Spinwings - whats does this mean??

[buzz lite beer]

Originally Posted by Kae

I can't do better than Joe, but I can answer your second question.

It means that you stick the spinwings on the wrong way up. So that they wrap themselves around the shaft. Then you bend them back on themselves - so that they stand up.
This makes them easier to apply, and gives them a lower profile.

Kae.

I have been thinking about this before, "does it actually lower the profile"? My engineers rule says it remains the same, say the applied tape is 2mm thick, and applied to the shaft in the manor the instructions state, you have lost 2mm off the width, now by applying on the opposite side and folding back there is still the exact same 2mm stuck to the shaft as there was before the only conceivable lowering of profile would be what ever you lost in the actual crease.

[EVC]

Originally Posted by joetapley

The top vane points towards the bow RH = > LH = <

vane holder holds and aligns the vane to the shaft - doesn't connect to the nock (there is the tri-liner for this if you want) See

Werner Beiter | Dauchingen | Germany | Products | Wing-Holder

FWIW the wing holder works fine for 1.5" kurlys as well. It just requires some care to align the vanes to apply the tape whereas the 1.75" just fit.



Elder.

[whiz]

Originally Posted by joetapley

That's the one - muchas gratias if you have it. If my memory is correct (ha ha) the overall RPM showed a number of dips on the overall upward trend.

Well, this is a case of one report which I am incredibly dubious of to the point of calling it flat out wrong. Regardless of the spotless credibility of the person involved. Arrow rotation is a passive reaction. There is nothing powering that arrow the instant it stops being pushed by the string. After that, it's an energy loss equation.
There is a slight rotation caused by the compression of the arrow. The rest of the rotation is caused by aerodynamic loads on the fletches.
Those aerodynamic loads are directly related to speed. The arrow is pinwheeling.
If you can prove to me that a pinwheel will speed up as the relative velocity slows down then you will win acclaim throughout the physics world as you have discovered perpetual motion.

Essentially, this SINGLE report which claims that arrows accelerate in spin as they slow down is the sole point of reference here? Does this sound a little bit like "Putting all your eggs in one basket"?


Yet the laws of conservation of energy that you can not help but experience in every second of your life somehow gets disregarded?


I'm betting that I'm a bit more educated in the effects of low reynolds number airfoils than the average archer. I have experience in the effects of laminar and turbulent airflow and have practical knowledge of the uses of both for various purposes and applications.

I've seen some interesting things, but never in my life have I seen energy come from nowhere.

What I have seen however, is a hell of a lot of people with absolutely no idea who will trust blindly a single point of reference that backs up what they want to believe.

[jimlee]

Whiz, what you're implying is that as the arrow slows down then the rate of spin generated by the fletchings cannot increase, but you should consider the fact that when the arrow nock seperates from the string the arrow has not started spinning yet and it is the action of the fletchings converting forward motion to rotational that generates the spin, so therefore while the arrow speed is dropping the spin rate will increase until the arrow slows to such an extent that it can no longer increase the rate of spin, this point is probably beyond the 90 metres that we're worried about.

Cheers, Jim.

[whiz]

Originally Posted by jimlee

Whiz, what you're implying is that as the arrow slows down then the rate of spin generated by the fletchings cannot increase,

You're dead right.

Originally Posted by jimlee

but you should consider the fact that when the arrow nock seperates from the string the arrow has not started spinning yet and it is the action of the fletchings converting forward motion to rotational that generates the spin,

The fletches still are imparting a torque to the arrow shaft the instant that they start moving forward while the arrow is on the string. The arrows start to turn the INSTANT that the string stops restraining them.
They take a short time to get to top rotational speed but as spin rate is related directly to airspeed, as airspeed drops, the spinrate goes down.

Originally Posted by jimlee

so therefore while the arrow speed is dropping the spin rate will increase until the arrow slows to such an extent that it can no longer increase the rate of spin, this point is probably beyond the 90 metres that we're worried about.

Cheers, Jim.

Nope. The arrow is slowing down from the instant it isn't being powered by the string. The arrow gets to the rotational speed imparted by the fletches very quickly and it slows down in rotation from the instant that the equilibrium between forward speed and rotational relationship is met.

It does this because rotation is related to speed and the speed is dropping.
Once that arrow gets up to speed, it will NEVER speed up as there is no energy devoted to making it spin faster. Only slowing it down.

The mere fact that you have issues at 90 metres is fall off in velocity.
If your stability margin is lacking, you'll get wobbles as your velocity falls off. Why do you think aircraft wobble around at low speeds?

[John (OSF)]

Originally Posted by whiz

What I have seen however, is a hell of a lot of people with absolutely no idea who will trust blindly a single point of reference that backs up what they want to believe.

I'm not saying you're wrong but the odds are (imo) that something may be happening during the flight of the arrows that you don't fully understand.

When I came across the info I was surprised and at the time was experimenting with different vanes and poundages and was looking for information on spin at different ranges and that was the only info available.

If you have any actual results that disproves this please post them as I'm always willing to learn and any new info is appreciated

If you don't, then why should you I believe you and not the other source?

[whiz]

Originally Posted by John (OSF)

I'm not saying you're wrong but the odds are (imo) that something may be happening during the flight of the arrows that you don't fully understand.

Well, I fully admit that it is a possibility. Never let yourself be 100 percent totally convinced by anything.
However, the aerodynamic effects that apply to arrows also apply to other well known fields that have been explored countlessly.

The energy required to increase spin rate is magically coming from somewhere. In real life, it just doesn't happen.

If this information can be produced and how it was obtained can be established as creditable and repeatable, I'll believe it.
Until then, conventional physics totally and utterly disproves it.

A long exposure photo of an arrow in flight, across an arc with a half reflective wrap on it can totally disprove this theory.
I'm waiting on an Easton LED nock for exactly this purpose...