Light arrows

[willie]

Sure!  I’m Certainly willing to give it a try to see if this approach helps out with getting the most out of your bows.

Thanks, Alan. Will post my set up and ask more later.

[avcase]

  Allen, could you estimate an arrow distance for me.   Ipe, 240 grains, launch speed 216 fps, max dia .220", length 25", spine about 38#.

What span is the spine measured across?  Is the spine measured on the dowel that the flight arrow was made from, or on the actual finished flight arrow?  All I need is the weight used, distance between supports, and amount of deflection.

Something doesn’t seem right. In order to get a 38# spine from a .220” diameter barreled Flight arrow, it would need to be made of something far stiffer than the stiffest ipe I have ever measured.

Thanks!

[Badger]

   I mixed up my measure, the arrow is only 24" long, so I was likely measuring on about 22" center. I need to get my arrow stuff out of my shed. I am guessing too much here. Using 2# of water in a cup and ballancing while I slide stuff underneath to measure the gaps. LOL.

[avcase]

   I mixed up my measure, the arrow is only 24" long, so I was likely measuring on about 22" center. I need to get my arrow stuff out of my shed. I am guessing too much here. Using 2# of water in a cup and ballancing while I slide stuff underneath to measure the gaps. LOL.

You don’t need to use a 2# weight. Any weight will do as long as you accurately know what it is. One of Thebes weight led that I use for spine testing is 1.612#.   A deflection of .500” @ 1.612# is equivalent to 0.500” * (2#/1.612#) = 0.620” for a 2# weight.

Alan

[Badger]

    I will get my set up going again tomorrow so I can take some close measurements.

[Badger]

 I had a 3# weight sitting around and it was off the chart at about 1.8" deflection with 23" span.

[avcase]

I had a 3# weight sitting around and it was off the chart at about 1.8" deflection with 23" span.

Steve,
That’s about right for Ipe, maybe a bit higher deflection than expected, but it depends on how the arrow is shaped. This arrow is probably way under spine deflection for clean Flight with your bow, but let’s run with it.

At sea level, 70 deg f, zero wind, 42 degree shooting angle, perfectly clean Flight, 323 yards.

But I based on your spine deflection test, I estimate the maximum diameter for the ipe flight arrow would have to be increased to about 0.255” to get enough spine, which would increase arrow mass to about 321 grains, dropping the arrow launch speed to about 180 fps, and giving a distance of 255 yards. 

If the same stiffness arrow was made of your best Tamarack/Larch, then the maximum diameter wouldn’t be much different than the ipe arrow, but the arrow would be much lighter at around 200 grains, launch speed much quicker at 211 fps, and distance much better at 283 yards.

Alan

[Selfbowman]

Alan are the wall hung  Ace spine testers accurate enough? They can measure shorter arrows. Arvin

[avcase]

Alan are the wall hung  Ace spine testers accurate enough? They can measure shorter arrows. Arvin

I would hope these are accurate, but I have no experience with these.  I just use a dial indicator with the spring removed from the plunger to measure deflection. My setup resembles an arrow straightener.  I’ll take a picture.

[willie]

Alan, the idea of having an algorithim to predict flight distance potential is intriguing. Are you willing to share the dimensions of the taper of your reference arrow? I need to make a few 24" arrows for 35 lb limbs. Perhaps you have some suggestions so that any actual chrono tests or flight results may help with your evaluation of the formulas or constants you use in your calcs?

[Matthias Wiltschko]

   I saw some tests done of different weight arrows to see how much they slowed down over a distance of about 30 yards I think. The difference between a 500 grain and a 400 grain was shocking. The heavier denser arrows carry much better. I wish the test was between 300 and 200 grain. That would have been more interesting. I am leaning more and more toward 260 grains up to 300 just to see how they do.

So the 400 grain arrow would come out of the bow faster than the 500 grain arrow.
The 400 grain arrow would loose speed a lot faster but at 30 yards it would stilll be faster than the 500 grain arrow?

[Badger]

   I saw some tests done of different weight arrows to see how much they slowed down over a distance of about 30 yards I think. The difference between a 500 grain and a 400 grain was shocking. The heavier denser arrows carry much better. I wish the test was between 300 and 200 grain. That would have been more interesting. I am leaning more and more toward 260 grains up to 300 just to see how they do.

So the 400 grain arrow would come out of the bow faster than the 500 grain arrow.
The 400 grain arrow would loose speed a lot faster but at 30 yards it would stilll be faster than the 500 grain arrow?

   Not sure if it was still faster at 30 yards but at the rate it was slowing down the 500 would have passed it before too long.

[PatM]

I have some well cured Phragmites reeds that are feather light and very stiff. Going to give them a try for 500 yards.

[Badger]

I have some well cured Phragmites reeds that are feather light and very stiff. Going to give them a try for 500 yards.

  Try them for 300 yards first, how big is the diameter?

[PatM]

  Varied diameters.  A few are very slim but with closer nodes which  boosts the stiffness and strength.