Heavy arrow build thread

[DanielB89]

Ashby says the opposite. In his research you want an almost neutral arrow at impact. The twisting of the arrow through game is accomplished by the broadhead. Single bevels are a simple machine and they rotate in relation to the medium they are in. Rotation will be less in softer tissue but the harder the substrate the more torque the broadhead generates.

I can get behind this.

 

[GTel]

Ashby says the opposite. In his research you want an almost neutral arrow at impact. The twisting of the arrow through game is accomplished by the broadhead. Single bevels are a simple machine and they rotate in relation to the medium they are in. Rotation will be less in softer tissue but the harder the substrate the more torque the broadhead generates.

And Ashby and RF both use straight fletching and recommend not using helical or offset.

Sent from up in a tree

 

[Allegheny Tom]

And Ashby and RF both use straight fletching and recommend not using helical or offset.

Sent from up in a tree

But they still match the wing to the bevel.

You can ask Ashby a question on his website (Ashby Bowhunting Foundation) so I asked him about spinner inserts, arrow rotation and its effects on single bevel penetration.
I'm eager to hear his answer and I will share it when (if) he answers.

I'm still stuck on the concept of matching the fletching wing to the bevel. If arrow rotation had no effect on the efficiency on penetration of a single bevel, then why would the wing of the fletch matter?

 

[GTel]

But they still match the wing to the bevel.

You can ask Ashby a question on his website (Ashby Bowhunting Foundation) so I asked him about spinner inserts, arrow rotation and its effects on single bevel penetration.
I'm eager to hear his answer and I will share it when (if) he answers.

I'm still stuck on the concept of matching the fletching wing to the bevel. If arrow rotation had no effect on the efficiency on penetration of a single bevel, then why would the wing of the fletch matter?

I'm pretty sure they would fight against each other and cause wonkiness if they didn't match.

My earlier post was saying that I don't think arrow spin will affect penetration, that's what the single bevel is for. But arrow spin definitely helps with flight.

Sent from up in a tree

 

[Weldabeast]

If we are into building heavy foc and reading Ashby reports arrow integrity #1 so why add another potential fail point with an insert that spins? We need as much beef as possible to help keep everything together especially on a hit that isn't 100% square

 

[Allegheny Tom]

I'm pretty sure they would fight against each other and cause wonkiness if they didn't match.

Exactly. There would be a conflict of energy transfer.
That suggests to me that the spin of the shaft does contribute to the leverage of a single bevel to some degree.



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[AKMonkey]

I havent shared it yet, I want to add some bells and whistles first

. The tricky part is calculating FOC for an arrow you dont have in front of you- more specifically, calculating what the balance point will be. I've tried a couple formulas that should have worked but they are off. My bro-in-law is a math whiz and is taking a look at it to figure out what I'm doing wrong. It will basically be a fully functioning arrow calculator when I'm done. Will definitely share it in this thread as soon as its ready.

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Awesome. Looking forward to seeing it.

Can I request that you include Linkboy arrows, which are avaiable from many different vendors on AliExpress and eBay? (if you don't already have them in your spreadsheet). They are now offering shafts with spine up to 250, at pretty good prices. I've used both their standard layered construction arrows and their 3K woven fabric shafts, and find that they shoot pretty well.

 

[AKMonkey]

Exactly. There would be a conflict of energy transfer.
That suggests to me that the spin of the shaft does contribute to the leverage of a single bevel to some degree.



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I've always thought that matching up the fletch rotation with the single bevel just helps the head initiate its rotation immediately upon impact with the target, instead of wasting energy reversing the arrow rotation that the vanes or feathers have already established in flight. Suddenly reversing the rotation also seems likely to unnecessarily flex the arrow in some wonky way, further sapping energy.

My first reaction to the spinning inserts when I saw them on the Ethics website was that it seemed like you'd lose whatever rotational momentum the arrow might otherwise contribute to rotation of a single bevel head as it penetrates. It seems like spinning the arrow independently of the broadhead might be useful for double bevel heads that might be slowed by the rotation, but counterproductive for single bevel heads, that can harness that rotational momentum. I don't know how much energy that would be - maybe its just a pop tart's worth (new rotational force unit of measure!). Maybe its more.

I asked Hoss at Ethics this very question by email. He assured me that the spinning inserts helped single bevel heads rotate better, but didn't offer any test data or other evidence. I'd like to see some controlled experiments comparing penetration and rotation by otherwise identical single and double bevel heads mounted on static and rotating inserts.

 

[ericabbott]

I have read the claims. I just can't believe them though. I can't believe that centrifugal momentum isn't stopped the moment the broadhead gets deep enough for both sides of it to touch tissue. I would have to see some form of test on this to believe this claim.

As far as my reference to a pop tart, that was just a material that I believe would split - much like bone - but still have a little rigid.

Sounds like a super scientific and technical study.

I don’t have a test case on a live animal (yet) but shot some single bevels (Maasai 200 & Cutthroat 250) through the front elbow joint from a deer leg, the arrow split the bone and still drove almost fully through the block target behind it, with little deflection. And I was using my old setup of a 340 FMJ with the HITT (or SH*TT insert as RF likes to call it). I’m planning a retest with my new setup, a 250 spine arrow with the 180 grain Ethics insert/footer and expect equal or better performance. A block target obviously isn’t tissue, but it does give me confidence that a single bevel will drive through any bone in the front end of a whitetail and still get good penetration afterward.

Edit: I’m shooting 73 lb Hoyt Defiant

 

[Allegheny Tom]

I've always thought that matching up the fletch rotation with the single bevel just helps the head initiate its rotation immediately upon impact with the target, instead of wasting energy reversing the arrow rotation that the vanes or feathers have already established in flight. Suddenly reversing the rotation also seems likely to unnecessarily flex the arrow in some wonky way, further sapping energy.

My first reaction to the spinning inserts when I saw them on the Ethics website was that it seemed like you'd lose whatever rotational momentum the arrow might otherwise contribute to rotation of a single bevel head as it penetrates. It seems like spinning the arrow independently of the broadhead might be useful for double bevel heads that might be slowed by the rotation, but counterproductive for single bevel heads, that can harness that rotational momentum. I don't know how much energy that would be - maybe its just a pop tart's worth (new rotational force unit of measure!). Maybe its more.

I asked Hoss at Ethics this very question by email. He assured me that the spinning inserts helped single bevel heads rotate better, but didn't offer any test data or other evidence. I'd like to see some controlled experiments comparing penetration and rotation by otherwise identical single and double bevel heads mounted on static and rotating inserts.

You are pretty much saying the point Im making.
I would like to hear Hoss' explanation how a spinning insert HELPS single bevels.
I can understand if it turns out that spinners make little, or no negative influence, but BETTER for single bevs?
I sure hope Dr Ed addresses my question. I'm going to trust what he says. There is nobody on the planet who has more real life experience with this stuff...AND HE ISN'T SELLING ANYTHING.

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[loujo61]

High speed broadhead video

www.archerytalk.com

Click on the this AT link and the thread and video will come up

 

[michigandrake]

Exactly. There would be a conflict of energy transfer.
That suggests to me that the spin of the shaft does contribute to the leverage of a single bevel to some degree.



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You are spot on. The arrow can contribute .... for or against .... but the idea (for perfection) is to not let it.

 

[Allegheny Tom]

High speed broadhead video

www.archerytalk.com

Click on the this AT link and the thread and video will come up

Interesting.
I wonder why the number of rotations varies from a left helical to a right helical? The right helical always rotated (clockwise) substantially less than the left helical.
But even the bare shaft had a natural clockwise rotation. It appears that an arrow (shot from a right hand bow in the video) naturally wants to rotate clockwise, so why would it actually rotate a lesser amount of revolutions than the left helical? I mean, if an arrow (bare shaft) already wants to rotate clockwise, then why does (right wing fletched) arrow produce fewer rotations than a left rig?

It would have been interesting if the video would have demonstrated the differences (if any) in penetration with the various combinations of bevels and fletch wings.

 

[woodsdog2]

But they still match the wing to the bevel.

You can ask Ashby a question on his website (Ashby Bowhunting Foundation) so I asked him about spinner inserts, arrow rotation and its effects on single bevel penetration.
I'm eager to hear his answer and I will share it when (if) he answers.

I'm still stuck on the concept of matching the fletching wing to the bevel. If arrow rotation had no effect on the efficiency on penetration of a single bevel, then why would the wing of the fletch matter?

I am very interested in Ashby's response to your question as I am considering spinning inserts as well.

 

[GTel]

Interesting.
I wonder why the number of rotations varies from a left helical to a right helical? The right helical always rotated (clockwise) substantially less than the left helical.
But even the bare shaft had a natural clockwise rotation. It appears that an arrow (shot from a right hand bow in the video) naturally wants to rotate clockwise, so why would it actually rotate a lesser amount of revolutions than the left helical? I mean, if an arrow (bare shaft) already wants to rotate clockwise, then why does (right wing fletched) arrow produce fewer rotations than a left rig?

It would have been interesting if the video would have demonstrated the differences (if any) in penetration with the various combinations of bevels and fletch wings.

The video in post 7 and his explanation in post 12 explain why it rotates faster for left helical - because of which direction the string and serving is wound. I read the opposite, in that the arrow naturally turns counterclockwise for him (and for most bows). Seems to me that if you want the arrows to spin as fast with a right helical, you need to have the the string wound counterclockwise, which is the opposite of the default way most bows are setup. Whether it impacts penetration or not is a great question.

Sent from up in a tree

 

[loujo61]

The video in post 7 and his explanation in post 12 explain why it rotates faster for left helical - because of which direction the string and serving is wound. I read the opposite, in that the arrow naturally turns counterclockwise for him (and for most bows). Seems to me that if you want the arrows to spin as fast with a right helical, you need to have the the string wound counterclockwise, which is the opposite of the default way most bows are setup. Whether it impacts penetration or not is a great question.

Sent from up in a tree

Yup that's the theory, how you have the loop attached might make a difference too.

 

[Allegheny Tom]

I am very interested in Ashby's response to your question as I am considering spinning inserts as well.

His Foundation did answer me already, but they did not really understand what I was asking, so the answer doesn't apply. They thought I was asking if the arrow rotation is what caused the single bevel to torque. That is not what I'm saying. What I wonder about is about the stored energy of the shaft rotating. Where does that centrifugal energy go upon impact? I'm assuming a spinner has some effect. Positive or negative, I don't know.
Hey, if a spinner helps a single bevel, even if its only 1%, then I'm all-in. If there is no benefit or even a negative, then why spend the money on them.

 

[loujo61]

New slow motion video - Arrow vs Water Jug

www.archerytalk.com

Found some more of nestly's videos that might interest Yous

 

[KyleND]

Not sure if this was already stated or not and not sure if I'm sold on the spinning insert either.
I am thinking because the head can spin freely from the shaft when broadhead impacts tissue it does not need to try to SPIN the Entire shaft also. So no energy is lost trying to spin shaft though tissue instead all energy can be focused on pulling arrow through. When broadhead meets a rib or other bone since it spin freely from shaft maybe it allows broadhead alter it's S cut pattern to make a pass though easier.
That all sounded very SMRT in my head anyway haha.

 

[loujo61]

The blades of the broad head slow down the rotations, i'm thinking that the theory is with a free spinning insert the shaft will have more rotations during flight. Don't know about energy transfer and rotation but you can see in the video that even a water substrate stops the rotation quickly. The bevel is going to spin when it hits flesh, it doesn't seem like it would take much energy to stop or change the rotation of the arrow.