# Vane distance from nock



## b0w_bender (Apr 30, 2006)

the farther towards the nock the vanes are set the more leverage they have however moving them closer to the front affects FOC. Higher FOC also improves flight. I doubt you would be able to see a difference moving them 1/2" in either direction. The Olympic archers use a heavy point and vanes near the back of the arrow to minimize wind drift. The arrow tends to follow the mass and the vanes in the back will fol;low inline with the heavy fron weight. The closer to the front of the arrow the vanes are the more they will tend to move the entire shaft.

A mind experiment: Imagine the vanes 2" from the point and wind was blowing on the vanes that wind would be able to actually push the point in the direction away from the wind. This would cause massive wind drift. Now with the vanes at the nock end of the arrow the vanes are blown off course but that causes the arrow to point into the wind right. This allows the dynamics of the arrow to "fight the wind causing less wind drift.


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## celtpaddy (May 16, 2011)

So say I move the vanes back from 1'' to 1/4' it would serve me best go from a 100gr. tip to 125gr. kind of a balancing act? How would a helical do with vanes closer to the rear.


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## b0w_bender (Apr 30, 2006)

Well helical gives you such an improvement on accuracy that I don't think I would ever use anything else. 

As far as tip weight goes you would want to use that to adjust both arrow spine and FOC. A heavier tip makes the arrow bend more as it leaves the bow, essentially making the practical arrow spine lighter. Changing tip weight is a significant change in the aerodynamics or the arrow so that should be a carfully calculated change.

Moving vanes 3/4" won't make that big of a difference in the FOC but moving them back would require a heavier tip to maintain the same FOC.
Here is a good article on FOC. 
http://www.huntersfriend.com/carbon_arrows/hunting_arrows_selection_guide_chapter_4.htm
and this explains spine and tip weight
http://www.huntersfriend.com/carbon_arrows/hunting_arrows_selection_guide_chapter_3.htm

Read that article I think it will answer a lot of your questions.
Also take a look at the Easton Arrow Tuning Guide that has a lot of insight as well.
http://www.eastonarchery.com/img/downloads/software/tuning_guide.pdf


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