The Parallel Node, Calfee

[primerate2]

Nopd

Your difinition of how NOPD works is correct and well stated. You seam experianced and knowledgable in the subject. I believe you are saying that the bullet leaves the barrel before the reactions of the particles has any damping effect. Correct?
I have not studied the reaction time of various type of particles but I have seen test results showing that tungston has the best damping effect.
I would like to see a test done with multiple holes drilled in a barrel with non compressed tungston or sand filled about 1/2 way then caped. If the pockets were near the muzzle there would be more of an oppertunity for the damping to have an effect as the vibrations are traveling at the speed of light and far ahead of the bullet.

We have been able to "tune a barrel " with a device on the muzzle, on the side or bottom of a barrel and on the receiver when its floating. The point that I have found to be the most sinsitive and tunable is about 13 inches in front of the receiver with a 26 inch barrel.

There is a old patent that claims that by adding weight to the muzzle you can stabilize vibrations. I think they found that 8 oz worked the best. I will try to find it again.

We also used visco elastic materal on the outside of a barrel with metal curved plates with sharp edges. The concept was for the plates to transmit the vibrationd out of the barrel at the poing of the sharp edges. As we constrained those plates we lost damping effect. There was an optiom thickness of the visco elastic that delivered the best damping effect on the high frequencies.

I have felt that a team comprised of people with a varity of knowledge and skills is what it will take to solve this vibration tuning the best.

 

[Don]

Your difinition of how NOPD works is correct and well stated. You seam experianced and knowledgable in the subject. I believe you are saying that the bullet leaves the barrel before the reactions of the particles has any damping effect. Correct?
QUOTE]

Correct.

I seem to vaguely remember that the very best NOPD damping rates were in the neighborhood of 1/64 per khz activity..................so in a 2 millisecond firearm firing event, NOPD damping would be almost immeasurable/negligible...............Don

 

[primerate2]

Don you may be right

I wanta try it any way.
However, I think you are right.

Question: Have you any thoughts on the SIMS Deresonater? I could not find any changer on any of my heavy barreled rifles. It may have some effect on a light barrel.

I wish I could see either a picture or a drawing of the test device that is going to be run today.

 

[Don]

primerate2;393229]I wanta try it any way.
However, I think you are right.

Probably one of the closest NOPD style dampers to resemble a cantilivered steel gun barrel, that I have seen in use, are the tungston filled hollow boring bars used in deep hole boring lathe applications...............but again, this is long cycle, repetitive cyclical damping.


Question: Have you any thoughts on the SIMS Deresonater? I could not find any changer on any of my heavy barreled rifles. It may have some effect on a light barrel.

Put "SIMS Deresonater" in the topic search engine for this website and several threads will appear about this topic, much of it hosted by Boyd Allen who has had some thoughts on this device.



I wish I could see either a picture or a drawing of the test device that is going to be run today.

Jackie will sometimes post pictures of items he is working on, if there is enough interest and requests.............Don

 

[Vibe]

I may be wrong on this but I think a Bourdon tube must be flattened slightly to make it straighten out. (Barrels do flatten slightly as they droop but this would be insignificant.) Also, I think the effect, if it was there, would be very small and would not be the driving force in barrel vibrations. As stated many times before - it's the recoil effect, the inertia effect of bullet mass, and minor "sound" effects that causes vibration.

Most Bourdon Tubes are flattened to save space and to make then a bit easier to curl up, not so much as the way they function. Watch a round section garden hose pressure up sometime, it too will try and straighten out, the more pressure applied the more it will try and form a straight tube.

 

[pacecil]

All tubes flatten as they are bent, so hoses will have a slight tendency to straighten. Most of the "straighting" will come at the end of the hose from the jet effect. I don't think Bourdon tubes are flattened to save space, they are flattened so pressure will act to push the oval cross section into a more round cross section. This tends to put the inside diameter of the tube bend into compression and the outside in tension - this will tend to straighten out the tube. A perfectly round cross section would change very slightly under pressure and thus cause the tube to change only very slightly.

We sure get a long way from the original question in these threads, don't we - anyway it's still fun I guess. That may be why Calfee gives up and goes away! He could learn something though if he keeps reading them.

 

[Vibe]

We sure get a long way from the original question in these threads, don't we - anyway it's still fun I guess. That may be why Calfee gives up and goes away! He could learn something though if he keeps reading them.

LOL. Yeah it does seem to happen that way don't it.

All tubes flatten as they are bent, so hoses will have a slight tendency to straighten. Most of the "straighting" will come at the end of the hose from the jet effect.

Well that actually opens up a whole 'nother can-o-worms, as the jet of material leaving the hose actually has an "unstraightening" effect due to the various vortices in the exhaust fluid. Which is why an unconstrained fire hose whips around.

I don't think Bourdon tubes are flattened to save space, they are flattened so pressure will act to push the oval cross section into a more round cross section. This tends to put the inside diameter of the tube bend into compression and the outside in tension - this will tend to straighten out the tube. A perfectly round cross section would change very slightly under pressure and thus cause the tube to change only very slightly.

Well with rifle barrels we are speaking of very slight movements - even though they have much larger effects at the target. I don't guess I really feel the need to argue much over whether or not it's due to flattening or not, you seem to be on the same page that pressure will cause a tube to try and achieve a straighter shape - which was what my reference to a bourdon tube was intended to convey anyway.

 

[seymour fish]

What if there is much more going on that the 3rd mode of oscillation of a cantilevered beam? how about shock-wave reflection??? like, anybody out there know how a header works? Seymour Fish

 

[Carp]

Talk about digging up a T-Rex? I know where Seymour is and I ain't bitin'......but talk about something stinkin'............................

Carp

aka John M. Carper