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TAC 15/15i Basic Unpublished Information

 
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  #29  
Old 03-14-2011, 08:37 PM
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Join Date: Aug 2010
Location: North West Washington
Posts: 80
Re: TAC 15/15i Basic Unpublished Information

There are a number of issues that can contribute to “large” groups as compared with shooting a single projectile.

1: Not all shaft cutting equipment does a good job (or even a fair job) of making a square cut. Poorly cut shafts on either end results in forces not applied equally across the nock end of the shaft surface.

There are two good devices for addressing the task.

http://www.lancasterarchery.com/advanced_search_result.php?keywords=squaring+tool& osCsid=vr4po5mhjvagagebhnkuja8hi1


A point end cut will not allow the insert to properly seat against its rear flange. In addition, removal of material from one side of the wall and not the other introduces rotational mass instabilities that can degrade accuracy potential.


2: Improper installation of inserts (specifically, poor/uneven distribution of the adhesive) also introduces rotational imbalances related to item #1. Sadly, most shops use an epoxy compound when gluing inserts into shafts and the heat required for removal damages the epoxy binders used in most carbon composite constructed shafts. I would be tempted to cut the entire insert off and start from scratch.

An advantage to this is if you use a slow setting compound (highly suggested); you can orient all of your broadheads in the same fashion before the glue takes a set. Should you decide to do this, do not try to remove the broadhead until the complete cure time is elapsed. Many folks will start with a bare shaft, install the insert, install the broadhead and then spin the shaft point down on a hard surface and observe for a wobble. If there is perceived wobble, rotate the insert 90 degrees and spin again. When you find a minimum wobble, stop.

Then apply fletching.

3: PSE states their shafts have a standard deviational run out of plus or minus .003 inches. Read that .006 total indicated run out (TIR). No professional FITA archer would enter any contest with new shaft inconsistencies of this magnitude. FITA or Olympic competitions range out to 98 yards.

Bow hunters often believe .003 inches is pretty good; however, most modern bowhunters rarely shoot at game beyond 50 yards…and that is considered extreme distance by most.

4: Large shaft to shaft completed arrow weight deviations will not make you happy either.

The basic problem may be an ammunition one at its root.
I hope this helps,
Konrad

PS
Questions:

What is the clearance between the fletching and buss cables?

Is there actually enough room to experiment with rotating the nock without hitting the cables?
__________________
“The rifle itself has no moral stature, since it has no will of its own. Naturally, it may be used by evil men for evil purposes, but there are more good men than evil, and while the latter can not be persuaded to the path of righteousness by propaganda, they can certainly be corrected by good men with rifles.”

Col. Jeff Cooper

Last edited by Konrad; 03-14-2011 at 08:40 PM.
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  #30  
Old 03-14-2011, 09:52 PM
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Join Date: Dec 2010
Posts: 391
Re: TAC 15/15i Basic Unpublished Information

Hi Konrad,
Let me open this thread response by saying "Please don't leave us". I can't tell you how nice it is to have another member join us who understands the archery and arrow technology as well as you do. Like you, I've written numerous articles about how to properly clean shafts, or numerous other facets of building arrows, tuning shafts and set up and tuning of bows.

You may well be the third Musketeer in our trio on this forum. Super 91 is also very experienced. Much of what is being written and discussed here has many variables, so every bit of information is correct, it just depends on the application it's used in.

A couple of quick points on your last response. We would typically assume that a major shaft producer would be using good shaft cutting equipment, so I've sort of discounted that as a problem. That said, I agree with thye possibility and have seen shafts get out of balance when people try to use hand saws and cheap cit off wheels to cut there own shafts.

As I stated previously, these shafts are very unique. The straightness tolerances for these particular shafts as posted by PSE are as follows:

The TAC15 arrows takes carbon arrow design to a new level with radial X Weave technology. Incredible straightness of +- .001 the Carbon Force Pro is the straightness arrow PSE offers. A patented computer process wraps individual carbon fibers to create a weave pattern to make the arrow stronger, straighter and faster than conventional carbon arrows. Shafts are full length with inserts loose and nocks installed. Arrows are fletched with either 3" Duravanes or Blazer vanes.

The arrows are fletched in a 4 fletch configuration, but not 90 degrees per vane as usual. They use a 60 x 120 degree configuration placing two vanes close together on either side of the arrow shaft to achieve optimal flight performance.

The method you described of tuning broadheads to arrow shafts is the standard method we've used for many years. That's because when nocks are uniformly indexed to the stiff part of an arrow spine, we want the broadheads to align the same way to each arrow spine to maintain identical flight characteristics. This achieves consistent flight performance from arrow to arrow.

This has not turned out to be possible with these new fiber filament weave arrows because the spines do not align in the same manner as normal so the nocks are not indexed to the spine at all. Also the shaft compression from arrow to arrow varies considerably. This means the flight characteristics are different from arrow to arrow.

All arrows or shafts are pre-cut to 26.5 inches, so cutting down the shafts to replace inserts has not been possible. When wobble is detected in a shaft by spinning them, we typically remove the insert, discard it and replace with a new one. Then re-spin and rebalance the shaft.

Some TAC owners have been having more success by sorting their TAC15 arrows into groups based on the performance of each shaft at a long distance. Also rotating each broadhead to achieve centering at 70 to 100 yards has worked. We are still searching for ways to identify a fool proof set of tuning steps that will permit all arrows in a given dozen to perform the same for tighter groups.

Regards,

XBOW755
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  #31  
Old 03-14-2011, 11:02 PM
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Join Date: Dec 2010
Posts: 391
Re: TAC 15/15i Basic Unpublished Information

The answer to your last couple of questions is as follows:

What is the clearance between the fletching and buss cables?
The TAC arrows vanes are only at 60 degrees to the nock and are very low profile vanes (3''L x .43"H), so they have good clearance to the main bus cable.

Is there actually enough room to experiment with rotating the nock without hitting the cables?

The nocks can not be rotated. As of mid January the manufacture began gluing their nocks to prevent the nocks from moving up the carbon shafts. They do not use a nock insert the way Easton or other carbon arrow manufacturers do, so the nocks are bonded to prevent damage to the arrow shaft during the firing and impact processes. This also makes tuning and indexing very difficult unless the nocks are broken lose and re-glued.

I'm in total agreement that this is a necessary step in getting the arrows to group correctly.

XBOW755
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  #32  
Old 03-14-2011, 11:15 PM
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Join Date: Feb 2011
Location: SW virginia
Posts: 82
Re: TAC 15/15i Basic Unpublished Information

There is much to reply to here, but I've typed my fingers to a nub tonight and must get some rest for tomorrow. I will be jumping in here in the am. Good stuff right here.
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  #33  
Old 03-15-2011, 12:00 AM
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Join Date: Dec 2010
Posts: 391
Re: TAC 15/15i Basic Unpublished Information

Hi Konrad,
I thought you and our other members might find the information in this article to be of some interest and possibly beneficial. I've supplied a link that will guide you to the article. It's definitely worth the read, even if it's only a review for you.

The article shed more light on the information we've been discussing in this thread and further points to the number of possible variables we've been discussing.

Bowhunter's Guide to Accurate Shooting - Google Books


I'm not the author, since it comes from a very well written, current book that's on the market for anybody interested.

Regards,
Jon
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  #34  
Old 03-15-2011, 08:14 PM
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Join Date: Aug 2010
Location: North West Washington
Posts: 80
Re: TAC 15/15i Basic Unpublished Information

Good information and after reading I have more questions than answers.
It was my understanding that the radial weave technology was specifically invented to alleviate some manufacturer’s issues of having a stiff spot or side of a shaft (referred to as “spline”) of a carbon composite shaft. I would think that in order to really get a handle on these TAC 15 shafts, one would be required to do static spine testing around the shaft and find the spline (if any). A trip to an archery shop with a tester would be fun and cheaper than buying a tool. This way, you would know for sure whether or not you actually needed to buy one in the future. Then, mark the shaft and then investigate aligning all of the nocks to said mark. Sort the shafts by weight and then the fletching would have to be adjusted accordingly.

Regarding run out on these shafts: All of the information I have been able to uncover says they are indeed + or - .030 inches. Rolling shafts across a glass topped coffee table also reveals the truth of advertised straightness of shafts, points and nocks.

As to the use of the TAC specific nock: I wonder if the main issue is it’s compatibility with the anti-dry fire feature of the bow? I realize the factory is trying to protect itself; however, it has also cornered the ammunition market for itself using this ploy. The advertising quotes projectile speeds using 425 grain arrows. I would imagine they use this weight specifically to avoid a dry firing situation from using too light of a projectile. Over-all weight is an easy thing to correct if, after trimming, additional needs to be added.

Another question: Is the 75x105 fletching orientation for clearance of the buss cables or hardware on the bow?

As an aside, I received a reply to my inquiry regarding the use of the Blazer vane at Bohning Archery:
Konrad, the PSE TAC 15 requires a special vane configuration which is a 4 fletch in a 75 x 105 degree. This configuration can be accomplished on any Bitzenburger Jig and we are working on an adaptor for one of our jigs also. The Blazer vanes will perform excellently with the TAC 15.

Regards,

Dale Voice
VP Sales & Marketing
The Bohning Company, Ltd.
TEL : (231) 229-4247 ext 2109
FAX: (231) 229-4615




Quote:
HI, this is Len

the actual TAC vane angle is 60/120
__________________
“The rifle itself has no moral stature, since it has no will of its own. Naturally, it may be used by evil men for evil purposes, but there are more good men than evil, and while the latter can not be persuaded to the path of righteousness by propaganda, they can certainly be corrected by good men with rifles.”

Col. Jeff Cooper

Last edited by Len Backus; 03-16-2011 at 12:33 PM.
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  #35  
Old 03-15-2011, 09:15 PM
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Join Date: Feb 2011
Location: SW virginia
Posts: 82
Re: TAC 15/15i Basic Unpublished Information

Konrad, this is the issue we are in the midst of uncovering. Does the TAC-15 shaft have a definitive spine? I certainly think so. I think the biggest problem is does it only have one spine, or varying areas that make it more hard to predict the actual spine?

I happen to have a RAM QC Carbon Arrow tester. It shows that each shaft does indeed have a spine. There is no way to test to see if the spine is variable. But I will be testing and indexing several dozen shafts to get one dozen that shows the exact same spine deflection. Once I get the dozen, I will have indexed them and will fletch them so that the hump is up on each shaft in relation to the fletching and way the nock attaches to the string. I will then be shooting groups and will see what kind of groups compared to unsorted shafts I get.

I will also be testing a variety of fletching configs as well. I have tried Blazers and found that the high profile was not as optimal as the lower profile vanes. I do have a number of vanes similar to the Duravane 3-D like what comes on the TAC shaft from the factory.

Just so you will know, Firenock makes a nock for the TAC shaft as well. It is the "D" nock and works VERY well. I have since tossed all my TAC nocks and replaced them with Firenock "D" nocks. They are so much better it is not even funny. You do not have to use the lighted circuit with the nock if you don't want to. But it makes shooting them fun to see the arrow going down range. These arrows are traveling so fast it is nearly impossible to track them down with the naked eye without some sort of aid. As to the dry fire, the nock plays a part but the length of the "D" loop is the real key here. Too long and the anti-dry fire mechanism will pop up before the "D" loop passes by.

I use 60 x 120 spacing on my TAC fletchings. The picatinney rail that goes over the shaft is the main reason the fletchings are spaced that way. I talked with one guy and he was saying that he wanted to cut that part of the rail away and use a standard 3 fletch config which in my opinion will work just fine. We may do this as well just to test our theory. Let me show you a pic for clarification.



And here are a few pics of some fletchings and their spacings I was trying last year.

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