Stu Millers Dynamic Spine Calculator
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Heroes of Archery
When it comes to archery heroes I imagine that like me most archers will have their own, it could be Fred Bear, Saxton Pope what about Howard Hill or Byron Ferguson ( I like Byron but imagine he is in fact his own hero ), the list is seemingly endless, mighty archers taking their place in the hall of fame. There would be a strong claim too from those bowyers that are constantly improving and making innovations to the bows we use both in performance and handling.
Here is someone though that will make more of a difference to your archery than the most expensive bow, the most gifted coach or the latest nick nack or gizmo offered at your local dealer, strangely enough someone you may not have even heard of.
It's often said that any bow will cast an arrow but a crappy arrow will make even the finest bow a worthless stick in the hand and the most important piece of kit for me is the arrow I shoot.
So here he is, the answer to your arrow prayers, the guy that will save you bundles of cash in wasted trial and error arrow testing sessions and the one who took the pain and frustration out of tuning arrows and choosing the right shaft.
Fellow archers, I give you one of my heroes of archery Stu Miller. Right now there will be folks nodding sagely and muttering "yes indeed - I use his calculator, it's on the money". There may well be others saying " Stu who ?", it's to these folks I say " the information Stu is about to give you will change your archery forever, this is the best archery gift you ever had and he is going to give it to you for free !"
You see Stu created a calculator in to which you enter all the bow data and your draw length and a number of other variables regarding your personal shooting - it will then tell you what dynamic spine you will require - it doesn't end there though because the other part of the calculator will tell you what bare shaft to take, how long to cut it, what weight point to use and even the size of Fletch that will give you an arrow as near to perfect as has ever been designed... what about that then !!
I had been shooting for over 15 years when I first came across his calculator, because I tend to shoot a lot of different bows, sometimes getting through 5 or 6 a year ( I just like bows, in fact my own personal collection at one point approached 60 bows) I have a lot of arrows, but even so when I get a new bow or when I am setting one up it still takes time to test and fine tune the right arrow for the bow and even a small error can mean shooting an arrow which is almost but not quite there. Any experienced archer will tell you that the difference between an "almost there" arrow and an arrow that is "bang on" is incredible and will often mean the difference between a medal at a 3D shoot, winning or losing at a target event or even the difference between the trophy on the wall and the tall tale of the one that got away - oh yes, forget clothes making the man it's arrows that maketh the archer.
Nowadays when I pick up a new bow I head straight for Stu's calculator, just seconds later I have the spec for the arrow... 99.9% of the time you won't have to mess with it at all and in all probability they will be the best arrows you ever shot and you will see your target scores take a leap, you will see the number of 3D kills going up and you will see your broadheads flying better and cleaner than you ever dreamed.
Now before you go running off to check out how bad and out of tune the arrows you have been shooting really are -( and if you haven't been using Stu's calculator, I'll bet that when you make Stu's recipie up they will fly better than your current ones.) you should know a little more about the guy who just gave you one of the toughest parts of archery on a plate, in fact the first time I used Stu's calculator to prepare some arrows I had to go sit down and I even said to my wife - " I have 15 years of experience, I've shot more arrows than were loosed at Agincourt, I've made 10's of thousands of arrows both commercially and privately and as archery is my business I eat, sleep and drink it.... and Stu Miller just put all that and more in an excel programme- how I wish that this had been available when I first started"
We tracked Stu down for you and put a few questions to him on your behalf...
Where are you based ?
I am located in Kalamazoo, Michigan USA.
What do you do for a living ?
I work for a German based global company named MANN+HUMMEL as the Product Design & Development Manager. Here is the US we specialize in developing Air Filtration Systems and Intake Manifolds for the automotive market. We supply all the major automotive manufactures including General Motors, Ford, Chrysler, BMW, VW, Toyota, Nissan, etc.
When and how did you first get in to archery ?
I remember shooting a recurve at a very early age but quickly fell into hunting with firearms. The majority of my adult life I collected firearms, mostly German and Austrian machine guns. As I got older, my interest in these began to diminish and I cam full circle wanting again to hunt and target shoot with the bow. About four years ago, I made the conscious decision to put the guns away and only focus on traditional archery. I focused on firearms for 25 years and Lord willing I will now do the same with the bow!
There must have been a very good reason and a lot of frustration to make you design the tool in the first place, can you tell us how it all came about ?
As an Engineer, just shooting a bow didn't fully satisfy my thirst so I quickly took to making my own equipment. It started with arrows and then transitioned into bows. I greatly underestimated the amount of factors that went into the dynamics of good arrow flight and, needless to say, my first attempts at tuning a traditional bow/arrow combination were less than spectacular. Frustration quickly turned into an engineering quest to "Find the Better Way". I began gathering as much information on the subject that I could find and also began to document all of my personal experimental results and data. Soon, the quantity of data became overwhelming so I set off to define a method of storing and arranging it electronically. That was really the turning point where I could start to clearly see quantifiable causes and effect of all the specific variables. God defined the physics of how these things work together and gave me the perseverance to define and mature a set of equations that balance all the variable into an output I called Dynamic Spine. From the beginning I wanted something simple enough for all to use so they were defined in such a way that you could simply match the bow's dynamic requirement to the arrow's dynamic spine number and that bow/arrow combo would be tuned close enough that excellent flight could be obtained in short order.
How long did it take to design ?
It took about a year to gather information and empirical data from my own experiments. From there it took nearly another year to "tune" the equations and mature the user interface. The current release is actually the fourth version with the "new and improved" fifth version to be made available in a few weeks.
Was there a lot of trial & error ? or did the science just get you straight there ?
It was truly a combination of both. Science got me half way down the road, but tuning the equations took a lot of trial & error.
What is your current bow and set up ? your arrow spec ?
I have many recurves and longbows and it is quite fun to change periodically between them. Sometimes when I pick one up that has been on the rack for a while, it is like getting reacquainted with an old friend. Sometimes it is like arguing with your big sister! Currently, I am shooting a deflexed/reflexed longbow made by a Bowyer here in the US named Bateman. It draws right at 47# for me and is an AMO 60" length. My favorite arrows are ones I make from Douglas Fir, a great wood shaft for durability and hunting.
As regards your archery….do you hunt, 3D &/or Target.
I do all three when the season permits. Mostly, I consider myself a target shooter not for competition but for the pure joy of the sport. When not shooting, I spend my free time making custom designed wood arrows for fellow archers. I rely solely on the calculator to define the appropriate arrow specification needed. Typically, the recipient of the arrows cannot believe how well they fly right out of the box!
Do you get a lot of feedback from archers ?
I do get a lot of feedback for the archery community, usually on a weekly basis and sometimes even daily! Some provide suggestions for improvements, additional shaft selections of added features, and I greatly appreciate their inputs. Some write with questions on what setup I would recommend or for help in tuning the bow. Other simply write to say "thank you" for saving them the frustration and money wasted in wrong arrows.....the same things I went through as a beginning traditional archer. Often a question will be asked about why I dedication so much time an effort into making something valuable and then just giving it away for free. These are the ones I like most as it gives me to opportunity to explain my motivation. God has blessed me in many ways. He reconciled my relationship with Him, He gave me a loving, understanding family and also provided the discernment and skills necessary to make this Dynamic Spine Calculator. He did all this for me for free. To honor Him I try my best to do the same for others and consider it a privilege to pass along any gift I can for free.
We note you have recently revised the calculator with some fine tuning to variables, are there plans for another version ? is this an on going project ?
As mentioned above, there will be a new version coming out that will offer more shaft selections. It also will incorporate the recent studies done with "skinny" fastflight string materials. The string type drop down menu will contain a selection for fastflight strings ranging from 14 to 6 strands. This is now very popular here in the US and makes a significant difference on the dynamic spine required in an arrow as well as the predicted speed and energy it carries. I do look at this as a "living project" and will continue to take into consideration all request for improvement.
Here is the link to the Stu Miller calculator:-
Stu tells us that his new tweaked and revised version is out soon and we here at Archery Review will be getting it first to test run so stand by for the full review coming soon. Stu's passion for perfection and minute attention to detail also shines through in the stunning arrows he produces, so not only do his arrows fly right they look sublime, if you want him to make some for you, you better get in the queue...
Stu, here is a raised glass to you - a true archery hero...... hip hip... Huzzah!