Dynamic Spine calculator. .NEW DOWNLOAD AVAILABLE

[calgarychef]

Wow!!!  It's a darned miracle, I don't know how to thank you.  I've been scratching my head for a long time about shafts for Africa and you've just confirmed everything I needed to know.

The chef

[Curtis Haden]

Based on what I've seen out of my bows, the calculator seems to be spot-on for my aluminums.  The CE line looks to tend towards the weak side however, given my tuning results.

Example: A CE 150 cut to 29" with 15 grains nock end weight (estimated - 9" arrow wrap) and 250 grains point weight, shows a dynamic spine of 47.8 pounds.  I'm shooting a 52@28 r/d longbow, with the shelf built out to 1/16" before center, FF string, and a 28.5" draw.  That setup gives a dynamic arrow spine required output value of 58.2 pounds.  ...Yet the arrows I described bare shaft, and shoot fletched, perfectly out of that bow...not weak at all.

I think it's a wonderful tool for getting a good starting point on aluminums.  Not too sure about the carbon values.  No criticism implied.  It's a heck of a lot better than anything I could put together!!!

[LeTuB]

Thanks Mike for the job done, very useful !
I have few questions :
Regarding the centershot (I've seen that I am not the only-one): on my recurve the shelf is cut 3/16 past center (information given by the bowyer), if I use a 1/16 thick rest, do I have to enter 1/4 or 1/8 in the calculator ?
In my opinion, the shaft size has to be taken into account in the calculation, for instance if my bow needs a .300 static spine shaft, the tuning will be very different if I use a 2514 or a FMJ 300 (18/64) shaft despite the static spine are the same. Assuming that the formulas were established for a 21/64 shaft (mean value) a centershot correction could be taken into account so that the dynamic spine required by the bow would increase if I use smaller  diameter shafts.
Another point concerns the use of long brass inserts, I think that the flight is different if I use a 200 grains field points with standard aluminum insert and a long 100grain brass insert with a 100 grains field point due to more stiffness in the last 2 inches on front of the shaft  . This effect could be taken into account by an artificial reduction of the shaft length equal to the difference between the used brass insert and a standard insert for which the calculations were established.
Just my 2 cents....

[Molson]

Did the calculator get moved somewhere?  Both the first link and updated link are bringing up Yahoo home page and no calculator.

[daveycrockett]

Me too!

[loco_cacahuate]

ditto

[Stringslap16]

TTT,  I need this bad.  Fellas?

[PowDuck]

All I get when I click on the link is a Yahoo news page. What am I doing wrong?

[wingnut]

I let Stu know that the link is broken.  I'm sure he will fix it.

Mike

[Toklat1]

Same here, yahoo news page!

[hkmp5]

Hello Guys,
I appologize but Yahoo has decided to discontinue their "briefcase" and this was the only place where I had access to store documents on the web.  I will look for somewhere else to put the file but right now I have no options.  If you need a copy, feel free to email me at:
[email protected]
I will then send you the file directly.  Sorry for the inconvienence, if anyone has any suggestion please feel free to pass them along.
-Stu

[PowDuck]

If it's a spreadsheet (excel) type file, you could get a gmail account and put it on their online documents.

Mike, when I click on the link, it goes to a Yahoo search page? I don't see anything about a spine calculator.

Bisch

[daveycrockett]

If Stu don't mind I have it on my e-mail and can forward it to anyone who asks.

[wingnut]

I also have a copy that Stu told me too share.

Email me at

[email protected] and I'll forward you the latest edition.

Mike

[mudbug]

updated link
 http://www.heilakka.com/stumiller/