Author Topic: Regulator for BAM B51 (Read 26080 times))

MartyB · « **Reply #100 on:** April 06, 2016, 07:43:38 AM »

Quote from: taso1000 on April 06, 2016, 12:18:22 AM

Scott,

Thank you for the guidance. I am currently using the original brass transfer port. Mike Melick had sent me two delrin rod pieces drilled with 3mm and 2mm holes respectively. I can try those but I'm gonna need to figure out how to "slice" them and keep them flat. Do you think they will be ok flat or do they need to be shaped like the original?

It may be easier for me to fill the original transfer port with JB Weld and drill the port out in increments and test in between.

Would that work Scott?

Thank you,

Taso

I use a flat delrin TP in my .22 B50 without issue.

Taso1000 · « **Reply #101 on:** May 07, 2016, 05:12:11 PM »

Hi All,

Sorry for the big gap since my last update. Life and work keeps on getting in the way.

I ended up lowering the regulator set point to get to the velocity I wanted. Next I want to fill to 2000 psi and shoot the rifle down to the set point or 100 shots, whichever comes first, and analyze the chronograph data.

I did try re crowning the barrel but am not getting nice lands and grooves on the crown. Has anyone else seen this? Could it be that the rifling is that shallow and not as noticeable or do I have a bad spot in my barrel?

So then I thought about choking the barrel.

http://www.gatewaytoairguns.org/GTA/index.php?topic=108629.msg1034807#msg1034807

I haven't decided on how to proceed. Maybe see how the rifle shoots before I worry about crowns and choking lol.

That's my update for now. Hopefully I can put some rounds through the rifle tonight.

Thanks,

taso

Taso1000 · « **Reply #102 on:** May 15, 2016, 02:20:02 PM »

Hello All,

After some issues with my chronograph not picking up my shots 10 feet away I setup 3 feet away. I pumped the B51 up to 3000 psi and shot it down to where the valve couldn't hold the remaining air in the tube and dumped. That last shot registered 462 fps

Initially I thought I would do a hundred or two hundred shots and be done. Nope. I got 378 shots! I never expected to get that many! The data shows 377 but after I had 99 shots in the first shot string I shot the 100'th shot but the chrono didn't count it. So after that I switched strings after the 99th shot.

I imported the data from the ProChrono Digital and made the attached graph. When I first saw the 4 shot string graphs separately I saw the velocity rising and dropping and I thought this isn't very good.

So when I got all the data together and made the complete shot group I though, "Hmm, that's not too bad." What should a regulated shot string look like?

Now I will have to ask the experts to give me their opinions as I'm not sure what I should do next? I know ruler flat probably isn't achievable. Could I restrict the transfer port to limit the flow to bring down the 580 fps shots down?

I can't find the post I read it in but I "thought" a transfer port restriction would not increase efficiency. The results from that post showed that efficiency and shot count does increase.

I have done nothing to the ports in this rifle. They are as they were born.

Thank you all for hanging around and helping!

Taso

rsterne · « **Reply #103 on:** May 17, 2016, 11:32:06 AM »

I haven't been following this thread, but that string certainly doesn't look like one from a regulated PCP.... You have nearly a 10% ES.... What is your setpoint pressure?....

Bob

Taso1000 · « **Reply #104 on:** May 17, 2016, 11:51:02 AM »

Bob,

I have no way to tell what the set point is exactly as I have no way to measure. Milo set the regulator at 1200 psi originally but I've reduced it since then. I got the regulator set to where my setup would no longer produce a rise in velocity when I increased hammer spring preload. Then I backed the regulator down to where I felt the knee would be. I'd have to check my notes on how much.

The valve and hammer springs are very light and the hammer is a nylon one Motorhead made for me.

Taso

rsterne · « **Reply #105 on:** May 17, 2016, 12:07:16 PM »

No idea what's happening there.... Sorry.... The only thing that comes to mind is that the regulator output pressure is falling as the reservoir pressure drops.... ie you have it set for, say, 1000 psi, and it's starting at 1000 when the reservoir is at 3000 and drops to, say, 600 by the time the reservoir is at 600.... It may be that you are way outside the parameters of the regulator's ability to regulate.... The only way to know for sure is with a gauge on the output side, IMO....

Bob

Taso1000 · « **Reply #106 on:** May 17, 2016, 12:38:53 PM »

Bob,

Milo had said the regulator was "adustable from 100 to 2100 psi". I don't know what to make of the curve. I thought it should average out to be ruler flat.

I mean I could live with it, as I'm tickled pink at the 378 shots.

I always thought restricting the transfer port did not help efficiency but a couple months ago I found out that it did actually help. I can't find the post now.

Bob, do you think a little transfer port restriction will squash the higher velocities? Does 378 shots sound right? I don't think I will always fill to 3000 psi. I can do some strings from 1500 and 2000 psi to see what the curve and shot count looks like.

Thank you,

Taso

BigTinBoat · « **Reply #107 on:** May 17, 2016, 12:46:33 PM »

Quote from: taso1000 on May 17, 2016, 12:38:53 PM

Bob,

Milo had said the regulator was "adustable from 100 to 2100 psi". I don't know what to make of the curve. I thought it should average out to be ruler flat.

I mean I could live with it, as I'm tickled pink at the 378 shots.

I always thought restricting the transfer port did not help efficiency but a couple months ago I found out that it did actually help. I can't find the post now.

Bob, do you think a little transfer port restriction will squash the higher velocities? Does 378 shots sound right? I don't think I will always fill to 3000 psi. I can do some strings from 1500 and 2000 psi to see what the curve and shot count looks like.

Thank you,

Taso

Before the restrict the port you need to get the regulator working right.

Motorhead · « **Reply #108 on:** May 17, 2016, 12:50:22 PM »

Regulator most definitely IS NOT doing its job well as it could.
Have to agree with Bob that the Reg is operating OUTSIDE its range and is indeed changing output pressure with changes in storage pressure.

As good of luck as i have had with Milo's Regs ... seen 2 later versions / revisions that frankly though were a step backwards.
Personally have a 1st get that has HP intake down the adjuster cap direct to seat ... this style Has next to no changes in output as tank pressure rises / falls.
Milos later versions used a SIDE INTAKE for HP which placed HP on the HP end of spool outside of the seats diameter. This style the pressure exerted on the end of spool directly changed with tank pressure & regulator was less stable to set point as tanks pressure rose & fell.

Scott

rsterne · « **Reply #109 on:** May 17, 2016, 05:51:30 PM »

A side intake regulator should be less stable, and could very well be causing the exact problem you are having.... I don't think choking up the transfer port is the answer....

Bob

Taso1000 · « **Reply #110 on:** May 17, 2016, 06:02:02 PM »

I will check and take pictures when I get home from work. Is the side intake visible externally or should I take the regulator apart?

Thank you all for your help! ☺

Taso

rsterne · « **Reply #111 on:** May 17, 2016, 06:34:04 PM »

I would doubt you can tell without disassembly, but Scott would know for sure....

Bob

Taso1000 · « **Reply #112 on:** May 17, 2016, 06:39:27 PM »

I have the 2nd regulator still new in the bag, never installed. I can take pictures of that one easily.

Taso

Motorhead · « **Reply #113 on:** May 17, 2016, 08:41:51 PM »

Side intake has the HP bleed hole into the side of the regulators body upper reduced diameter end.

End HP intake has a bleed hole dead center of the adjustment bonnets screw.

Taso1000 · « **Reply #114 on:** May 17, 2016, 10:38:33 PM »

Scott,

Do these pictures show the ports you are referencing?

Thank you,

Taso

Motorhead · « **Reply #115 on:** May 18, 2016, 02:22:33 AM »

Quote from: taso1000 on May 17, 2016, 10:38:33 PM

Scott,

Do these pictures show the ports you are referencing?

Thank you,

Taso

No, Spool pictures don't tell what we trying to ascertain.
need to see the assembled regulators Adjuster bonnet / reg body at HP tank end

Taso1000 · « **Reply #116 on:** May 18, 2016, 10:27:51 AM »

Scott,

Here are the external pictures. Aside from the vent hole that vents to atmosphere there aren't any other holes around the circumference of the regulator. If you need more pictures please let me know.

Thank you All,

Taso

Motorhead · « **Reply #117 on:** May 18, 2016, 12:21:37 PM »

Looks to be a center intake ? ... DOES the aluminum housing have a hole in the side of it in the upper reduced diameter adjustment nose area ?

Taso1000 · « **Reply #118 on:** May 18, 2016, 12:24:03 PM »

Scott,

I'm 99.9% sure it does not. I didn't see one but I will verify when I get home from work.

Taso

Motorhead · « **Reply #119 on:** May 18, 2016, 02:35:09 PM »

If the case it DOES NOT ... then that is indeed a center intake and would honestly say with the profile of strings shown using it, it is operating OUTSIDE of an optimum bevel spring configuration internally.

It would be an educated guess that to operate at such a low pressure and have accurate metering the bevels would do better being in opposing singles such as ()()()()() ... which maybe how oriented, tho the pic would look the same if 5 sets of doubles like (())(())((

JMO ....
Scott

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Regulator for BAM B51

Author Topic: Regulator for BAM B51 (Read 26080 times))

BigTinBoat