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Author Topic: Tip Weight/Spine  (Read 3244 times)

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Offline DC

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Tip Weight/Spine
« on: April 18, 2019, 09:45:26 am »
In my quest for light arrows I'm playing with tip weight. If I reduce the tip weight by 25gr I can take 5# spine out of the arrow. Same dynamic spine and the arrow still flies nice and makes the arrow maybe 30gr lighter. Then I can do it again. Another 30gr etc. Obviously there is going to be a point where this goes bad. Is it when the FOC moves too far back?
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Offline Pat B

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Re: Tip Weight/Spine
« Reply #1 on: April 18, 2019, 11:00:42 am »
25gr lighter tip weight will increase spine value by 5#. Lighter tip make spine stiffer.
 Spined arrows shafts are sold as if they were a 28" finished arrow with a 125gr tip.  ie. shafts with an indicated 50 to 55# spine weight are to be used as a 50 to 55# spined, 28" arrow with 125gr point. Any changes to tip weight or arrow length will change the effective spine value.
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Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

Offline Danzn Bar

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Re: Tip Weight/Spine
« Reply #2 on: April 18, 2019, 11:45:06 am »
 Seems like I've heard you say that before Pat....
 ;D ;)
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Offline DC

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Re: Tip Weight/Spine
« Reply #3 on: April 18, 2019, 12:05:25 pm »
That's what I said. If I take 25gr off the tip it makes the arrow 5# stiffer so I can reduce the spine by 5#. Yes he has said it before and I think he misunderstood me then too.
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Offline Pat B

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Re: Tip Weight/Spine
« Reply #4 on: April 18, 2019, 01:31:45 pm »
Yes, I guess I misread what you wrote.
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Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

Offline DC

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Re: Tip Weight/Spine
« Reply #5 on: April 18, 2019, 01:38:23 pm »
Sorry Pat sometimes I don't write very clearly.
So  "Obviously there is going to be a point where this goes bad. Is it when the FOC moves too far back?"
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Offline Pat B

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Re: Tip Weight/Spine
« Reply #6 on: April 18, 2019, 08:46:11 pm »
I've not dealt much with FOC so I doubt I could give you a good answer. I guess if you are bare shaft testing the arrow would loose stability the farther back the FOC is. Fletching would change that though due to drag.
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Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

Offline TSA

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Re: Tip Weight/Spine
« Reply #7 on: April 18, 2019, 09:16:26 pm »
the turkish flight arrows actually have a negative FOC.
usually though negative foc is purported to cause arrows to somersault once the velocity bleeds off.
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Offline DC

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Re: Tip Weight/Spine
« Reply #8 on: April 19, 2019, 08:35:11 am »
There must be a saw off point with the FOC where accuracy starts to suffer and increasing the fletching size to compensate just bleeds off speed. I have to do some reading on your website.
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