Author Topic: FOC, center of pressure and performance  (Read 590 times)

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Offline avcase

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Re: FOC, center of pressure and performance
« Reply #15 on: September 12, 2017, 05:20:09 pm »
I think there could be some errors in the measurements of the Turkish Flight arrows. I would expect at least some minor difference between the center of gravity and the maximum diameter. It would be great if there are other measurement data on these types of arrows available.

The long taper to a very tiny point like the flight arrows in the Archery Antiqueries article have never worked very well for me. I am not sure why the Turkish archers adhered to this standard so rigidly. The shape of these arrows are probably driven by other factors such as shooting technique and attempting to get the most stiffness out of the lightest arrow possible.  I am not that well educated in the history behind Turkish flight archery, so I am just guessing.

It looks as though the wings on the harpoons serve a function similar to fletching on an arrow.

Thanks for the links.

Offline avcase

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Re: FOC, center of pressure and performance
« Reply #16 on: September 14, 2017, 09:27:10 pm »
I dug through my stash of natural material flight arrows and pulled a couple that have consistently outperformed the others.

They are in pretty rough shape after 8-9 years of flight shooting. Let's see if the images post okay...





« Last Edit: September 16, 2017, 02:55:35 pm by avcase »

Offline willie

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Re: FOC, center of pressure and performance
« Reply #17 on: September 16, 2017, 03:41:37 pm »
Hoping to see the pics, but cannot, even after your edit. Perhaps It's just my setup. Can anyone confirm if they are visible?

Offline Aaron H

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Re: FOC, center of pressure and performance
« Reply #18 on: September 16, 2017, 04:15:19 pm »
I don't see anything
But those who put their trust in the Lord will find new strength. They will soar high on wings like eagles...     Isaiah 40:31

Offline avcase

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Re: FOC, center of pressure and performance
« Reply #19 on: September 16, 2017, 11:25:38 pm »
I think I have the way to post pictures finally figured out.

Both are split cane.  The top one is 23" long, 23" long, and a maximum diameter of 0.215". The bottom one is 26-1/8" long, 212 grains, with a maximum diameter of 0.234". Balance points for both are just behind the center of the arrow. I am not sure why these have shot so well out of a such a large variety of bows. They totally contradict my earlier statements that the classic Turkish shaped arrow was not the best performer for me, are they are not even very straight!  Hahaha!



Alan

Offline Tuomo

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Re: FOC, center of pressure and performance
« Reply #20 on: September 17, 2017, 10:01:33 am »
Nice arrows! What is spine of the arrows? How much they are bending for example a 2# weight on 22" centers, or something like that?

Offline avcase

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Re: FOC, center of pressure and performance
« Reply #21 on: September 17, 2017, 02:48:07 pm »
I rarely spine test the flight arrows the usual way. My spine test usually consists of balancing the arrow on my finger tip, tapping it, and listening to the frequency it naturally rings at. I can try to measure the spine of these the normal way and let you know, but it doesn't seem particularly high.


I figure I may as well post more detail now that I finally figured out how to post images here:
Metal point on the smaller arrow is about 1/8" diameter.




The nocks are reinforced with thin silk thread soaked in hide glue.  It hasn't held up well to moisture. Fletches are stiff but thin, and are either duck or goose. Pheasant tail feathers are another favorite.

Alan

Offline Beadman

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Re: FOC, center of pressure and performance
« Reply #22 on: Today at 08:48:57 am »
I think I have the way to post pictures finally figured out.

Both are split cane.  The top one is 23" long, 23" long, and a maximum diameter of 0.215". The bottom one is 26-1/8" long, 212 grains, with a maximum diameter of 0.234". Balance points for both are just behind the center of the arrow. I am not sure why these have shot so well out of a such a large variety of bows. They totally contradict my earlier statements that the classic Turkish shaped arrow was not the best performer for me, are they are not even very straight!  Hahaha!



Alan
I'm in the dark about making flight arrows but split cane?From the sidewalls of thicker walled bamboo?Maximum diameter of under 1/4"?If so they should be pretty darn stiff I'd think but what do I know.Nice arrows BTW.
You got to stand for something or you'll fall for anything.
Ed

Offline avcase

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Re: FOC, center of pressure and performance
« Reply #23 on: Today at 12:12:43 pm »
The split cane flight arrows are made from six splits off a Tonkin Cane bamboo culm or stalk that are shaped and glued together to form the arrow shaft.  The process is the same as used to make a split cane bamboo fly rod.

Deflection of the 26-1/8" long flight arrow shown above is about .57 inches with a 22 inch span and 2-pound weight.  So stiffness is similar to that measured on old Turkish flight arrows. A good spruce flight arrow would have to be about 0.313" diameter to match the spiny/stiffness of the 0.234" diameter split cane flight arrow.

This is interesting. The weight for my larger diameter spruce flight arrow and equivalent stiffness of the split cane Tonkin arrow is almost identical.

Alan

Offline willie

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Re: FOC, center of pressure and performance
« Reply #24 on: Today at 12:44:38 pm »
  I am getting an itch to build some arrows for distance shooting. Wading thru the physics and aerodynamics at present, quite a complex and fascinating study. Maybe I can apply some old learning about fluid mechanics, to a new endevor, now that I have the time.

Just curious if any  shooters can comment on shooting flight arrows at lesser angles or bow poundages. Having a suitable range nearby, where one does not loose too many arrows, seems to be desirable.

Thanks for taking the time to post your work, Alan. I am surprised to learn that some of your arrows  "have shot so well out of a such a large variety of bows." Seems to speak more to the qualities of the arrow it's self, than some of the exacting particulars of a bow, or how it is tuned.

And thanks for posting the spruce specs, as I am keeping my eye out for some primo local wood.

Offline Marc St Louis

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Re: FOC, center of pressure and performance
« Reply #25 on: Today at 01:00:15 pm »
I made several flight arrows out of HHB many years ago, they were quite small in diameter.  I tried a carbon arrow to see if it would shoot farther than the HHB arrows, it did not.  My HHB arrows shot fairly consistently at around 330 yards and the carbon arrow fell at least 10 yards shy, consistently.

P.S.  Forgot to mention that the carbon arrow at about .25" was roughly the same diameter as the HHB arrows
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Offline avcase

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Re: FOC, center of pressure and performance
« Reply #26 on: Today at 01:46:33 pm »
Marc,
Anything over 300 yards with a primitive bow is really good!  I wonder if the worse performance of the carbon arrow was mostly tuning related?  The carbon arrow should be a lot stiffer than the wood arrow if the diameter was close to the same. Those must be pretty impressive wood flight arrows to work so well at only 0.25" in diameter!

I believe my Sitka spruce arrows would really shine if I could keep them from rehydrating after heat treating them.

Alan