What would be the optimal techinical specifications in a setup that you try to achieve? For instance...kinetic energy, your arrow FOC...stuff like that.
I prefer a minimum 15% FOC (I like exceeding this though) and an arrow weight of approx. 7 grains per pound of DW . Everything else will be whatever it is.
IMO heavy arrows make the bow and arrow work together more efficiently, have and maintain better momentum, penetrate better, tune easier and are more durable (due to thicker walls) than lighter arrows.
I'd agree Bruce, seemingly, guys can achieve HIGHER momentum and KE by using a little heavier arrows. I think somewhere in or around 500grains is where optimal energy transfer seems to occur in a lot of bows today. However, I sit in the middle usually shooting something around 425-445gr, opting to get a little more of that speed to go along with my decent KE. A compromise between speed and optimal energy.
I asking these questions because I'm getting a completely new setup and I'm trying to select my arrows, arrow length, head weight, etc. based on these factors (if that makes any sense). My next setup is going to be a 70# Quest Primal in 27.5" draw. That means I need to shoot at least a 490 gr arrow. Which is fine because the arrow I plan to use will weigh right at 495. From what I can gather, I think I'll get roughly 265 - 270 ft/sec with the 495 gr arrow. That puts the KE at about 77 - 80. That's a lot! But I guess there's nothing wrong with that. Then trying to get the proper FOC on that arrow. Is there a way to figure out FOC on an arrow without actually cutting it down to size and finishing it? The arrow I plan to use with my new setup is a 28" CX Piledriver Hunter 350 which is 11.3 gr/in; so 316.4 gr arrow shaft + 125 gr broadhead + 11 gr point insert + 4 gr nock collar + 8.7 gr nock + 30 gr quickfletch = 495.1 arrow weight. FWIW...I currently shoot a 70# Mathews Drenalin with a 27" draw length. The actual maxed out draw weight was 68# if I remember correctly. I went with the recommendation on the Easton arrow chart which suggested ACC 3-49 at 27". My arrow weight is roughly 410 grs. And, if I remember correctly, it shot about 270 through the chrono. Not exactly sure on the speed and poundage since it's been 3 years since I checked it all out, but I believe it's close. So...with this setup, I'm only a little over 6 gr/ # of DW; not good. But, it's pushing over 66 lbs of KE; plenty good.
I use software, On Target 2, to get my arrows close to what I want and then adjust from there. There are other ways but they take time and lots of effort, plus you would need an arrow saw. I took the above data and plugged it in. The arrow, as configured above, spines out nicely but the FOC calculates to about 10%. You can get the FOC up to 13% by using a 50 grain brass insert and turning your DW down to about 68#. Your calculated arrow weight then is 534 grains, 257FPS, 78.6 ftlbsKE, 7.8 grains per pound. and, as stated, 13% FOC. That is a kick ass setup right there.
Can I get away with using Gold Tip hunters 29" arrow with a 29"DL using the 5575 at 70lbs? 100 Gr head with blazers and arrow wrap.
Depends on the bow...... With a 300fps IBO rated bow maybe, with anything over 310 or so, you're gonna be weak.
With the Iceman flx at 70# and the other specs you provided you shouldn't be using 5575's. They are too weak. You would be better off with the 7595's and a 125 grain tip. That combo spines out real well and you have a better FOC.
Probably, but I can check for sure when I get home this evening. You still would have an FOC of somewhere around 10%, if I remember correctly. I'll double check that also.
Still gonna be pretty weak Tony, at 63# you still need something about .375 stiffness for a good match, and it drops lower to .360 if you put a BH on the end of that arrow. Sorry if you're trying to use arrow you already have, you'd have to drop to 60#, and use a 28" arrow with a 75gr tip to work well for the Iceman, then you're gonna have LOW FOC, and that's not going to help arrow flight much either.
Thanks Gents and I will follow your advice. I was trying to use the following but their is more to it then this chart I see. http://www.goldtip.com/build-arrow/images/arrow-chart.jpg
Cam aggression and BH play into it a LOT!!! What really is being measured is STORED energy, and when you apply "X" amount of energy to a projectile, then it needs to absorb "X-Y" energy, and the shaft will flex in response to that energy transfer, too much flex equals poor flight or worse yet, broken arrow!!! Many of the guys are outdated and are more based on bows with an IBO around 300fps from what I've seen and MOST bows today are well over that 300fps IBO rating. And those charts NEVER factor in tip weight, another part of the equation that can make a significant difference.
There certainly is a lot more to it than just using the arrow manufacturers charts. I'm really surprised more archery shops don't talk about FOC and how to build an arrow that actually fits your bow. Maybe some do, just not around here. Bruce- I downloaded the trial version of Shaft Selector Xpert of On Target 2; the most basic version. I'm going to at least get that part of it but may get the full meal deal. Do you use the full version? If so, what else do you use the software for? Thanks, Derek
The pro shops I am most familiar with, excluding just one, do not know how to properly build an arrow let alone even know what FOC is. I actually have, and use, two programs. OT2 full version and Archer's Advantage. Mostly used for looking at different configs for different things. I used them to help set up my most versatile arrow, one I use with and without a 100grain brass insert. I can use all kinds of BH's with it. I also have more than a few of bows so I use the software to check out different setup configs to use for different things. I set up my friend's bows and arrows too. I also like to look at trajectories so I have an idea of how my arrow will travel. It helps when there may be some small branches in my shooting lanes ( If you have a 15 inch arc then the small branch dead in line at the midway point should not be a problem ). I use both programs to check the other and, one great thing about Archer's Advantage is that it prints awesome NFAA hunter targets for different ranges. OT2 prints awful targets.
Derek, For the $$$, it(the full version) is well worth it if you like to tinker with set-ups (and I believe Bruce has the full version like I do). You can also get annual updates and once you figure out how to use it, it's a very valuable tool that I've been very happy with. As far as shops and FOC or any technical spec's for that matter, I'm not too surprised at all, I'll often times throw out little tidbits when I'm in my shop, and the owner often times listens, the kid that does a lot of his bow work really does a good job, and is always open ears when chatting about set-ups, but they really don't know too much TECHNICAL stuff. I'd love to offer a service for $10/yr to give guys the best set-up they could use with a bow at whatever settings. A lot of bow shops charge a guy a fee to "tune" his bow when in all honesty, only the guy who is going to shoot that bow can REALLY tune it. I couldn't count the number of guys who had a shop "tune" their bow then didn't understand why it didn't shoot BH's right with FP's. It's all about the grip, release, and follow through, and not any two of us do it EXACTLY the same. I set up a bow for my nephew, BH tuned it, and put it in his hands, it was 4" off with him shooting, consistent, but 4" off. We spent some time, on his form, grip, follow through, and getting a consistent sight picture, in the end, he was shooting about a 2.5-3" grouping at 25yds, BH's were to about a 3.5-4" grouping at 25yds. His hunting limit was set at 25yds for this year. He's capable at 25yds. of putting an arrow where it needs to be. His first ever shot at a deer a week ago was a kill, in a big part because he was limited in his shooting distance, and he'd practiced and gotten his bow tuned fairly well to him. MANY, MANY guys don't even realize this, and those of us on these forums are probably only about 5% or less of the total bowhunters, and I'd like to believe that many of us one here are a good bit more well educated on archery and the technical aspects than about 95% of those that don't occasionally frequent forums. I know that most of my friends that USED to bowhunt knew almost nothing about tuning a bow, and 10 yrs ago, I knew almost nothing about tuning a bow.
