Author Topic: deflex and reflex theory  (Read 38224 times)

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Offline Bayou Ben

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Re: deflex and reflex theory
« Reply #75 on: October 24, 2019, 03:18:59 pm »
I'm silently enjoying this thread.
My next build will be for performance and I've changed the design parameters 3 times as this thread has evolved  :OK

Offline Stick Bender

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Re: deflex and reflex theory
« Reply #76 on: October 24, 2019, 03:24:25 pm »
I saw you sand bagging Ben  :D  I was waiting for you to chime in it will be interesting to see your bow is it a BBO ?
If you fear failure you will never Try !

Offline Bayou Ben

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Re: deflex and reflex theory
« Reply #77 on: October 24, 2019, 03:31:11 pm »
I saw you sand bagging Ben  :D  I was waiting for you to chime in it will be interesting to see your bow is it a BBO ?
;D
BBI, Pyramid, r/d.  I want it to have almost no set, so I plan to overbuild it, especially the inner limbs. 

Offline Stick Bender

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Re: deflex and reflex theory
« Reply #78 on: October 24, 2019, 03:35:33 pm »
Sweet !! sounds good now add a forward handle  >:D glad your finding some time to build ! Looking forward to your results !
If you fear failure you will never Try !

Offline Bayou Ben

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Re: deflex and reflex theory
« Reply #79 on: October 24, 2019, 03:50:13 pm »
Sweet !! sounds good now add a forward handle  >:D glad your finding some time to build ! Looking forward to your results !

I really don't have time but I plan to squeak it out in the middle of the night sometime soon.
I like the way forward handles shoot but man they are a PITA to get right...Not sure I'm up for that on this one but we'll see! 

Offline Halfbow

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Re: deflex and reflex theory
« Reply #80 on: October 24, 2019, 05:23:46 pm »
Stick Bender, I love your experiments. I prefer working with primitive materials, but modern ones sure make bow science easier. Have you ever explored the limits of reflex? If you want a challenge, could try something like this:



I call it the extreme reflexed, small working area, stiff ended, straight at full draw D/R bow. ...Still working on the name.

But this seems like the direction of the ideal to me. It gets you the best of all worlds with few drawbacks. Light limbs with very high string tension from the reflex, good harmonics from the stiff outer limbs, good lever length and string angle from the deflexed handle in its finest form (straight limbs at full draw),

The only thing it lacks is ease of make. It would be pretty sadistic. I've never worked with materials that can take it, but you seem like a good man for the job. I don't know the limits of glass, but I know they're high.

Oh, and ease of use would be lacking too. Good luck trying to string the thing. ;D Though it should be easier than some extreme asiatic designs.

Offline Badger

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Re: deflex and reflex theory
« Reply #81 on: October 24, 2019, 05:35:09 pm »
  I have built several with that profile, there is a huge amount of tension on the string at brace it it wants to turn the bow inside out, short working area will help to mitigate the torquing but no wood that I know of can stand up to that much bending unless you make it in the 10# or 15# range. I made my osage bow almost 3" wide and had nore working area than the bow in the pic and it almost could take it but not quite.

Offline Deerhunter21

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Re: deflex and reflex theory
« Reply #82 on: October 24, 2019, 05:44:30 pm »
i feel like this should be archived once its done! really good discussions here!
Life before death. Strength before weakness. Journey before destination.

Offline Halfbow

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Re: deflex and reflex theory
« Reply #83 on: October 24, 2019, 05:46:01 pm »
Yeah I'm definitely not proposing that that design be made out of wood. I'm imagining more horn and sinew. I agree, the high string tension will make the stability something to contend with. But considering bows reflexed like this are real:



Nothing seems unrealistic about it to me. Plus, both the small working area and the deflexed handle help to make the design more stable than the bow in that photograph.

Edit: I'd love to see the bows you made with that design. I've never seen one like that.
« Last Edit: October 24, 2019, 07:41:22 pm by Halfbow »

Offline Badger

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Re: deflex and reflex theory
« Reply #84 on: October 24, 2019, 08:19:03 pm »
  I don't think a hornbow or fiberglass bow could hold up to not twisting with that design. Not too hard to brace but once braced the string is under a huge amount of tension. Too much for a bow to stand up to. Maybe with the very small working limb area it might make it. I bet it would be a screamer.

Offline avcase

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Re: deflex and reflex theory
« Reply #85 on: October 25, 2019, 09:53:35 am »
  Allen, they do store more energy. And they tend to be more efficient as long as they remain stiff in the outer limb. If someone tillers amn r/d bow to look like a d bow when braced they loose all the benefits.

Yes, there is some mild cam-like effect that gives a deflex-reflex bow a better force-draw curve. Stiffening the outer limb always helps.  Any recurvature present at brace also has a stiffening-like effect.  I thought I ran some comparisons several years ago between a straight pyramid-style bow with constant thickness, and a deflex-reflex design with constant thickness.  I’ll have to dig that up.

Alan

Offline avcase

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Re: deflex and reflex theory
« Reply #86 on: October 25, 2019, 10:44:32 am »
The ultra-reflexes horn bows are pretty interesting. They don’t have a particularly impressive force-draw curve, but are extremely efficient due to the small bending area and minimal flex in the outer part of the arms. Much of that unbraced reflex goes away during a conditioning process while it is strung where the bow it tortured into a stable braced position. When unstrung after shooting, most of that reflex is gone.

Alan

Offline Badger

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Re: deflex and reflex theory
« Reply #87 on: October 25, 2019, 11:09:15 am »
   Something interesting about bows with curves in the limbs. They don't bend just according to thickness, every inch of the limb responds to the pull according to its current angle in relation to the string. So if you have a little whoop te do in the limb it will bend more even if it is the same thickness.

Offline backtowood B2W

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Re: deflex and reflex theory
« Reply #88 on: October 25, 2019, 11:17:31 am »
My latest bows have been mostly D/R.
Following this with high interest. Cannot add much but what I recognized in the tillering process, when the string starts to lift from the limb, lets say you are rising brace height, its a very critical part and you loose most of the incredible string tension.
Thanks for all the thoughts
B2W
« Last Edit: October 25, 2019, 11:32:23 am by backtowood B2W »

Offline bradsmith2010

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Re: deflex and reflex theory
« Reply #89 on: October 25, 2019, 11:45:47 am »
yes but one of Marcs fastest bows, is just refelxed,, white lightning I believe