Tag Archives: arrows

One More Time (Arrow Tuning While Changing Draw Weight)

QandA logoI got this question as part of a larger issue from one of my Olympic Recurve students:
My Arrow cut length is 29.25˝, so if I buy these new shafts should I cut them at 30.5˝ for now? Or should I cut them at 31˝?”

This student is working his way to a higher draw weight but wants to explore different arrows at the same time. Here’s what I said (with slight modifications).

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My standard recommendation is to make the draw weight change first, then fit yourself for new arrows. (Shooting to accustom oneself to a higher draw weight can be done blank bale and need only take weeks or at most a few months.) But the question here is basically: How do I fit arrows to allow for a higher draw weight in the future? So, that’s what I will address.

apple-arrow-saw

An arrow saw. This one is made by Apple.

A start is to fit your current draw weight and cut length in the new arrow’s spine chart. Then move up one spine group on the chart (stiffer) and then add 1˝ to the cut length or move up two spine groups and then add 2˝ to the cut length. It all depends on how much draw weight you want to add. Roughly 5# = 1˝ of cut length, so if you are looking to go up five pounds, then you need just one spine group and one inch of cut length more than you are shooting now to allow for that change.

This is based upon how spine charts are set up by the manufacturers. They basically define spine groups, defining them by each inch of shaft length or 5# of draw weight for recurve bows. (There are some variations in the draw weights; Easton just made significant changes in their target recurve chart draw weights, for example.)

By buying an arrow that is stiffer, then cutting it longer you can create an arrow that is the same spine as the shorter weaker shaft that would be an exact fit. This arrow will shoot well and as you crank the draw weight up, you can shorten the arrows as you do so, keeping them reasonably well tuned. If you go up five pounds of draw weight and cut off that extra inch of shaft length, you have an arrow that is one spine group stiffer which is required at that higher draw weight.

Longer arrows than needed can also stretch the usable limits of a riser-attached clicker. While such changes are being pursued, using a clicker attached to one’s sight extension bar may be helpful. When arrows are cut shorter, the clicker needs to be moved in the exact amount of the cut.

This is a lot of fussing, but the advantage is this: it is very hard for archers to ignore where they arrows land. If one is shooting an untuned bow, the arrows will not group well and the archer will often think it is because they are doing something wrong and change their behavior for no reason other than their bow is not tuned. So having a reasonably tuned setup at all times can be beneficial.

 

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Point Weight Woes

QandA logoI got an email from a friend regarding a problem you may have encountered in your coaching. Here it is.

Hi, Steve!
I wanted to bounce something off of you if you have a moment. I had some unexpected issues with arrows over this past weekend when I was shooting my first FITA. I was struggling much more than anyone else with the light wind we were having. Right before the competition, I had been trying to tune in my new arrows that were acting too weak and I ended up reducing the point weight to 90 grains, which had them finally performing well in practices. I put up some personal best practice scores with my adjusted arrows right before the FITA round and was feeling good about my performance. I suspect, though, that the light point weight was my downfall and part of what was giving me such problems. My longer distance scores were the worst I’ve ever done in my life, however my shortest distance score (30m) was right on the money with my normal practice scores, even though the wind was the same and I should have been the most fatigued and dropping points at the end.
            I bought my arrows slightly long and am thinking about cutting off a 1/2˝ and putting 110 grain points back in the shortened arrows. My theory is that that will have a similar effect as having the longer arrows with lower point weight, but will give me more ability to cut through the wind. However, I can’t find any literature online or in my many archery books about point weight vs. arrow length in trying to make adjustments to arrow spine. Which is a better adjustment to make, and is there any such equation such as “each 1/2˝ of length = 20 grains of point weight” or whatever? I’m not keen on cutting down my arrows if that might not give me the results I’m looking for.
           
Thanks in advance for any help or advice you can give!

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I doubt your point weight made all that much difference so it may or may not have been the source of your woes.

First I have to ask: when you were tuning in these arrows, did you have a reasonable centershot, plunger button resistance, nocking point height, and was your aperture centered above your arrow? If not, you were tuning to a less than optimal setup. It is always important to have a bow in a proper setup when trying to tune. If your aperture is off center, for example, you are then trying to tune your arrows to a dynamic spine that will compensate for a mis-set sight!

Most Olympic Recurve archers have a FOC balance point of 13-15%, so that is something you might want to check. (FOC guidelines are the equivalent of the “equation” you desire.) The vast majority of OR archers have 100 gr points (110 gr being in second place, I think), unless … you are shooting a very lightweight all-carbon arrow such as McKinney IIs, then 90 gr and even 80 gr come into play.

As far as wind stabilization goes, there are two strategies: use a heavier arrow (like Easton X10s) or a lighter arrow (like Carbon Tech McKinney IIs or Carbon Express Nano Pros or Medallions). The heavier arrows have more mass and therefore require more wind force to move them (inertial stabilization). The lighter shafts are faster and hence spend less time in the wind for the wind’s forces to act on them (speed stabilization). When an arrow is shot long distance, a higher FOC is generally desired to keep the arrow on track during those longer flight times. When I was shooting field archery a lot I was using 60, 70, and 82 gr points in very long arrows with little downside. But shooting FITA rounds, I was using 100 gr or even 120 gr points (again, in very long shafts).

So, research Front-of-Center (FOC) balance and how to measure it (it is easy) and check your current arrows. If you are close to 13-15%, then it was not your point weight that was a problem. If it is 6-9%, then maybe so.

If it was not your point weight, I suggest you go back to a basic setup and retune (nocking point height 1/2˝ above square, centershot has inside edge of arrow point visually lined up with outside edge of bowstring with string centered on the riser (visually), plunger pressure mediumish, aperture centered above arrow when bow is vertical (I just run the aperture down to the bottom of the sight bar and eye-ball it)). Also, you need to take off all vibration absorption devices (Doinkers, et. al.); they can only mask the feel of good shots.

You may find that the tune you had wasn’t all that good.

The reason the tune is so important is the tune establishes the launch angle of the arrows (at what ever angle the bow is being held), so if the centershot is way outboard, for example, the arrows are launched point left. Then the fletching has to correct for that, but if the wind is blowing more than a bit, that “sideways” launched shaft is going to be blown in unpredictable ways (the shaft itself is a bigger source of drag than the fletches) and you are going to have very large groups as a consequence.

I hope this helps!

Steve

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So Much to Learn … About Arrows

The following question came in recently from a “non-beginner:” “If an aluminum arrow has a dent in it, is it still usable?”

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Coaches need to be aware of how much our students do not know about archery equipment. It is easy for grizzled veterans of archery to forget how much there is to learn.

As all-carbon arrows become more prevalent, archers get less and less experience with aluminum arrows, even though the pathway up from a “beginner” usually is paved with aluminum arrows. There seems to be a growing opinion that aluminum arrows are “obsolete,” but this is incorrect. Marketing forces are always on the side of “new and improved” (an oxymoronic claim, by the way) and seem to denigrate the prior models as “old” or “inferior.” So, an impression is created that older designs are less capable, limiting performance somehow. This is not true.

There is nothing wrong with aluminum arrows. They, like their carbon counterparts, have strengths and weakness. One weakness is they can be bent and become unshootable. They, can, however be straightened. They are also less expensive than most other options. All-carbon arrows don’t bend, but they do crack and once cracked are not repairable.

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To answer the question asked: if an aluminum arrow is dented, it may be still useable but it depends on the dent (location, size). If the arrow is still straight and groups with the others, it is at minimum a good practice arrow. If the shaft is a shaft that accepts “glued on” nocks, one of the places it can become dented is in the cone-shaped section designed to accept a nock. (This typically happens when a nock gets broken by a subsequent arrow.) And there is a tool for reshaping dented nock cones on aluminum arrows, even if a hole is punched into that section. If the nock can be glued on securely and isn’t “out of round,” it is probably still useable.

Minor dents, along the shaft can be acceptable as long as the shaft is still straight. A hole punched in the side of a shaft is a clear sign of an unsafe shaft, though. Dents near the tip are often negligible because the shaft of the arrow point reinforces the shaft outside of it. But if the tip is “out of round” retire that arrow.

Aluminum arrows get dinged and banged up quite a bit over time so many archers keep a competition set and practice set. As the competition arrows get banged up or no longer group with the others, they get retired to the practice set. Even arrows that don’t group well are fine for blank bale shooting.

There are, by the way, aluminum-carbon arrows (e.g. Easton X-10s, ACEs, ACGs, ACCs, and the weird “Full Metal Jacket” shafts). These still sell well because of the attributes they share with all-carbon and aluminum shafts. SMFAThey are intermediate between all-carbon and aluminum shafts in a number of parameters like shaft weight but not in cost or toughness. They seem to be tougher than either of the other two options. (This is with regard to target shafts. There are all-carbon hunting shafts you could drive a Humvee over and they would not crack.)

There is so much to learn and few sources to learn from. I suggested to Lancaster Archery (the largest target archery distributer in the U.S.) that they establish a YouTube Channel in which they could explain equipment choices and show basic maintenance tasks. This would give coaches a trustworthy site to send beginning-intermediate archers and archery parents to for such information. I have not heard back from them, but it isn’t as if they have nothing better to do. (Just search YouTube or any othe rsite for archery maintenance information produces the usual mixture of 1-5% wisdom and 95-99% of misinformation/nonsense.) Until such sources become available I will continue to recommend (highly) the book “Simple Maintenance for Archery” by Alan Anderson and Ruth Rowe, now out in a second edition (if you can only find the first edition, that is fine).

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