Arrow tuning findings ---> Come be a part of an arrow tuning study.

[DanielB89]

I have noticed over the years that I have some findings that may not be what some others have found and I would like to test a scenario to see what others experience. 

(I will do my best to describe and i'll also give an example)


Scenario #1 (this scenario will work well with an arrow that is trimmed some). 
Take an arrow that is tuned for your bow.  One that naturally hits middle AND flies straight with a broadhead to the same area; no tail wag, dropping, etc.  Just straight in flight. Now, take an arrow that everything is the same, except longer.  Shoot them and see where the longer arrow naturally hits. 

EX:  I have some .400 spine GT arrows that I bare shaft tuned and had it hitting where it needed to be, flying straight both naked and especially fletched! 

The arrow length ended up being around 31".  Now These particular arrow shafts come 32".  I have the exact same shaft that is full length with same wraps, feathers, inserts and tip weights.  I have shot them quite a few times and was surprised with what I was finding.  I plan on trimming a little more off of another shaft this evening and seeing what the results there are as well.  So today I'll be able to test 3 different shafts.  1 will be full length(not touched tuning wise).  1 will be trimmed 1" and tuned to the bow.  1 will be trimmed 2" and a little stiffer on the bow. 

I hope some of you will join me as if i'm the only one finding it, i've got to be the problem!

 

[McDave]

In your examples, you used arrows that are 1” different.  Would you prefer that we use arrows that are 1” different in our tests, or do you care?

[ozy clint]

i have found in my experience that the relationship between shaft length and dynamic spine is non linear. that is, the shorter you trim the stiffness increases at a much faster rate. for numbers sake- a shaft might be tuned at a certain length and point weight. chop it an inch and it might need 50gr more point weight. chop another inch and it needs more than 50 gr. chop another inch and you need an additional 300gr.

[Bldtrailer]

I have found that the Goldtip trads have a spine difference  a soft/weak side and a stiff heavy side . So now I tune each shaft by flexing, then bare shafting, turning the nocks as needed to group with known tuned arrows. each shaft is footed and wrap or paint added just not fletched till the above. It really helped ridding me of  those flyers that will not group.

[ozy clint]

i found the same thing with gold tips. i then switched to axis.

[McDave]

i have found in my experience that the relationship between shaft length and dynamic spine is non linear. that is, the shorter you trim the stiffness increases at a much faster rate. for numbers sake- a shaft might be tuned at a certain length and point weight. chop it an inch and it might need 50gr more point weight. chop another inch and it needs more than 50 gr. chop another inch and you need an additional 300gr.

I've found the same thing.  Probably the effect on spine of shortening the shaft is exponential, but I don't know what that exponent is. 

I suspect that the effect on spine of increasing point weight is proportional, rather than linear or exponential.  For example, to get the same effect on spine of increasing a 100 grain point to 125 grains, you would have to increase a 200 grain point to 250, a 300 grain point to 375 grains, etc.

[Gdpolk]

Part of the problem may actually be that Gold Tips really don't have a very consistent spine.  They are tough as nails and I like them, but their consistency in spine is pretty poor (at least in the Traditionals line).  When I build arrows I spine test every shaft with a dial indicator and make sure to get the cock feather aligned with a consistent spine reading so that all of my arrows flex around the riser the same amount upon release.  After that a combination of good tuning, high FOC, feathers, and fast recovery times from carbons seem to take care of the inconsistencies in spine within each individual shaft.

[DanielB89]

McDave:
I am fine with you using whatever your like.  Just share your findings.

Here is a pretty good review of arrows spines consistency.

[DanielB89]

Another example of how you could do this test would be just to shoot at a close distance(20 or less yards) and shoot 2 arrows with two different head weights.  1 could be a 150 grain, the other could be a 250 grain.  I am just curious as to where the arrows will hit in reference to where you're tuned arrows hits. 


I have been finding that on my shots, a weaker FLETCHED arrow will actually show stiff in the location that it hits on the target, and to take it 1 step further, if you shoot it with a broadhead you'll get a true reading instead of the false one previously mentioned.  I know it has baffled me over the years when tuning.  I am trying to see if it is just me, or are there other crazy people out there too.


**After doing some filming yesterday, I noticed I have a pretty bad pluck at this time.  Which could be a cause of some of my findings. **

I look forward to hearing your findings.