The High Pitched Ping Noise
Now that the hammer spring noise has been tamed by our damping the HS with a piece of tubing, rubber grommet, or a foam ear plug, there is still another high pitched ping noise.
On my 0.22, it lasts about 1 – 1.5 seconds after firing. It is much fainter and higher pitched than the twang the hammer spring once generated.
The sound reminds me more of a solid piece of metal ringing than a spring.
I had thought adding a air cylinder de-pinger and cushioning the plenum spacer would do the trick, but no.
This faint, high pitched ping wasn’t affected by those maneuvers.
Today, I found one can replicated this ping by dropping the plastic handle of a small screw driver against the breach block from about 1/2 inch.
The noise isn’t as readily elicited if one simply holds the screwdriver while tapping.
The light dropping of the screwdriver handle makes the ping noise happen.
It can also be elicited by at the breach end of the air cylinder, but NOT the front or middle of the cylinder.
The significance of being able to elicit this ping by tapping is that we eliminate confusion with the hammer spring twang AND do it without firing the gun.
That means we can test the air cylinder for this ping when it is removed from the gun.
Knowing this, it is now possible to check if this ping source is in air cylinder or the breach block.
I’m hoping that the next time someone is pulling the air cylinder, they first check for this before separating the two.
That lets you learn the ping.
Then test the cylinder and breach block independent of each other once they have been separated.
That will help identify where this high pitched ping originates and work on squelching this additional ping source.
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I think I would go with the way Ernest has figured out to fix the issue — cutting grooves in the spacer and adding 2 o-rings. He fixed the problem successfully even without fully elucidating the mechanism. My theory as to why the ringing can occur matches his solution and the finding that only some of the Vulcans have this issue. I would follow his lead for solving this.
The spacer doesn’t HAVE to be aluminum, but personally I’m not really interested in having about 1.5 tons of force being buttressed by a plastic tube. The aluminum spacer avoids that worry. Yes, I know Delrin is strong, but that IS a lot of continuous pressure in an oxidizing atmosphere.
Increasing plenum volume can be helpful in getting more power out of a shot, but it could also reduce air efficiency. The interplay between the poppet valve and pressure drop in the plenum may change in ways one doesn’t expect. Too many variables to predict just how or if there would be an effect. Here is where the experience of a tuner is valuable. Otherwise, you get to do a LOT of experiments to find the best combination of plenum volume, poppet valve spring tension, air port sizes, hammer spring tension, hammer weight for your desired velocity and shooting distance. If you are willing to put in the weeks of work needed, dive in. You’ll end up with amazing knowledge and maybe a fuxed up or improved gun. Otherwise, have a tuner do it or at least follow a recipe that tends to work.
For myself, I enjoy experimenting and reporting results – whether bad or good.
My plan for the next level is to do test firing at my target distance (25 yards) and try to find the tightest grouping velocity for my Vulcan.
Then, work backwards from that velocity and adjust the regulator to be at its knee for that velocity.
It still won’t be the best setting, but will probably be as good as I will achieve with reasonable effort.
Finding the actual best would require a lot more iterative testing – more than I want to do.
After all, this is supposed to be FUN, not a job for me.
Does the spacer have to be aluminum? Could it be delrin? It could be made with a tighter tolerance too and thus no o-rings necessary since apparently the o-rings are added only to keep it centered. Or should the delrin not have a tighter tolerance to prevent it from possibly getting stuck and still have o-rings?
With the extra machining that Ernest did on Zonk’s gun, that would increase the area for air on that side of the regulator and change the harmonics. Is there an advantage to more air space?
No. It sounds like a ring of a metal bell. Not a whistle. Not a twang. It is a metallic ring.
The closest thing to that sound that a significant portion of you would have access to is strike the large side wheel of a scope with a fingernail
Thant renting has the same character except the one the gun makes is higher in pitch.
is it not like a whistling noise? some guns(not Vulcan) do that when the reg refills.
That spacer fits loosely in the AT so no turning required.
In your video, it looks like the space is the same diameter as the regulator. The regulator uses 25 X 3. If it is the same diameter, do you just stretch the 1.5 x 18 o-ring onto the spacer? A 7 mm stretch seems like a lot.
Thanks, GKU. Really appreciate you posting all those pictures and yes it helps with the cocking spring, but I already did the foam for that spring.
I used some gray foam so it is barely visible. I use a clear cover plate over the hammer assembly so I can keep an eye on how things are doing.
Of course you’d have that up your sleeve given your instrument building background!
I ran into the foam maneuver for guitar tremolo springs
I don’t own a Vulcan but my Cricket had a ring that I had a hard time finding after doing all the obvious de-pinging.
If you haven’t check it already, it turned out to be the little springs inside of the receiver.
I cut strips of foam from the ones found in the tins of pellets and tide them and pull them through with dental floss, no need to take the spring off.
hope that helps yah ………..
~ Greg
I have an air tube depinger. It has NO effect on this particular ringing sound.
Tapping the forward portion of the air tube does not elicit this sound. It is only at the breach end of the air tube.
Has the Manufacture added a standard Depinger
If the gun still has a ping… I would add a dePinger in the Airtube. Made right it may take up 1 shot.
Just because it has a regulator doesn’t mean it wont ping. If the regulator flows really fast it will ping My lane regulated P12 pinged before adding a simple delrin depinger.
No. What I am hearing is a soft, high pitched, metallic ringing noise that lasts about 1.2 seconds after a shot.
It’s like a high pitched bell.
Like I wrote, it is perfectly elicited by use of a small screwdriver handle dropping against the breach or breach end of air tube.
I can recreate the noise without firing the gun. With firing, it is the same noise except louder and longer.
It differs from the hammer spring “twang” in pitch and duration. That HS noise is essentially gone from my gun.
Waiting for my compressor and regulator tester to arrive before opening the tube again.
Was not a lot of fun manually pumping the gun back up from empty.
As for just drilling and adding rubber feet, I’d go with the o-rings because they add damping.
Just a thought, would you say that high pitch ping may be more of a short Shrill Whistle ❓
Other than o-rings could 3 small holes be drilled equally spaced near each end and maybe small rubber feet be inserted as centering devices ❓
And would drilling numerous holes work both to add volume and de-tune the ping ❓
That spacer fits loosely in the AT so no turning required.
Thanks!!
Guy you might be nailed it. Your brain sure seems to function well
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I may have figured out how the spacer is able to ring despite the massive clamping force squeezing it between regulator and valve assembly.
The quandary was how it could possibly be free enough to ring despite being clapped so tightly. The next idea was that perhaps it is
somehow able to become loose during the shot cycle.
I don’t believe it become loose. The pressure difference between the high pressure chamber and the plenum
is about 1500 psi. That’s maybe 1.5 tons of force pushing the regulator towards the breach end of the tube.
Hard to imagine the friction of lubricated o-rings holding the regulator in a smooth tube against
that kind of force. It isn’t happening..
Therefore, the spacer IS being clamped in place and very tightly.
The key is that the regulator, valve assembly and the spacer each have a diameter SMALLER than the ID of the air tube.
The spacer is quite a bit smaller. Also, the end of the valve assembly is not a flat surface.
>—–The spacer is NOT self centering. <——
So, sometimes when the assembly is put together, the spacer is off to the side and gets clamped along only
a fraction of its ends. The rest is then free to vibrate like a bell. If the spacer gets clamped down off center,
it can ring even with 1.5 tons of clamping force. On the guns that are not ringing,
the spacer is either clamping in nearly centered position OR both the valve assembly and regulator ends
are perfectly flat. Clamping the entire end —> no ringing.
Ernest adding his o-rings makes the spacer self centering and adds damps vibration of the spacer.
That kills the ping.
Now my brain isn’t hurting as much over this mystery.
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So, above Ernest said he used 1.5 X 18mm o-ring. Based on the videos, the spacer is the same (or very close) diameter as the regulator. According to the manual the regulator uses 3 x 25.2 mm o-ring. I would think there was a typo in Ernest’s post and maybe he used 1.5 x 25 mm o-ring. Or the 18 mm would need to be stretched 7mm.
What should be the o-ring size for the spacer mod?