[cockerpunk]

heres a sneak peak at a what i want to do in the near future - a steady state reg test.

just today i was fitteling with my RT which has a gauge for the tank output. and i was noticing some made weird steady state performance out of my tank regs. one tank would recharge to 850ish PSI real quick, but if i left it alone for 5 minutes often it would be up near 1000 PSI. in some cases if i left it alone i would notice it leak back down to something lower.

i have talked to ray from ninja about doing a test of this nature and to also test other steady state values for tank regs. a creep test would be interesting, but an input/output pressure curve would be interesting too.

anyway, thats an upcoming test in the line up for sure. probably wont be till summer, but we'll try it out.

[Merc4Hire]

didn't azreal already do the input/output part of that?

[Texas Cheezburgr]

Just accept things for what they are.

[Jack Wood]

lol, another bucket of worms.

A lot of regs, not just tank regs, generate some kind of creep. It takes only the smallest defect, dint, knick, or piece of debris in either the Reg Seat or the Reg Seal to generate some creep. My god, you shoot an Automag.......you more than anyone should know about reg creep!!

The problem with this kind of test is it's like testing paintballs. Every one is different and will give a different result. You would need to tst 20 of each type of reg to get anything like a meaningful mean figure for the values you are looking at.

[CrazyLittle]

This came from Pirate Mafia over on PBN:

Quote

A = pressure prior to shot, in PSI
B = lowest pressure during shot, in PSI
C = % pressure drop
D = recovery time 95% of pressure in MS


NAME / A / B / C / D

ACI bulldog / 710 / 487 / 31% / 122ms

Armageddon / 807 / 661 / 18% / 90ms

Centerflag / 801 / 675 / 16% / 14ms

Crossfire / 770 / 662 / 14% / 10ms

DYE throttle / 830 / 573 / 30% / 173ms

EVIL Scion / 556 / 472 / 15% / 18ms

Guerrilla Air Myth / 653 / 597 / 8% / 7ms

Ninja Paintball / 804 / 714 / 11% / 8ms

Pro Toyz / 804 / 508 / 26% / 41ms

Pure Energy / 840 / 724 / 14% / 10(30*)ms

WDP A.I.R. / 797 / 648 / 19% / 45ms

[Jack Wood]

CrazyLittle, on Mar 30 2009, 11:37 AM, said:

This came from Pirate Mafia over on PBN:

Quote

A = pressure prior to shot, in PSI
B = lowest pressure during shot, in PSI
C = % pressure drop
D = recovery time 95% of pressure in MS


NAME / A / B / C / D

ACI bulldog / 710 / 487 / 31% / 122ms

Armageddon / 807 / 661 / 18% / 90ms

Centerflag / 801 / 675 / 16% / 14ms

Crossfire / 770 / 662 / 14% / 10ms

DYE throttle / 830 / 573 / 30% / 173ms

EVIL Scion / 556 / 472 / 15% / 18ms

Guerrilla Air Myth / 653 / 597 / 8% / 7ms

Ninja Paintball / 804 / 714 / 11% / 8ms

Pro Toyz / 804 / 508 / 26% / 41ms

Pure Energy / 840 / 724 / 14% / 10(30*)ms

WDP A.I.R. / 797 / 648 / 19% / 45ms

Fantastic...........not.

What was the tank pressure for each of these tests? Who did all these tests? Where they tested on the same day shot with the same gun?

These results seriously mean nothing without further investigation.

[Snipez4664]

I feel like the only way to adequately test for creepiness (other than the aesthetic creepiness of certain taiwanese regs) is some kind of torture test. Seat durometers that are more tolerant of dirt (less creepy) may be inherently more inconsistent.

[Jack Wood]

In my experience, seats of a more tolerant material also offer the slowest recovery. They may not creep in the same way over extended pariods, but they do often display short-creep that can effect recharge rates.

It is a difficult balance between durability and performance when choosing seal material (and thickness).

[Leafy]

One of the regs on my protege does this, if I let it sit I get fsdo (I know its on the gun cause its done it with 4 different tank regs, and the lube doesnt matter). Also seen the creep in regs too, like how the pos traccer will shoot the first shot at the chrono station at either 250 or 350 and then shoot in the 285-298 range for the next 5.

[Snipez4664]

Sort of makes one ruminate on the possibilities of having a dedicated regulating vent. That's a difficult technical problem, though, and not very elegant.

I suppose the other thing you could do is change the dynamics of the regulator system - you can can clearly see the driving force diminish on normal regs as sealing begins. I'm thinking of a solution that would allow for cleaner on/off cutoffs - I think the RT valve may use something similar. (But for a different purpose - I've never looked deep into it but as I understand it the RT essentially puts a delay in the information to the piston - it moves to close quickly after lagging behind a bit?)

[Jack Wood]

Yes, that is indeed the mecca of good reg design. Clean shut-off. This is easier with a hard seal than it is with a soft, more tolerant seal.

However, most NC designed regulators (Bob Long, 2 ltr, etc) tend to display the under-damped behaviour you describe in the RT reg. It just seems an inherent function of that type of design.

[Leafy]

the reason they close slowly is the same reason that almost all valves with a stem close slow (valves in an engine, poppets, etc) closing too fast causes damage and shock to the system, like in a car if you have too aggressive of a cam (one that closes the valves to fast) you slam the valves onto the seats and you'll torque your rocker arms, mushroom and bend you pushrods, mar you lifters, snap your valve stems, scar your cam, etc. In a reg you'd have the same problem and in fluid system you have to worry about hammer back and with delrin poppet cup seals like in a lot of markers today that would be a very bad thing.

[Jack Wood]

Sorry, slight mis-understanding. I am not saying that feature was designed into those regulators. I am saying it is a consequence of that style of regulator. There is nothing in theri designs that limit closure rate of the poppet, there just seems to be something intrinsic in that style of regulator that causes this "under-damped" over-shoot of the output pressure.

Sorry for the confusion.

[Leafy]

but my reasoning is sound too right?

[Snipez4664]

Jack Wood, on Mar 30 2009, 09:44 AM, said:

Yes, that is indeed the mecca of good reg design. Clean shut-off. This is easier with a hard seal than it is with a soft, more tolerant seal.

However, most NC designed regulators (Bob Long, 2 ltr, etc) tend to display the under-damped behaviour you describe in the RT reg. It just seems an inherent function of that type of design.

That must have something to do with the dynamics of the valve proper @ shutoff. I don't have the animation in front of me but just conceptualizing it mentally it seems that it probably has to do with the shifting dynamics of the valve itself outrunning that of the piston. In a ion-reg-style NO reg, I wonder if you could simulate it with a larger seat area that bites into a softer seal from the outside first - you'd lose consistency in the ratio though.

[Snipez4664]

OH huge fail, I had the result backwards - those dynamics are easy to visualize - it's a ratio thing again, I would think. The overpressure then naturally locks the seat down tight. Not sure its desirable theoretically, but in practice if you overshoot the same amount each time you're good to go.

I don't really see where you're going with it, Leafy - although some harder reg seats certainly consider durability (the old air america seals were kevlar)

[Leafy]

Snipez4664, on Mar 30 2009, 10:10 AM, said:

I don't really see where you're going with it, Leafy - although some harder reg seats certainly consider durability (the old air america seals were kevlar)

I was basically saying that the reg seat cant close too fast without risking damage to itself or the rest of the system. even Ti reg seats and stems would get damaged if they slammed closed like they would have to if they didnt slow down before closing.

[Snipez4664]

Right, but I don't think that really enters in at the design phase - the seat takes the brunt of the impact and so is really the only failure point. Given the size of a regulator I can't imagine a situation in which materials limitation would become a problem.

That and if you have a reg that closes let's say linearly (no decel) it behooves you to use a softer bumper anyway, since the compliance travel is less of an issue.

[Leafy]

Snipez4664, on Mar 30 2009, 10:17 AM, said:

Right, but I don't think that really enters in at the design phase - the seat takes the brunt of the impact and so is really the only failure point. Given the size of a regulator I can't imagine a situation in which materials limitation would become a problem.

That and if you have a reg that closes let's say linearly (no decel) it behooves you to use a softer bumper anyway, since the compliance travel is less of an issue.

yes but then when you use that softer seat it experiences normal wear and tear much faster, not to mention it could cause harmonics in the stem (like bouncing open just a tad a couple times) this is some really complicated stuff when you think about the whole system. but thinking about this is a nice distracting from this damnable linear algebra snoozefest homework.

[cockerpunk]

Snipez4664, on Mar 30 2009, 09:10 AM, said:

OH huge fail, I had the result backwards - those dynamics are easy to visualize - it's a ratio thing again, I would think. The overpressure then naturally locks the seat down tight. Not sure its desirable theoretically, but in practice if you overshoot the same amount each time you're good to go.

I don't really see where you're going with it, Leafy - although some harder reg seats certainly consider durability (the old air america seals were kevlar)

if you over shoot the same amount?

thats not going to have a very good response curve to varying input pressures. the mass and thus natural frequency of the piston/spring will remain constant, and the input pressure will change, and thuse the overshoot will get worse and worse and worse.