Main Discussion Area > Flight Bows
High gear/low gear
willie:
--- Quote from: sleek on March 28, 2019, 12:07:47 pm ---Thought experiment: Applying arrow paradox to bow limbs on release. The most motivated part of a bows limb will move first and may move faster than the limbs tips. This loads the other parts of the limbs with energy until all energy is spread equally across the limb. Under slow motion, it probably looks like a wave. If the timing of this wave could be done correctly, the tips would be be at tje crest right when brace heightis hit, snapping the last of the energy into the arrow.
--- End quote ---
I can see it looking like a wave if it is jim hamms turtle bow in TBB, but we always go with tips as light as practical in real life
willie:
good videos Pat.
going to .25 speed it looks like any part of the limb getting ahead of any other part only happens after the arrow is gone
Tuomo:
Bow: 36#@27"
200 grain arrow: https ://www.youtube.com/watch?v=izv2y9qgJ8g
1100 grain arrow: https ://www.youtube.com/watch?v=Y4JCD2_O5uI
No difference in bending of the limb.
It is all about efficiency - string, arrow and limbs are moving as a one moving part. The bow is storing certain amount of potential energy, which depends on many things - and hysteresis is one of the most important factor in wooden bows. As Steve said earlier, a bow which is the most energy efficient, is the fastest bow: "the fastest bow with any arrow will usually stay the fastest regardless of arrow weight".
Marc St Louis:
--- Quote from: Tuomo on March 28, 2019, 11:30:58 pm ---Bow: 36#@27"
200 grain arrow: https ://www.youtube.com/watch?v=izv2y9qgJ8g
1100 grain arrow: https ://www.youtube.com/watch?v=Y4JCD2_O5uI
No difference in bending of the limb.
It is all about efficiency - string, arrow and limbs are moving as a one moving part. The bow is storing certain amount of potential energy, which depends on many things - and hysteresis is one of the most important factor in wooden bows. As Steve said earlier, a bow which is the most energy efficient, is the fastest bow: "the fastest bow with any arrow will usually stay the fastest regardless of arrow weight".
--- End quote ---
No difference in limb bending but big difference in limb vibration
avcase:
I always figured a low gear design is one that simply lacks “high gears”. It is one of those bows that is said to “like heavy arrows”.
A straight bow with zero brace height and long flexible limbs could be considered the ultimate low gear bow. The bow stores lots of energy in the draw, but the limbs won’t be able to get out of their own way fast enough when shot. The archer would almost be better off throwing the arrow!
For maximum efficiency, the ideal situation is where all parts of the bow return along the same path as when drawn. When a bow shoots a very heavy arrow, this is approximately what is happening and efficiency is relatively high. If the design can maintain this for very light arrows without additional waves of limb distortion or vibration, then the light arrow efficiency will also be very high. There would also be little visible difference in post-shot vibration on the high speed video between the heavy and light arrow.
Alan
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