Fun with Numbers

[The Hawk]

Shot my Martin Hatfield through the chronograph today and I am a little surprised at the results.  The bow is 55# @ 28" and scales a little heavy.  I draw to 29 1/2" and the bow scales 63 lbs @ 29 1/2.  My lightest arrow 563g is alot faster than I thought (201.5fps in a 5 shot average)with 12.5% less Momentum than my heavy arrow (712g @ 178 fps/10 shot average).  The biggest surprise was that the speed difference between getting those back muscles good and tight between the shoulder blades and not getting the muscles completely tight (a difference of maybe 1/16"-1/4") translates to about 10fps with the lighter arrow and about 6fps with the heaver arrow (I am thinking this is do to the bow being closer to max efficiency with the heavy arrow) At any rate, the more I learn, the more I think form is important. Arrow weight and speeds 563g@ 201.5, 590g@189fps, 680g@185fps, 712g@178fps.  I didn't see a sharp drop in performance and wonder if I should try a heavier arrow?

[Looper]

You should be more than ok with your heavier one.  Of course, there's no harm in experimenting.  Just be aware that going up too much will possibly require a different spined arrow.  You just want to make sure your getting excellent flight.

What arrow are you shooting now?

[The Hawk]

Looper, thanks for the reply, I'm shooting the 680g 32" Goldtip with 5 1/2" bananas right-wing, cock in, in a 75-95 (seems to be my best arrow).  I am shooting a 125g Bullhead and hoping for a lop-a-top gobbler.  Thinking that I may want the same arrow for elk in the fall.
My other arrows are Goldtip traditionals 55-75, 32" left wing, cock out (I am using weight tubes to get the weight up).

[Looper]

That should be more than sufficient for elk.  Have you footed them?

[The Hawk]

Footed?

[Looper]

Footing a carbon arrow is adding a sleeve of aluminum over the point end.  This will keep the end from splitting if you hit something hard.  Adding a footing will also increase the stiffness.  The longer the footing, the stiffer the shaft will become.  So, if you add a whole lot of point weight and weaken your shaft too much, you can add a footing and stiffen it back up.

If you haven't tried it already, try bareshaft tuning.  Here's a link:   http://www.acsbows.com/bowtuning.html

To temporarily attach the footings, use a little bit of saran wrap around the shaft.  That way you can easily pull the footing off to try a different length.  To permanently attach them, look at this link:   http://tradgang.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=1;t=074690

It's a good idea to add a 1/4" "collar" around the nock end of your shaft, too.  Carbon shafts have been known to split on the nock end upon hitting a solid object.

Your Gold Tips will take a 2216.