Arrow rotational energy

[Zac]

Interesting. All of mine have went in one direction.

I think the point is that no one really knows what factors play a role in which way the arrow turns. Obviously there is more going on than string direction alone. Interestingly enough I believe Rogue Bowstrings has changed the direction that they twist their strings in order to combat the left hand arrow rotation epidemic.

 

[N2TRKYS]

I'll take a shot at this. Let's see if morning coffee's working...

You put a fixed amount of energy into the arrow. That depends on your draw length, draw weight, cam profile - effectively your draw force curve, and the overall efficiency of your system (arrow plays into that too).

When the arrow leaves the string, you will begin to lose energy to friction and drag, and you will also transfer some energy from forward motion into rotation. As rotation slows, it's as you're dissipating energy via drag and friction and the overall arrow is slowing.

Remember: Energy is conserved. You put energy into the arrow with the bow, and then it is distributed into rotational and forward motion, and then transferred into the air and eventually your target.

So, to answer your original question, a loss in rotational energy (i.e. as the arrow slows down down range) does affect the total energy of the system. But, if you initially transfer less energy to rotation, that energy instead would be maintained as a (slightly) faster forward speed.

I was thinking that it had to effect the overall energy of the arrow, all be it how small. If an arrow wants to rotate left and you fletch it right(either helical or offset), it has to correct it at some point down range, ie, losing energy in doing so. That was my theory anyway.

Good discussion, guys. Good luck this season.

 

[N2TRKYS]

I think the point is that no one really knows what factors play a role in which way the arrow turns. Obviously there is more going on than string direction alone. Interestingly enough I believe Rogue Bowstrings has changed the direction that they twist their strings in order to combat the left hand arrow rotation epidemic.

Yeah, I don’t know what causes it either. In my researching it, the string reasoning was all I found. I missed the video that you posted and never read where folks had two different rotations off the same bow. Thanks for posting it.

 

[Brendan]

I was thinking that it had to effect the overall energy of the arrow, all be it how small. If an arrow wants to rotate left and you fletch it right(either helical or offset), it has to correct it at some point down range, ie, losing energy in doing so. That was my theory anyway.

Good discussion, guys. Good luck this season.

Any additional drag to induce rotation does cause frictional losses and slow the arrow down some. So yes, the more helical, the more offset, the more surface area of fletching - the more drag you get. More rotation, means more stability to overcome planing of a fixed blade broadhead, but you do lose some amount of speed which increases the further out you get from the bow.

If you were to test a reasonably practical example - build two arrows, one with a 4 fletch, offset, helical clamp, 3" length 2" height vs. small straight fletch target vanes, and equalize the weight in the rear of the arrow with a small insert of sorts - you'd see the large fletch arrow drop more as yardage increases. Test it at 30 - probably nothing. Test it at 80 or 100, you'd see it. But, the one with more drag will also give you smaller groups with broadheads.

How much it matters - up to the individual.

The more cross sectional area you have, larger fletching, you also get more wind drift too.

 

[N2TRKYS]

Any additional drag to induce rotation does cause frictional losses and slow the arrow down some. So yes, the more helical, the more offset, the more surface area of fletching - the more drag you get. More rotation, means more stability to overcome planing of a fixed blade broadhead, but you do lose some amount of speed which increases the further out you get from the bow.

If you were to test a reasonably practical example - build two arrows, one with a 4 fletch, offset, helical clamp, 3" length 2" height vs. small straight fletch target vanes, and equalize the weight in the rear of the arrow with a small insert of sorts - you'd see the large fletch arrow drop more as yardage increases. Test it at 30 - probably nothing. Test it at 80 or 100, you'd see it. But, the one with more drag will also give you smaller groups with broadheads.

How much it matters - up to the individual.

The more cross sectional area you have, larger fletching, you also get more wind drift too.

Good points and I’m aware of those. How do you think those losses would compare to the presumed losses I referenced in my question?

 

[Trial153]

John Stallone did a YouTube series with comprehensive down range arrow velocity comparisons of fletching, offsets and helicals. It then best I ever seen. Suffice to say the difference is so negligible in down range velocity lose there is no reason not go with the most helical and offset you can get on given shaft size. The testing on the different shapes/size of fletching is very interesting also.

Very well done.

 

[IdahoHntr]

I was thinking that it had to effect the overall energy of the arrow, all be it how small. If an arrow wants to rotate left and you fletch it right(either helical or offset), it has to correct it at some point down range, ie, losing energy in doing so. That was my theory anyway.

Good discussion, guys. Good luck this season.

An arrow doesn't change spinning directions at some point down range even if you fletch opposite of the natural spin of the bareshaft. An arrow that rotates left as a bareshaft, if fletched right, will immediately spin right out of the bow. The fletchings have immediate wind resistance as soon as the string is released and this force is much stronger than any natural spin of a bareshaft. You could argue that there is some slight loss of energy from this, but it would be so negligible that there really is no reason to worry about it. No human person could tell the difference between fletching with the natural spin or against it, and honestly I'd doubt you'd even see a difference through a hooter shooter. We are talking an extremely minor loss of energy.

 

[N2TRKYS]

An arrow doesn't change spinning directions at some point down range even if you fletch opposite of the natural spin of the bareshaft. An arrow that rotates left as a bareshaft, if fletched right, will immediately spin right out of the bow. The fletchings have immediate wind resistance as soon as the string is released and this force is much stronger than any natural spin of a bareshaft.

That would be great, if true. However, my test didn’t indicate that. Thus, the reason for my question. Now, does it reverse its rotation or stay with natural rotation? I don’t know the answer to that, cause I don’t have a slow motion camera.

I’ve never squared arrow shafts, nock or insert tuned, spine index, or any of the other stuff that seems to be all the rage these days without any accuracy issues.

With all that being said, it seems odd that this is the one thing that folks don’t pay attention to. Lol

 

[Trial153]

 

[IdahoHntr]

That would be great, if true. However, my test didn’t indicate that. Thus, the reason for my question. Now, does it reverse its rotation or stay with natural rotation? I don’t know the answer to that, cause I don’t have a slow motion camera.

I’ve never squared arrow shafts, nock or insert tuned, spine index, or any of the other stuff that seems to be all the rage these days without any accuracy issues.

With all that being said, it seems odd that this is the one thing that folks don’t pay attention to. Lol

I would like to see some slow mo video myself. In my experience, it does not matter which way my bare shaft is spinning, my arrow is spinning whichever way my arrow is fletched at 5, 10, and 15 feet out of the bow.

If it's already spinning with the fletchings by 5 feet, I just don't see how it could correct that fast. Not many people pay attention to it, cause it really doesn't matter, especially for a hunting application. Fletching with the natural rotation is not even something a lot of target archers do, because it's just extra work for no gain. I have fletched both directions without a lick of difference out to 80-100 yards, except for one way my field points tend to come loose more.. that's about it.

 

[Billy Goat]

That would be great, if true. However, my test didn’t indicate that. Thus, the reason for my question. Now, does it reverse its rotation or stay with natural rotation? I don’t know the answer to that, cause I don’t have a slow motion camera.

I’ve never squared arrow shafts, nock or insert tuned, spine index, or any of the other stuff that seems to be all the rage these days without any accuracy issues.

With all that being said, it seems odd that this is the one thing that folks don’t pay attention to. Lol

So you are saying that your arrow is rotating counter to your vane rotation initially? How are you determining this?

I have tested for rotation with bareshafts, never checked it after fletched. Find it hard to believe that something is able to put enough rotation on them to counter the vane direction for any time, but I guess it's possible. I do know all of my arrows out of multiple bows have gone ccw. Even with a Rogue string that is twisted up opposite. Maybe I twist my d-loop at anchor. I have talked to people who say they have seen arrows within a dozen go different directions off of the same bow.

 

[N2TRKYS]

I would like to see some slow mo video myself. In my experience, it does not matter which way my bare shaft is spinning, my arrow is spinning whichever way my arrow is fletched at 5, 10, and 15 feet out of the bow.

I had heard the same as what you’re saying, but felt like it had to change at some point. So, I tested it and it was still trying to go left with a right offset at 5 feet. Maybe it would be different with a full right helical? Idk.

 

[N2TRKYS]

So you are saying that your arrow is rotating counter to your vane rotation initially? How are you determining this?

I have tested for rotation with bareshafts, never checked it after fletched. Find it hard to believe that something is able to put enough rotation on them to counter the vane direction for any time, but I guess it's possible. I do know all of my arrows out of multiple bows have gone ccw. Even with a Rogue string that is twisted up opposite. Maybe I twist my d-loop at anchor. I have talked to people who say they have seen arrows within a dozen go different directions off of the same bow.

Yes. I tested it the same way I checked my bareshafts. It didn’t rotate nesr as much as the bareshafts, though.

 

[IdahoHntr]

I had heard the same as what you’re saying, but felt like it had to change at some point. So, I tested it and it was still trying to go left with a right offset at 5 feet. Maybe it would be different with a full right helical? Idk.

Is this factory right offset, 3 fletch? Do you know what degree? If it isn't switched by 5 feet, I don't think it is going to.. I guess this is where the slo mo camera would come in handy.

 

[Mighty Mouse]

I would like to see some slow mo video myself.

I don't think there's a noticeable benefit to clocking your arrows and fletching accordingly, but the video below does show that fletching opposite of natural rotation can cause an arrow to reverse rotation direction mid-flight (at around 4 yds in this test).

 

[IdahoHntr]

I don't think there's a noticeable benefit to clocking your arrows and fletching accordingly, but the video below does show that fletching opposite of natural rotation can cause an arrow to reverse rotation direction mid-flight (at around 4 yds in this test).

Interesting. I wonder if the speed has anything to do with it. 208 fps is pretty slow. Maybe the increased speed, creates more drag on the fletching and spins it fletching direction sooner in my case.

 

[N2TRKYS]

Interesting. I wonder if the speed has anything to do with it. 208 fps is pretty slow. Maybe the increased speed, creates more drag on the fletching and spins it fletching direction sooner in my case.

Idk. My arrow speed is 290fps.

 

[Billy Goat]

Interesting listen. Sounds like he definitely isn't a fan of extreme foc. Makes me wonder if the higher degree offset stabilizes the arrow faster than the 1 degree. That's where the additional speed would be coming from, arrow is stabilized faster and doesn't shed as much energy straightening out.

 

[Brendan]

Good points and I’m aware of those. How do you think those losses would compare to the presumed losses I referenced in my question?

Not sure exactly what you're referencing.

 

[N2TRKYS]

Not sure exactly what you're referencing.

Fletching against the natural rotation of the arrow.