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Hysterisis and performance

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Badger:
  That might not have qualified for the present primitive classes because of the arrow rests and overdraws. I wish I could find more info on that bow. I rememeber Dan saying that Harry felt that the Yew on that bow was the best he had ever seen. I would have been interesting to see how the arrows performed as the bow was being shot in. I think that bow shot 603 yards. Don Brown currently holds the unlimited complex composite record with 619 yards, not sure if Harry built that bow or Don built it. They never listed the bowyers only the shooters.

PatM:
They were both built by Harry. The yew bow shot 544 according to most sources.
 However many of the old time bows were not shot with an overdraw. that seemed to be a later feature.
 The picture of Murray Yantis shooting well over 400 yards(I think 466) shows no evidence of an overdraw and he has the long arrow cranked past his jaw.
 PS  Are you including sinew backed and simple backed composites in this discussion?

Badger:
  As long as they are natural materials. I know they had several guys shooting bows over 400 yards in the 60 and 70 pound range. I am not sure if they were all natural or not. I really don't think it would have made a lot of difference.

avcase:
Steve,
Your opening post on this thread is excellent!  I always viewed hysteresis as a fixed loss that I had no control over, so I never bothered giving it much more thought. But you have put together a really novel idea, to use hysteresis and virtual mass as a tool to explain the health of the materials in the bow.  The challenge is being able to easily measure it. I wish I had a draw board that would measure the force draw curve of a bow in as little as a few seconds. Wouldn't that be nice to have?



Alan

Badger:
  Allen, It would be nice. That was the reason I chose to use an extemely heavy arrow and just measure the speed instead of plotting the curve. Plotting the curve doesn't pick up on much of the hysterisis. The part I avoided going into here involves juggling a few percentage points at the start and finding where the virtual mass seems to either hold at the most stable point or change in a more linear fashion. Using the heavy arrow to figure stored energy I am forced to estimate somewhat the efficiency but because of the weight I am only working around a couple of percentage points.

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