# How Straight is Straight Enough for Target Arrows?



## Gregjlongbow (Jun 15, 2016)

Trial and error are the only way to truly know if there is a difference. For me once I have found a tune that feels "perfect" then I upgrade to higher quality arrows. 


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## Harperman (Sep 3, 2006)

Cutting off both ends of an arrow cam make them straighter for the length....According to most folks that are experts on arrows, spine consistency is more important than how straight an arrow is.... component fit on the nock end is critical also....Jim


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## limbwalker (Sep 26, 2003)

.006 is more than good enough for all but the top archers. 

I once shot a 320 at 70 meters with wood arrows out of my Olympic recurve. They were closely matched in spine, but had a 20 grain spread in weight and were anything but straight. Spine, weight and straightness matter in that order.


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## Stash (Jun 1, 2002)

This topic comes up regularly, and everyone who has an opinion backs it up with anecdotal experience, but I have never seen or heard of anyone doing a proper experiment under controlled conditions to come up with a definitive answer. 

The only way you could do this is to test a set of arrows which have been sorted accurately by straightness, and shoot a statistically significant number of arrows in a "blind" test where the shooter doesn't know the straigtness of the arrow he's shooting, and score the results to see what you get. 

Anything else is opinion only. Informed, expert opinion, perhaps, but not proven fact.


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## limbwalker (Sep 26, 2003)

Very true Stash. I know what arrows advertised as .006" straightness are capable of though, and few archers can outshoot them.


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## grantmac (May 31, 2007)

NFAA field nationals have been won many times in the last several years with full length .006 VAPS

Save your money.


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## Bigjono (Apr 21, 2009)

Unless you use a mechanical release, .006 or .001 won't make any difference to 99% of us, except in the mind maybe.


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## arrowchucker222 (Jun 17, 2013)

I just shot my personal best with VAP 6. 780 trad equipment.


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## Stash (Jun 1, 2002)

But how do you *KNOW* that your PB wouldn't have been several points higher with straighter arrows? Or that the NFAA wins wouldn't have been by a greater margin?

If I was still a serious competitor I wouln't risk it by cheaping out on the arrows. It always amuses me to see people with $1500 bows, who "can't afford" .001" rated arrows because they're $50 or $100 more than the .003s.


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## limbwalker (Sep 26, 2003)

Likewise, it amuses me to see people who pay the extra $ for arrows when their mental game or fundamental form is what's holding them back. 

Like I said, I proved years ago that wood arrows are capable of 320's at 70M. I did it more than once with arrows you could feel wobble in your hands. There are a lot of places to look for points besides the difference between .006 and .001" arrows, esp. when - using your own logic - nobody has proven the .001" arrows are statistically better. 

What has been proven 1000 times over, archers and their money are easily parted, and the peer pressure to be "seen" shooting expensive arrows is very real.


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## jmvargas (Oct 21, 2004)

if you use the straightest and best matched arrows available and still can't shoot your best believe me it's not the arrows..it's the *****!


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## dchan (Jun 29, 2004)

Somewhere I have an article written by Rick Mckinney where he did the research.

Consistent spine trumps straightness as well as weight and indian trumps arrow every time.


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## Stash (Jun 1, 2002)

Maybe so, but if you're headed for the top, you'd best supply yourself with arrows that are consistent in spine AND weight AND are perfectly straight.

This question "straight enough?" needs to have a qualifier. Maybe a .006 arrow is "straight enough" for 320, but I doubt if you'll ever find anyone using them to shoot 350.


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## jmvargas (Oct 21, 2004)

Stash said:


> Maybe so, but if you're headed for the top, you'd best supply yourself with arrows that are consistent in spine AND weight AND are perfectly straight.
> 
> This question "straight enough?" needs to have a qualifier. Maybe a .006 arrow is "straight enough" for 320, but I doubt if you'll ever find anyone using them to shoot 350.


i agree..

when you get the best available arrow you know that any problem will not be due to the arrow.

holds true also for any other piece of equipment..

of course the problem is when the best is not within your reach hence the question of the best compromise arises..


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## whiz-Oz (Jul 19, 2007)

Stash said:


> This topic comes up regularly, and everyone who has an opinion backs it up with anecdotal experience, but *I have never seen or heard of anyone doing a proper experiment under controlled conditions to come up with a definitive answer.*


Yes you have. 
Either that or you weren't paying attention.


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## Bob Furman (May 16, 2012)

Carbon Tech Arrows site was down, but here's a pasted copy of the article Rick McKinney did years ago. Skip to the paragraph labeled Straightness.


Arrow Spine, Weight and Straightness

Unraveling the Secrets

As many more companies are attempting to build arrow shafts it gets more and more confusing as to what makes a good arrow. Since most companies do not actually build their own arrows and others who may build arrows are not archers of any length of time, it becomes more and more critical to explain the mechanics of an arrow and why it is important to choose arrows that are truly the quality you should expect.

There are three specific areas that determine a good arrow which are spine, straightness and weight. These three items are discussed by many but it appears that they are a little misunderstood. Let's dissect each one and determine what makes them critical. Obviously, we could go further in talking about other reasons for good arrows as to surface finish, durability and ease of use (bonding adhesion and pulling out of targets), but we will stick with the areas that may be difficult to tell without the proper equipment.

Weight:*
Since weight is the easiest category for most consumers to determine accuracy of an arrow, companies focus their attention on it. Let's face it, anyone can purchase a simple grain scale and then check out the weight of each arrow. However, the weight of an arrow shaft only gives you a hazy picture at best when you have to add glues, vanes, nocks and points/broadheads. How many people weight their broadheads? Few at best. When you switch the broadheads, do you really think they are exactly the same? However, the weight of the arrow shaft is critical? To a point, yes, but if you learn to weigh the broadhead or points and the complete arrow with vanes, nocks and inserts installed, you can get a dozen arrows close to 2 grains apart with no trouble at all.

A simple test is to take the heaviest and lightest arrow in a group of 12 arrows. Without knowing which is the heaviest and which is the lightest, mark them as 1 and 2. Then go to 20 yards or even 50 if you want to and shoot them. Plot their impacts and do this about 5 or more times. Then go weigh them to determine which one is the heaviest and which is the lightest. Usually if the arrow is 7 or 8 grains difference you will probably not notice much impact difference at 50 yards, unless you are one of the top 50 archers in the world. Thus, the gimmick of weight deviation is just that, a gimmick to scare you into believing weight has a huge difference on impact. You can't even aim good enough to determine the weight differences!

Straightness:
The second most highly talked about category that many manufacturers push is straightness tolerances. It's funny that several years ago, when there were no carbon arrows, arrow straightness was constantly being drilled into our heads about how important it was to have super straight arrows. This may be true with aluminum arrows and aluminum and carbon mixed. But when it comes to all carbon arrows it is not as factual. In the late 1980's AFC and I ran tests to determine how straight does the arrow need to be in order to carry a 3 inch group at 50 meters or 55 yards. We used a recurve, fingers with a speed of near 200 feet per second. We found that .010" T.I.R. (Total Indicator Reading) was the maximum in order to keep a 3 inch group at this distance.

Although when you spin a .010" T.I.R. arrow you would freak out, it proved to me that the impact is the key, not just physical observations. Thus, if you shoot an arrow of .005" plus/minus, you actually have a .010" T.I.R. and it will group exceptionally well. However, those 50 top archers of the world will argue on this point, and rightly so. They are the 8 hours per day training athletes and demand accuracy of the highest nature. Over 90% of the population will not even notice this deviation or I should say that they may use it as it really is, an excuse and not the real reason for poor performance!

There are many ways to determine straightness and since there is no consistency in the industry, it makes it very difficult to determine what companies are really saying in their advertising. Most give you a number but may not state that it is a T.I.R. If you see a plus or minus type statement, it means that it is half of the T.I.R. Thus a .003" plus/minus is actually a .006" T.I.R. Now you have to find out what distance do they measure this reading. Some use a 14" reading while others use 28" and anything in between, thus again you need to find out just what they are really stating. Straightness has some effect on shooting performance but not as much as one would think.

The question still comes up about why carbon straightness is not as critical as aluminum straightness. Let's look and see why aluminum straightness is so important. There is a frequency vibration occurring when launching an arrow. When you have a straight arrow, this frequency is fairly consistent and the shooting impact is very good. However, when the arrow becomes bent, the frequency of the arrow changes, thus causing the oscillation to change as well.

This causes bent arrows to not impact in the same place as straight arrows. The all carbon arrow cannot be bent. It can be bowed but not bent. A straight all carbon arrow and a bowed all carbon arrow have the same frequency. Thus, the frequency harmonics do not change and the impact of the arrow does not change. Now, can we say if an aluminum arrow is slightly bowed, would it have the same frequency as a straight one? Yes. However, bows very seldom occur in an aluminum arrow. You may even have heard some people commenting that depending on where the arrow is bent it still may fly into the group. Generally this is a "bowed" aluminum arrow. Does an aluminum/carbon arrow have the same characteristics as an all carbon or a 100% aluminum? It has more qualities as an aluminum. Thus, keep an eye on those aluminums. You can straighten the all aluminum, but it is almost impossible to straighten a carbon/aluminum by the average person.

Spine:
Spine is probably the most important part of the arrow shaft and the most ignored. I presume the main reason for this is because it is the hardest for a manufacturer to get right and keep consistent. Also, it is one that cannot be measured very easily by the average person. Let's determine what spine is and do not confuse it with spline! Spline is what the fishing industry uses in order to get sort of the "back bone" of the fishing rod.
This is sort of an overlap of material in order to get the stiffer side. Keeping this stiff side on the upper side makes it easier to handle when reeling in that big one! In archery you do not want a spline! You want an even consistent spine all the way around the shaft (circumferentially). Spine was established in modern times by Easton who uses a 29" arrow. You place this arrow on two posts measured out 28" apart. You then place a 1.94 pound weight in the middle of the shaft and measure how far the arrow shaft drops down. This gives you a static (non-moving) spine.

When an arrow is launched from a bow, the arrow flexes (dynamic spine). This flex needs to be a specific amount and stay consistent among all the arrows in order to carry a group. If the arrow flexes too much it becomes exceptionally critical. The smallest mistake made by the arrow increases substantially if the arrow is too weak.

If the arrow is too stiff it is not as critical, but does not give the best possible grouping. Thus it is far better for the arrow to be too stiff than too weak. That is why you may note that some companies fudge on the size arrow recommended towards the stiff side. This is far better than on the weak side. Since the arrow flexes upon being launched, you would want it to flex the same.

If the arrow is too stiff it will favor the left side while if the arrow is a bit weak, it favors the right side. Thus you will get lots of rights and lefts if you have lots of inconsistent spines in your arrows and that is exactly what you will get with many of the arrows on the market today. Since most of the archers do not know how to measure this spine, they are unaware of why they are not grouping so well. Also, you will note that most arrows that are sold in dozen groups, only 6 to 8 arrows will group and the rest will not. Again, this is due to the spine more than anything else. Sometimes they can get a few more arrows to group by moving the nock around the shaft a little in order to find a near correct spine.
Many companies do not keep very tight tolerances on spine consistency. This causes all types of problems for the archer and the dealer. Of course, since most archers are not very good or accurate, they do not realize that the arrow is making them look even worse than what they really are. According to tests that I have been involved with, the tighter the spine tolerances the more accurate the arrows become. Keeping them .005" plus or minus is what was set years ago with aluminum arrows and their accuracy has been proven over the years. Some companies have spine deviations of over .040" plus or minus! Thus, it would be like putting spines of a 2113, 2116 and 2119 all in one group of arrows and expect them to shoot well. It will not happen!

Part of the reason for having so many spine inconsistencies is due to the material used. Some companies look for the cheapest product they can find in order to keep costs down. This severely causes huge spine deviations. Also, how the arrow is manufactured will cause spine inconsistencies. Most companies put the spine determining material on the outside and then grind it down to get as close to the weight they can get. However, this causes spine inconsistencies and breaks down the fibers that actually determine the spine. Cutting the materials requires tremendous precision in order to get the exact spines and many companies use like a paper cutting device to get their patterns. This gives a lot of spine inconsistencies as well. It also gives them a "spline" as talked about in the above paragraph.

Now if you consider the inconsistencies of spine, the straightness factors and weight factors, you can see why there is so many discrepancies in arrow shafts. The degree of importance is determined by what material is used. With aluminum arrows, the degree of importance is straightness, spine and then weight. With all carbon it is spine, straightness and then weight. The spine of an aluminum arrow is normally very good to start with.

However, this spine breaks down over time. Depending on the wall thickness spines of an aluminum arrow can break down as fast as 10 shots! This has been proven time and again by some of the best archers world wide. Although the only American manufacturer of aluminum shafts disputes this, the "proof is in the pudding"! Top archers will replace these arrows very quickly without anyone knowing any different.

Most all carbon arrows start to loose their spine over several hundred shots due to wear. As the arrow penetrates the target, the friction microscopically wears down the outer layer of carbon and since most companies have their spine determining layer on the outside, the spine gets weaker and weaker over time. The aluminum arrow breaks down for different reasons. The flexing of the shaft upon impact of the target, pulling the arrow out of the target and the launching of the arrow from the bow continues to flex the aluminum tube constantly and we all know what happens to metals when continuously flexing them back and forth.

Now you can understand some of the simple physics of what is happening to an arrow and why it is important to choose wisely when purchasing arrows.




"I have not failed. I’ve just found 10,000 ways that won’t work –*Thomas Edison"


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## limbwalker (Sep 26, 2003)

Stash said:


> Maybe so, but if you're headed for the top, you'd best supply yourself with arrows that are consistent in spine AND weight AND are perfectly straight.
> 
> This question "straight enough?" needs to have a qualifier. Maybe a .006 arrow is "straight enough" for 320, but I doubt if you'll ever find anyone using them to shoot 350.


350 shooters don't have to buy their own arrows.


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## Stash (Jun 1, 2002)

whiz-Oz said:


> Yes you have.
> Either that or you weren't paying attention.


The testing proposed on Archery-forum? I haven't checked in there for a long time because of forum issues. Also, as I recall, the discussion was in a private room, and the methodology as proposed did not meet what I felt was what was required to investigate the original question.

Are the tesults available?


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## Stash (Jun 1, 2002)

While I greatly respect Rick McKinney and everything he says about archery, one test 30 years ago with "primitive" carbon arrow technology is not definitive.

Again, what I described above, a double blind test of a set of identical arrows sorted by straightness and tested by actual shooting and scoring is really the only way to answer the question.


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## limbwalker (Sep 26, 2003)

I'm sure the arrow manufacturers will rush out to conduct this test, just like they have with ILF vs. Formula, Stealth shots vs. w/o, Beiter nocks vs. conventional, fom core vs. wood, etc. etc.

There is little room in the cottage industry we call "archery" for such objective testing. Mostly because archers are sheep and they will always believe that more expensive = better, and the manufacturers know this.


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## j.conner (Nov 12, 2009)

limbwalker said:


> 350 shooters don't have to buy their own arrows.


Bingo. And they are the manufacturer's showcase for what their best product can do.


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## limbwalker (Sep 26, 2003)

Whenever the topic of paying top dollar for equipment comes up, I always tell the archer/parents that I will let them know when it's time to invest. Every archer is an individual case, and for many there are so many areas that need attention before their equipment becomes their limiting factor. 

And then there are those head cases who want the best of the best to "take equipment out of the equation" and then realize that form and mental game trumps equipment every time. I like those people because their gear is cheap on the classifieds.


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## j.conner (Nov 12, 2009)

limbwalker said:


> I'm sure the arrow manufacturers will rush out to conduct this test, just like they have with ILF vs. Formula, Stealth shots vs. w/o, Beiter nocks vs. conventional, fom core vs. wood, etc. etc.
> 
> There is little room in the cottage industry we call "archery" for such objective testing. Mostly because archers are sheep and they will always believe that more expensive = better, and the manufacturers know this.


This is typical marketing - product differentiation and price descrimination. It is done all the time with things like toothpaste, toilet paper, cars, gasoline, coffee, etc.

It is interesting to note the lack of scientific rigor in this topic. Even McKinney's article does not state materials, method, specific results, or present data. It is all anecdotal evidence with no publication for peer review. I believe this is for a number of reasons, as follows:

(1) The manufacturers don't want it. It is rational to use marketing techniques to maximize profit margins.

(2) High profile archers don't want it. Sponsored shooters who perpetrate it risk losing their funding or killing the goose that lays the golden egg.

(3) The competition between products is not strong enough to force such rigor. It is a niche market with relatively few players and substitutes.

(4) Customers want it. Arrows are not a commodity, so archers expect differentiation. The sport also has enough subjectivity in it to support the possibility of that silver bullet or whammy that magically produces results.

(5) The tests might not be meaningful. Although it would be relatively easy to set up a hooter shooter and collect data, we would likely find that other sources of variation creates overwhelming noise in the results. This includes weight and dimension tolerances of the components (points, nocks, vanes, inserts), precision of arrow assembly (cuts, vane location), and variation in the archer themself (if greater than the variation in the arrow then a shooter could not detect the difference).

It is an interesting topic, but perhaps there is inadequate motivation to get solid answers.


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## JustSomeDude (Jan 27, 2013)

The bigger issue at play...just because your arrows aren't GUARANTEED to be within a certain margin of weight/straightness and spine doesn't mean that they aren't.
I buy GoldTip "Blems" and Entrada and Warrior arrows. Sometimes you get lucky and they are very well matched.

Once, I had a GoldTip Blem that was 75 grains heavier and a couple that were 25-40 grains heavier in one batch of a dozen.

75 grains even showed up in my shooting


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## Nick728 (Oct 19, 2014)

Gold tip has several videos covering straightness. Furthermore, just because you buy a .001 doesn't mean it will remain .001 after you build it and shoot it. At the club we go through this often, I have a few dozen GT 22s .006 that fly the same as my buddies 001s out to 50 yards. At 60 yards well matched arrows in any straightness group will out shoot mismatched arrows. But past 50 yards form has no margin of error with a compound and more so with a recurve. Matching weight is just as or more important than a hair thickness. Few shooters I know can tell the difference, not that there isn't a diffence just good luck noticing the difference. I know a very good shooter than matches arrows and indexes the nocks. His form is flawless with every shot! You can bet your lunch money perfectly matched arrows makes a huge difference for him. Again, this is a compound release shooter 3D and spots. With the recurve variables the difference between a pro shooter and most others is apples and oranges.


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## whiz-Oz (Jul 19, 2007)

j.conner said:


> It is interesting to note the lack of scientific rigour in this topic. Even McKinney's article does not state materials, method, specific results, or present data. It is all anecdotal evidence with no publication for peer review.


Just wait a few more months. Just because you don't know about something, doesn't mean it hasn't happened.


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## jmvargas (Oct 21, 2004)

for those with limited resources there are ways to assemble a finely matched set of arrows..

all you will need is a reliable spine tester, weighing scale, an arrow spinner for straightness and a lot of time and patience..


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## Bigjono (Apr 21, 2009)

jmvargas said:


> for those with limited resources there are ways to assemble a finely matched set of arrows..
> 
> all you will need is a reliable spine tester, weighing scale, an arrow spinner for straightness and a lot of time and patience..


True that


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## j.conner (Nov 12, 2009)

whiz-Oz said:


> Just wait a few more months. Just because you don't know about something, doesn't mean it hasn't happened.


Sorry, I can find no published research on the topic. This topic of arrow straightness has existed for many decades, it is not something new or novel. If it is not published in a peer-reviewed journal, or publicly published in a reputable fashion, then it's not what would normally be considered science. Here is a list of published research, as best I can determine without a huge amount of effort - apologies for not conforming the entries to a standard format:


Klopsteg, P. E. (1992). Physics of bows and arrows. In The Physics of Sports (edited by A. Armenti), pp. 9{26. Woodbury NY: AIP Press.

Kooi, B. W. (1991). On the mechanics of the modern working-recurve bow. Computational Mechanics, 8, 291{304.

Kooi, B. W. and Sparenberg, J. A. (1997). On the mechanics of the arrow: Archer's Paradox. Journal of Engineering Mathematics, 31(4), 285{306.

Leonardi, L. M., Gallozzi, C., Pace, A. and Dal Monte, A. (1987). Reduction of lateral bow displacement using different torque compensators and stabilizers in archery. In Biomechanics: Basic and Applied Research (edited by G. Bergmann, R. KÄolbel, and A. Rohlmann), pp. 633{638, Dordrecht, The Netherlands: Nijho.

Pekalski, R. (1987). Modelling and simulation research of the competitor|bow|arrow system (in Polish). PhD thesis, Academy of Physical Education, Warsaw.

Pekalski, R. (1990). Experimental and theoretical research in archery. J. of Sports Sciences, 8, 259{279.

Kooi, B.W. & Sparenberg, J.A. 1980 On the static deformation of a bow. Journal of Engineering Mathematics, 14(1):27-45. 

Kooi B.W. 1981 On the mechanics of the bow and arrow. Journal of Engineering Mathematics, 15:119-145. 

Kooi B.W. 1983 On the Mechanics of the Bow and Arrow. PhD thesis, Rijksuniversiteit Groningen. 

Kooi, B.W. 1991. The 'cut and try' method in the design of the bow. In Eschenauer H. A., Mattheck C., and Olhoff N., editors, Engineering Optimization in Design Processes, volume 63 of Lecture Notes in Engineering, pages 283-292, Berlin. Springer-Verlag. 

Kooi, B.W. 1991. On the mechanics of the modern working-recurve bow. Computational Mechanics, 8: 291-304. 

Kooi, B.W. 1994. The Design of the Bow. Proc. Kon. Ned. Akad. v. Wetensch, 97(3), 283-309. 

Tuijn, C. & Kooi, B.W. 1992. The measurement of arrow velocities in the students' laboratory. European Journal of Physics, 13:127-134. 

Kooi, B.W. & Bergman, C.A. 1997. An Approach to the Study of Ancient Archery using Mathematical Modelling. Antiquity, 71:124-134. 

Kooi, B.W. & Sparenberg, J.A. 1997. On the Mechanics of the Arrow: Archer's Paradox. Journal of Engineering Mathematics, 31(4):285-306. 

Kooi, B.W. 1998. Bow-arrow interaction in archery. Journal of Sport Sciences, 16:721-731. 

Kooi, B.W. 1998. The Archer's Paradox and Modelling, a Review. History of Technology, 20:125-137. 

Kooi, B.W. 1991. Archery and Mathematical Modelling. Journal of the Society of Archer-Antiquaries, 34:21-29. 

Kooi, B.W. 1993. On the Mechanics of some Replica Bows. Journal of the Society of Archer-Antiquaries, 36:14-18. 

Kooi, B.W. 1996. Functioning of ears and set-back at grip of Asiatic bows. Journal of the Society of Archer-Antiquaries, 39:73-77. 

Lanting, J.N., Kooi, B.W., Casparie, W.A. & van Hinte, R. 1999. Bows from the Netherlands. Journal of the Society of Archer-Antiquaries, 42:7-10. 

Zanevskyy Ihor 2006 Archer-Bow-Arrow behaviour in the vertical plane. Acta of Bioengineering and Biomechanics, Vol. 8, No. 1, 2006

Modeling and Computer Simulation of Bow Stabilization in the Vertical Plane, International Journal of Sports Science and Engineering Vol. 02 (2008) No. 01, pp. 03-14

Zanevskyy Ihor 2006 Bow tuning in the vertical plane, Sports Engineering 05/2006; 9(2):77-86.

Robazza, C., Bortoli, L., & Nougier, V. (1999). Emotions, heart rate and performance in archery: a case study. Journal of Sports Medicine and Physical Fitness, 39, 169-176.

Aerodynamic properties of an arrow: Influence of point shape on the boundary layer transition K Mukaiyama et al, Procedia Engineering 13 (2011) 265-270

Free flight and wind tunnel measurements of the drag exerted on an archery arrow K. Okawa et al, Procedia Engineering 60 ( 2013 ) 67-72

J L Park, December 2011 (DOI: 10.1177/1754337111407124), The aerodynamic drag and axial rotation of an arrow

H. O. Meyer, Physics Department, Indiana University, 6 November 2015, Applications of Physics to Archery

T.Miyazaki, K. Mukaiyama, Y. Komori, K. Okagawa, S.Taguchi and H. Sugiura, Aerodynamic properties of an archery arrow, Sports Engineering, 16, 43 – 45 (2013)

K. Okagawa,Y. Komori, T. Miyazaki, S. Taguchi and H. Sugiura, Free flight and wind tunnel measurements of the drag exerted on an archery arrow, Procedia Engineering 60, 67-72 (2013)

Park J. L. Arrow behaviour in free flight. Proc. IMechE, Part P: J. Sports Engineering and Technology, 2011, in press. DOI: 10.1177/175433711139854210.1177/1754337111398542


There is also a quite a bit of research specific to biomechanics and sports performance/psychology but those are unlikely to be pertinent to arrow straightness.

It would be relatively easy to test using a compound bow with a mechanical release and a hooter shooter, but it would be tricky with a recurve bow especially with respect to developing a finger-shooting hooter shooter. I suspect that the manufacturers are not really interested and there may be too many other variables to conclusively identify a result.

I also believe that the straightness ratings are achieved via a QC process, not a different manufacturing process. In other words, the stock is the same but it is graded and cut based on straightness measurements and tolerances. Presumably, the .001 would be carefully measured and checked, the .003 would be quickly measured and checked, then what's left and within the overall manufacturing spec is .006.

If anyone here knows of any solid published results relating to arrow straightness -vs- accuracy, please share - it would be very interesting to see!


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## Bender (Dec 6, 2006)

Rather subjective, but experience based. For the non-sight finger release shooter, the advantage to be gained from tight spec straightness is from the psychological/confidence perspective rather than from the actual mechanics/physics. That is until such time as the arrow is so crooked it becomes visible to the naked eye. If you're gap shooting it could really mess with your head. 

What about this as a potential test methodology? Take some simple aluminum shafts, get baseline specs off them and then shoot them for score. Record that result. Then begin a series of additional scoring runs, bending them an incremental, measurable, repeatable amount for each subsequent run until such time as the arrows are bent enough that the score shows a statistically significant drop.

Yes it would cost some $ but wouldn't break the bank. And I think it could provide a valid result.


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## whiz-Oz (Jul 19, 2007)

j.conner said:


> Sorry, I can find no published research on the topic.


See where you quoted two sentences of mine in your post?

Would you like to maybe explain what you think I meant in that first sentence?


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## whiz-Oz (Jul 19, 2007)

j.conner said:


> It would be relatively easy to test using a compound bow with a mechanical release and a hooter shooter, but it would be tricky with a recurve bow especially with respect to developing a finger-shooting hooter shooter.


Oh, the only thing you have to do to get finger shooter characteristics is to get some high speed video footage of the string and arrow coming off the fingers and then replicate that same displacement with an adjustable ramp. James Park did that for some of the research that you've already noted above. When I asked how big the ramp was, he said 12mm (half an inch) which impressed me no end. I expected a bit longer. 

If you're not aware of it, he produced a program which accurately models Easton Protours and X10's 
The instructions to get it running and a new link to the download (at the bottom of the thread) is here: https://www.archery-forum.org/forum...are/12358-recurve-bow-arrow-dynamic-behaviour

You can change most aspects of the arrow and then hit auto tune to see how much poundage increase is required to make the nodes exit correctly to achieve a perfectly vertical travel, ie tuned.

The hint here is that it is not ever going to have more than those two arrows selectable. It was never designed as a consumer tool for arrow choice, but to test that the modelling calculations were correct.


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## lksseven (Mar 21, 2010)

limbwalker said:


> 350 shooters don't have to buy their own arrows.


:darkbeer::cheers::mracoustic:
All of the 350 shooters could fit in my van.


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## limbwalker (Sep 26, 2003)

lksseven said:


> :darkbeer::cheers::mracoustic:
> All of the 350 shooters could fit in my van.











Yea, but I don't think they're into that kind of thing.


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## lksseven (Mar 21, 2010)

limbwalker said:


> View attachment 6209351
> 
> 
> Yea, but I don't think they're into that kind of thing.


Maybe they should consider it - probably some good beta-blockers in that van!


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## Astroguy (Oct 11, 2013)

I have had X7's nearly .010 out , that flew great at NFAA field rounds. Arrows spin and balance out. Good spine and weight will keep you on the same plane. 

.010 x 80 yards is off .800 thousandths , if you buy into that logic. Most cant aim that good at distance. Sure I buy the .001 arrows for peace of mind. Just not the premium brands.


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## whiz-Oz (Jul 19, 2007)

Astroguy said:


> .
> 
> .010 x 80 yards is off .800 thousandths , if you buy into that logic. Most cant aim that good at distance. Sure I buy the .001 arrows for peace of mind. Just not the premium brands.


It's not a geometric relationship of bend which expresses itself as varied impact at distance. 

Bows have a predisposed bend plane, depending on bow type, arrow rest configuration and method of release. The forces involved will try to bend an arrow in a consistent manner and direction during the power stroke.
Once you have an arrow which is not perfectly straight, it will react differently in relationship to that predisposed bend plane in the power stroke after release. 
If you have a lengthwise bend at 90 degrees to the bend plane, or at 0 degrees to the bend plane, you'll get the arrow DEPARTING the bow in different directions. 

Have you ever wondered why rotating the nock brings some arrows closer together on the target and yet does nothing for others?


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## arrowchucker222 (Jun 17, 2013)

I am currently unemployed. A blessing and a curse at the same time. I get to shoot everyday as much as I want, go. To as many shoots as I want. As long as I can find some money. I have very little debt so bills are low but still need equipment.
I have been buying used stuff for years and now I really look for bargains. The VAP's can be found for $30-$50dz if you are patient and look around. Currently I shooting used 600's , 2 different color patterns, V6. I weighed 14 of the arrows I have been shooting 11 were 246 gr s, 2 were 247, 1 was 245. Spin test for straight could feel slight wobble in 2. I'm going spine test them today. They are marked spine aligned so we'll see. By the way I have been shooting these my best scores over and over. I'll let you know how the spine test comes out and I'll check them with my straightener dial gauge.


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## Stash (Jun 1, 2002)

Congratulations or condolences on your situation - you pick 

But the point of the thread is not to simply confirm that you have shot your best scores with lower quality arrows, it's to determine whether or not higher quality arrows would have made that best score even a little higher.

So if you can get them all to weigh exactly the same and confirm they are all the same spine and indexed the same, then go ahead and shoot them enough times to get a fair average. I'd suggest you number them and score each arrow by number to get an average score for that arrow, and AFTERWARDS check the straightness of each arrow to determine its average score. If you check them for straightness first and know how straight the arrow you're shooting is, it might affect your shot and give a biased result.


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## Astroguy (Oct 11, 2013)

whiz-Oz said:


> It's not a geometric relationship of bend which expresses itself as varied impact at distance.
> 
> If you have a lengthwise bend at 90 degrees to the bend plane, or at 0 degrees to the bend plane, you'll get the arrow DEPARTING the bow in different directions.


I believe a .010 bend still falls into way less than 1 degree. Think about it.... one degree would put you off the target. 

After a shoot, I check my favorite numbered arrows and find that they are not always the best in the quiver. Which has led to spine testing sets of arrows. Which then led to nock tuning bare shafts. And the marks and rotation were still not equal on every arrow. 

I have shot thousands of XX75 , X7 and ACC arrows and keep shooting near equal scores with any of them when tuned. 

I believe what throws an arrow out , is the type of bend.

And if it can balance in flight. 

Which I think is what you were getting at.


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## granite14 (Nov 10, 2014)

Interesting stuff. Last week I was bare shaft testing .001 carbons at 30yds (crawl), 7 fletched and 2 bare. Nice group for fletch. 1 bare shaft 12 inches high and the other bare shaft was 12 inches right on several ends. I twisted the nock on the right arrow and it moved to 10 o'clock 10 inches high repeatedly. That's on 2 random samples. The fletched group itself is very sensitive to brace height as well. This got me thinking to try some different arrows.

Sent from my SAMSUNG-SM-G930A using Tapatalk


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## Nick728 (Oct 19, 2014)

Nock indexing seems to work well. The proper way to do nock indexing is still a mystery to me.


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## whiz-Oz (Jul 19, 2007)

Astroguy said:


> I believe a .010 bend still falls into way less than 1 degree. Think about it.... one degree would put you off the target.
> 
> After a shoot, I check my favorite numbered arrows and find that they are not always the best in the quiver. Which has led to spine testing sets of arrows. Which then led to nock tuning bare shafts. And the marks and rotation were still not equal on every arrow.
> 
> ...


Do you have a shooting machine or were you doing this all hand held?


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## dchan (Jun 29, 2004)

So in this conversation of spine vs weight many are forgetting the relationship between the two.

Having two arrows weigh exactly the same but one having 1grain more of point weight, i grain less of tail weight (combined total of fletches pin, nock), and the second arrow with one grain less point weight and one grain more tail weight, will have dramaticly different dynamic spines.

You are better off having 2 arrows differing in total overall weight but working out the balance of point to tail.

So if you are OCD enough to be weighing each component of your arrows as you build, consider that you don't want to balance the overall weight by making up point weight, by matching the lighter tail components or the other way around.


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## Stash (Jun 1, 2002)

No disrespect, but I don't think the terms "one grain" and "dramatically different" belong in the same sentence when discussing arrows.


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## Astroguy (Oct 11, 2013)

dchan said:


> So in this conversation of spine vs weight many are forgetting the relationship between the two.
> 
> Having two arrows weigh exactly the same but one having 1grain more of point weight, i grain less of tail weight (combined total of fletches pin, nock), and the second arrow with one grain less point weight and one grain more tail weight, will have dramaticly different dynamic spines.
> 
> ...


I knew an arrow builder who would grain scale everything and use glue to adjust weight. He shot NFAA Freestyle and wanted perfection. A teen ( J. Broadwater) could beat him with 5 pins and used XX75's. 

None of us had Hooter Shooters back then. I guess it took some real OCD to build one.


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## dchan (Jun 29, 2004)

Stash said:


> No disrespect, but I don't think the terms "one grain" and "dramatically different" belong in the same sentence when discussing arrows.



It's all relative of course but if someone is shooting at the level where they are making changes of crimp on nock locators to tie on nock locators to bring their system in tune, then a 2 grain swing (one each way from center) will move the dynamic spine of the arrow enough to be "dramatic" if you are talking abot some that is just obsessing about if their arrows all weigh the same but are not shooting at the level to match the amount of detail, then it will not be as dramatic. It is however much easier and faster to take 2 doz bare shafts and shoot them Several times. Take the set that groups together, and nock index tune the rest (turn the nocks) to see if you can get them to join the group. Then fletch them and repeat. 

It's probably more accurate to real world shooting then weighing and measuring with grain scales, dial indicators, spine testers.


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## whiz-Oz (Jul 19, 2007)

dchan said:


> So if you are OCD enough to be weighing each component of your arrows as you build, consider that you don't want to balance the overall weight by making up point weight, by matching the lighter tail components or the other way around.


Actually, if you're OCD enough and have read the current, actual scientific research, you'll know that weight variation in the tail end makes significantly more difference to weight variation in the point. 
With carbon arrows, it's between nothing and virtually nothing. This has been proven by modelling with the physical properties of the arrows and the forces involved AND backed up by rigorous peer reviewed physical testing with shooting machines. This research has already been listed.
Plenty of people still cling to outdated ideas, so I don't expect anything to change any time soon. 

If you want to see where point weight DOES make a difference on carbon shafts, experiment with the arrow simulator. You'll find that the closer to optimum tune you are, the less difference is made. Conversely, the further out your arrow is from matched to the bow, the greater difference point weight makes. 

Try adding weight to the back end of the arrow and getting the software to work out the tune weight. 
Contrast that to changing point weights and watching how the tune weight changes. 

This software has actually been verified to predict the real world.


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## cekkmt (Nov 29, 2013)

whiz-Oz said:


> Actually, if you're OCD enough and have read the current, actual scientific research, you'll know that weight variation in the tail end makes significantly more difference to weight variation in the point.
> With carbon arrows, it's between nothing and virtually nothing. This has been proven by modelling with the physical properties of the arrows and the forces involved AND backed up by rigorous peer reviewed physical testing with shooting machines. This research has already been listed.
> Plenty of people still cling to outdated ideas, so I don't expect anything to change any time soon.
> 
> ...


Is there a link to this software, just for curiosities sake?

Also I'm not contesting that adding weight to the nock end has a lot more effect than messing with the point weight on how the arrow flies, but I think one of the reasons for that is most people adjust point weight by breaking off the rod on their arrows. When you do that you might be decreasing the point weight, but you are adding more length for the arrow to flex. Those seem to cancel each other out, whereas switching points (for example from ACE 100 to ACE 120 grain points) has a much greater effect, since you are only changing the point weight and not the effective flexing length of the arrow.


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## whiz-Oz (Jul 19, 2007)

cekkmt said:


> Is there a link to this software, just for curiosities sake?


Yep. Read everything in the entire thread link at the end of this sentence, right down to the last post before you ask any more questions. https://www.archery-forum.org/forum...are/12358-recurve-bow-arrow-dynamic-behaviour


cekkmt said:


> Also I'm not contesting that adding weight to the nock end has a lot more effect than messing with the point weight on how the arrow flies, but I think one of the reasons for that is most people adjust point weight by breaking off the rod on their arrows. When you do that you might be decreasing the point weight, but you are adding more length for the arrow to flex. Those seem to cancel each other out, whereas switching points (for example from ACE 100 to ACE 120 grain points) has a much greater effect, since you are only changing the point weight and not the effective flexing length of the arrow.


Yep. That's a nice explanation which sounds plausible if you don't consider everything, including actual testing.. Go check out column loading and see where the bend is in a beam. Also go and do some point swapping and measuring deflection before and after having a longer insert. 
Then you might notice something rather interesting.


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## whiz-Oz (Jul 19, 2007)

The current issue of Bow International magazine has a run down of the research on the effects of arrow straightness research published here: https://eprints.qut.edu.au/112788/


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