I am new to bowhunting and have recently started fletching my arrows. While fletching I have wondered about some things and I haven't really seen these topics discussed here so I thought I would ask.
Is there a best distance for the fletching from the nock? I was thinking that if you move the fletches far enough forward, but not far enough tohit the rest, it would move more weight FOC and that would be good, right?
Is there any advantage to having offset fletching and by this I mean have each fletching a different distance from the nock?
This question is not related to fletching so much but, if you have an arrow that is fletched so that it spins a great deal after leaving the bow what happens to the momentum/KE when it hits the deer and stops spinning immediately? Does the energy from the spinning motion get tranfeered to the forward motion (I would think not) or does it have some negative affect on the forward motion?
Thanks in advance for any help with these questions.
__________________
Nature does nothing uselessly.
- Aristotle -
Distance from the nock: arrows are drag guided, meaning the fletching provides drag on the back of the arrow which keeps it flying straight. The fletching will work better the farther back it is. That being said, moving it and inch or so up or back will have no measurable performance impact. Most archers I know set their fletching as far back as they can without having it contact their face at full draw.
Offset or staggered fletching: People have tried this for a number of years with mixed results. All in all I don't see any real benefit to it.
There is no real negative impact to the arrow stopping rotation on impact. Any benefit that you would gain from an arrow that did not spin in flight would be negated by the fact that it would probably not be accurate. No arrow is built perfectly nor is it areodynamicly perfect. If the arrow did not spin, any small misalignment of the broadhead or vanes would cause the force due to air pressure to be applied to that side of the arrow during the entire flight, causing it to veer off course. By spinning, any misalignments or inconsistencies are applied at all angles during the arrow flight, in essence averaging out any inconsistencies. As for it's effect on penetration, theoretically there is some small impact on overall penetration, however it is probably so small that it is not measurable.
Since they are drag guided it would seem you would get more spin from four fletches as opposed to three but most arrows I see only have three. Is there a give and take relationship between number of fletchings/arrow spin and speed of the arrow? Do more fletchings slow the arrow?
__________________
Nature does nothing uselessly.
- Aristotle -
Adding more fletches while it does add more drag surface also adds more weight to the back of the arrow.
More weight obviously means less speed and being in the back it can also have some effect on FOC.
That being said, using 3 fletches and putting some offset or helical on them will get you what you need with respect to spin without the need to add the weight of another fletch.
The other consideration is that arrow trajectory and accuracy can be adversely effected by too much drag. As the arrow slows, the fletches do less and less work, causing the arrow to potentially stray off course. Your mission, should you decide to accept it, is to find that sweet spot, that stabilizes your arrow effectively while maintaining enough energy downrange.
In general 3 fletches will get you where you need. If you want more stabilization, use more offset or for the ultimate, use helical.
There are some broadheads out there that also are helicaled so when arrows hit targets theycontinue to spininto them how much they spin when hitting is the question but I bet when they pass through there spinning still.
Fletching ?'s
