Author Topic: What does reflexing do?  (Read 2504 times)

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Offline sleek

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What does reflexing do?
« on: August 24, 2016, 04:32:47 pm »
Does it only increase earle draw weight, or does it also increase final draw weight? Does it strain the belly more, the back, both, neither?

I have recurved tips after a bow was built. No draw weight increase only string tension went up. The brace height didnt change with the same string either. So, if a limb were to be reflexed evenly across  the entire limb, what effect would it have verses if it were straight?
Tread softly and carry a bent stick.

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Offline Del the cat

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Re: What does reflexing do?
« Reply #1 on: August 24, 2016, 04:50:56 pm »
Woo, now there's a question  :o
It will take a brave or foolish man to answer, but seein' as how I'm a little of both I'll say how I see it ::).
Now I reserve the right to be wrong here!
Basically it changes the force draw curve and acceleration profile.
The problem with a simple straight bow is that maximum force and maximum acceleration is all at full draw, if you imagine trying to get the best acceleration out of your car, you don't simply red line it and drop the clutch.
reflex will increase early draw weight, but due to the change in string angle can give less change at full draw. The effect is even more accentuated if the reflex is severe and the string touches the limbs (like hooked tips or levers).
The problem with it is you are always limited by the wood and the skill of the bowyer. The best design made with poor timber by an average bowyer will be worse than a basic bow made with good wood by a good bowyer.
As far as I know the actual maths and physics of how reflex works is beyond most of us, and even thos who analyse it tend to use simplified models.
A compound achieves the ultimate improvement of FD curve and acceleration, by getting the arrow to speed up smoothly at an increasing rate, low poundage at full draw gets the arrow moving and then the full force ramps up giving a smooth acceleration not the hard lick up the backside that a simple bow gives.
Anyhow, I've popped my head over the parapet to be shot at... feel free one and all.
Del
Health warning, these posts may contain traces of nut.

Offline Badger

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Re: What does reflexing do?
« Reply #2 on: August 24, 2016, 04:54:53 pm »
Does it only increase earle draw weight, or does it also increase final draw weight? Does it strain the belly more, the back, both, neither?

I have recurved tips after a bow was built. No draw weight increase only string tension went up. The brace height didnt change with the same string either. So, if a limb were to be reflexed evenly across  the entire limb, what effect would it have verses if it were straight?

  Sleek, you have several questions. You recurved a bow and the draw weight did not go up? This means the bow lost the reflex from the recurves in additional set or it would have gone up.

  It does increase final draw weight and it also increases strain on the back and the belly. The idea to adding reflex is to increase early draw weight so it can build slower to reach final draw weight and store more energy. You need to allow for wider and thinner limbs on a reflexed bow to avoid taking set.

Offline sleek

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Re: What does reflexing do?
« Reply #3 on: August 24, 2016, 05:32:21 pm »
Awesome responses. Thanks, I have a more clear grasp on it. Though I feel like a ninny asking basic questions sometimes.
Tread softly and carry a bent stick.

Dont seek your happiness through the approval of others

Offline DC

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Re: What does reflexing do?
« Reply #4 on: August 24, 2016, 05:40:55 pm »
The next question should be ,"What does deflexing do." Then ,"What do they do together." The simpler a question sounds the tougher it is to answer. The simple ones should be asked more often. Keep them coming.

Offline Badger

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Re: What does reflexing do?
« Reply #5 on: August 24, 2016, 05:47:22 pm »
The next question should be ,"What does deflexing do." Then ,"What do they do together." The simpler a question sounds the tougher it is to answer. The simple ones should be asked more often. Keep them coming.

  Deflexing by itself plays hell with your force draw curve, not a good thing unless you are making a survival bow with compromised wood species. When used in tandem with reflex it can give you improved string angles that will further lower your pound per inch gained and allow for even higher early draw weight.

Offline sleek

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Re: What does reflexing do?
« Reply #6 on: August 24, 2016, 05:49:35 pm »
Well, deflexing I know requires a thicker limb to allow for draw weight because the string angle has leverage advantage over it before its ever drawn. Based off of what badger said above, I assume it should be narrower as well. It also allows for a less stressed belly and back, which is often the reason I do it, and it decreases string tension which is a huge draw back. But, with the lower set, and less stressed wood, going narrower on tje limbs, should allow for a lighter limb and more effecient limb is my thought.
Tread softly and carry a bent stick.

Dont seek your happiness through the approval of others

Offline sleek

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Re: What does reflexing do?
« Reply #7 on: August 24, 2016, 05:52:36 pm »
The next question should be ,"What does deflexing do." Then ,"What do they do together." The simpler a question sounds the tougher it is to answer. The simple ones should be asked more often. Keep them coming.

  Deflexing by itself plays hell with your force draw curve, not a good thing unless you are making a survival bow with compromised wood species. When used in tandem with reflex it can give you improved string angles that will further lower your pound per inch gained and allow for even higher early draw weight.

So Steve, would it stand to reason that a bow with set, could bennefit some by reflexing its tips? I know it will take more set as a result but will the string angle help?
Tread softly and carry a bent stick.

Dont seek your happiness through the approval of others

Offline Badger

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Re: What does reflexing do?
« Reply #8 on: August 24, 2016, 05:53:35 pm »
Well, deflexing I know requires a thicker limb to allow for draw weight because the string angle has leverage advantage over it before its ever drawn. Based off of what badger said above, I assume it should be narrower as well. It also allows for a less stressed belly and back, which is often the reason I do it, and it decreases string tension which is a huge draw back. But, with the lower set, and less stressed wood, going narrower on tje limbs, should allow for a lighter limb and more effecient limb is my thought.

  Sleek, you don't have to give up set on any bow as long as you stay within its capabilities. All bows regardless of draw weight, design, reflex, recurves etc should have the same amount of strain when fully drawn. If a bow takes set it is because you asked too much of the design. A 150# 62" bow should have the same strain as a 10# childs bow.

Offline sleek

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Re: What does reflexing do?
« Reply #9 on: August 24, 2016, 06:03:44 pm »
That much i did know. But knowledge and execution are often seperated by skill level.
Tread softly and carry a bent stick.

Dont seek your happiness through the approval of others

Offline George Tsoukalas

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Re: What does reflexing do?
« Reply #10 on: August 24, 2016, 09:22:23 pm »
Does it only increase earle draw weight, or does it also increase final draw weight? Does it strain the belly more, the back, both, neither?

I have recurved tips after a bow was built. No draw weight increase only string tension went up. The brace height didnt change with the same string either. So, if a limb were to be reflexed evenly across  the entire limb, what effect would it have verses if it were straight?

Reflexing increases early draw weight resulting in more energy storage. Yes, it would result in a higher final draw weight.

Strains the back more.

It also decreases string angle making for a smoother draw with little of no stacking as the final few inches of draw don't result  in as much increase as earlier in the draw.

Jawge
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