TAC 15/15i Basic Unpublished Information

[jon.henry755]

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

 

[jon.henry755]

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

 

[Super 91]

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.

 

[jon.henry755]

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

 

[Konrad]

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

HI, this is Len

the actual TAC vane angle is 60/120

 

[Super 91]

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.

 

[jon.henry755]

Hi Konrad and Super 91,
Thanks for keeping the thread going until I had time to add my two cents, as usual.

Konrad,
The gentleman from Bohning was just slightly off his details. The Bitzenburger nock receiver used by PSE (Carbon Force) is the product #3012. I've spoken directly with the owner of Bitzenburger and with the PSE Customer Support Engineers to validate this. The #3012 is a 4 fletch receiver that spaces at 60 x 120 and PSE has their jigs set with no offset, so it's a perfectly straight fletch.

I have two Bitzenburger Jigs set up with these 4 fletch receivers, so I can reproduce identical fletching to that of the factory. It requires moving the Bitzenburger single BB in the receiver to the rear most position and then putting the set screw back in place.

Like you and Bob, I'm not a fan of the PSE Nock and also agree that between these shafts and their nocks they are holding all the cards and taking huge advantage of it while it lasts. This may be why they have been very tight on releasing many details about the entire TAC15 product line.

I would love to see somebody come out with a nock and a uni-bushing as used on XX78's, Easton ACC's or Easton ACE's to prevent nock alignment problems and support easy rotation and tuning of nocks.

Super 91 and I are both aware that the special nocks that PSE uses on their TAC arrows leave a great deal to be desired. Alignment is one key concern and the other is the nock seems to lose its memory after enough shots. By this I mean that it initially holds onto the string fairly well, but it loses its shape for a snug fit after a couple dozen shots and then has an undesirable loose fit. As we all know, this should never happen, but especially not on nocks that are selling for $25 per dozen.

As Super 91 stated, he's recently begun static spine testing the TAC shafts with his RAM Carbon Spine Tester. Although the readings are all over the place with multiple stiff points, that's not unusual for certain types of carbon shafts. One spot around the circumference of the shaft should test slightly lower than any of the other readings, even if it's only lower by .002. For that arrow, this spot will be the stiff part of the spine and needs to be marked for both indexing the nock and alignment of the vanes.

We know the manufacture is not pre-sorting their shafts by spine deflection, they are not spine testing the arrows and they are not indexing their nocks to anything other than their spray on TAC labeling. The spray on labeling is what they've been using to align their nocks and vanes to on the shaft.

All this said, it would clearly be easier to build our own shafts from scratch, but until very recently PSE was not selling raw shafts for these XBOWs and as you've already stated most people don't have access to a carbon arrow spine tester.

If Bohning, Bjorn or Beiter comes out with a nock that will handle the force of the TAC15i, I would be very interested. I'm fairly confident that any good nock that is enlarged to fit the thickness of the PSE TAC Cable will depress the anti-dryfire lever to allow it to work properly. That's theory, not fact because I haven't tested it out to verify it, since only Firenock has come out with a replacement product.

If a manufacture is going to mass produce nocks, the shaping of the injection mold for the plastic is easy to shape to accommodate extra length if needed.

Regards,


Jon

 

[Konrad]

I am currently in touch with Easton Technical Products concerning all of the arrow issues we have been discussing here. While one many not save any money, I believe the Easton Full Metal Jacket Dangerous Game model shaft will serve quite nicely in this application.

I have NOT received a confirmation on my suspicion as yet (you know how e-mailing goes with tech types) but will pass on any data as soon as I receive it ether positive or negative.

As to the loose nock condition: My testing with both recurve and compound bows shows a nock that has a slight "snap" as it goes onto the string but has enough room to rotate the string (or in this case cable) without disturbing the arrow when it is hanging freely from the string actually provides a much more consistent/accurate/small group.

More issues to address: My understanding is that the TAC is using the Carolina Archery Products, now Trophy Ridge Whisker Biscuit arrow rest. That alone should provide for considerable stability while an arrow is loaded and waiting to fire without undue concerns for the arrow becoming dislodged.

Another accuracy issue often faced by numerous Biscuit users is incorrect sizing of the whiskers to the shaft. The manufacturer suggests a small amount of clearance between the top of the shaft and the top of the whiskers for optimum accuracy. In the TAC owner's case, some prudent trimming may be required. I don't know. Please inform me as to what you guys find with the TAC arrows.

One would suppose everything would be the correct size as all of the components originate from the factory???

http://www.trophyridge.com/arrow-rests/whisker-biscuit/

Please follow the above attached link and look in the lower right hand corner of the page for a good graphic of what I am trying to describe.

The quest continues…

PS My old Bitzenburger has settings for 120, 90 and the 75x105 degree positions by loosening or tightening the appropriate set screw using the same nock receiver.

 

[Konrad]

Another point: Many tests have shown it next to impossible to properly stabilize an arrow with a fixed blade broadhead and straight fletching. As in rifle or pistol ballistics, rotation is required for optimum accuracy. Straight fletching only provides for drag at the rear of the shaft and may be sufficient for field tips but will be insufficient for optimum accuracy with blades at extended ranges regardless of the broadhead used.

 

[jon.henry755]

Hi Konrad,
Once again thank you for your help and input. If nothing else it clearly points to additional possibilities that are worth digging into.

I'll be very interested in hearing what comes back from Easton Archery on their Full Metal Jacket Dangerous Game shafts. My guess is that they've never tested these shafts with this particular crossbow, but that can always arranged and might be a very worth whiled test.

Like you, my Bitzenburger Jigs have the same 3 positions that you've outlined, however your nock receiver is only one of a number of receivers that Bitzenburger makes and sells. You are correct in that you are using the 75 x 105 position on the jig, but when you install the #3012 Nock Receiver it changes the rotational settings of that position to 60 x 120. PSE ordered 100 jigs from Bitzenburger with the #3012 Nock Receiver pre-installed. That's how we know exactly what they are using. The receicer is only about $15. each and anyone can order them direct or through Bowhunters.

Below From Bitzenburgers Website:
Bitzenburger Nock Receivers

Bitzenburger interchangeable nock receivers are precisely indexed for 120 degrees 3 fletch, 90 degrees 4 fletch, 75 degrees x 105 degrees 4 fletch and 60 degrees x 120 degrees 4 fletch. Many models are available to match your fletching and shooting style. Nock receivers fit all Dial-O-Fletch jig frames.
Nock Receivers Available With Jig
Cat #3000 Straight (or standard) Nock Receiver
Indexed at 120 degrees, 90 degrees and 75 degrees x 105 degrees
Recommended use: Straight Clamp
Cat #3002 Right Nock Receiver
Indexed at 120 degrees, 90 degrees and 75 degrees x 105 degrees
Recommended use: Right Wing Clamp
Cat #3004 Left Nock Receiver
Indexed at 120 degrees, 90 degrees and 75 degrees x 105 degrees
Recommended use: Left Wing Clamp
Optional Nock Receivers
Cat #3006 TMStraight Nock Receiver
Indexed at 120 degrees for cock fletch up or down
Recommended use: Straight Clamp
Cat #3008 TMRight Nock Receiver
Indexed at 120 degrees for cock fletch up or down
Recommended use: Right Helical Clamp
Cat #3010 TMLeft Nock Receiver
Indexed at 120 degrees for cock fletch up or down
Recommended use: Left Helical Clamp
Cat #3012 60 x 120 Nock Receiver
Indexed at 60 degrees x 120 degrees 4 fletch (for maximum fletching clearance)
Recommended use: Any Clamp


The majority of the arrow flight problems that we've been discussing are not unique to the TAC arrows when using broadheads. I understand and agree totally with your comments about broadheads magnifying flight problems, but please keep in mind that what Supper 91 and I are describing to you are arrow to arrow flight inconsistencies with the 85 grain field points.



When you zero in at 60 yards with a single arrow, so you are centered on the bullseye (1" dot) at that distance you can either get same hole type accuracy with each shot (as long as you are shooting the same shaft) or very close to it, with the subsequent holes touching one another. As soon as you change to another arrow, the shots widen to 3" at 60 yards and they can spread to 6 to 9" at 100 yards. That would not be so surprising if the accuracy wasn't so solid with a single shaft and repeating the shots with only one shaft.


Can you imagine how ridiculous it sounds to be complaining about 3" groups at 60 yards with a crossbow? I guess you have to shoot a TAC 15 to understand it, but that's the deal.


Again, thanks for all your help and input. Friday is supposed to be very mild and no wind, so I'm planning on spending a good part of the day shooting and recording some of my results. I'll definitely look into the Whisker-biscuit sizing and trimming, since I don't have much experience with them as a rest.


I'm a Bodoodle fan and have shot the 535 for years. I use these rests for my hunting and 3-D competition bows, but I have other rests I prefer for competition set ups.


Regards,




Jon

 

[Konrad]

Out of morbid curiosity, what is the average static spine deflection you guys are getting when testing the shafts? Exactly how is this testing device using the industry standard of a 29 inch arrow with supports 28 inches apart and a 1.94 weight hung from the center?

Also, if the bow has a 155 pound draw weight and the TAC15 arrows weigh 425 grains completed, that translates into a VERY light 2.74 grains per pound of draw weight. I wonder if shaft integrity has been sacrificed at the alter of velocity?

 

[Super 91]

Konrad, The RAM tester has the 28" span along with the 1.94 pound weight, but since the TAC shaft is only 26.25" it conforms to none of the charts. I am spanning 24" approximately and still using the weight. But when I record the spine it is for my own references only.

But according to my testing the spine seems to be around 80 or heavier even though the shaft is light in overall weight. So I think the shaft integrity is still there, but as you said, the weight is not which ups velocity.

 

[Konrad]

Woof!
You are right, 80 is pretty stiff.

Does the phrase "Grasping at straws" mean anything to you? The reults you describe do continually point back to wide shaft tolerances.
Still waiting on another response from Easton.

Have fun at the range,
K

 

[jon.henry755]

Hi Konrad,
Without getting into to much detail it's necessary to test carbon spines with the fletching, nocks and inserts removed. The best testing should be done with new raw shafts for the most accurate results.

I'm not sure if that's ever been done, since until the last couple of weeks PSE has only ever sold finished arrows.

In the next couple of weeks we are hoping to receive a couple dozen raw shafts that we can begin testing from scratch.

The testing on the current arrows which is still very valid needs to be with all components removed and all that' necessary is to test for the stiff side of the spine. Once this has been done, one can easily determine on each numbered shaft if the nock and vanes had previously been applied consistent with the location of the stiff part of the spine.

If not, issues identified and spine problems proven. The fix then becomes obvious.

No question we should then be challenging everything else about these arrows, such as the nocks fit to the arrow shaft and all of the other points that have been made in this thread. At that pint we have a major manufacturing problem that the maker will need to resolve before most people will touch their products.

To match proper deflection you need 28" of testable arrow shaft, but truthfully there aren't any deflection charts for these arrows because of the length of shafts and the pull weight of the xbow. Nobody has ever produced a spine deflection chart that goes up that high, so we're in no-mans land with that data.

Your weight ratio calculation seems correct to me, but please keep in mind that unless the static spine testing is done with all components removed the readings are not very useful.

If you drop below 9 grams per inch of arrow weight, it will void most manufactures limb warranties on regular compound bows. We've seen some of the IBO competitors do this, but there's always a risk and trade off when it's done. I can't speak to the weight ratio on these arrows until I have more specific readings from the spine testers. It seems unlikely that PSE would have invested the time and money to have their own arrow making division produce shafts that were that far out of spec. for their crossbows, but stranger things have happen?

Regards,

XBOW755