❓ Acoustics Question: Projectile Flight Noise 𐃘 How to keep it down?

[6gun]

yes but at least they were not purposely aiming at you..umm with im assuming AK 47 and full auto burst .. yes let's disappear into the woods..
Mark

No, I meant I feel your pain exactly . Got shot at by somebody on horseback with a rifle, I was on a motorcycle with permission for those trails from the owner. That sorta thing. The ak incident for me was very different, but scary. Glad you're OK too.

 

[6gun]

@markhooper Gyroscopically stable = stabilized by spinning. This refers to slugs.

Pellets are stabilized by drag as air moves across and around the pellet’s skirt.

This is my understanding.

And a small amount of twist. You're correct with my understanding of a stabilizing shape too.

 

[lbc_PSI]

Probably similar to high drag arrow fletching. Low profile low offset plastic vanes were much quieter than feathers of any size. The vane made a slight whooshing noise.while the feathers sounded like a V2 buzz bomb. You could hear the feathers coming way before the arrow hit the target..like as soon as they left the string.

Now I’m going to have to stand down range to hear pellets vs slugs for myself..safely, of course.

 

[Ezana4CE]

Probably similar to high drag arrow fletching. Low profile low offset plastic vanes were much quieter than feathers of any size. The vane made a slight whooshing noise.while the feathers sounded like a V2 buzz bomb. You could hear the feathers coming way before the arrow hit the target..like as soon as they left the string.

Now I’m going to have to stand down range to hear pellets vs slugs for myself..safely, of course.

Interesting.

 

[markhooper]

@markhooper Gyroscopically stable = stabilized by spinning. This refers to slugs.

Pellets are stabilized by drag as air moves across and around the pellet’s skirt.

This is my understanding.

thank you, it's more than I know.
always good to learn something.
Mark

 

[markhooper]

No, I meant I feel your pain exactly . Got shot at by somebody on horseback with a rifle, I was on a motorcycle with permission for those trails from the owner. That sorta thing. The ak incident for me was very different, but scary. Glad you're OK too.

I'm sure military guys get that a lot, and are very fortunate to come home, we should all be thankful for their service..
but is civilians? getting shot at on purpose is one bad thing.. AK 47 full auto is another..
to be honest I started packing a 45 Ruger old army black powder.. figured one round in their direction might get them behind cover instead of shooting but more importantly if have plenty of smoke cover to vanish into the woods, not sure dates but it's possible I had my baby girl with me.. now that's fighting matter if it was.. but I don't remember..
Mark

 

[JungleShooter]

Just now reading — had a full Sunday, like always.

Thanks for all your attempts to get to the bottom of this.
It is intringuing, that's for sure.


Mark, I'm sorry you've had some health issues!

Dave and you all, thanks for your concern about safety.... — we've got some dividing walls in place.


So, my guesstimates are as good as yours (or a bit worse, since I failed physics in school at least once ):
➠ I might achieve less flight noise with:
⭓ lower velocity
⭓ smaller caliber
⭓ slugs (rather than waisted pellets)


Still need an accustics engineer to respond to this thread — or I need to get out there and do some test shooting. Any volunteers for the listening post...? Any?!?

Matthias

 

[dgeesaman]

@markhooper Gyroscopically stable = stabilized by spinning. This refers to slugs.

Pellets are stabilized by drag as air moves across and around the pellet’s skirt.

This is my understanding.

Pellets are stabilized by air moving over the skirt but those particular aerodynamic forces are not technically drag. Drag has a specific definition in aerodynamics that drag is the part that does not stabilize.