Author Topic: Energy storage vs arrow speed  (Read 1226 times)

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Offline sleek

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Energy storage vs arrow speed
« on: September 25, 2017, 04:53:04 pm »
I have a bow that stores around 90% its draw weight in energy.  However only shoots a 10gpp arrow in the low 160s. Is tiller limb bending distribution a primary cause for low speeds? It has a little thump in the hand when shot. Not bad but noticable. The tips are thin, so it cant be tip weight. Would a change is brace height adjust this?

What can be potential causes for high energy storage and low speed?
Tread softly and carry a bent stick.

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Offline Marc St Louis

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Re: Energy storage vs arrow speed
« Reply #1 on: September 25, 2017, 05:26:52 pm »
If you get hand-shock with 10 GPP arrows then that is where the energy is going.  If the tips are thin then possible causes are an imbalance in mass between the 2 limb tips which would cause a limb timing issue and/or an imbalance in the way the limbs bend in relation to each other, again that would contribute to limb timing.  Another thing that can affect performance is tiller shape.  How about you post a full draw?
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Offline sleek

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Re: Energy storage vs arrow speed
« Reply #2 on: September 25, 2017, 05:36:58 pm »
Thanks Marc. Here you go.
Tread softly and carry a bent stick.

Dont seek your happiness through the approval of others

Offline sleek

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Re: Energy storage vs arrow speed
« Reply #3 on: September 25, 2017, 05:45:23 pm »
This is after unbrace after an hour braced and 10 shots.
Tread softly and carry a bent stick.

Dont seek your happiness through the approval of others

Offline sleek

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Re: Energy storage vs arrow speed
« Reply #4 on: September 25, 2017, 05:46:53 pm »
The lower limb has more set than upper. I guess that's causing my imballance. Im gonma heat treat that limb to stiffen it up some.
Tread softly and carry a bent stick.

Dont seek your happiness through the approval of others

Offline DC

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Re: Energy storage vs arrow speed
« Reply #5 on: September 25, 2017, 06:16:33 pm »
Leonwood pretty much pegged his low speed to his release over here
http://www.primitivearcher.com/smf/index.php/topic,61556.30.html

mikekeswick

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Re: Energy storage vs arrow speed
« Reply #6 on: September 26, 2017, 02:35:38 am »
Everything Marc said for the handshock and too much set. Once you start pushing limits like that bow you are into the realms of set/slow return speed of the limbs.
If you really want a short bow then horn/wood/sinew is the way to go :) Stop torturing these short pieces of wood! They would be in much better shape if you only drew 24" but....