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Discussion Starter #1
Hello

Got trial versions of TAP and OT2.

Entered my Bow for computations getting totally different readings from tap and OT2

here is my specs

07 Drenalin
28" 70#

Carbon Express Maxima Hunter 350 26.625 raw shaft
9 grain wrap
3-5grain Flex fletch flash vanes
13.1 grain Beiter Nock
4 grain Bulldog collar
12 grain insert
10 grain insert weight
100 grain broadhead


First is TAP with hunting setting...showing just weak spine barely
Second is tap with target setting showing just stiff spine barely...which is perfect for me using my bow as both target and hunting rig...wanted to be just between the two...thinking im all good...

third is OT2 with the both (target and hunting) setting chosen...showing very stiff spine...

unsure if i set all the settings correct in the fields or what...but if i did it all correct and they are this different then whats the point of getting software if they can say whatever they want...

some help please...

thanks in advance from anyone that helps...

hopefully ill get some input from TAP or OT2 themselves...
 

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I would have to say you are putting something wrong in TAP, since I ran it through OT2 also and it showed the same as yours , extreme overspine. I would have to agree with the overspine since that is a .340 spined arrow and being that short makes the static extremely stiff. Hopefully the guy that does the program for TAP will get on here and figure out what went wrong. I have seem the two programs differ a little but not to this extent. They are both good programs.
 

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Discussion Starter #3
I would have to say you are putting something wrong in TAP, since I ran it through OT2 also and it showed the same as yours , extreme overspine. I would have to agree with the overspine since that is a .340 spined arrow and being that short makes the static extremely stiff. Hopefully the guy that does the program for TAP will get on here and figure out what went wrong. I have seem the two programs differ a little but not to this extent. They are both good programs.
i hope not cuz that is why i cut my arrows...cuz of tap...
 

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Discussion Starter #4
If I plug in Maxima Hunter 250 with 100 grains it gets me close to perfect...that doesnt seem right to me...
 

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You got it right! ;) Can't go wrong with your selection. Here's a bit of advice for you. If you get a discrepency like this, you can always revert back to the charts (paper) to see what they say. If you do this you will see that Carbon Express also suggest the 350 @ 27" and they say you can use the 250 @ 26" in target.

If you notice in TAP changing the arrow weight, tip weight is all very granular...meaning it also changes the spine graph in equally granular draws. It is possible in OT2 (I dont know for sure) that changing your arrow lenght just as little 1/2 inch might put you right in the middle from too stiff....(TAP used to be that way in the early stages of development when it was mostly chart based, now it is 100% my own algorythm and displays slight changes slightly!)

I stand behind this recomendation with 100% certainty as the correct arrow.
 

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TAP will probably get on and tell you his thoughts, but I think with your arrow length being only 26 inches you could get away with a 400 spine arrow.
 

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I didn't see where TAP compensated for weight on the back of the arrow. Thie weight on the back effectively stiffens the arrow. Did I overlook it or is it on another sheet. That could be why if not.


But since TAP already answered, you can ignore me.
 

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Discussion Starter #10
You got it right! ;) Can't go wrong with your selection. Here's a bit of advice for you. If you get a discrepency like this, you can always revert back to the charts (paper) to see what they say. If you do this you will see that Carbon Express also suggest the 350 @ 27" and they say you can use the 250 @ 26" in target.

If you notice in TAP changing the arrow weight, tip weight is all very granular...meaning it also changes the spine graph in equally granular draws. It is possible in OT2 (I dont know for sure) that changing your arrow lenght just as little 1/2 inch might put you right in the middle from too stiff....(TAP used to be that way in the early stages of development when it was mostly chart based, now it is 100% my own algorythm and displays slight changes slightly!)

I stand behind this recomendation with 100% certainty as the correct arrow.
Thanks for the response...i may have done something wrong with my bow in the OT2...
 

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CE weight adjusts
70
+8 high energy cam
-5 65-80%
-5 110-120 gr point
+1 26"+
==
69

From the CE charts...

Hunting
26"= MAX250
27"= MAX350

Target
26"= MAX250
27"= MAX250


TAP recommends
target=0.3476
hunting=0.3273


OT2 at specs
target=0.4195
both=0.4111
hunting=0.4026

OT2 removing all weight from string and back of arrow
target=0.3852
both=0.3767
hunting=0.3683

OT2 removing all weight from back including fletch
target=0.3776
both=0.3691
hunting=0.3607


The CE hunting chart indicate you're on the border between the 350 (0.337) and 250 (0.417) Maxima shaft sizes. The CE target chart shows the 250 as the choice, but close to the 350 cell.

In OT2, small changes to shaft length, nock weight, point weight, etc. all affect dynamic spine. If you change 0.1" in shaft length or 1gr in point weight, you'll see a change to dynamic spine.


Observations...

You used 27gr for peep weight, Your sig lists G5 Meta peep..depending on aperture size those range from 3.5-6.5 grains. Your first post listed 9grs for wraps, but that number isn't in the wrap field on the OT2 screen grab. That's going to make a small difference in the spine calc.

As mentioned above OT2 takes into account weight on the nock end of the shaft. Weight added to the nock end of an arrow stiffens dynamic spine. It's possible that TAP does not take nock end weight into account...so that could be causing the difference in spine recommendations you're seeing with the software.

You list a drop away. The software doesn't take rest type into account, but I've noticed on my personal bows with dropaways that they prefer a slightly stiffer arrow as compared with the exact setup with a launcher style or full capture rest.

Check your Dren for cam lean by laying an straight edge...like an arrow..on the cam. Does the straight edge align with the string or does it point away from the string to the left when looking from the back? If there is cam lean to the left, your Dren (if it's like mine used to be) will prefer slightly stiffer shafts.

Have you determined by testing whether the 350s are indeed spined right for your Dren..IE shooting a fletched shaft and a bare shaft or shooting a fletched shaft with a field point and a fletched shaft with broadhead to see were they impact relative to each other?
 

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Discussion Starter #15
I havent tried to tune recently but I had my BH hitting within 2 inches of FP so just adjusted for hunting...

I plan to do more tuning when i change my string...all my shooting actually showed weak spined shafts...Bareshaft to the right ...nock left tears...

I think i need to adjust my idler wheel lean...

I had the arrows shooting well last year...but changed strings and i dont think i had everything tuned just so...

Thanks for everyones help...looks like i am right on the border of shooting the 250 and 350...hmmm...

hopefully i can get this bow shooting tacks again...
 
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