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Main Boards => PowWow => Topic started by: Jethro21 on February 21, 2011, 12:28:00 AM

Title: Dynamic vs Static spine
Post by: Jethro21 on February 21, 2011, 12:28:00 AM
Could someone explain the difference to me between Dynamic and Static spine?

I ask because in a recent post about adding weight to carbons the poster said that weighting the arrow with his method static spine wasn't affected but dynamic spine would show slightly weaker.

So....I don't know the difference. Could someone explain it to me in simple terms that a dumb, bald cop could understand?

Thanks,
Jethro
Title: Re: Dynamic vs Static spine
Post by: bowslinger on February 21, 2011, 01:00:00 AM
Static spine is the measure of arrow stiffness at rest.  Typically, the static spine is measured by resting an arrow on two narrow points either 26 inches apart or 28 inches apart.  A weight of a certain size (2 pounds I believe) is hung from the center of the arrow shaft, and the deflection of the arrow (think sagging) from horizontal is the measure of static spine.  Downward pressure using a gauge (spine tester) can be used instead of hanging a weight.

Dynamic spine is a measure of how much the arrow flexes when fired.  Things like smoothness of release, how tight a nock clamps to the string, draw weight, draw length, string material (dacron versus fastflight) all may or will have some impact on how much the arrow flexes.
Title: Re: Dynamic vs Static spine
Post by: jarhead_hunter on February 21, 2011, 11:36:00 AM
Think of static load as a dead load, at rest.

Dynamic load is a live load, in motion.

What part of PHX are you in???

Charles.
Title: Re: Dynamic vs Static spine
Post by: Jethro21 on February 21, 2011, 12:38:00 PM
Jarhead, I am in north phoenix, 101 and cave creek rd
Title: Re: Dynamic vs Static spine
Post by: Jethro21 on February 21, 2011, 12:39:00 PM
And thanks for the explaination, that makes sense
Title: Re: Dynamic vs Static spine
Post by: jarhead_hunter on February 21, 2011, 12:57:00 PM
Glad it helped.

What PD are you with???

I shoot rifles and such with a bunch of retired TPD guys every Wednesday.

Lotsa stories and some lies....

Charles.
Title: Re: Dynamic vs Static spine
Post by: Jethro21 on February 21, 2011, 02:50:00 PM
I work for Glendale. As far as the lies go, I like to quote George from Seinfeld- "it's not a lie if you believe it"
Title: Re: Dynamic vs Static spine
Post by: jarhead_hunter on February 21, 2011, 03:24:00 PM
Well said.

I like Seinfeld.

Keep in touch.

Charles.