T = (K * D2) / L
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All handloading data posted on Full-Bore UK from 23/2/2021 must reference the published pressure tested data it was sourced from, posts without such verification will be removed.
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All handloading data posted on Full-Bore UK from 23/2/2021 must reference the published pressure tested data it was sourced from, posts without such verification will be removed.
Any existing data without such a reference should be treated as suspect and not used.
Use reloading information posted here at your own risk. This forum (http://www.full-bore.co.uk) is not responsible for any property damage or personal injury as a consequence of using reloading data posted here, the information is individual members findings and observations only. Always verify the load data and be absolutely sure your firearm can handle the load, especially older ones. If in doubt start low and work your way up.
Re: T = (K * D2) / L
John25 wrote:How?
clapclap-
DOGGER2UK
Re: T = (K * D2) / L
The Greenhill Formula is a simplified method for determining mathematically the amount of spin necessary to stabilize a bullet.
I prefer to use Gyroscopic Stability (GS) = the spin rate (in radians per second, squared) times the polar moment of inertia, squared, divided by the pitching moment coefficient derivative per sine of the angle of attack times the transverse moment of inertia times the air density times the velocity squared.. For the bullet to be stable, GS > 1.0.
This is actually a short version as the pitching moment coefficient component is a complicated calculation that derives the center of gravity and the center of reverse air pressure. The equation is basically calculating the linear difference between the center of gravity and the center of reverse air pressure on the nose of the bullet. The greater the difference, the greater the spin required to keep the bullet pointed nose forward.
I prefer to use Gyroscopic Stability (GS) = the spin rate (in radians per second, squared) times the polar moment of inertia, squared, divided by the pitching moment coefficient derivative per sine of the angle of attack times the transverse moment of inertia times the air density times the velocity squared.. For the bullet to be stable, GS > 1.0.
This is actually a short version as the pitching moment coefficient component is a complicated calculation that derives the center of gravity and the center of reverse air pressure. The equation is basically calculating the linear difference between the center of gravity and the center of reverse air pressure on the nose of the bullet. The greater the difference, the greater the spin required to keep the bullet pointed nose forward.
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John25
Re: T = (K * D2) / L
Do you think then, that your method is more suited for the higher muzzle velocities?
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tackb
Re: T = (K * D2) / L
I just load em and shoot em , if they go through the target sidways i try something else ?DOGGER2UK wrote:The Greenhill Formula is a simplified method for determining mathematically the amount of spin necessary to stabilize a bullet.
I prefer to use Gyroscopic Stability (GS) = the spin rate (in radians per second, squared) times the polar moment of inertia, squared, divided by the pitching moment coefficient derivative per sine of the angle of attack times the transverse moment of inertia times the air density times the velocity squared.. For the bullet to be stable, GS > 1.0.
This is actually a short version as the pitching moment coefficient component is a complicated calculation that derives the center of gravity and the center of reverse air pressure. The equation is basically calculating the linear difference between the center of gravity and the center of reverse air pressure on the nose of the bullet. The greater the difference, the greater the spin required to keep the bullet pointed nose forward.
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pe4king
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Re: T = (K * D2) / L
Works for me :goodjob:
What is a Sapper? This versatile genius condenses the whole system of military engineering and all that is useful and practical. He is a man of all work of the Army and the public ready to do anything or go anywhere, in short, he is a Sapper.
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John25
Re: T = (K * D2) / L
pe4king wrote:Works for me :goodjob:
Do you use his original formula or one of the modified ones?
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waterford103
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Re: T = (K * D2) / L
Brilliant Royal Artillery Officer I believe
"This year will go down in history. For the first time, a civilized nation has full gun registration. Our streets will be safer, our police more efficient, and the world will follow our lead into the future!"
Adolph Hitler – 1933
Adolph Hitler – 1933
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pe4king
- Posts: 1402
- Joined: Sat Nov 06, 2010 9:59 pm
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Re: T = (K * D2) / L
I use the "use a bigger hammer" formulaJohn25 wrote:pe4king wrote:Works for me :goodjob:
Do you use his original formula or one of the modified ones?
What is a Sapper? This versatile genius condenses the whole system of military engineering and all that is useful and practical. He is a man of all work of the Army and the public ready to do anything or go anywhere, in short, he is a Sapper.
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