Author Topic: Recurves  (Read 425 times)

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Offline Allyn T

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Recurves
« on: January 13, 2021, 09:09:52 am »
On static recurves which is most important, the degree of the curve or the height of the curve above the back?
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Offline PatM

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Re: Recurves
« Reply #1 on: January 13, 2021, 10:04:45 am »
If the length devoted to the static portion is the same then these two are the same thing.

Offline Pat B

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Re: Recurves
« Reply #2 on: January 13, 2021, 10:42:12 am »
TBBII has a chapter on "Recurves" with good info.
Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

Offline HH~

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Re: Recurves
« Reply #3 on: January 13, 2021, 10:44:21 am »
Not sure what PatM or PatB is telling you? Cant see those posts.
 All my big loop radius statics out perform all other. With or without reflex in the limbs.

HH~
Readily will I display the intestinal fortitude required to fight onto the Ranger objective and complete the mission though I be the lone survivor. RLTW

Offline Allyn T

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Re: Recurves
« Reply #4 on: January 13, 2021, 11:04:56 am »
I ment the height of the tips above the back. Assuming the tips are the same distance above the back, so longer tips on a lower degree curve. Is a sharp turn more desirable or a gradual one? Is string liftoff the guiding action? What do people prefer? I want to make a jig.
« Last Edit: January 13, 2021, 12:21:02 pm by Allyn T »
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Online mmattockx

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Re: Recurves
« Reply #5 on: January 13, 2021, 11:06:26 am »
On static recurves which is most important, the degree of the curve or the height of the curve above the back?

I will second the mention of the recurves section in TBBV2.

You can't say either of those is more important than the other, because you haven't defined 'important'. They both matter and affect how the bow feels and performs.

The height above the back also defines how far in front of the handle the nocks are. The farther forward they are, the more stress the limbs see. This increases early draw weight and energy storage but may over strain the wood.

The degree of the bend (and the radius of the bend) affects the point where the string lifts off the recurves during the draw and what the final string angle is at full draw. This will affect the draw cycle feel and if there is noticeable stacking or not.


Mark

Offline Allyn T

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Re: Recurves
« Reply #6 on: January 13, 2021, 11:34:55 am »
Mark so I guess what I am asking is which features are most important to you guys as individuals building them. Pat I have all 4 tbb books but I know people have different opinions than what is contained in the books. Hedge, so you like a big sweeping hook more than a sharp curve? Does that make liftoff more gradual?
In the woods I find my peace

Offline ssrhythm

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Re: Recurves
« Reply #7 on: January 13, 2021, 12:00:36 pm »
If you use the “take it to extremes” method to try to see what’s going on...then visualize a bow with a 90 degree, right angle bend.   How far into the draw would it take for the string lift off and only touch at the tips?
To the other extreme...if you made the static bend barely perceptible until your tips reached the same position in front of the back as the first extreme example, the bow would need to be longer than the tree it came from, and if that whole portion were static, then that would cause ridiculous mass beyond the working portion of the limb...and seems like it would only represent a stiff tipped reflex.

Visualizing those extremes, it seems to me that example 1 would come closer to producing the desired effect of recurves vs example 2.  So...it seems like the sweet spot would be something toward the “tighter radius”  end of the spectrum.  Also, it seems like a tighter radius would mean a shorter non-working area of limb...meaning more limb able to work and less tip mass to-boot. 

That’s my theoretical take on the question...which I fully understand could be highly flawed based on possible misunderstand of what I’ve read and studied.  I also tend to believe real world vs theoretical, and we’ve already had one vote for sweeping curves vs tight curves...so...there’s that.


Offline bownarra

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Re: Recurves
« Reply #8 on: January 13, 2021, 12:12:23 pm »
Yes the recurve is essentially like a lever allowing you to bend a thicker limb, storing more energy, for the same effort. It works by keeping string angle lower than on a straight limbed bow. So yes tighter and sfairly short is my preference.
Big long 'working' recurves have the potential to be great bows IF they hold the recurve/reflex. Read the section on the Duoflex in TBB.
Sometimes you have a lightbulb moment and think ahha i'll just change x to increase y but then........you lose z.....then introduce subjectivity on draw feel etc and you realize there is no perfect answer....just make what you feel like.

Offline scp

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Re: Recurves
« Reply #9 on: January 13, 2021, 01:45:14 pm »
All my big loop radius statics out perform all other. With or without reflex in the limbs.

Good to know. The size of recurved tips is a major issue. So far as I know, many experts here prefer smaller but tight recurve tips on mildly reflexed limbs. It's a matter of compromise and preference. A lot would depend on what you are trying to accomplish with what kind of materials.

Offline HH~

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Re: Recurves
« Reply #10 on: January 13, 2021, 03:44:31 pm »
My longer radius hook out perform my tight small one of my tight longer ones. I shoot a lot its noticable. Could be better or worse wood in the different bows to know.

You always will have the weight of limb tip to deal with. Thats never goign to go away. make them as light as you can to keep them from flexing while maintaining good durability. Theres know pefect of better bend build em how you like. Play with some scrap wood in you jig before you put you bow in it and bend that first.

Shawn~
Readily will I display the intestinal fortitude required to fight onto the Ranger objective and complete the mission though I be the lone survivor. RLTW

Offline Allyn T

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Re: Recurves
« Reply #11 on: January 13, 2021, 05:18:43 pm »
Alrighty thanks fellas I'll try a couple different designs and slowly test em for myself, and hedge trying a scrap piece first is a good idea.
In the woods I find my peace

Online mmattockx

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Re: Recurves
« Reply #12 on: January 13, 2021, 06:53:25 pm »
Alrighty thanks fellas I'll try a couple different designs and slowly test em for myself, and hedge trying a scrap piece first is a good idea.

Also worthwhile is testing some sample recurve pieces for strength to see how big they really need to be, like DC did a while back.


Mark

Offline PatM

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Re: Recurves
« Reply #13 on: January 13, 2021, 08:07:43 pm »
Also test your ability to actually bend wood to various shapes.  Often the plan people have is not what they are able to achieve.

Offline bownarra

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Re: Recurves
« Reply #14 on: January 14, 2021, 12:30:49 am »
Yes there is some skill in it for sure :)