Variable aiming points

While practicing at 30 meters today, I was frustrated by variability of my aiming point.  In the course of 36 arrows, my aiming point dropped by about 18 inches on the target face.

That the aiming point dropped means either one or both of two things:

1. My draw length was getting longer.

2. The bow was getting stiffer.

I can imagine the wood in the bow getting stiffer with lower temperatures, but the temperature remained rather constant during that time period, from about 2:00 in the afternoon to about 2:45. 

So something in me or the bow was changing, and it’s important to know what.  If it was something I was doing, then I can make it stop.  If it’s something in the bow, I can compensate for it.

At the moment, I have no idea.  If you have any ideas, drop me a line!

4 Responses

  1. Addendum to this post:

    I have been thinking about purchasing a chronograph, which measures the speed of arrows. This would tell me how much additional speed is imparted to the arrow when my draw length extends by an inch.

    I would also like to measure the speed of the arrow as it approaches the target. People have told me that there is little difference between the launch speed of an arrow and the speed of the arrow after some distance, but I’m finding this difficult to believe. Just the act of stabilizing the arrow in flight will bleed off some speed.

    This would also allow me to calculate the optimum angle for distance. We learn in freshman physics classes that the best angle to launch an arrow the furthest distance is 45°, but what if you take into account air friction? Although the closer the final speed is to the initial speed, the closer the angle will be to 45°, I suspect the angle is much lower in the real world, and I would like to know what that angle is.

    But that would simply satisfy my curiosity. I doubt it would improve my skill as an archer much, and I have better uses for the money.

  2. Did the humidity change during the time you were shooting? That would affect a wooden bow.

  3. The wood is sealed, so it shouldn’t be affected by humidity. have you heard differently? Can humidity affect the characteristics of a bow even if the moisture can’t get to the wood?

    • Sealing a bow just slows it’s adsorption of moisture from the air- it doesn’t prevent it. That said just taking the bow out for a day of shooting won’t be detectable assuming the finish is even halfway decent. The only american bow wood that’s affected by humidity to an appreciable extent is hickory. Left for several weeks in a high humidity area (e.g. my garage in the summer), a hickory bow- even with 3 coats of polyurethane will turn into a wet noodle.

      I’ve enjoyed this blog!

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