Main Discussion Area > Flight Bows
Virtual Mass revisited
willie:
--- Quote --- I have always suspected that a tiller where the limb bent progressively from outer to inner could also help to control this vibration by simply returning to brace over a more extended period
--- End quote ---
like this?
s1 is a 65" 50 # stiff handled pyramid with strain that drops off steadily toward the tips.
(I can quickly re-draw it any way you like)
sleek:
Potential Energy of the Bow = Bow Hysteresis + Kinetic Energy of the Bow + Kinetic Energy of the Arrow
The bows efficiency has more losses than only hysteresis. Its has losses through any tiller less than perfect. Not just from set or from moisture, but from less than perfect energy transfer due to whip tiller or limbs not being timed exactly.
sleek:
--- Quote from: willie on September 26, 2020, 09:57:30 pm ---
--- Quote --- I have always suspected that a tiller where the limb bent progressively from outer to inner could also help to control this vibration by simply returning to brace over a more extended period
--- End quote ---
like this?
s1 is a 65" 50 # stiff handled pyramid with strain that drops off steadily toward the tips.
(I can quickly re-draw it any way you like)
--- End quote ---
I've tillered my bows for years with the thought of a wave being set up upon string release. The idea being the limbs act as a whip, with the energy flowing and being concentrated as it flows from the inner limbs towards the tips. I have the saying, last to bend, first to release. If all the limbs energy releases at once, like an explosion, the energy does not flow and many losses occur. So I tiller the working limb closer to the tips to bend first as I draw it the bow, and the inner limb to bend last. The inner limb is last to bend on draw but first to release its energy upon string release. This flows like a wave all the way to the tips allowing the most energy efficient delivery of energy possible.
willie:
sleek,
the equation is from the other site. it shows the basics, but does not include all the ways tillering can be done poorly.
Here is the same bow with the strain increasing towards the tips. Is this what you mean? Whether any part of the limb bends first or last as it is drawn is an interesting idea, and might depend on string angles. How it returns to brace could be different, as the arrow is accelerating. maybe.. I think you would have to have a slo-mo camera to actually tell.
Badger:
Willie that is pretty close but I like to keep outer limbs stiff to further reduce working limb area.
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