Testing new discovery

[grand-galop]

Has anyone made one with lead shot and maple syrup?
Asking for a friend.   

If ever I was looking for a friend,  I wouldn't looking for you.

[BackStop]

Yes, but the the majority of the MAD devices being made are using lead shot (mercury in some) and oil or some other viscous liquid, not a solid weight.  And the spring may introduce more harmonics to the equation.

But lead could be molded onto the middle of the spring and make the ole spring float in the viscosity desired but will return to it's initial place in the reservoir..

Now THAT I did not think of.  Putting the weighted spring into the viscous fluid!


It might work!

[avator]

This

[grand-galop]

Yes, but the the majority of the MAD devices being made are using lead shot (mercury in some) and oil or some other viscous liquid, not a solid weight.  And the spring may introduce more harmonics to the equation.

But lead could be molded onto the middle of the spring and make the ole spring float in the viscosity desired but will return to it's initial place in the reservoir..

  more people with their brain might come to a near solution.

Now THAT I did not think of.  Putting the weighted spring into the viscous fluid!


It might work!

More brains to solved the puzzle might be a good thing.

[HunterWhite]

Kerry, Alain, Tater, I think that is pretty much what they do in cars. The weight of the car held up by springs and dampened by an oil filled shock.

Perhaps when the design is more defined DonnyFl will reconsider making a combined LDC with Kad.

[avator]

Yes, but the the majority of the MAD devices being made are using lead shot (mercury in some) and oil or some other viscous liquid, not a solid weight.  And the spring may introduce more harmonics to the equation.

But lead could be molded onto the middle of the spring and make the ole spring float in the viscosity desired but will return to it's initial place in the reservoir..

  more people with their brain might come to a near solution.

Now THAT I did not think of.  Putting the weighted spring into the viscous fluid!


It might work!

More brains to solved the puzzle might be a good thing.

Dang.... I think I just got eliminated from the conversation.

[JungleShooter]

I'm interested in trying this out for a bullpup (Skyhawk, it just cleared customs, but it'll be a few more days before I get it). 

Below the shroud I have an airtube, basically all the way forward.

Above the shroud I normally would have a scope must remain clear of visual obstructions.

But because it's a bullpup the scope is high up on a raised rail.

Sooo, could I just mount the MAD Pipe on top of the shroud?  

Matthias

[K.O.]

yep maple syrup great on penut butter, banana sandwiches...

some barrels will be low amplitude High frequency others can be higher amplitude lower frequency... and shades in between... so one size fits all will definably not work...

wonder if a xylophone mallet would get a mounted freq that could be recorded and analyzed with audacity or similar... then just might have a clue about which freq it is resonant (reacts most)at... then design the damper to be most effective for/near those freqs..

 

[grand-galop]

yep maple syrup great on penut butter, banana sandwiches...

some barrels will be low amplitude High frequency others can be higher amplitude lower frequency... and shades in between... so one size fits all will definably not work...

wonder if a xylophone mallet would get a mounted freq that could be recorded and analyzed with audacity or similar... then just might have a clue about which freq it is resonant (reacts most)at... then design the damper to be most effective for/near those freqs..

 

Let me explain my thinking of the mechanical effect...  Take as an example the swinging pendulum..  The two extreme are equal weight and they react to each other with EQUAL FORCE.. During this time, the middle weights are stabilize.. So!!  I consider the projectile and the weight inside the device to be the 2 extremes of the pendulum.. The barel would be the stabilize weight in between the two..

[KnifeMaker]

So, just out of curiosity

you could make an LDC with an extra outside chamber ( all around the unit ) as a damper right ?

it would be a bit thicker looking LDC but it wouldn't look as bad as would  an extra device hunging from the barrel/shroud,


How off am I ?

Manny, this is exactly what I suggested to DonnyFl. I was thinking a removable addition as a sleeve on the ldc. Still think it would work just fine.     I did discuss this with Travas at JSAR, and would like to talk with him further on the subject. However,they have kinda gone dark for the moment. A lot of pressure to get the  two new Rifles out.   


Why not design one similar in appearance to the ldc on the .30 Ed gun, where the bore is in the top partition rather than the bottom like Ed's. It would allow a chamber inside to hold the fluid adn shot.


the Maple Syrup, much less Peanut Butter won't work here. Too many Dayum Ants, (I shoot off a picnic table, and I don't want ants at my picnic)!
Not to mention ever deer in the county would be trying to lick it. 


Mike

[Hoople]

I too like the combo ldc-mad design. But for tune-ability and flexibility why not take it one step further and make it modular. Start out with an outer tube exactly say 6"- 8" inside length (plus room for a compression washer to hold everything together). Then make sections of baffles and mad modules exactly 1" or 2" or even 1/2" long. Mad modules could also be made of various materials: plastic, aluminum, brass, steel, and/or different fillers, steel or led shot and oil or mercury.

[Mole2017]

yep maple syrup great on penut butter, banana sandwiches...

some barrels will be low amplitude High frequency others can be higher amplitude lower frequency... and shades in between... so one size fits all will definably not work...

wonder if a xylophone mallet would get a mounted freq that could be recorded and analyzed with audacity or similar... then just might have a clue about which freq it is resonant (reacts most)at... then design the damper to be most effective for/near those freqs..

 

Let me explain my thinking of the mechanical effect...  Take as an example the swinging pendulum..  The two extreme are equal weight and they react to each other with EQUAL FORCE.. During this time, the middle weights are stabilize.. So!!  I consider the projectile and the weight inside the device to be the 2 extremes of the pendulum.. The barel would be the stabilize weight in between the two..

In a single spring-mass-damper system, they design the damper (and spring, if that's an option) to get the desired damping ratio. Low damping ratios don't damp the motion as quickly, but they don't have high forces either (important in ride comfort for cars, which aren't quite single spring mass damper systems, but are close to it for some design issues). High damping controls the motion, but can start feeling harsh, and so on. "Optimal" depends on the application.

I think the rifle barrel problem may be closer to a tuned mass damper problem, e.g. John Hancock building and Taipei 101. But those ideas work best when you get the damping ratio correct. More or less mass will also change performance, but the damping level has to be right for whatever mass you decide on.

So two ideas to throw into the mix:
1. The other day, I thought about the similarities between these devices (this idea, barrel weight, and "limb savers") and harmonic dampers used on engine crank shafts. May or may not be a good option for a "one off" event like firing a rifle, but they work in engines...

2. We've been talking about mass and fluids; for something else, how about "fluid harmonic dampers"? Could it work, or do we need the lead shot for sure? For that matter, we might be back to the question of whether is the movement of the lead shot or the "slosh" of the viscous fluid--or both together--that makes Knife's idea work. Does it have to be lead shot, which is theoretically active in multiple directions, or would concentric rings do the trick acting coaxially with the LDC, shroud, or barrel? How about a big ole dab of peanut butter smeared over the end of the barrel? (Seriously, someone has to try it now...make sure it is always a 1/4 cup or whatever will fit, re-applying it after each shot...)

It doesn't help that this is a very fast event, making putting instrumentation and data acquisition to work on the problem a somewhat more demanding application. However, re-reading K.O.'s idea, I am reminded that many microphones can double as accelerometers: seal the ends of a condenser mic and you are left with only the inertia of the diaphram and enclosed air to move under acceleration--a low cost, high frequency accelerometer that is friendly with just about any computer that can run Audacity. Calibration might be a bear, but for relative measurements it might work.

Actually, when he mentioned Audacity, my first thought was to simply hold the microphone very close the underside (or topside) of the shroud, barrel or LDC. The vibration of the barrel with set air moving and the microphone has a chance of seeing it. I once handled a microphone that had such a low frequency response that it could "see" my hand waving slowly near the mic--nothing to hear, but the air was moving. The rifle will have a lot more going on, so the question is, can you make it out with the noise of the shot going on? You have half a chance with a PCP or pumper, though even the hammer will add to what you see at the mic. A spectral plot might help when looking at the data--by adding some weight to the barrel, you might be able to shift its frequency and find it in the spectral plots. Once you know what it looks like, add the device and watch what happens next...

[grand-galop]

David!!  I like your CORRELATION of the crank shaft because it's closer to what I mentioned earlier.. The offset weight is EQUALLY DISTRIBUTE on either side of  the axis.. To match the weight of the projectile is proportional to what they do with crank shaft... The weight being supported with spring is to let the weight move to where the NODE OF THE AMPLITUDE will be...  A barrel tuner is there to counteract the node in the amplitude by moving it to the optimal position.... By eliminating  the best position with spring is convenient and has more room to work with a variety of velocities and twist rates.. I don't mean to discredit anyone here .…. But I have read multiple articles and especially the one with Eric Bostrom where he show graph and results of moving the weight with small increments..  The spring idea is to let the spring CHASE THE INCREMENT for you..

[rsterne]

IMO using a fluid with a low density, instead of lead shot (with or without fluid) as the dampening medium, just requires a much larger device.... Let's say you use oil with a density of 1, instead of lead shot with a density of 7.... You would need 7 times the volume to get the same mass and effect.... If you use mercury instead of lead, you could use about half the volume.... The higher the viscosity, the less the fluid will move in a sort time frame, which a shot certainly is.... With lead shot, and the damper 3/4 full, you give it a shake and it sloshes around, ie it ACTS like a fluid.... Take the same weight of lead in a cast block, not so much.... Put that mass inside the same damper, with a spring both ends, yep it will rattle around, but with different properties than a fluid, that's for sure.... Mount that lead block solidly to the barrel and you will get yet another effect.... Some guns may prefer one over the other, and my guess is that every device you can build may benefit from sliding it fore and aft on the barrel to tune it for each pellet/bullet and velocity.... We do that with mass dampers (and limbsavers) today....

Mike's "discovery" was that making a damper partially full of lead shot (and oil) to create a dense, moving "fluid" inside it.... and then clamping it near the muzzle (actually beyond it, in his original tests, it was on the LDC)…. reduced the group size with all but one bullet he tried, in relatively high powered PCPs.... He never thought it would work with pellets or low powered PCPs but in some cases it seems to (and some it doesn't).... IMO using a solid mass mounted on springs, or a pendulum, or a glob of peanut butter that must be reapplied precisely after every shot.... is dragging the original idea soooooooooooo far off course we are just getting deeper into the woods without a compass, or even a trail of breadcrumbs to follow.... It is not my intention to discourage innovation and development, far from it.... but realistically if you have an idea to try, get out and try it, instead of suggesting something you haven't tried.... JMO....

Bob

[avator]

TY Bob.

[grand-galop]

IMO using a fluid with a low density, instead of lead shot (with or without fluid) as the dampening medium, just requires a much larger device.... Let's say you use oil with a density of 1, instead of lead shot with a density of 7.... You would need 7 times the volume to get the same mass and effect.... If you use mercury instead of lead, you could use about half the volume.... The higher the viscosity, the less the fluid will move in a sort time frame, which a shot certainly is.... With lead shot, and the damper 3/4 full, you give it a shake and it sloshes around, ie it ACTS like a fluid.... Take the same weight of lead in a cast block, not so much.... Put that mass inside the same damper, with a spring both ends, yep it will rattle around, but with different properties than a fluid, that's for sure.... Mount that lead block solidly to the barrel and you will get yet another effect.... Some guns may prefer one over the other, and my guess is that every device you can build may benefit from sliding it fore and aft on the barrel to tune it for each pellet/bullet and velocity.... We do that with mass dampers (and limbsavers) today....

Mike's "discovery" was that making a damper partially full of lead shot (and oil) to create a dense, moving "fluid" inside it.... and then clamping it near the muzzle (actually beyond it, in his original tests, it was on the LDC)…. reduced the group size with all but one bullet he tried, in relatively high powered PCPs.... He never thought it would work with pellets or low powered PCPs but in some cases it seems to (and some it doesn't).... IMO using a solid mass mounted on springs, or a pendulum, or a glob of peanut butter that must be reapplied precisely after every shot.... is dragging the original idea soooooooooooo far off course we are just getting deeper into the woods without a compass, or even a trail of breadcrumbs to follow.... It is not my intention to discourage innovation and development, far from it.... but realistically if you have an idea to try, get out and try it, instead of suggesting something you haven't tried.... JMO....

Bob

Thank you for your help Bob my fellow Canadian!!!  It is funny how low comment members are disregard on here like ANY DISCUSSION FORUM..   I WILL from now on observed from distance who will be the chosen one..
As a bonus gift I will put a picture of my test mule..  Enjoy!

[Lani52]

I am thinking put the dampner inside my Skyhawk shroud, replace the shroud with a longer one and replace the air stripper with a oil barrier baffle and turn the rear area it diverted air into a dampner.

I have a tube coming from China to make a longer shroud to replace the incorrectly threaded and now too short shroud on my LW 20 inch poly chocked barrel.

I posted a better description on my JSAR Skyhawk thread.

Roachcreek

[darkcharisma]

Alain. I don't think matching the pellet weight is a good idea. You have to be able to see that...the whole front barrel moves, not just the pellet. So matching the pellet in weight will be inefficient. If you have to counter the whip of the barrel...at least use half of the barrels weight. Of course I have no mathematical equations to back this up but I think it Dallas into the common sense bracket. And from there just a bunch of trail and errors.

[grand-galop]

Alain. I don't think matching the pellet weight is a good idea. You have to be able to see that...the whole front barrel moves, not just the pellet. So matching the pellet in weight will be inefficient. If you have to counter the whip of the barrel...at least use half of the barrels weight. Of course I have no mathematical equations to back this up but I think it Dallas into the common sense bracket. And from there just a bunch of trail and errors.

I think you are right..  I forgot that is not only the projectile weight that make the barrel move.. The rush of air being displaced in front of the projectile and the TWIST  counteracts that occurred during the shot cycle have to be taken in account..

I will try to beef up  my device and use the same 1/5 scale RC shock spring that are in my sleeve.. If I go 1/8 bigger than my TKO I could fit a brass plumbing joiner to give room for bigger weight..

NOTE:  Since I shoot with my device I use jsb beast 16.20 g  at 824 fps and have not see any improve results since I think the weigh use might be too tight and not moving freely.

[Lani52]

I am beginning to think the reason our airguns shoot better once we find the upper limit, and then turn then down a bit, is that vibration Kinfemaker has revealed to us.


Roachcreek