Aerodynamic Stability of Pellets

[Ignoto]

The lag time was explained in this original post https://www.airgunnation.com/threads/how-wind-causes-pellets-to-drift.1278969/ where its relationship to down wind drift was also explained. Why the wind does not blow on the side of a pellet was also shown in the diagrams.

Thank you sir!
I did read the post entirely more than once to fully understand what you were telling like a little bird with its mouth open waiting for more food.

I simply did not know you had so much more great posts beside this one so I touched lag time in hope you would elaborate more about it.
I listen to podcasts most days at work from Mr Jayden Quinlan while he explains the physics involved in all of this and lag time was one of those things that open my eyes to how things happen.

I feel very happy to have you in the forum and think you are doing an excellent service to us all, specially since you are applying examples more directed to airguns in specific.

Keep at it!
Cheers

 

[HeyU]

A lead shuttlecock

 

[JungleShooter]

Miles is a gem — over and over he gifts us his extensive knowledge.

Which is based on real science from a government ballistic lab, not hearsay, or school physics....


And how Ron in the beginning of the thread expressed: Miles has a gift of writing — describing extremely complicated things with relatively simple words and sentences.



Miles, I appreciate your efforts. A LOT.

Your contributions to airgunning are UNIQUE.


Matthias

 

[ape]

Hey @Ballisticboy thanks for simplifying this for the common man.

My question is, if you were to design a pellet to be stable (and accurate, of course, like we all want), as far as flight aerodynamics, CP, and CG are concerned, what would you focus on refining? Cos it seems like a lot of trial and error is required.

 

[Ballisticboy]

I would try to make the distance between the CG and the CP as large as possible. This would mean putting as much mass as possible in the pellet head and keeping the flare as light as possible. Of course if the flare walls are made too thin the risk of damage when in the tin and distortion on firing increase which is undesirable. It may be possible to change the shape of pellets to try to move the CP as far back as possible. The Sniper series of pellets may have evolved into a suitable shape for this, certainly many shooters found them accurate.

For heavier pellets, I would try to extend the pellet head rather than fill up the flare as most designs do currently. Filling the flare moves the CG backwards and increases the chances of spiralling, particularly at long ranges and high speeds. A big problem may be pellet length, though there is probably some room for development.

 

[Motorhead]

Been testing some pre-production .30 caliber Diablo 60 grain pellets. There very long tailed having a shallow divergent angle from the diablo waist.
Very head weight bias having a deep & somewhat thin skirt profile.

They fly quite well, but due to weight require quite the push to make the speed into the mid / upper 800's or better.

 

[olde grunt]

I wonder if it would be advantageous to use a traditional lead aloy head and a lighter yet stronger skirt material, aluminum aloy perhaps. Allowing for thinner and stronger skirts,

 

[Motorhead]

I wonder if it would be advantageous to use a traditional lead aloy head and a lighter yet stronger skirt material, aluminum aloy perhaps. Allowing for thinner and stronger skirts,

As in ... Bi-Metalic

Or .. Perhaps made similar to the Hungarian SKENCO 2 material pellets having a metal front & plastic rear ?