It's a helical question...

[stovie]

...Put simply...does helical and/or offset of fletchings truely make a difference to arrow performance???

The principle being to gain spin (as with rifling of a gun barrel) increasing accuracy of projectile.

But, others claim that it is drag that makes arrows accurate, and that the spin only slows an arrow...

Your thoughts.......



ps. Thanks for the badge, Tony :You_Rock_

 

[Bardster]

...Put simply...does helical and/or offset of fletchings truely make a difference to arrow performance???

The principle being to gain spin (as with rifling of a gun barrel) increasing accuracy of projectile.

But, others claim that it is drag that makes arrows accurate, and that the spin only slows an arrow...

Your thoughts.......



ps. Thanks for the badge, Tony :You_Rock_

Like everything in archery its a balance isn't it? same with the size othe fletching. Yes you can shoot an arrow with no fletching - but it becomes very unstable over more than 5 or 10 yards.
When I make flight arrows I try to keep the fletching as small as possible - the larger the fletching the greater the drag - but it does need some for stability.

 

[Goose]

Don't know a lot about arrows but the spin on a missile, same principles, balances it in flight.
Assuming the arrow/missile has a slight imbalance, due to weight or on launch, without spin it would carry on turning in the direction of imbalance, with spin it corrects itself as the imbalance evens itself out.
It still doesn't fly dead straight but in a slight corkscrew, the faster the spin the tighter the corkscrew so the less noticeble the imbalance is.

 

[Ogri the trog]

Stovie,
The extra drag that a spiral fletch will add to the arrow will definately slow the arrow and introduce innaccuracy (certainly on a wooden shaft). I recon if the spine is right for the bow and the arrow straight, small fletches would allow a flatter shot and a faster cast, both of which will give you better accuracy and range.

ATB

Ogri the trog

 

[stovie]

Stovie,
The extra drag that a spiral fletch will add to the arrow will definately slow the arrow and introduce innaccuracy (certainly on a wooden shaft). I recon if the spine is right for the bow and the arrow straight, small fletches would allow a flatter shot and a faster cast, both of which will give you better accuracy and range.

ATB


Ogri the trog

You see, you are claiming the opposite of what I have been led to believe. Some claim that spiralling increases accuracy (you can see the logic) and yet others say no... How to go about proving the issue?????

 

[Longstrider]

A .270 calibre rifle bullet will leave the rifle at about 3000 feet per second, and the rifling in the barrel might be as tight as one turn in every 12 inches, this gives a spin rate of some 3000 RPM. This rate of spin has to be this fast to keep the relatively short, fat bullet stable as it flies through the air. A non-spinning bullet is far more likely to tumble than an arrow due to it's short length and the way the air turbulence around it acts on it due to it's very high speed.
An arrow will only require enough drag (provided by the fletchings) at the rear to keep it flying nose first through the air. The fletchings are best kept as small as will do this satisfactorily, to avoid excessive drag on the arrow which will slow its flight. The arrow does not need to spin at all in flight. Spinning may well not only add more drag than is needed, but may actually impede the arrows accuracy and speed through the air.

 

[stovie]

so these guys are talking Rubbish ???

You can understand my confusion

 

[Goose]

A bullet, I beleive, uses the spin of rifling as a gryoscopic stabiliser.
A missile spins, comparativly, slowly and (usually) uses fins for stabilisation as does an arrow.
The spin in this case is less for stabilisation and more for accuracy, as nothing is perfect but it equals out the imperfections.
Even if you had a "perfect" arrow as it is fired it flexes so therefore is bent as is fired, if say it bends to the left, the arrow would fly left without spin, with spin the "left" would turn through 360 degrees and the arrow tip would make a corkscrew flight which would overall be straighter.
Perhaps people are used to accounting for their own equipments innacuracies and your kit is zeroed to yourself, so it depends on what you are used to?

 

[stovie]

So when I fletch my arrows in the new year with my lovely goose primaries, do I bother off-setting them, or not...???

 

[jongir]

If I was you I would try some with and some without and then let us know the outcome of which is the better way.

 

[Ogri the trog]

...so these guys are talking Rubbish ???

You can understand my confusion

I don't think they are talking rubbish, but they are talking about carbon arrows, which is a world apart from wooden ones.
Drag is a factor of the cross-sectional area of your arrow, and spiral fletches can only increase that area. If you are experiencing accuracy problems in your shooting, then there are possibly other reasons for it than requiring rotating arrows. There is also a question, for me anyway in the link mentioned, of penetration of a broadhead pile if it were to be spinning on entry to a target - surely it would not penetrate as deeply as a non-rotating one.

As a recreational archer, I am happy with my equipment and I like it the way I have set it up. I'm all for other folk doing their own experiments to find what works best for them. Let us know if you do any back-to-back testing of the different arrows.

ATB

Ogri the trog

 

[2blackcat]

What sort of archery are you doing?

Small fletchings are better for flight or the long roving clouts

Target, I used ACE's anyway until I got into ......

Field, where the shorter distances mean you need stability quicker

If your arrows are spined for the bow then fletch size is not critical. A lot of the time it's hit and miss with the equipement until you find what works (it took almost a year to sort out the best combination for the co-pilots set up ...... then she changed bow )

I just like the look of helical fletchings ..... and I can miss just as well either way

 

[Doc]

I believe helical fletching is very much preferred for arrows with broadheads. A broadhead arrow with tiny fletching is a bit like shooting an arrow backwards.

Bowhunting ranges are short - often 20 yards or less - and drag is perhaps less of an issue - hence the popularity of feathers and helical fletching. A target archer shooting at long distances would obviously want less drag.

I bought my first batch of arrows from a reliable source. They all had a slight offset. I set my fletching jig to replicate this offset when making my own. I should really experiment to see what works best, but shafts and feathers are quite expensive.

 

[stovie]

I have decided to make half a dozen of each in the new year, and trial them over different distances.

Thanks for all your input, it will be interesting to see what happens

 

[nooky]

I don't think they are talking rubbish, but they are talking about carbon arrows, which is a world apart from wooden ones. ATB
Ogri the trog

I think Ogri is right they are talking about the carbon and the aluminiun arrows. And more specifically I believe it is the arrows being shot out of the high powered compound bows. With the wood arrows I would just stick with the straight fletches. But as has already been said It is a personal thing and you go with what works for you and your bow.
Andrew.

 

[AUSSIE]

If you have something like a 125 to 145 grain broadhead on heavy hunting arrows then you definitely need four or five inch helical fletching to stabilize your arrow quickly. The planing effect a broadhead has in flight needs to be counterbalanced by helical fletching at the other end of the shaft. All in all this does equate to superior accuracy providing the bowhunter does his bit with the bow / arrow combination.

 

[stovie]

Just been reading on this site SPTA in the links section "How to train in Archery" By Maurice and Will H. Thompson published in 1879. In the chapter headed "Some Remarks on the Trajectory and the Rotary Motion of Arrows"....

"It might seem that in order to give an arrow the rotary motion of a rifle-ball it would be necessary to put the feathers on spirally. We have seen this done, but it is a mistake. Arrows made after the ordinary English style, with feathers practically parallel to the stele of the arrow, we have found to have a very rapid rotary motion This happened to be demonstrated in our presence as follows: An arrow was shot into a target distant 100 yards, and chanced to touch a long iron spike which projected from the rude target easel we were using. This spike had a very sharp corner which cut a groove in the stele of the arrow as it passed, which groove, upon examination, was found to run spirally around the shaft three times in six inches, or once in two inches. Now, an arrow shot with the full force of a 52 pound bow will fly 100 yards in about two seconds. There are 3600 inches in 100 yards. Therefore, if an arrow flies 3600 inches in two seconds and turns once in two inches, it will turn 900 times in a second, a pretty rapid rotation. Of course, it starts with a much greater velocity. The average would probably be at least I 200 revolutions in a second."

The plot thickens....

 

[C_Claycomb]

Large spiral feathers go a long way to stabilize an arrow at close range. I am not entirely sure what causes fishtailing, incorrect spine (dynamic stiffness), will make arrows fly left or right of where you want and fishtailing is probably part of that.

In bow hunting close shots are the rule. An arrow flying a little slower, but flying straight, will give better penitration than one flying sideways fast. That, along with the planing effect, is a reason for big feathers.

The arrow/bow set up can be funny. The most accurate arrows I have shot from my bow used 5" high parabolic fletches and sported 100gr broad heads. When i swapped to 100gr field points they didn't shoot as consistantly.

If you use modern equipment it is much easier to get say 24 arrows that accurately match your bow. If you are making your own bows, and are both learning, and trying new things, you aren't going to get arrows that are that well matched to your bow. Bigger feathers will slow your arrows, but make them more forgiving of differences between one bow and another.

I have found that at short ranges large helical feathers were on average more accurage than same size straight feathers, or low cut helicals. At long range the low cut helicals dragged less and shot flatter than the high cut straights, but there wasn't much to choose for left/right accruacy.

Why not start with long high cut fletches, and experiment by trimming them shorter and lower until you find where you are happy?

 

[stovie]

Thanks for that Chris, it's very helpful.

Yes i am continuing to make my own bows, and my own arrows, and no, they rarely match very precisely (but they are not terribly mismatched either).

I have made a dozen arrows so far, with varying fletch designs, mostly shield/kite style, varying length and height, but have not made any as large as those you describe. I shall probably fletch a couple along those lines and see how they compare.

Once again, thanks...