Hello Folks,
I told you I would report back when I received answers from all the manufacturers regarding my hysteresis question.
Many factories had no facility for submitting an e-mail question (i.e. Mathews). Other factories did not answer at all (i.e. Bear Archery)
Frankly, I was surprised by both the responses and the lack of response to what I felt was a fair question.
Find below the direct quotes from the two engineering departments that did respond.
My thanks go out to Martin Archery and Hoyt Archery, both of whom replied promptly. I was hoping for additional communication but was disappointed.
Konrad,
Thanks for the inquiry. Here is a response that I received from our engineering manager:
The change in efficiency of the limbs is minor when compared to the other variables of the system. We typically run a test where we cycle (draw, let-down, repeat) a bow system for 30,000 times in a 12 hour period. This creates “significant” thermal conditions in the entire system (not just limbs). The system is then tested and the efficiencies are minimal when comparing to impact points of shot arrows. Typically the system will lose about ˝% after this grueling test is run and the effects on accuracy require a shooting machine to measure at 60 yds.
I know that this answer is a bit short compared to the length of your inquiry but I hope that it helps answer some of your question.
Please let me know if you have further questions.
Regards
~Tom
Hoyt CS Team
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Hysteresis is something that can be measured, but it doesn't seem to change very much if a bow is fired at a high rate, vs. a lower rate.
I personally do not believe that hysteresis accounts for a very high percentage of the wasted energy released during the shot.
I think the overwhelming majority of energy loss, is due to the limbs having to move so much "stuff" that doesn't leave with the arrow. The string, cables, cams and limbs, all possess mass, that must be moved. High speed video shows how much kinetic energy remains in the bow following the shot.
As archers, we feel and hear it as vibration following the shot. If we use a heavier arrow, the ratio of arrow-to-allthatotherstuff mass, is improved and the efficiency of the bow is increased. As a result, less energy is left over to make everything "bounce around" and the bow will be quieter as well.
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