Flight arrow design & tradeoffs

[Badger]

       Getting the most out of arrows seems to be a bigger challenge than making a fast bow when it comes to regular flight shooting. This is an area that seems to baffle me more than anything. I thought I would just lay out a bunch of scenarios and try to figure out the best way to deal with them.

Scenario: You have 4 arrows, they all have the same fletches. Arrow 1.                  150 grains, 280 fps            150 grains      260 fps
                                                                                                             2.                  200 grains  250 fps            200 grains      235 fps
                                                                                                             3.                  250 grains  225 fps            250 grains      220 fps
                                                                                                             4.                  300 grains  210 fps            300 grains      210 fps 

  I just answered my own question when I layed these two bows out side by side. The slightly slower bow on the right outshoots the faster bow on the left. Obvious reason is arrow flight. Bow one is a regular flite recurve bow, while bow 2 is an r/d longbow. Our goal right now is 400 yards with a 50# bow. This was done in the 1930's and 1940's I understand but my generation has not beeen able to repeat it yet. It is very possible that in those years a lot more arrows were being cast in a lot more competitions so that one great arrow would have much better odds of surfacing more often. A lot more guys were building flite bows instead of shooting longbows in a flite class as well. These little flight bows will shine with the light arrows. Finding out how to tune those very light arrows to your bow and then getting that light arrow to fly well is the big challenge. Allen Case seems to have a good grip on it. But I am thinking that simply shooting my heavier arrows because they are performing better is kind of a cop out if I am not going all out. We know from history that 150 grain arrows can fly, we just have to figure out how to do it.

 

[PatM]

They also shot shorter "longbows" over 400 yards as well.

[PatM]

BTW Are  bamboo/cane or reed arrows allowed in flight shooting?
 They should be.

[Dan Perry]

Yes they are. It was a fight to get them allowed in the ELB class, but we one out in the end.

Alan gave me a stiff spined, bamboo flight arrow to try. It overshot the range into the marsh, and I never found it. I seated in close for an exploded arrow etc. and found nothing. The marsh was at 400 yards. The bow was a 43.5 pound hickory self bow. The best I did with other arrows, was 350 yards in competition, and around 367 in practice. Alan makes a great arrow.

[redhawk55]

Reading Klopsteg's and other researches on Osmanian flightarchery, the arrows are about 200grs., depending on their length from 23" - 251/2".
All arrows are barrelled, max. diameter is 0.3. Deflection is 0.88 - 0.3, the wood is said to be pine.
The 0.33 deflection is driving me crazy, I have really done a lots of thrials, I ended up with 0.45 in deflection and 0.25 in max. diameter to be my best, but still 278grs. in weight.
How the hell they got such 200grs.!

Michael

[Badger]

    Tradeoffs in stiffness for smaller diameters is something I have been debatiing. I can make 200 grains with pine and maintain good stiffness but a larger diameter. With the larch I have been using I can get the diameter down to .25 or below and my weight to 200 grains but struggle with enough spine. I think the larch would be ideal for 80# bows and above.

[avcase]

Michael,
There may be an error in the spine deflections reported in the following report:

http://margo.student.utwente.nl/sagi/artikel/turkish/

Notice how the arrow deflections are listed from higher to lower, but arrow diameter is listed lower to higher. The trend is perfectly opposite what it should be. I think the author may have typed in the deflection data backward. I'd expect the .25" diameter arrow to deflect 0.88", and the 0.30" diameter arrow to deflect .33", not the other way around.

The 0.58" average deflection of the 18 arrows, with an average diameter of 0.27" is more plausible, but still outstanding.

Arrow stiffness is proportional to the diameter raised to the fourth power, so a very small diameter difference makes a very large stiffness difference.

I believe I can match the average deflection of the Turkish flight arrows using a high grade of heat treated Sitka Spruce. I plan to make a serious effort at it later this year.

Another observation, these Turkish flight arrows averaged just over 190 grains, but they were shot out of very heavy bows. If we assume one of the lighter Turkish Flight bows pulled 125 lb, then that would be the equivalent of shooting only 76.4 grain arrows out of a 50-lb bow!

Alan

[avcase]

I believe that a 200+ grain flight arrow for a 50# flight bow leaves a lot of untapped potential unless the bow has a long draw length.  By long draw, I mean the arrow is drawn 26" or more past the arrow contact point or arrow rest on the bow.

The trade-off going to light arrows is that the arrow becomes much more sensitive to tuning and release issues. Excessive paradox/wiggle has a huge effect too. Wind tunnel testing indicates that paradox on even a very well tuned arrow shot by an Olympic-level target archer can induce double the drag of an arrow launched from an air gun without paradox.  The same doubling in drag was shown for an arrow launched with as little as three degrees misalignment to the direction of flight.

I have a pretty extreme example of this from my foot bow shooting last year(sorry, non primitive).  Only two arrows were found on my last day of shooting. Fortunately, I have video of these shots and saw that my release loop broke at just past half draw. Based on my chrono testing, that arrow was traveling around 480 fps, but it left the bow very clean, and landed nearly 1300 yards away. The release loop broke free early on the other arrow too, but it was drawn 3-4" farther than the first, and probably left the bow around 580+ fps. But I had also forgot to tighten the arrow rest and it was blasted off the bow with the arrow. I assume this resulted in a misaligned arrow launch because the second arrow landed a few hundred yards SHORT of the first, despite the longer draw and much higher launch speed.

Alan

[Badger]

   Allen, those are just the kind of things I feel we really have to learn to control if we ever want to establish some serious records. The year before I entered flight shooting I had a very light but very stiff river cane arrow, taperred from front to back that weighed about 240 grains with a 60 grain tip up front. I got better distances from that arrow than I am getting today from much faster bows. I hope in the future you will open some threads on this topic and discuss it more at length.

[redhawk55]

Alan, I suspect the numbers to be somehow wrong, but Klopsteg is Klopsteg, almost every info about Osmanian flight- arrows are based on his researches. Thanks for clearifying.
Your post has driven me much more suspicious. A 76grs. arrow shot by a 50lbs bow will explode.
Asking a turkish friend and consulting wikipedia is showing that maybe the "avoirdupois" method used by Klopsteg for to convert the weights is wrong!
Obviously Klopsteg used " dram" instead of "dirham".

Go here: https://en.wikipedia.org/wiki/Dirham and here:https://en.wikipedia.org/wiki/Avoirdupois

An Osmanian dirhem(dr.) is equivalent to 3, 1gr. or 47grs.. So these arrows are weighing at an average of about 320grs., which is much more realistic.

Nowadays flight- arrows are matching these measurements quite exactly, no more brain racking over it!

Klopsteg, where had you been last night?

Michael

[avcase]

Michael,
I believe the arrow weights in grains are pretty reasonable. 190-200 grains is a typical weight for Turkish flight arrows shot from heavy flight bows.

I was just pointing out that the arrow deflections were misleading. It initially gave me the impression that the minimum 0.25" diameter arrow had only a 0.33" deflection, but in reality, it just says the smallest diameter of all the arrows measured was 0.25", and the smallest deflection of all the arrows in the group was 0.33".  I think the average values are the most meaningful.

I would shoot a 76 grain arrow from a 50# primitive flight bow if I could get clean arrow flight and it was safe. The barrier to doing this is that we currently have a 23" minimum arrow length rule for all our primitive divisions under our USA Archery rules. I think one rule change I would advocate for is to allow shorter arrows at our events.  But making a change at this point can be seen as unfair to the prior record holders who competed under the 23" minimum arrow rule.

Alan

[Badger]

  Allen, thats a very important point, one of the reasons I am pushing for a 21" minimum in the new organization. I would also like to see longer overdraws allowed on all the regular fligth bows but I am open to anything.

[avcase]

Steve,
My proposal for the World Archery adaptation would be to further reduce restrictions on the bow designs used. I would propose adopting the same 14" minimum arrow length rule used for the modern bows eliminate handle depth and overdraw restrictions. Finally, I would be tempted to have the Turkish shot under the Complex-Composite.

These are just my personal opinions. Any changes would require agreement of the entire Flight committee.

Alan

[Badger]

  I would go for that also, I was afraid pushing shorter than 21 might raise eyebrows.

[avcase]

I'm sure 14" arrows may be pushing it, but if the change is made, I figure we might as well go all the way.  Also, such a change wouldn't be made haphazardly. We do need to consider fairness to the current record holders. This is where I'd love to have Dan Perry's feedback.

My philosophy is, the job of a flight archer is seeing how far they can fling an arrow. In the case of primitive, I feel the only restrictions should be placed on the materials used for the archery tackle.  The form of the equipment will evolve to suit this function.

Alan