# How do you find the Node in an arrow?



## DK Lieu (Apr 6, 2011)

The front node is usually located around 2-3" from the point; the rear node is located around 4-5" from the tail. To get a more precise location, gently hold the shaft between your thumb and forefinger near the expected location of the node, so that the shaft is nearly horizontal. You will need to excite the first resonant frequency, which has two nodes and an anti-node near the middle of the shaft. Gently rap the shaft at its middle to excite the shaft near the anti-node. The first resonant frequency is rather low, so rap it against something soft, like the back of an upholstered chair. You will feel some vibration between your thumb and forefinger. Change the holding location on the shaft, rap it again, and feel the vibration. It will take several tries, but the location of the node will the point on the shaft where you feel the least vibration. Location accuracy will be within 1/4". A mathematical formula can be developed, but is rather complicated. The node location depends not only on the mass, geometry, and stiffness of the shaft material, but also on the mass of the components (point, pin, nock, vanes) attached to it.


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## Greysides (Jun 10, 2009)

Could you expand on the resonant frequencies please. Simple guide for Dummies version.
I'm curious as to how an arrow can resonate in more than one way at a time. Does the arrow resonate in a way that is the sum of the different resonant frequencies?
What are the implications of the different modes of resonance?
Thanks.


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## Scott.Barrett (Oct 26, 2008)

What I've found in my limited testing is that if you hold an arrow at the nock end and let it drop so that it is at a 45 degree angle to the edge of a table, you will see it bounce and make a higher pitched sound until you get to the node which will bounce much less and have a thud sound. As DK Lieu mentioned, it was about 5 inches back from the end of a 29" Fatboy with a 150gr tip in it.....

I am going to try some different arrow lengths and tip weights to see how the node moves....

SB


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## DK Lieu (Apr 6, 2011)

Greysides said:


> Could you expand on the resonant frequencies please. Simple guide for Dummies version.
> I'm curious as to how an arrow can resonate in more than one way at a time. Does the arrow resonate in a way that is the sum of the different resonant frequencies?
> What are the implications of the different modes of resonance?
> Thanks.


More info about arrow vibration can be found on a link here: http://www.ocf.berkeley.edu/~archery/?page_id=75

You are essentially correct, Greysides. The free vibration of any elastic object, including an arrow, is the combination of all its natural frequencies. An elastic object will have an infinite number of natural frequencies, but the higher order frequencies are more difficult to excite, so people usually worry about the first few frequencies. The lowest natural frequency in an arrow has two nodes, and is the easiest to excite because of the way the arrow is released (i.e. the tail is pushed to one side as the string goes around the fingers). From my testing, the second natural frequency (3 nodes) has only around 10% of the energy contained in the first natural frequency; the third natural frequency (4 nodes) has only around 10% the energy contained in the second natural frequency. For all practical purposes, therefore, the only frequency and mode we need to worry about for archery is the first. It is possible to excite a higher order frequency with a pulse that has approximately the same duration as half the period of the higher frequency, but this is hard to do.


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## Greysides (Jun 10, 2009)

Thanks for that. I've already the Arrow Flight Mechanics paper. The engineering/mathematics is way above my head.

It interesting that looking at the three modes of resonance, one could (visually) seem to lead to the others.
Combining them it looks like a wave moves along the arrow.


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## cc46 (Jan 22, 2005)

and if you know where the node is what do you do with that information? to improve your shooting I mean..


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## Hank D Thoreau (Dec 9, 2008)

DK,

So you are saying that the first normal mode of the arrow does not have its nodes at the two ends of the arrow, rather they are somewhat inside of the tip and tail?

Any idea how many periods the arrows goes through before it clears the bow; or how far the arrow travels before the first period is complete?

How much impact does nodal tuning really have on the shot, or this just an interesting theoretical exercise? I am curious since us barebow guys often use long arrows and I am sure that we do not place the nodes in the same place relative to the plunger, as the Oly guys do -- certainly not with my full length, 35 3/5 inch nock groove to point, 2315 X7 arrows that I shoot indoors.

And by the way, I like the cool uniforms the Cal archers wear. That's as far as I am willing to go in my compliments of Cal; I went to USC.


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## Huntmaster (Jan 30, 2003)

There are some good vids on youtube from Beiter that show slow motion arrow reaction


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## whiz-Oz (Jul 19, 2007)

cc46 said:


> and if you know where the node is what do you do with that information? to improve your shooting I mean..


It's one of those "interesting to know about" things. Most serious archers I know of don't give it a second thought. This includes one ex World Champion and Olympic Gold medal winner.


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## Scott.Barrett (Oct 26, 2008)

I believe it is one of those things that makes one set of arrows better than another. Do you pick a shorter arrow with more point weight or a longer shaft with less weight? Both may equate to the same spine, but one just flies better and perhaps this is part of the reason....


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## DK Lieu (Apr 6, 2011)

Greysides said:


> Thanks for that. I've already the Arrow Flight Mechanics paper. The engineering/mathematics is way above my head.
> 
> It interesting that looking at the three modes of resonance, one could (visually) seem to lead to the others.
> Combining them it looks like a wave moves along the arrow.


The mathematics is usually above my head too. I just like to include it to make me look smarter than I actually am. For problems that involve a lot of math, I usually like to assign it to one of my graduate students. Engineering graduate students love math.


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## DK Lieu (Apr 6, 2011)

cc46 said:


> and if you know where the node is what do you do with that information? to improve your shooting I mean..


I use the node location to tell me if I am properly clearing the bow at the node. The arrow flexes and bends on the way to the target, but it flexes and bends around the nodes. If you draw a straight line between the front node and the rear node, that line should point directly at the target during its entire flight, for a well tuned set up. The rear node will always barely clear the plunger button, even for a well tuned set up, while the arrow itself bends around the button. If the rear node strikes the button, as indicated by a small streak at the location of the rear node, then I know I have a release problem (which I have quite often). A rear node strike is caused by over-displacement of the node, as would occur in a pluck or otherwise poor release. However, a mark on the tail of the arrow, behind the node or on the vanes, would be indicative of a frequency problem, e.g. as caused by an arrow that was too stiff or too weak. A button strike at the rear node will cause the tail of the arrow to kick out, producing an artificial "weak" tune. When I teach tuning, I tell my students to check their arrows for a mark at the rear node. If there is such a mark, then there is a release problem that must be solved before the tuning process can continue.


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## Huntmaster (Jan 30, 2003)

whiz-Oz said:


> It's one of those "interesting to know about" things. Most serious archers I know of don't give it a second thought. This includes one ex World Champion and Olympic Gold medal winner.


Many more serious archers give it more than just a thought....probably more than you would think.


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## DK Lieu (Apr 6, 2011)

Hank D Thoreau said:


> DK,
> 
> So you are saying that the first normal mode of the arrow does not have its nodes at the two ends of the arrow, rather they are somewhat inside of the tip and tail?
> 
> ...


Glad you like the uniforms! The Team designed the uniform themselves. I'm a Cal graduate myself, and had a few of my own ideas about uniforms. But the team members didn't like the idea of ski masks. Hank, if you can tolerate my Cal-ness, I can tolerate your USC-ness.  

Yes, the nodes of the arrows are inside of the point and nock, on the shaft, not on the tips. In an ideal set up, the arrow will go through 1.25 cycles of the first mode while clearing the bow. Nodal "tuning" merely maximizes the clearance between the arrow and the bow as the arrow is launched. The correct frequency probably has more to do with the design of the arrow shaft itself than anything you can add (or not add) to it. History has shown that there have been some shaft models that had a reputation of being terribly difficult to tune. I wonder how much of that had to do with improper clearance due to improper frequency. I suspect that many of the shaft models we use today have survived as a product because they produced the correct frequencies.


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## lksseven (Mar 21, 2010)

I have been told that the front node, at full draw, should be, as a general rule, approx. 1" behind the plunger button.


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## caspian (Jan 13, 2009)

Huntmaster said:


> Many more serious archers give it more than just a thought....probably more than you would think.


I suspect a lot more serious archers go and practice their archery skills rather than worrying about nodes. it's one of those subjects that seems to infatuate beginner archers, right up to the point where they realise it doesn't matter and just get on with shooting arrows.


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## Huntmaster (Jan 30, 2003)

caspian said:


> I suspect a lot more serious archers go and practice their archery skills rather than worrying about nodes. it's one of those subjects that seems to infatuate beginner archers, right up to the point where they realise it doesn't matter and just get on with shooting arrows.


and you're more than welcome to your oppinion.


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## Joe T (Apr 5, 2003)

Of as much practical use to archers as square wheels to a cyclist but Dennis might be interested:

http://scholar.google.co.uk/scholar_url?hl=en&q=http://data.mecheng.adelaide.edu.au/avc/publications/public_papers/2011/Rieckmann_Acoustics2011_manuscript.pdf&oi=scholaralrt&ct=alrt&cd=2&sa=X&scisig=AAGBfm3zu_FtvtStODcnQHDXZT55fL8B5w


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## Joe T (Apr 5, 2003)

Of as much practical use to archers as square wheels to a cyclist but Dennis might be interested:

http://scholar.google.co.uk/scholar_url?hl=en&q=http://data.mecheng.adelaide.edu.au/avc/publications/public_papers/2011/Rieckmann_Acoustics2011_manuscript.pdf&oi=scholaralrt&ct=alrt&cd=2&sa=X&scisig=AAGBfm3zu_FtvtStODcnQHDXZT55fL8B5w


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## Koorsboom (Dec 13, 2008)

> The node location depends not only on the mass, geometry, and stiffness of the shaft material, but also on the mass of the components (point, pin, nock, vanes) attached to it.


I presume this list would include length as well ...

If I am not mistaken, in his DVD George talks about finding the nodes of the arrow and then to cut the arrow so that the node is on/just behind he rest ... and this is where he lost me because when you cut the arrow you change the resonance frequency and hence the position of the node.

And what if the node on your choice of arrow is not near where you want it to be? I have to agree with Caspian and Whiz-Oz, I cannot see too many top archers spending their time on this ... not actively in any case.


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## zal (May 1, 2007)

I though it was, as a practical use, buried once in 90's and then again in mid 00's when it rose again in the bb's. Even those who were vocal about it previously have since dismissed its practical use. In concept, it surely might have something to do with something, but how much?


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## ButchD (Nov 11, 2006)

Given that spine selection is more critical than node location, as far a tuning is concerned, would a proponent of node assessment give a FITA shooting level necessary to benefit significantly from attention to this detail and its affect on tune?
1200?1250?
Thanks, Butch


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## dchan (Jun 29, 2004)

Maybe not directly related to node location in tuning but does indirectly affect tune is brace height. By finding the correct brace height, you can tune your bow so the arrow releases from the string at the exact point the whole arrow is "straight". Going to Dennis' information about arrow strikes (behind or in front of node) you can sometimes figure out at what stage of the cycle the arrow is in when the nock releases from the string. Ideally it would be when the arrow is at it's straightest and moving straight.

Most of us non math/engineering archers that love to tinker use the sound of the bow to help us identify when we get the brace height correct but it's all cool info.

Now that my head is about to explode (to much thinking) time to go do some work.

DC


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## traditionalrj (Jun 8, 2011)

Koorsboom said:


> I presume this list would include length as well ...
> 
> If I am not mistaken, in his DVD George talks about finding the nodes of the arrow and then to cut the arrow so that the node is on/just behind he rest ... and this is where he lost me because when you cut the arrow you change the resonance frequency and hence the position of the node.
> 
> And what if the node on your choice of arrow is not near where you want it to be? I have to agree with Caspian and Whiz-Oz, I cannot see too many top archers spending their time on this ... not actively in any case.


this is where I find the argument of nodal positioning and venturing into this a problem....

if you cut the shaft the resonance changes. If you change the point weight it has the same effect. Changing brace height doesn't effect the nodes so much as the force affecting them. So does the increase in poundage. 

if you have node position X initially on the shaft and then cut it and reinstall the components you've stiffened up that original nodal point and changed it's location. 

Am i analyzing this wrong? I don't see the point in doing this if you tune the bow to the best arrow possible and it delivers a consistent group and shot down the pipe.


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## traditionalrj (Jun 8, 2011)

ButchD said:


> Given that spine selection is more critical than node location, as far a tuning is concerned, would a proponent of node assessment give a FITA shooting level necessary to benefit significantly from attention to this detail and its affect on tune?
> 1200?1250?
> Thanks, Butch


from what I've read and processed in my feeble traditional brain, once you have the proper spine and solid arrow flight, if you cut the shaft to get the node to it's respectable position that's recommended then you've changed the spine of the shaft which could potentially stiffen it the point it's no longer effective for the archer's setup. 

so after thinking through this...the idea is to get a WEAK shaft, find the nodes, and ensure that once cut...the shaft spines right. 

I however shoot a method I developed that requires shooting the longest shaft possible...and right now that is a full length shaft. So cutting and node work would be either out of the question or could get expensive.


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## traditionalrj (Jun 8, 2011)

so do nodes change position in a shaft or they are always set no matter the length they are cut to? Where are our AT engineers? I can see this methodology working in the follow process...


1)pick a shaft that would be spined slightly weak at full length and find the front node...so that when cut and the node is in the proper position, the shaft is also spined right for your setup

2)cut to appropriately after finding the node positioning with the components you wish to use in your rig. (What weight would give you the best possible spine and FOC

3) complete the arrow assembly and test shoot...

4) fine tune the shot with minor brace height adjustments and tiny point weight changes like inserts, washers, etc. 


am i thinking this through right?


(i think I need to take my ADD meds right about now...)


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## Huntmaster (Jan 30, 2003)

Not that dificult. Pick an arrow that spines correctly at about an inch or a little bit more in front of the rest. Node "tuning" is a bit of a misnomer....There's really no "tuning". More like picking an arrow that leaves about the correct ammount of arrow in front of the rest. Not cut off right at the rest, not hanging 3 inches in front of the rest. Like someone said, the goal is to get the node ABOUT an inch behind the rest.....that's "give or take", as in not exact.


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## Koorsboom (Dec 13, 2008)

DK Lieu, you must now help me ... it has been many years since I had to struggle through physics class ...

This is how I understand arrow reaction when the shot is fired...

On release the bowstring suddenly pushes with a lot of force on the back of the arrow trying to get the arrow moving forward. At the same time the point of the arrow due to its weight, resists being pushed away and for a very short time acts as a wall the arrow shaft is being pushed against. So, how does an arrow bend when pushed against a wall like that? As far as I know it bends in one direction along the whole length of the shaft ... that is no oscillation yet, only bending in one direction.

Then the point of the arrow starts to move and the arrow then flexes in the other direction and I presume again a more or less complete bend. It is only later during the flight of the arrow that this bending to and fro gets the arrow vibrating which then may or may not be at the first, second or however manyeth resonance frequency.

The way I therefore see it, and please correct me if I am wrong, is that the arrow is long gone out of the bow before any resonance and/or nodes come into play ...

DK Lieu, over to you now :wink:


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## jhinaz (Mar 1, 2003)

Huntmaster said:


> Not that dificult. Pick an arrow that spines correctly at about an inch or a little bit more in front of the rest. Node "tuning" is a bit of a misnomer....There's really no "tuning". More like picking an arrow that leaves about the correct ammount of arrow in front of the rest. Not cut off right at the rest, not hanging 3 inches in front of the rest. Like someone said, the goal is to get the node ABOUT an inch behind the rest.....that's "give or take", as in not exact.


I never gave it much thought before but I'm guessing what Huntmaster is saying equates to Easton's instructions for determining 'correct arrow length', in that we are to cut the shaft a minimum of 1" in front of where the arrow contacts the most forward position of the arrow rest. It appears that will put the front-node in the proper place just behind the arrow rest. - John


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## cc46 (Jan 22, 2005)

let me pose a thought or two...

If you had an arrow with a 100 gr point and also 100 grains for the nock and vanes then would the nodes be equal distance for either end? I assume yes.

but since we commonly place 100 gr points on arrows and only say 20 gr nock and vanes and wraps at the back then the equal node distance from the ends doen't hold true. It's commonly thought to be 2"-3" at the front and 4"-5" at the back as stated earlier. 

also is it true that the distance from the front node to the back node x the grains per inch equals half of the arrow weight? I assume yes

next since the string moves around the finger tips it sets up a sideways displacement that starts the forward force on the arrow eccentrically, and the arrow bends. The forward force continues after the sideways force is fully applied and now recovers to the centre of the bow. Given this it's not a straight forward equation, probably some calculus to be done. 

But if you look at a hundred accomplished archers they almost all have the arrow cut such that the clicker hits the clicker plate. If nodes are that much different or if aligning a node on the rest is really that important then I think we'd see a different trend in use. 

Not sure it's worth the effort to really find out where it is..but hey it's been 30 yrs since I sat in a physics lecture. But I think I'll get arrows about an inch shorter next time. 

Cheers


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## Seattlepop (Dec 8, 2003)

cc46 said:


> let me pose a thought or two...
> 
> If you had an arrow with a 100 gr point and also 100 grains for the nock and vanes then would the nodes be equal distance for either end? I assume yes.
> 
> ...


Yes, but it seems also that the clicker hits the clicker plate at or in front of the riser edge closest the target. This means that most use an arrow whose point tip is around 2" past the plunger. 

I think that the suggestions that top archers don't "worry" about nodes is misleading. They probably don't "worry" about it, but they assume there is something to it so simply select arrows that will tune with the point tip 2" or so past the plunger. You don't have to "worry" about something that is accepted as fact. Or maybe someone would like to name a world champion or Olympic gold medalist who purposely cut their arrows short?


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## DK Lieu (Apr 6, 2011)

Koorsboom said:


> DK Lieu, you must now help me ... it has been many years since I had to struggle through physics class ...
> 
> This is how I understand arrow reaction when the shot is fired...
> 
> ...


I think you may be thinking of axial oscillation, such as the phenomenon called "pogo'ing" when a rocket is launched. Although there is a certain amount of pogo'ing in an arrow, it is not the main form of vibration. The axial modes are very high frequency and difficult to excite, and the resulting deflections are very small.

When an arrow is released, there are two forces. The main force if the string pushing the arrow straight forward. On a recurve bow, there is a secondary, sideways force from the fingers as the string goes around the fingers. The sideways force, combined with the fact that the tip of the arrow doesn't want to move right away (due to the inertia of the point), causes the arrow to immediately buckle and bend inward (toward the bow). Since the forces are rather short-lived, almost impulsive, the arrow starts to vibrate almost immediately, even before it leaves the string. Most of the vibration will be contributed by the first mode (2 nodes) because it is the easiest mode to excite. On a compound bow, there is very little sideways force when a release aid is used. Thus arrow vibration, frequency, and spine are less of an issue for compound archery.


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## zal (May 1, 2007)

Seattlepop said:


> Or maybe someone would like to name a world champion or Olympic gold medalist who purposely cut their arrows short?


How about Park SH, with some arrow setups she has used (not only that, but she uses steel points in her X10). Plus majority of archers outside US.

There are distinct advantages with short as possible arrows, rather than leaving them long for something that might or might not have any effect on grouping.

Edit: also, how about this strapping young lad: http://www.youtube.com/watch?v=kUM5aw8oSEc


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## DK Lieu (Apr 6, 2011)

A lot of you are over-thinking this. Offhand, I can't think of any advantages or disadvantages, practical or theoretical, of having the front node in front, behind, or right on top of the button or arrow rest. The behavior of the arrow might be slightly different at launch for each case, but this is taken care of by the tuning process. I keep an eye on the rear nodes of my arrows to make sure I'm not having a release problem, but I otherwise don't think about nodes. If the arrows clear the bow and tune, just shoot and have fun.


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## Seattlepop (Dec 8, 2003)

zal said:


> How about Park SH, with some arrow setups she has used (not only that, but she uses steel points in her X10). Plus majority of archers outside US.
> 
> There are distinct advantages with short as possible arrows, rather than leaving them long for something that might or might not have any effect on grouping.
> 
> Edit: also, how about this strapping young lad: http://www.youtube.com/watch?v=kUM5aw8oSEc


Park shows us long arrows here: http://www.youtube.com/watch?v=rIeBGcaETYw 

Have you surveyed the majority of archers outside the US? Do they include the current world's best archers? 

Pace is an all-time great, of coarse, but at least show me some modern equipment please. 

Check any video clip with Brady Ellison, all his arrows that I can see reach the target side edge of his riser. Ie, around 2" beyond the plunger. 

Don't get me wrong, I could care less about node theory, but when selecting arrows I do care that the vast majority of the world's top archers seem to prefer their arrows a bit out from the plunger. For new archers especially, why would anyone recommend a short arrow that leaves no room for change? 

Longer is better.
View attachment 1212765


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## zal (May 1, 2007)

If you actually look at that video, you'll notice that she's using long steel points and the arrows are cut very close to shelf. You could cut perhaps 1/2" more out of that arrow with that point. Tune she used earlier had even shorter arrows.

All 1300+ archers I know prefer to cut their arrows short rather than long.

We were talking about best archers in the world, of course new archers should leave their shafts long.


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## Rick McKinney (Mar 4, 2008)

Nodes. A mystical system that needs to be set right but so far I have not read anything that relates to what I know is important. Don’t forget, this is my opinion and through my experience of what I have found. Most top archers “used” to like long shafts. Easy to explain, the longer the shaft, the more stabile it is. Imagine throwing a stick. Short ones don’t fly very well. I personally have found that with “parallel” shafts you can use shorter shafts but still they are more stable when longer. The barreled shafts created a more “unstable” affect, thus the need to have the shafts extremely long. The clicker plate was introduced after the barreled shafts were introduced which required the arrow to be much longer and the Cavalier clicker that was attached to the sight allowing you to have the shaft even longer. The last archer who used a parallel shaft to win the World Target Championships in the men’s recurve division was a Korean in 1997. He used a 60 grain point and the clicker was as close as he could get it to his arrow rest. It worked but was very “uncommon”. I played a lot with short and long arrows to find the right chemistry for my setup. I shot a 1346 with the point against the plunger (yes, the point popped up on the rest) and a 1352 with a clicker plate that was about ½” in front of the riser. What I determined that was most important was the tune as most of you have stated here. 

However, the nodes are important but more in alignment with each other upon the launch of an arrow not the location. The two nodes need to be in line with each other towards the target upon launch. Obviously the compound and release have no issues with this since the launch is direct to the target and the arrow does no buckle side ways (archer’s paradox) upon release. The plunger collapses (if tuned properly) just right and this is when the two nodes need to line up. If this happens, then you have a good nodal alignment and it really does give you more forgiveness. However, I seriously doubt that most average archers will notice a 10 point gain on a FITA round, thus it is minor for most but major for the elite archer.


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## ButchD (Nov 11, 2006)

Thanks Rick,
"However, I seriously doubt that most average archers will notice a 10 point gain on a FITA round, thus it is minor for most but major for the elite archer. "
I'll work on form

"The two nodes need to be in line with each other towards the target upon launch."
This relates to plunger tension adjustment. Some day...


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## Georgemay (May 27, 2008)

ButchD said:


> Thanks Rick,
> "However, I seriously doubt that most average archers will notice a 10 point gain on a FITA round, thus it is minor for most but major for the elite archer. "
> I'll work on form
> 
> ...


You are right about the form. 1100 or less FITA archer can easily pick up 50-100 points working on the form alone. Aligning two nodes require plunger to be moved out/in or adjusting spring tension. Rick in his book 'The Simple Art of Winning' in "Micro tuning" chapter explains how to do it with all the details. 
George


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## Vittorio (Jul 17, 2003)

Theory of nodes needing to be aligned to get a forgiving setup has never been verified, as we have seen any sort of arrow flight getting top level scores in recurve. 

There are too many factors influencing the( dynamic) position of the front node, were surely the most important is the arrow lenght in front of plunger, but also and of same importance the insert lenght of the point. So, while the rule of thumb was ever "front node never in front of the plunger", I suspect that very few coaches and top archers in the world are consciously considering this rule when starting to set up a bow/arrow system. We all just base what we do to previous practical experience, not on nodes theory. 
Very few are nowdays getting a proper oscillation across the two nodes during arrow flight; majority have a snake tipe oscillation of the arrow during flight. But practical results are the same.


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## TheAncientOne (Feb 14, 2007)

Vittorio said:


> Theory of nodes needing to be aligned to get a forgiving setup has never been verified, as we have seen any sort of arrow flight getting top level scores in recurve....
> 
> Very few are nowdays getting a proper oscillation across the two nodes during arrow flight; majority have a snake tipe oscillation of the arrow during flight. But practical results are the same.


I suppose that at 70 meters the oscillations have time to smooth out and that any minor flight issues are corrected by tuning and sight adjustments.

TAO


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## zal (May 1, 2007)

You can see that snaking constantly these days with high-speed cameras. With both hobbyists and top level archers. I'm not sure if anyone's taken time to study it thoroughly yet, and where it comes from, new, faster limbs which hit with less sideways deflection or if the arrow materials have changed, without us knowing. It causes very strange clearance problems sometimes. It sort of behaves like the arrow would have three nodes.

I'm really not sold on nodes, and the issue I'm struggling with is, if you start to tune for nodes, do you actually move from tune that causes best groups, if you initially tune for groups (which all better archers do eventually). It has been verified previously that guidebook bareshaft tune is not perhaps the tune that gives best groups, maybe best nodal position doesn't either.


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## spangler (Feb 2, 2007)

Some of us are just engineers and enjoy different nuances of the sport. Sometimes we like to do things like create flight simulators or find the nodes of arrows. We just like to know how/why things work which is why we became engineers in the first place.

Some of us just think it is cool. I know I do. 

Does it help my shooting? No, spending less time coding an arrow flight simulator and more time shooting would be more effective at improving my game. Are both aspects of it interesting/enjoyable for me? Yes.


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## Rick McKinney (Mar 4, 2008)

Vittorio. I can appreciate your feelings on how unimportant the node alignment is. I tested it three times and each time I was able to prove that my performance was better with the alignment than without it. I was able to shoot over 1340 when I was able to get them aligned properly. Yes, I know that those scores are small now, but 20 years ago, they were not. I usually just averaged about 1320 without the right alignment but when the alignment was achieved and with the correct tune of the arrow and bow, I did shoot better scores. 

Some of you may misunderstand the nodal alignment versus flexing around the nodes. The two nodes are the two points that do not appear to bend when the arrow is in flight. The rest of the arrow is flexing around these two points A simple procedure for you to be able to see the nodes is take a bare shaft, preferably uncut and put a 100 grain point in both ends of the shaft. If the points are just snug it will work. If they are a bit loose, just use some rubber cement and slide the points in the shaft. Find a florescent light and put two chairs or posts or something to lay the arrow on under the light. The arrow ends should be about 1-2” on each chair. Then grab the middle of the arrow with your thumb and finger and bend it down about 3-4”. Then let go and watch the arrow flex. You will see two points that appear not to flex. Those are the node points. These node points should be equal from each other when everything is equal in weight on both ends of the shaft. The node points will move towards the weight when you start adding it. 

What many of you are seeing in your high-speed shots is the natural flex of the arrow and it does flex all the way to the target. It is the archer’s paradox. What I am talking about is something that cannot be seen other than watching the flight characteristic just out of the bow in high speed filming and also you can see the impact characteristics of the nodal alignment at the four distances. In most cases when shooting a bare shaft at the four distances you may get the impact of the arrow to hit differently at 30 meters and 70 and or 90 meters. This is due to the nodes trying to align themselves when first launched. 

I have included a drawing (please excuse the poor artistic impression – I am not an artist!). I have “exaggerated the alignments to give you an idea of what is happening. Generally speaking the actual flight pattern will probably be no more than 24” maximum difference from right to left. This is so small it would not be noticeable to the naked eye. 

Does it matter? It’s hard to say. Like Spangler states, sometimes we are just very curious as to “why”. I am not an engineer, but most tests I have taken have indicated that I am very much like an engineer when it comes to asking why. Yes, you can go overboard in looking for answers and trying to find a better way, but it has it’s place. When I was training a lot, I had lots of time to think about why these things happen and I did experiment during my training to keep from getting bored. It served me well.


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## DK Lieu (Apr 6, 2011)

spangler said:


> Some of us are just engineers and enjoy different nuances of the sport. Sometimes we like to do things like create flight simulators or find the nodes of arrows. We just like to know how/why things work which is why we became engineers in the first place.
> 
> Some of us just think it is cool. I know I do.
> 
> Does it help my shooting? No, spending less time coding an arrow flight simulator and more time shooting would be more effective at improving my game. Are both aspects of it interesting/enjoyable for me? Yes.


+1. :thumbs_up Couldn't agree with you more. The engineering aspect of the equipment was one of the biggest draws for me when I started this sport. I was fascinated by the behavior of the equipment, and wanted to understand it more. The mechanics of the equipment and shooting process are actually quite complex, for a sport that appears to be so simple. I'm still in the learning process, and probably will be for the rest of my days.


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## DK Lieu (Apr 6, 2011)

Rick McKinney said:


> Some of you may misunderstand the nodal alignment versus flexing around the nodes. The two nodes are the two points that do not appear to bend when the arrow is in flight. The rest of the arrow is flexing around these two points A simple procedure for you to be able to see the nodes is take a bare shaft, preferably uncut and put a 100 grain point in both ends of the shaft. If the points are just snug it will work. If they are a bit loose, just use some rubber cement and slide the points in the shaft. Find a florescent light and put two chairs or posts or something to lay the arrow on under the light. The arrow ends should be about 1-2” on each chair. Then grab the middle of the arrow with your thumb and finger and bend it down about 3-4”. Then let go and watch the arrow flex. You will see two points that appear not to flex. Those are the node points. These node points should be equal from each other when everything is equal in weight on both ends of the shaft. The node points will move towards the weight when you start adding it.
> 
> What many of you are seeing in your high-speed shots is the natural flex of the arrow and it does flex all the way to the target. It is the archer’s paradox. What I am talking about is something that cannot be seen other than watching the flight characteristic just out of the bow in high speed filming and also you can see the impact characteristics of the nodal alignment at the four distances. In most cases when shooting a bare shaft at the four distances you may get the impact of the arrow to hit differently at 30 meters and 70 and or 90 meters. This is due to the nodes trying to align themselves when first launched.


Another way to look at the problem is to assume that the two node points define the rigid body motion of the arrow, as if it did not flex. The best orientation would be the arrow pointed straight at the target, i.e. with the two nodes in-line. This orientation results in the least amount of re-orientation and work required for the vanes.


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## Greg Bouras (Nov 17, 2006)

DK Lieu said:


> The mathematics is usually above my head too. I just like to include it to make me look smarter than I actually am. For problems that involve a lot of math, I usually like to assign it to one of my graduate students. Engineering graduate students love math.


That's not fair Doc!


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## Greysides (Jun 10, 2009)

How does this relate to the patterns produced during walk-back tuning by having the plunger too far in/out?

Seems to me, there should be some relationship, but what?


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## Joe T (Apr 5, 2003)

DK Lieu said:


> Another way to look at the problem is to assume that the two node points define the rigid body motion of the arrow, as if it did not flex. The best orientation would be the arrow pointed straight at the target, i.e. with the two nodes in-line. This orientation results in the least amount of re-orientation and work required for the vanes.


Once you've said that a line drawn through the nodes defines the orientation of the arrow in space then you have said all there is to be said about nodes. So Rick's nodal alignment on arrow launch is really about arrow alignment on arrow launch. I think the term node causes a lot of confusion as people assign far too much significance to the word.

Greysides - Rick's nice drawing illustrates the walk back principle. If you don't have nodal (arrow) alignment then the arrow fishtails. Imaging having a moving target travelling from left to right on the drawing. The arrow impact point traces out an "S" shape as the distance increases.

I think the reality is that the effect on the arrow flight direction from arrow rotation at launch is far more significant than that from initial nodal alignment. This means that you only start trying to change nodal alignment (centre shot adjustment) following a good basic tune and is a very advanced level of tuning. For most mortals centre shot is just set via rule of thumb and not adjusted further. In this case tuning relates only to the arrow launch rotation aspect.


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## Greysides (Jun 10, 2009)

Joe T said:


> Greysides - Rick's nice drawing illustrates the walk back principle. If you don't have nodal (arrow) alignment then the arrow fishtails. Imaging having a moving target travelling from left to right on the drawing. The arrow impact point traces out an "S" shape as the distance increases.


Thanks for the answer Joe. My thoughts were more to how it would explain the direction of the lines as you walk back, /,\ , ( , ) .

/ and \ probably irrelevant for this.... ?

I can see it would depend on the wavelength of the crests which I assume would be more than the 5m walk back stages?


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## DK Lieu (Apr 6, 2011)

Greysides said:


> Thanks for the answer Joe. My thoughts were more to how it would explain the direction of the lines as you walk back, /,\ , ( , ) .
> 
> / and \ probably irrelevant for this.... ?
> 
> I can see it would depend on the wavelength of the crests which I assume would be more than the 5m walk back stages?


Rick has very nicely illustrated the combination of the first vibration mode of the arrow with what is called the rigid body mode. The rigid body mode, which can be defined by a line between the nodes, could be described as the motion of the arrow if it were not vibrating, i.e. acting as a rigid body. The tuning process, which includes adjusting the bending stiffness of the arrow, the stiffness of the button, the draw weight, and a side deflection upon release, ideally aligns the nodes so that both are in-line on their way to the target. However, the nodes can be shifted out of alignment if the button is too far out or too far in. Looking at the case of the button too far in, the arrow would be launched with the front node inside of the center-of-mass, and the rear node outside. Forgetting for the moment that the arrow is also vibrating and considering only what the rigid body is doing, the arrow would be launched pointed inside, but vanes would cause the arrow to eventually straighten and appear to "curve" back outside. The arrow doesn't actually continue to curve, but rather just straightens out and appears to curve. When the nodes have moved to be in-line, the inertia of the shaft causes an over correction, and the rear node moves to the inside of the center-of-mass. The vanes then re-correct the flight until the nodes are once more in-line, and the correction and re-correction process continues. The resultant flight is the S shaped curve in Rick's diagram. In walk-back-tuning, the ) or ( shaped pattern is the result of seeing only the initial part of the S curve, and the fact that the initial aiming point is actually on the first part of the curve. If the target was placed further away, the remainder of the S shape would appear. There will be some damping of the S curve as the arrow moves further way, so the arrow will eventually straighten out completely. Add back the vibration of the arrow, and you now have Rick's diagram. BTW, if there was significant misalignment of the nodes in the vertical direction, as would be caused by the nock point being too high or too low on the string, the result would be a vibrating arrow that corkscrews its way to the target.


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## Joe T (Apr 5, 2003)

Greysides said:


> Thanks for the answer Joe. My thoughts were more to how it would explain the direction of the lines as you walk back, /,\ , ( , ) .
> 
> / and \ probably irrelevant for this.... ?
> 
> I can see it would depend on the wavelength of the crests which I assume would be more than the 5m walk back stages?


My mistake 
Given that the sight has been zeroed there are two causes for the / \ overall pattern. In both cases the reason is the arrow is travelling horizontally at an angle to the bow to target line.

a) arrow rotation
If the arrow is launched rotating around a vertical axis then the arrow flies in a curve until the fletchings stabilize the arrow. End result is the arrow ends up travelling horizontally at an angle to the bow to target line. Direction of slope determined by the rotation direction. Arrow rotation is usually adjusted via the button spring tension (30m bare shaft tune say)
b) Initial launch direction
During the power stroke there are forces (from string and plunger) acting horizontally on the arrow. If these forces don't balance out then the arrow leaves the bow with a net lateral velocity - the arrow ends up travelling horizontally at an angle to the bow to target line. Arrow lateral velocity is usually adjusted via centre shot adjustment (walk back method following a bare shaft tune)

The curved ( ) pattern has two causes:
Already mentioned is the curved pattern from fishtailing. Both cases a) and b) above end up with the arrow nodal alignment not being in sync with the direction of travel of the arrow centre of mass - ergo fishtailing. The fishtailing frequency depends on the initial offset angle between the nodal line and COM travel direction so visually can be anything from a well defined S to a just slight curve.
The second mechanism generating a curved walk back arrow pattern is that the arrow is accelerating downwards under gravity so the drop between 20-25 yards is greater than the drop between 15-20 yards. So even if the arrow is travelling in a straight line offset to aimed direction you still get a curved walk back pattern.


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## Greysides (Jun 10, 2009)

Thank you both, Dennis and Joe, lots to digest there. It may not make me shoot any better but it's nice to understand what's going on.


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## Georgemay (May 27, 2008)

http://www.youtube.com/watch?v=JpywGv9Qg6M&feature=related

See the arrow flight at 0:30. She still shoots great, but wouldn't the grouping be better with the arrow exiting bow straight?
George


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## zal (May 1, 2007)

Georgemay said:


> http://www.youtube.com/watch?v=JpywGv9Qg6M&feature=related
> 
> See the arrow flight at 0:30. She still shoots great, but wouldn't the grouping be better with the arrow exiting bow straight?
> George


Well, she is an olympic gold medalist, shooter of women's wr and highest ever 70m 36 arrow score by any female or male archer, so maybe she groups well enough


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## Vittorio (Jul 17, 2003)

Rick, I have not said that node alignement is unimportant, I only said that many times great scores have been shot with arrow flights that are very far from those theoretically coming out from a good node alignemnt, specifically mentioning arrows flying with the "snake" pattern, instead of oscillating across the nodes. For sure, when you shoot arrows with different spine in differerent sections of the shaft, sometime very stiff in front, sometime very stiff on the back, arrow flight becomes quite different from the theoretical one. But still you can get all arrows inside a reasonable range of dynamic spine grouping very well by a "standard" tuning.


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## Georgemay (May 27, 2008)

zal said:


> Well, she is an olympic gold medalist, shooter of women's wr and highest ever 70m 36 arrow score by any female or male archer, so maybe she groups well enough



Yes, It means if you are better than anyone then you do not need to align stinkin' nodes:wink:


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## Joe T (Apr 5, 2003)

zal said:


> You can see that snaking constantly these days with high-speed cameras. With both hobbyists and top level archers. I'm not sure if anyone's taken time to study it thoroughly yet, and where it comes from, new, faster limbs which hit with less sideways deflection or if the arrow materials have changed, without us knowing. It causes very strange clearance problems sometimes. It sort of behaves like the arrow would have three nodes.


You can regard arrow vibration in flight in terms of of a coupled oscillator system (with many degrees of freedom in the jargon). For a barrelled arrow say you have the point section, a thin shaft section, a fat shaft section and then a rear thin section. Each of this sections can be regarded as a separate oscillator with its own mass and spring constant. And then of course you have the fletching action forces action on the system. The (lateral in this case) vibration of the arrow is highly complicated essentially chaotic - unpredicatable - in technical terms "a mess". Depending on the arrow construction and how it's shot (a variable) the vibrational behaviour of the arrow varies from shot to shot and in varies over time for each shot. 

There are lots of coupled oscillator simulators about ( http://www.lon-capa.org/~mmp/applist/coupled/osc2.htm is a very simple one).

So when an arrow is being shot from the bow we know from the mechanics and experiments that it doesn't have vibrational nodes. When an arrow is in flight its vibrational characteristics are continually changing (snaking seems to be the popular descriptive term) so talking about nodes is in practical terms meaningless. So why not stop confusing everybody by talking about arrow arrow vibrational nodes in the first place  .


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## ArtV (Jan 29, 2008)

I tapped several of my arrows on the edge of a table and was surprised to hear a rendition of " A White Christmas". My nod's seem to be tuned.:icon_1_lol::set1_rolf2:


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## Joe T (Apr 5, 2003)

One off or continuous play?


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## chrstphr (Nov 23, 2005)

Seattlepop said:


> Park shows us long arrows here: http://www.youtube.com/watch?v=rIeBGcaETYw



Park's X ten arrow is just shy of 26 inches from point to inside of nock. I'd say thats a short arrow. 

( Its a 550 spine and she shoots approx 44 lbs.)

Chris


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## ltfish (Oct 6, 2010)

*nodes and tuning*



DK Lieu said:


> Glad you like the uniforms! The Team designed the uniform themselves. I'm a Cal graduate myself, and had a few of my own ideas about uniforms. But the team members didn't like the idea of ski masks. Hank, if you can tolerate my Cal-ness, I can tolerate your USC-ness.
> 
> Yes, the nodes of the arrows are inside of the point and nock, on the shaft, not on the tips. In an ideal set up, the arrow will go through 1.25 cycles of the first mode while clearing the bow. Nodal "tuning" merely maximizes the clearance between the arrow and the bow as the arrow is launched. The correct frequency probably has more to do with the design of the arrow shaft itself than anything you can add (or not add) to it. History has shown that there have been some shaft models that had a reputation of being terribly difficult to tune. I wonder how much of that had to do with improper clearance due to improper frequency. I suspect that many of the shaft models we use today have survived as a product because they produced the correct frequencies.


So is it safe to assume that adjusting " plunger tension " merely allows the natural frequency of the arrow to be better matched to the bow, producing a " cleaner arrow flight " ??


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## DK Lieu (Apr 6, 2011)

ltfish said:


> So is it safe to assume that adjusting " plunger tension " merely allows the natural frequency of the arrow to be better matched to the bow, producing a " cleaner arrow flight " ??


No. Adjusting the plunger force has no affect on the natural frequencies of an arrow. Adjusting the plunger tension is akin to adjusting the stiffness of the arrow, and thereby affects the grouping of bare shafts vs. vaned shafts in the tuning process. The first natural frequency of the arrow affects how well the arrow will clear the bow. Both the natural frequency of the arrow and its stiffness must be properly matched to the bow in order to have good flight.


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## Greysides (Jun 10, 2009)

DK Lieu said:


> No. Adjusting the plunger force has no affect on the natural frequencies of an arrow. Adjusting the plunger tension is akin to adjusting the stiffness of the arrow, and thereby affects the grouping of bare shafts vs. vaned shafts in the tuning process. The first natural frequency of the arrow affects how well the arrow will clear the bow. *Both the natural frequency of the arrow and its stiffness must be properly matched to the bow in order to have good flight*.


Interesting, thanks, and Merry Christmas.


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## ltfish (Oct 6, 2010)

Great information and knowledge...Thankyou


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## Joe T (Apr 5, 2003)

DK Lieu said:


> No. Adjusting the plunger force has no affect on the natural frequencies of an arrow. Adjusting the plunger tension is akin to adjusting the stiffness of the arrow, and thereby affects the grouping of bare shafts vs. vaned shafts in the tuning process. The first natural frequency of the arrow affects how well the arrow will clear the bow. Both the natural frequency of the arrow and its stiffness must be properly matched to the bow in order to have good flight.


:thumbs_up Spot on
Note "stiffness" in this case is not the Easton spine equivalent but relates to the arrows going left or right.


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## Joe T (Apr 5, 2003)

!!!! system backup

Have to be a bit careful of what you mean by frequency. Time from launch to past bow is around 1.25 cycles in terms of the free-free vibration. However the frequency of the arrow under acceleration is lower than the free-free frequency so in terms of physical bending, cycles launch to past bow is only (net) 1 cycle. i.e. the arrow is not straight when it leaves the string (as often misquoted) but bent - fairly obvious if you consider that you need to get the string to exit the nock as cleanly as possible so the alignment and travel directions of string and nock need to match.


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## redman (Feb 22, 2003)

Does any one node tune arrows today


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## woof156 (Apr 3, 2018)

redman said:


> Does any one node tune arrows today


Old thread but interesting question and I am curious exactly what node tuning was meant to accomplish and did it accomplish anything? Does the plunger contact point make that much difference-- gee one more thing to abscess over-- I am all in.....


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## chrstphr (Nov 23, 2005)

for what its worth. node tuning gives optimal flex around the riser. Too long or too short an arrow will not flex well around the riser even though the spine is correct for the poundage of the bow. Also this does affect where the arrow pushes into the plunger. All of this together gives optimal arrow flight to target or not optimal arrow flight straight to target.

having said all that, generally if you use a clicker on the riser, you are pretty close to the nodes anyway. If you use a clicker on the sight bar, then your nodes are off and you could get a better tune having the arrow be shorter so the nodes are better.


Chris


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## DNez2001 (Sep 3, 2017)

in that context, anyone use the front hole in your riser for your plunger for longer arrows? 

Sent from my SM-N950U1 using Tapatalk


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## chrstphr (Nov 23, 2005)

DNez2001 said:


> in that context, anyone use the front hole in your riser for your plunger for longer arrows?
> 
> Sent from my SM-N950U1 using Tapatalk


Archers should. I discuss it in my tuning video.

Also the Women Korean teams do that when they shoot at Vegas. Then for outdoor they switch back to rear plunger.
I have a bunch of pictures of the whole team including Hyejin Chang using the front plunger hole on the riser. I think i posted a few on AT a few years back of that as a conversation.

Though their arrow isnt too long. They do it for quicker arrow reaction to 18 and node tuning.

Chris


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## cerelestecerele (Aug 5, 2019)

chrstphr said:


> Also the Women Korean teams do that when they shoot at Vegas. Then for outdoor they switch back to rear plunger.
> I have a bunch of pictures of the whole team including Hyejin Chang using the front plunger hole on the riser. I think i posted a few on AT a few years back of that as a conversation.
> 
> Though their arrow isnt too long. They do it for quicker arrow reaction to 18 and node tuning.


I don't think that's correct for the korean women. The year you had pictures for was 2014, but it looks like it was just a trend during 2014/15. The only data I've got is the matches on youtube, so if there were more archers using the front hole who were eliminated before the finals, i wouldn't know.

Here's the button position from all the finals I could find videos for - sometimes it's only the gold final and not both.
Vegas 2020 - Wi Nayeon, Chang Hye Jin, both with the button in the back hole.
Nines 2020 - Wi Nayeon, Kim Chaeyun, Sim Yeji, Chang Hye Jin, all back hole
Roma 2019 - Kang Chae Young back hole
GT open 2019 - *Kim Young Kyeong* with the button on the front hole and and Chang Hye Jin with it in the back
Vegas 2019 - Sim Yeji and Kang Chae Young, both with the button in the back hole.
Macau open 2019 - Ha Siyeon, Park Seon Jin, Park Sohee, all with the button in the back hole.
Nimes 2019 - Kang Chae Young with button in the back hole (vs Casey Kaufhold with a sight-mounted clicker about 3" in front of the riser and button in the back hole)
Roma 2018 - Kim SuRin back hole
Macao 2018 - Ryoo Su Jung, Jung Dasomi, Yun Mi Jin, Jeon Hunyoung all back hole
Vegas 2018 - korean women only in bronze match, not televised
Nimes 2018 - Jin Yun, Sim Yeji, Kim Surin back hole
Vegas 2017 - Song Jiyung, Jin Yun (back hole)
Vegas 2016 - Sim Yeji (back hole)
Bangkok 2015 - bronze match: *Jeon Sung Eun, Hansol Kang* - both front button hole, gold match: Sim Yeji (back hole)
Vegas 2015 - Kim Min Jung, Jo Seung Hyeon - both back hole
Vegas 2014 - *Park Se Hui, Chang Hye Jin* - both front hole
Vegas 2013 - Jeon Sung Eun, Kim Min Jong - both back hole
Vegas 2012- no koreans entered
Singapore 2011 indoor champs and earlier years - none entered


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## >--gt--> (Jul 1, 2002)

The intended purpose of the distal plunger hole was not to specifically affect the arrow tune. The archer who requested this modification (to a TD4 at the time) theorized that the location would work better with the riser mass balance and provide for less torque effect.

It was widely adopted later, specifically as a means to allow more convenient installation of bolt-on arrow rests, like the Cavalier Free-Flyte, which had widespread use at that time.

Some people do use it as another tuning parameter, but that’s not really the original intention.


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## chrstphr (Nov 23, 2005)

cerelestecerele said:


> I don't think that's correct for the korean women. The year you had pictures for was 2014, but it looks like it was just a trend during 2014/15. The only data I've got is the matches on youtube, so if there were more archers using the front hole who were eliminated before the finals, i wouldn't know.
> 
> Here's the button position from all the finals I could find videos for - sometimes it's only the gold final and not both.
> Vegas 2020 - Wi Nayeon, Chang Hye Jin, both with the button in the back hole.
> ...



it could have been a trend. And it could have been Vegas 2014. It could have been a one tournament thing as well and not tried again. I will look at my videos later tonight and see if i can see more than just Park Sehui and Chang Hyejin using the front hole and see what year it was. 

The years after that at Vegas i never had such a close seat to them shooting nor such good viewing angles. 

Chris


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## woof156 (Apr 3, 2018)

redman said:


> Does any one node tune arrows today


Jake Kaminsky has a video on it and its relevance to plunger position:






Interesting-- wish I were good enuf for this to be an issue.


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## chrstphr (Nov 23, 2005)

cerelestecerele said:


> I don't think that's correct for the korean women. The year you had pictures for was 2014, but it looks like it was just a trend during 2014/15.
> Vegas 2015 - Kim Min Jung, Jo Seung Hyeon - both back hole
> Vegas 2014 - *Park Se Hui, Chang Hye Jin* - both front hole


Not to derail the thread,
I went through my photos. Vegas 2014 five Korean ladies entered the shoot representing LH Corp.
Hyejin Chang, Park Sehui, Kim Minjung, Jeon Sungeun, and Kim Yumi.
All 5 used the front hole on the bow. Back then I think I posted Hyejin Chang and Park Sehui's riser photos.

here is Jeon Sungeun, Kim Minjung and Chang Hyejin









Jeon Sungeun









Kim Minjung









and Kim Yumi ( who shoots with a golf glove)









They possibly never did this again. But i remember i was surprised to see them all do this. I also remember these 5 ladies took the podiums at each stop that year. They all had a win or podium spot.

Chris


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## cerelestecerele (Aug 5, 2019)

chrstphr said:


> node tuning gives optimal flex around the riser. Too long or too short an arrow will not flex well around the riser even though the spine is correct for the poundage of the bow. Also this does affect where the arrow pushes into the plunger. All of this together gives optimal arrow flight to target or not optimal arrow flight straight to target.


Could you clarify what you mean by optimal flex? Here's (



) a video with a 32" and a 27.5" arrow that are both the correct spine for poundage. To my (amateur) eye it looks like they both flex well around the riser and they push the plunger in at the same time and for the same duration even though one has the node far in front of the button and the other has it far behind. Arrow flight after they leave the bow also looks pretty similar.
What am I missing?


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## chrstphr (Nov 23, 2005)

cerelestecerele said:


> Could you clarify what you mean by optimal flex? Here's (
> 
> 
> 
> ...


your video doesnt show the difference from front plunger to rear plunger nor does it show arrow flight to target at a close distance. Your video also doesnt show where the arrows landed on the target downrange.

Arrow flight down range "looking pretty similar" is because the plunger position didnt change for the arrows.

With that plunger position, the shorter arrow would do the best being closer to the nodes. 

Chris


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## cerelestecerele (Aug 5, 2019)

chrstphr said:


> your video doesnt show the difference from front plunger to rear plunger nor does it show arrow flight to target at a close distance. Your video also doesnt show where the arrows landed on the target downrange.
> 
> Arrow flight down range "looking pretty similar" is because the plunger position didnt change for the arrows.
> 
> ...


Plunger position relative to the front node changed for both arrows but the flight looked similar in that the shape (C vs S shape etc) and amplitude of the oscillations, and arrow direction of travel weren't affected.

Do you mean that instead of the arrow node position relative to the button being relevant, that it's the button position relative to the throat of the grip instead?

Moving the plunger 16mm forward wouldn't change the node being in front of the plunger for the long arrow and the node being behind for the shorter arrow.
The target was just beyond the long rod - the feathers of the longest arrow are still in the frame after it hits.
I've got outdoor range access with enough sunlight to film tomorrow so should be able to get some more suitable shots to see what you mean.


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## chrstphr (Nov 23, 2005)

cerelestecerele said:


> Moving the plunger 16mm forward wouldn't change the node being in front of the plunger for the long arrow and the node being behind for the shorter arrow.
> The target was just beyond the long rod - the feathers of the longest arrow are still in the frame after it hits.
> I've got a spare riser with a second hole and outdoor range access tomorrow.
> Arrow flight looked similar both with the node behind and in front of the button because the arrow left at the same point in its vibration cycle and had clearance.


Respectfully, test it at 18 meters where the arrow has to react some and then hit on the target. target just beyond the long rod will not be long enough for any results on arrow flight. 

I bareshaft tune to start on target at end of long rod. Results just show if arrow comes off bow straight. It has no bearing on where bareshaft will land at 18 meters or 70 meters acting weak or stiff. Same principle. 


Chris


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