Tale of THREE BRods - .25, .30 and .357 Completed, Page 19 !

[shorty]

If you had the time to change the transfer port too, that would really change the mapping for everyone (I think).

3 factorial design

[oldpro]

 Great Idea Tim. I was working on something similar with Excel but unfortunately I made and error that is all my fault and its been corrected I made the valve to easy to open and it became unstable with preload so Im sending everyone new internals that will allow for as much preload as you want  without using tons of air when pre-loaded . So for now until the new internals are out  this will be not really good to chart in mini tab or Excel as all the data will be changed. Sorry guys. Still the data Bob collected is awesome and will be similar except for spring the jet sizes will be different for the new internals. Your really getting some BIG power Bob from a low pressure thats for sure.

[shorty]

I am here if you need it Travis. As you can tell, I am itching to by a valve.

[rsterne]

I don't fully understand what you need, Tim.... Looking at any settings with preload on the spring (negative gap) are useless, because the efficiency is about 0.2 FPE/CI, accompanied by horrendous report, recoil, and muzzle jump.... The only useful data would be where the plateau starts, down to where the cliff is, IMO.... In addition, I have been testing two calibers, and several weights.... I have a reasonable amount of velocity vs preload data, much less efficiency data, because my stock of pellets is running low....

According to Travis, any jet size over about 0.050-0.060" won't make any difference, it will react the same as removing the jet completely.... so again, pretty hard to map something when those datapoints are out of the useful range....

Bob

[rsterne]

Travis, this valve is so easy to open I don't care that I can't run preload.... as I would run either an SSS or SSG with this valve, period.... Since I already have an SSG built for the BRods, they will never see preload, and in fact even small gaps are useless unless I run a 27 gram hammer and only 3 lbs. of preload on my 8 lb/in. spring.... From what I understand the "correct" internals will require a bit more hammer strike than the one you sent me.... which is no big deal.... so both should work.... Of course they WILL give different data in terms of required hammer strike....

Looks like I'm going to have to order more pellets, though.... 

Bob

[shorty]

That's Ok Bob. Sometimes I don't make sense right off the bat (or ever).

The numbers in the table were just made up from me from limited data (none of it makes real sense). It's better to run a DOE with numbers that are around the area you want to use so it can be optimized. Most importantly 2 tests, 1 wide open then one with the numbers closer.

Anyway,
I was looking for what makes the most interaction between the three factors. The program can simulate that like this. The numbers are just made up but gives the idea of what it can do.

[oldpro]

That's Ok Bob. Sometimes I don't make sense right off the bat (or ever).

The numbers in the table were just made up from me from limited data (none of it makes real sense). It's better to run a DOE with numbers that are around the area you want to use so it can be optimized. Most importantly 2 tests, 1 wide open then one with the numbers closer.

Anyway,
I was looking for what makes the most interaction between the three factors. The program can simulate that like this. The numbers are just made up but gives the idea of what it can do.

I really like that Tim and could be very useful in the near future.

[rsterne]

Well the data is non-linear once you hit the plateau velocity.... and that velocity is dependant on barrel length, pressure, SD, and port size.... For all my current data points, the barrel length is fixed, and so is the port size (within each caliber).... I have data for two pressures, and a few different weights (SD).... Here are some relative data points....

.25 cal - 23.8" barrel - 0.234" minimum port diameter (chamber minus probe) - barrel volume 19.15 cc....
.30 cal - 25" barrel - 0.257" port diameter (exhaust & transfer ports) - barrel volume 28.97 cc....

Pressures used 1900 psi and 3000 psi, constant pressure (tethered to regulator)....
.25 cal tested at 1900 psi with 25.4 gr. and 34.1 gr.... and at 3000 psi with 52.7 gr....
.30 cal tested at 1900 psi with 44.9 gr. and 49.7 gr.... and at 3000 psi with 49.7 gr. and 67.2 gr....

Initial setup 8 lb/in spring at 0.60" (4.8 lbs.) preload on the SSG guide.... later changed to 0.40" preload (3.2 lbs.).... SSG is 18 TPI (0.0556"/turn).... Initial ART/SS jet size # 87.5 (which I understand is 0.0344").... later removed, leaving a hole of about 1/8" (anything over ~ 0.060" irrelevant).... The last .30 cal trial used a 27 gram hammer instead of the 51 gram.... SSG guide assembly (spring and guide) weigh 22 grams.... Hammer stroke = 0.79" (at zero gap)....

Initial .25 cal. tests.... (0.60" preload, 0.0344" jet, 51 gram hammer)....

.25 cal. 25.4 gr. @ 1900 psi... plateau velocity = 1096 fps @ 2 turns gap or less
4 turns gap = 1085 fps
6 turns gap = 1068 fps
7 turns gap = 1058 fps
8 turns gap = 1042 fps
9 turns gap = 1020 fps
10 turns gap = 380 fps

.25 cal. 34.1 gr. @ 1900 psi.... plateau velocity = 999 fps @ 2 turns gap or less
4 turns gap = 982 fps @ 0.71 FPE/CI
6 turns gap = 965 fps @ 0.92 FPE/CI
7 turns gap = 954 fps @ 1.01 FPE/CI
8 turns gap = 940 fps @ 1.11 FPE/CI
9 turns gap = 887 fps @ 1.42 FPE/CI
10 turns gap = 335 fps

.25 cal. 52.7 gr. @ 3000 psi.... plateau velocity = 992 fps @ zero gap
2 turns gap = 979 fps
4 turns gap = 959 fps
5 turns gap = 942 fps
6 turns gap = 920 fps
7 turns gap = 826 fps
8 turns gap = 420 fps

Additional .25 cal. test with 0.40" preload @ 1900 psi using 34.1 gr.... plateau velocity = 989 fps @ 2 turns or less gap....
4 turns gap = 980 fps
6 turns gap = 963 fps
7 turns gap = 949 fps
8 turns gap = 900 fps
9 turns gap = 470 fps

Initial .30 cal. tests.... (0.60" preload, 0.0344" jet, 51 gram hammer)....

.30 cal. 44.9 gr. @ 1900 psi.... plateau velocity = 980 fps @ 2 turns gap or less....
4 turns gap = 971 fps
6 turns gap = 958 fps
7 turns gap = 945 fps
8 turns gap = 910 fps
9 turns gap = 860 fps
10 turns gap = 300 fps

.30 cal. 49.7 gr @ 1900 psi.... plateau velocity = 960 fps @ zero gap....
2 turns gap = 948 fps @ 0.92 FPE/CI
4 turns gap = 940 fps @ 0.95 FPE/CI
6 turns gap = 922 fps @ 1.04 FPE/CI
7 turns gap = 902 fps @ 1.11 FPE/CI
8 turns gap = 870 fps @ 1.29 FPE/CI
9 turns gap = 803 fps @ 1.39 FPE/CI
10 turns gap = 270 fps

.30 cal. 49.7 gr. @ 3000 psi.... plateau velocity = 1093 fps @ zero gap
2 turns gap = 1080 fps
4 turns gap = 1062 fps
6 turns gap = 1045 fps
7 turns gap = 1012 fps
8 turns gap = 390 fps

.30 cal. 67.2 gr. @ 3000 psi.... plateau velocity = 980 fps @ zero gap
2 turns gap = 970 fps
3 turns gap = 958 fps
4 turns gap = 933 fps
5 turns gap = 895 fps
6 turns gap = 850 fps
7 turns gap = 770 fps
8 turns gap = 480 fps

Additional .30 cal. data point.... 109 gr. @ 3000 psi.... 811 fps (159 FPE) with 1 turn preload (-1T gap)....

Jet removed for remainder of .30 cal testing.... Preload 0.40" (3.2 lbs).... 34.1 gr. @ 1900 psi....

With original 51 gram hammer.... plateau velocity = 960 fps @ 2 turns gap or less....
4 turns gap = 957 fps
6 turns gap = 940 fps
7 turns gap = 925 fps
8 turns gap = 896 fps
9 turns gap = 330 fps

With above, and lighter 27 gram hammer.... plateau velocity = 950 fps @ 1 turn gap or less....
2 turns gap = 945 fps
3 turns gap = 935 fps
4 turns gap = 917 fps
5 turns gap = 870 fps
6 turns gap = 670 fps (unstable, ES >100 fps)
7 turns gap = 225 fps

Efficiency testing was done by shooting 1 mag. (8 shots in .25 cal or 7 shots in .30 cal) tethered to a 500 cc bottle with 1900 psi regulated output and measuring the pressure drop in the bottle for that 1 mag. with a good gauge.... That is essentially all the testing I have done to date.... Have fun !!!

Bob

[oldpro]

 Man you were a busy Bee today!!! Glad its winter its the only time we get to see you posting Data. Bob do you have a .025 jet or just use a 4mm bolt and drill it. I think youll be surprised at what youll see. Or maybe not you have you look like you have a firm grip on it.

[rsterne]

Nope, only the one #87.5 jet (which I think is 0.034" ? ).... The only drills I have smaller than a #60 (0.040") are 1/32" (0.031") and 1/64" (0.016").... Nice to know that the threads a M4 though, thanks for that tidbit....

I guess the 6-32 SHCS jets I made for my homemade SS valve for the 6mm / .257 project are a bit too large.... They start at 3/64" (0.047") and go to 3/32" (0.094").... 

Bob

[MJP]

Nice looking test data you have gathered there Bob, you guys are having fun while I'm up to my neck in physics study and material technology.
At least later is interesting.

Does the valve act similar to Cothrans, where if you tap the valve just enough to open it it blows wide open?

Keep up the good work, it is interesting to follow.

Marko

[YEMX]

...Does the valve act similar to Cothrans, where if you tap the valve just enough to open it it blows wide open?

Keep up the good work, it is interesting to follow.

Marko

Two takes on the same idea- a balanced valve.  Yes, light strike= big power.  Although, the SS valve allows an even lighter strike and more adjustability, or tunability rather.  The Cothran valve is adjusted via pressure.  The SS valve allows for more tunability via pressure and hammer strike.  Or that's my grasp of the situation.  Please correct me if I'm wrong guys.

[shorty]

Thanks for taking the time to post all the data (seriously - wow). I may get a few things incorrect but I am trying. It is so much information and I am putting things together that are apples to apples testing ( I think ).
For the 25 I can only do SSG setting vs valve to have an output for FPS/FPE. If we had the efficiency numbers for both runs of the 34 grains at .4"/.6" preload at 1900psi I could have added that data in to see what the most efficient SSG set up would be for a given fps/fpe.

A little bit about the graphs first. A line that is close to or near horizontal typically means that adjustment does not influence major changes in the output. Although lines that are more vertical have a major impact in the output.

The interactions plots are used to do just that, and are fixed. They just show what things are doing. Although, the optimization plot is dynamic. Adjustments can be made to the factors (with in the range of the design) to predict the output (or in other words - optimize it).


So I wanted to put the SSG information into tables first to get an understanding of gap,preload, and cocking effort. In the DOE, I used just SSG setting but, it can be changed to cocking effort,gap, or preload for a better understand of energy needed to crack the valve.

Here's the SSG table

[shorty]

Main effects and interactions plot was kind of interesting. The interesting part for me was the interactions plot. It indicates that a high SSG preload is more stable within a desired fps/fpe range. Although, less SSG preload has more of a broad range of FPS/FPE but does not seem to be as stable. This may have to do with the free flight of the hammer at different distances ( I don't know ).

[Sfttailrdr46]

I wish to add this to the conversation. You guys do all the heavy lifting and every AG addict on the planet benefits either directly or indirectly form all the research and hard work.

Thank you all from one of the direct beneficiaries. The .30 Marauder that Lloyd built for me with the custom TJ's barrel , Cothran balanced valve and  I believe Huma Regulator it is a great proof of what you guys are accomplishing through research and collaboration.

So again thank you all

Regards,
Don AKA  Sfttailrdr46 

[shorty]

The best thing I like about Factorial design is that we can use the optimization plot dynamically and (guess) what should happen at any setting with in the scope of the design.

For example. If you wanted to set your gun up for a given "cocking effort" with a known gap that provides the best efficiency and shot to shot consistency, you just have to change the factors (settings) and you can see what the result "should be" without even shooting the gun.

It comes pretty close but I am off around 10 fps right now to the raw data. That's not as important as what the information is telling you though (IMO).

So I did three optimization plots trying to maintain 950 fps and trying to keep the gap a small as possible. Here's what it looks like.

[shorty]

Sorry I can't do the 30 with jet sizing. Missing 2 data points and don't want to guess. I guess this is a good start to understanding the valve a little more for me. Thanks again for all the data Bob. Great work

[YEMX]

Man, the wealth of knowledge astounds me!  Amazing work guys!

[shorty]

Whats really neat is, Bob did the initial screen test for the limits (max/min). If we were to do the DOE now (design before shoot), you can actually dial it in more accurately.

Whats even neater too me is just by doing 4 to 6 test shots with different settings can and will give you every possible setting of preload,gap,SSG turns, and jet size for a desired output such as efficiency,fps/fpe, and max cocking effort with the couple clicks of the computer instead of shooting gobs of pellets and using lots of air.

Testing goes from a couple days to a couple hours.

[rsterne]

Marko, I don't think the Cothran "blows open" exactly.... because if that were the case you could not reduce the air usage by using less hammer strike, or limiting the distance the hammer can drive the stem with an O-ring or energy absorbing bumper on the back of the valve.... It definitely has a "cycle" to it, however, whereas the ART/SS valve seems to act more "normally" in that you can adjust the velocity somewhat by changing the hammer strike.... Conventional valves will also reach the point where they only "pop" and deliver minimal velocity, but they arrive there much more gradually....

One thing I have noticed with both the Cothran and ART/S valves is that heavier pellets seem to increase the dwell, or rather light ones (or no pellet) decrease it.... When you get close to the cliff with either valve, if you shoot without a pellet, the valve just pops, hardly releasing any air.... This doesn't happen when the valve is opening lots (or at least you don't know it).... just when it is barely cycling properly.... which is of course when it is the most efficient as well.... This quicker cycling when dry fired (or using a light pellet) most likely is a result of the rapid decline in pressure on the downstream side of the poppet, which being barely open is then slammed shut by the pressure inside the valve.... The heavier the pellet, the longer the pressure difference across the poppet head is minimized....

I wish it was that easy, Tim, but perhaps your predictions will make it so.... IMO, the non-linearity of the preload/gap vs. velocity curves makes interpolation using 2 or 3 points inaccurate, if not downright misleading.... As an example, how would you deal with a Cothran valve, where there is no velocity change over many turns of gap adjustment, and then it basically quits working suddenly over just 1 turn more gap?....
 
BTW, the hammer stroke is 0.79", not 0.68" as you used in your data.... not sure where you got 0.68".... In addition, when I say "zero" gap, I actually have a very slight gap (something on the order of 1/6 turn) to make SURE that there is no preload on the spring, and zero chance that the SSG can add any closing force to the valve.... so you might be well advised to add 0.010" to all the gaps.... ie "zero" is actually about 0.010" gap, 2 turns is 0.121", etc.... Good Luck !!!

Bob