Was running some #'s for my TallTines thats on the way.
Should be low 60#'s @ my 29" draw.
Made up some Axis trad 340's with a footing. The calculator said I would be way under spined with even a 100 grain field point??? It didnt have TallTines listed as an option so I used a Schafer recurve instead.
I really hope that I just put something in wrong, but I'm lost any ideas?
In order for the calculator to give you a good base to start from you need to have all your numbers put in correctly. You can't substitute one bow for another if your bow is not listed you should go to the generic recurve and put in the proper info.
Ill give that a shot, thanks for the heads up.
Does that arrow sound like it should be in the ballpark? I will leave the shafts full length and bare shaft tune, have a field point test kit ready to go as well
You also have to mess with the "personal form" cell in order to get the calculator dialed in for you.
Good Luck!
~Shan
I've never understood that personal form part. It drastically changes the #'s if you play with it (the one on 3 Rivers that is)
I generally have the most trouble with my release but am not sure which # to use to quantify that
I have never been able to get it to work either.
Once I figured out that my personal form factor was in the neighborhood of minus 15 all the numbers made sense and it seems to work fine.
STU's calculator generates a theoretical optimal dynamic spine requirement for a bow & also calculates the configured arrows dynamic spine. I personally believe it is very accurate and useful. However, we each have unique form & the data going in the calculator must be accurate for the best results. Critical bow data like riser cut/strike plate thicknesses, string type, dynamic bow efficiencies goes into it, consistent draw length (no creeping or extra pulling, just good solid consistent bad tension), accurate draw weight, etc... In addition, its very important to enter arrow data in correctly. Sometimes using footings & wraps etc require some custom entries to get the weight & distribution accurate. "IF" you have everything entered in correctly it should be pretty close. If not, then you can tweak your arrows characteristics through bareshaft tuning to finalize your setup. After you have a working arrow you can enter that arrow into the calculator to reveal it's dynamic spine. Now you can use the form adjustments to effectively calibrate the STU calculator to adjust the bow & now user's dynamic spine requirement to match the arrow. Theoretically now you can use the form adjustment factor on all of your future setups or adjustments. This affectively should take the theoretical optimal setups and calibrate them to your unique form & efficiencies. Hope this helps. Another way to streamline the process is to take a setup that you know is optimal for you on a different bow/arrow and enter it in the calculator. If the calculator is showing differences, tune the form factor til they agree. Now you have a form factor to use for other setups...
CAUTION - Just make sure everything is entered correctly & accurately before you believe the calculator needs the form factor and adjust it OR you will chase your tail... :-)
You need to tune then enter all your info and then adjust the personl form factor till it brings the scale into alignment. You will need to plug in the numbers from a bow you know is tuned and shoots well to get your PFF, then use that number for your new bow.
QuoteOriginally posted by Robert Armstrong:
You need to tune then enter all your info and then adjust the personl form factor till it brings the scale into alignment. You will need to plug in the numbers from a bow you know is tuned and shoots well to get your PFF, then use that number for your new bow.
This is the best way to use the calculator imo.
I've never understood that personal form part. It drastically changes the #'s if you play with it (the one on 3 Rivers that is)
I generally have the most trouble with my release but am not sure which # to use to quantify that
I have worked with the calculator a lot. I have found that if I put in the exact-precise data, it is very, very close or deadon. The centershot variable is very important. If your bow is listed in the list, that is what the maker says he cuts centershot too, but not every bow is the same on handmade bows.
You have to put in the variable for the exact bow and arrow you are evaluating. It works for me, and I do not use the personal form factor.
The spine calculator, just like an Easton arrow chart, is only a starting point to get close. You still have to tune your set-up with bare shaft. I have found it very accurate, much more than a chart, but I also shoot off an arrow rest and make sure I have no clearance fletching issues in tuning.
It sounds like you do not have the actual bow yet. I have been where you are. Wanting to be prepared. I have also found that to get the exactness of data that the calculator requires, I have to have the bow in my hands and shooting it. I need the exact weight at my draw with that bow. I need the exact draw length for me with that bow. I need the exact centershot. I measure my leather for strike plate with a pair of dial calipers, so I enter in the exact thickness. As long as I enter in the "exact" information, the tool has worked for me. When I first used it, I made assumptions about data. I have realized that will not work. It has to be exact and factual info you put in. It is a precise instrument that has been extremely helpful to me.
Hmmmm. Thought I responded to this one, but maybe I forgot to hit send, or maybe it was pulled. Don't know.
Regardless, don't toss in the towel yet. I think the 340s, cut to one inch longer than your draw, with a light point might be just the ticket for your set up. I'd certainly recommend waiting until you get the bow and give them a try before purchasing something else.
The best way to determine your form factor is to input all the info for a setup you've shot that you know shot perfectly. Adjust the form until those numbers match and you should be pretty close.
With that said, I think most all the carbon arrow need to be used with a form factor of -10 to -15.
I know there are a lot of people who don't like the calculator. But I use it very, very frequently. Once I had my form factor set, it is shockingly close even with bows that are cut way off from center (Hill Style for example).
Also couldn't agree more about making sure the info you enter is accurate. As my boss likes to say about performance monitoring software we use...."garbage in, garbage out."
The calculator is a mixed blessing for me. It is a start but I usually end up using a lighter point than calculator wants me to. That is with carbons anyway. I have better luck with alum arrow setups. I rather have a buddy watch me bareshaft than use the form factor. Seems I can adjust form factor to get what results I want.
I'll give the 340's a shot seeing as I already have them. I keep getting mixed replies about higher FOC flight in wind. (Was hoping to use 200 grain points @ least, but seems like a lot of people feel the higher foc arrows dont fly as well in the wind.
The point may end up where I was aiming, but it would be at an angle=bad penetration. I think I would rather calculate for windage and just aim into the wind a little more and still have an arrow that hits the animal straight on
I find mine do just fine, even with very long fletching. I can get 35% or more FOC, and at that point the wind can't mess with them too much.
Gets pretty windy here in MT, specially pronghorn hunting out in the prairies
My arrows weigh a quarter pound. That might have a lot to do with it.
Haha yea I suppose. Im hoping to get real close to 10gpp
Jacob,
Just reread your post and saw that you put footings on those shafts.
Did you include that in the calculator?
I got curious and ran it in the calculator, 30" arrow, 75 gr insert HIT insert (which effectively gives the arrow a 1.1" footing) and got 125 gr. as being a ballpark tip weight with form factor at zero, and 200 gr. with form factor set at -15.
200 gr. tip puts you right at 10 gpp. If you are using the 50 gr. HIT insert or the 16. gr HIT insert, that will, obviously, provide some difference.
Also, if your external footing is greater than 1.1" you'd have to add that to the calculator as the value for your footing. The only other variable I didn't add (I believe) was the weight of your external footing. I think that should be minimal.
The new version of the calculator also has the Tall Tines recurve.
Here is with the form factor set at zero which shows 125 gr. should be close.
(http://i108.photobucket.com/albums/n15/ken613/3295248D-F663-41F3-8D53-06F3CF1FB8D5_zpsnrtzrefk.jpg) (http://s108.photobucket.com/user/ken613/media/3295248D-F663-41F3-8D53-06F3CF1FB8D5_zpsnrtzrefk.jpg.html)
If you set the form factor to -15 (where I find it works pretty good with most carbons), ball park starting weight is 200 gr.
(http://i108.photobucket.com/albums/n15/ken613/B6F2B5FD-CAA2-4550-A8A5-B508C8AD2D5D_zpsk3uvhexo.jpg) (http://s108.photobucket.com/user/ken613/media/B6F2B5FD-CAA2-4550-A8A5-B508C8AD2D5D_zpsk3uvhexo.jpg.html)
Hope that helps.
Ken
Jacob, 340s will be just fine. Put the head you want on, start full length, and trim accordingly. You don't need any "calculator".
Seems pointless to punch numbers in when your bow will tell you EXACTLY what it needs. And while we're at it, 15 grains of footing won't matter squat :knothead:
Steve is correct. Shooting and cutting and shooting and cutting will get you right where you need to be.
But since you specifically asked about Stu's calculator Jacob, hope my post above helps.
There are lovers and haters of Stu's calculator and the others. To each their own. That's what makes this sport great. No one way is the only way or the right way.
The one I tried looked different than that one, good to know! Is that an updated version I suppose?
The guys program I used shoots a 51# Black Widow, with 125 grain points and somehow he shoots a 340 spine cut just past his shelf on a 28" draw!
Im just ready for my bow to get here so I can stop worrying myself to death haha
I think the calculator probably does work in a perfect world. Problems that make the calculators more inaccurate are the data loaded in to them.
I am no longer amazed at how far off people are on their "true" draw length. I always ask first and then when possible watch them shoot when they aren't thinking about anything but shooting. Most are off by an inch or so yet I have seen a few off by as much as 3". And that doesn't take in account if the shooter collapses a little or a lot upon release. I rarely have anyone tell me that they collapse upon release...they all say they pull through. I wish I had time to video everyone...myself included.
The .340 should do the trick just fine and with the heavier weight up front too.
It is tough to shoot a .300 spine in the low to mid 60lb range unless you have a very long draw or your bow is deeply cut past center.
I am shooting a .300 spine with 311 g up front on a full length arrow. The bow is cut 1/8" past center, I draw too or right at 32"s and my bare shafts fly perfectly from my 65 and 66 lb bows but are slightly stiff out of my 61 lb bow.
I can't tell you how much or if I do collapse, but this is what works for me. I could only find this out by personal testing...even if the calculator might agree.
BigJim
I have found Stu's calculator to be very close.........once I got the PFF set for me.
Like said above, put in all the info for a setup that you know is tuned well. The arrow and the bow probably won't match. Then adjust the PFF till you get the bow and arrow to match.
Once I did that with a known setup, most every time I input data for new bows or arrows, it is always real close.
Bisch
Iowa: Re arrow flight in the wind, the lower FOC arrows don't fly straight either. They drift more than a High FOC arrow, and they won't be hitting the target straight on, though the tail of the arrow may not be as much out of alignment as the high FOC arrow.
IMO, the higher FOC's greater penetration potential offsets any loss of penetration resulting from an arrow that doesn't strike perfectly perpendicular to the critter. Something you'll have to test for yourself, I think. Good luck.
I use a very similar setup...BW recurve 62@29, 30 inch Axis trad 340's with brass insert and 200 grain point. Stu's calculator puts my arrow at 25-30 weaker than bow, but my arrows fly quite well. So yeah, 340's will work for you. Personally, I think its easier to cjange point weight rather than cut your arrows. Get you a few different point weights and see what works.
QuoteOriginally posted by BigJim:
I am no longer amazed at how far off people are on their "true" draw length. I always ask first and then when possible watch them shoot when they aren't thinking about anything but shooting. Most are off by an inch or so yet I have seen a few off by as much as 3". And that doesn't take in account if the shooter collapses a little or a lot upon release. I rarely have anyone tell me that they collapse upon release...they all say they pull through. I wish I had time to video everyone...myself included.
BigJim
I have to agree with Big Jim on this. So many people over-estimate their true draw length. I know I sure did in the past. If you take an arrow and mark it with Sharpie markers of different colors, then just go out and shoot without thinking about it, and have someone watch you, you will find out your true natural draw length as you will shoot in the field. Lots of archers with "29 inch" draws would realize that in reality they draw 27" or 26". I am not exaggerating...
The calculator has worked well for me with recurves. A Hill style bow, I do not use it and sort wood arrows by shooting them at 40 yrds.
I think those that don't like Stu's calculator should stay way far away from it. It won't work for them.
Those who are honest and conscientious about putting in correct, measured data will find it amazingly accurate and extremely helpful in checking changes such as a different shaft, point weight, shaft length, etc.
When I read someone posting that he "doesn't bother with this or that", or "doesn't know what the center cut distance is", I know he is going to say he's never had much luck with it. If your bow is listed in the choice of bows, the information will be what the bowyer has supplied. If he cut your bow somewhat differently, or you have substituted a different type or thickness of sideplate, you will get sloppy answers.
It all matters. If you put a wrap on the shaft, you need to add that weight as it stiffens the arrow. If you enter 28" draw, but you're really drawing 27" or 29", it will give you a bogus answer. If you have the cut to/past center wrong, or the sideplate thickness wrong, you get a garbage answer. I used to use it only to put me in the ballpark, fine tune my arrow to the bow and then play with the personal form factor until the dynamic arrow spine and bow readings matched. I recently started adding the total weight of the feathers, cap wrap and fletch tape to the fletching calculation. I actually weighed the insert with hot glue on it. By the way, they aren't always the weight the catalogs say they are. All of a sudden my "personal fudge factor" became zero or close to it.
I'm not saying I would enter the information, then, based on the results, order a dozen finished arrows cut to length and fletched as indicated and assume all will be perfect. I'm a trusting soul, but not that trusting.
Picture this, however. I am shooting a 1535 with standard insert, cut to 30.5" with a cap wrap and three 5" feathers and a 175 gr point and it is flying perfectly out of my bow. I have the calculator adjusted, if necessary, so the arrow specs and bow specs match. Now I want to shoot some 3555s, or even 5575s from that bow. I could know in advance what would be very close. The calculator would tell me if I leave the shaft full length and add the same wrap and feathers and put in an insert of a certain weight and point of a certain weight, I could be very sure that arrow would fly close to perfect - close enough that I could juggle the point weight a bit or trim a 1/4" of length and be right on with very little experimenting.
That's the value of Stu's calculator to me.
Stu's calculator has always done a good job of getting me good arrow flight for close to it....even considering my terrible release. Sometimes I dont believe what it says until I go out and try it...9 times out of 10 the calculator is correct...IF I PUT IN THE RIGHT DATA.
I just started playing around with the one on Three Rivers Archery. Just to see how it worked, I took an arrow that shot well through paper and in general practice, and entered all the data in based on that.
I was very surprised how close the numbers came out. I think it is worth spending more time on.
I've found it to be pretty close and a long ways off from good arrow flight with my set-ups.
I have to put in a form factor of -5 to make it work; is that reasonable?