHT pellet you wish to go 900 FPS and such info.
Having done MUCH regulated tuning you maybe chasing performance gun simply can't deliver
.177 cal shooting 10.3s at 900 easy !!
.22 cal shooting 18's at 900 NOT so easy !!

Thus the question asked 

[Pellgunfun]

Recently I've been using CPHP @ 14.3 gr, and JSB Exact Jumbo Express @ 14.35 gr.  That's in .22 cal of course.  I haven't tried the heavy 18 gr pellets.  I doubt I could maintain approx 900 fps if I switched to those heavier pellets.  Beside I like the 14.3 gr pellets.  I can snipe birds and rabbits at 100 yards just fine with them.

[Motorhead]

Recently I've been using CPHP @ 14.3 gr, and JSB Exact Jumbo Express @ 14.35 gr.  That's in .22 cal of course.  I haven't tried the heavy 18 gr pellets.  I doubt I could maintain approx 900 fps if I switched to those heavier pellets.  Beside I like the 14.3 gr pellets.  I can snipe birds and rabbits at 100 yards just fine with them.

14.3's in .22 making 900 fps is no problem under regulation with required valve mods.

[Pellgunfun]

Yeah, I haven't made any mods to the gun yet.  She is all stock right now.

After I get this regulator thing sorted out, I need to get a "muffler" for it.  If ya know what I mean.  It's really loud.  My neighbors thought I was shooting a .22 cal LR in my back yard.  I also want to make my own stock.  I want to convert my BAM B50 to a bull pup!  That way it will be MUCH shorter, and better balanced.  I live on a Golf course so when Golfers and my neighbors see me with it, they'll think it is some sort of a toy or a harmless BB gun.  Plus I think Bull Pups are cool looking:-)

P

[RFC]

Very interesting. 

For comparison, I  have my GenII Synrod tuned to give me 70 shots, 970-990-970, CPL's from 2500 to 1500.

How difficult is it to install a regulator in a Marauder?

[William]

ugh... all this regulator talk makes me want to get one for my disco double!!!!!!!

MichaelM,

Ordered one for my Disco Double yesterday, My Disco is modified for 3000 PSI so when I get the Regulator from Milo74 I will post results on the forum somewhere! Will let you and everyone know how it goes, first got to figure out the correct way to install and how much volume I need between the valve and regulator. Also need to know if I have to drill a vent hole or remove gauge block! I am pretty sure I need a vent hole as Motorhead talked about.

William

[Pellgunfun]

ugh... all this regulator talk makes me want to get one for my disco double!!!!!!!

MichaelM,

Ordered one for my Disco Double yesterday, My Disco is modified for 3000 PSI so when I get the Regulator from Milo74 I will post results on the forum somewhere! Will let you and everyone know how it goes, first got to figure out the correct way to install and how much volume I need between the valve and regulator. Also need to know if I have to drill a vent hole or remove gauge block! I am pretty sure I need a vent hole as Motorhead talked about.

William

Ah, does the spacer not come with the regulator???  I thought the spacer was all ready to go.  Just drop it in, and slide the regulator into it's new home.  Is that not the case?  I did know about the drilling the hole part.