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Post by Doegirl on Jan 28, 2009 22:03:31 GMT -5
I'm finding that creating an arrow that weighs @ least 650 grains AND has at least 19% FOC AND is properly spined for my bow is turning out to be quite a challenge. The software programs do not take into account the length of the broadhead when calculating FOC. The grizzly is 2 3/4" long and makes quite a bit of difference. Another concern I have is that the extreme FOC might skew the results of the testing. For instance, my heavier arrows might outpenetrate Stilllearnings, but was it the weight or the extreme FOC, or both?  For now I'll focus on building a heavy arrow with "normal" FOC (15% and under) |
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Post by BT on Jan 29, 2009 9:01:36 GMT -5
I'm finding that creating an arrow that weighs @ least 650 grains AND has at least 19% FOC AND is properly spined for my bow is turning out to be quite a challenge. The software programs do not take into account the length of the broadhead when calculating FOC. The grizzly is 2 3/4" long and makes quite a bit of difference. Another concern I have is that the extreme FOC might skew the results of the testing. For instance, my heavier arrows might out penetrate Stilllearnings, but was it the weight or the extreme FOC, or both? For now I'll focus on building a heavy arrow with "normal" FOC (15% and under) I knew this was going to be the case....tuning issues. So....If you want to keep that heavy & high Ratio head under control, I would recommend going to full length (5") feathers. Not because I am all about feathers either  The Feathers will impart the needed drag to control that flight. You may find that you will have to get the arrow coming off the ow tail low as well....start the nock at 1/32" below where you had it when you were shooting the standard shafts would be my first go to route. Funny....I dont remember Ashby ever writing about proper tuning fundamentals and objectives which should go hand in hand with his recommendations I never would have thought about it if you hadn't started this Doegirl  |
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Post by Doegirl on Jan 29, 2009 15:39:54 GMT -5
BT, personally I would much rather have the extreme FOC as opposed to the extreme weight. But my arrow would only weigh 490grains-laughable by Ashby standards.
I really do not think going above 500-550grains is going to make any bit of difference. But God forbid I shoot any faster than 190fps ;D
Right now, the FMJ's come in at 615grains w/ 5gpp weight tubes, 11% FOC, and 3 4" feathers. Next step is taking them to the range.
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Post by BT on Jan 29, 2009 16:08:47 GMT -5
BT, personally I would much rather have the extreme FOC as opposed to the extreme weight. But my arrow would only weigh 490grains-laughable by Ashby standards. I really do not think going above 500-550grains is going to make any bit of difference. But God forbid I shoot any faster than 190fps ;D Right now, the FMJ's come in at 615grains w/ 5gpp weight tubes, 11% FOC, and 3 4" feathers. Next step is taking them to the range. Oh trust me~I know what your saying!! ;D But your supposed to do both ;D Shoot Mr. A a letter and ask him just how your gonna do all this!! ;D |
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Post by BT on Jan 29, 2009 16:13:46 GMT -5
This is what I am looking for....in the big picture. There are three schools of thought, two being extreme. Both of these extremes may be un-shootable or require mofifications....or not. Both of these may kill effectively.....or not. This is part of the process. I am hoping that we will get an opportunity to run both these systems against one another during the team hunt as well as the general season  |
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Post by Buckshot06 on Jan 29, 2009 16:22:42 GMT -5
I can't wait  to see the results. Doegirl it looks like OL' Dr. A has some explaining to do. I have thoughts on what may happen I just would like to know for sure. |
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Post by BT on Jan 29, 2009 16:28:45 GMT -5
I really do not think going above 500-550grains is going to make any bit of difference. But God forbid I shoot any faster than 190fps ;D . Here is another interesting factiod.... Think about the cast speed of a modern recurve (50#) with this same arrow weight.....nearly the same in terms of losses prior to weight loading the system overall. While the recurve may loose 12% of it's cast speed, the compound loses nearly 50%....or more. This shows (IMO) the vast differences between tuning same across the board when referring to overall performance. That said....while arrow weight may increase penetration, it adds dramatic error to the system overall. At least, that is I disagreeertion. With that said....perhaps penetration is paramount to all else.....and that remains to be seen. |
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Post by Doegirl on Jan 29, 2009 19:47:52 GMT -5
Well I think I did it. I didn't want to buy another half dozen FMJ's , but I did. I got the 340 spine. The guy behind the counter at the proshop questioned my selection. I explained to him what I intended to do. "Uh-huh", which I guess is code for "lady, you're nuts" ;D So I have Axis FMJ 340's w/ 4" vanes cut to 26.25", 100grain brass inserts, 160 grain Grizzly BH's with 100grain steel adapters. Total estimated weight 682 grains with a FOC of 18%. I'll lose a little weight and gain some FOC when I rip off those vanes and put on feathers. The broadheads, adapters, and inserts, ready for some epoxy:  The broadheads with adapters, assembled and spin tested:  |
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Post by Buckshot06 on Jan 29, 2009 20:17:50 GMT -5
The guy behind the counter at the proshop questioned my selection. I explained to him what I intended to do. "Uh-huh", which I guess is code for "lady, you're nuts" ;D That is hilarious ;D ;D ;D You didn't have a couple of hours to kill to explain it all did you ;D. Sounds like you are about ready to let them rip and see what they will do. |
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Post by BT on Jan 29, 2009 22:03:57 GMT -5
Outstanding!! I'm pumped Doegirl  When are you going to have time to sling some of these things? |
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For now I'll focus on building a heavy arrow with "normal" FOC (15% and under) 
to see the results. 