Author Topic: Reflex/deflex questions  (Read 8627 times)

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Offline Kegan

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Reflex/deflex questions
« on: December 27, 2008, 08:57:05 pm »
I was thinking about R/D after reading Ferguson's book. First off, with reflex/deflex, the inner limbs would be thicker and more massive- so they don't bend too much- and the outter limbs being lighter- so they can still bend, depsite being relfexed. If tillered to bend in a nice even arc, this bow should be quite stable (like the heavy riser of a recurve), despite the extra boost in speed (beccaused of the light, reflexed tips), right?

Also, before you apply the R/D, the bow would be slightly whip-tillered, correct?

I'm wrapping up what I'm working on know, and figured this would be a cool project for my next one :)

Offline Jesse

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Re: Reflex/deflex questions
« Reply #1 on: December 27, 2008, 09:53:38 pm »
Are you talking about a selfbow or a backed bow? Depends how much reflex or deflex you add.  I know tillering it to a nice arc will look the best to the eye but I dont think it always uses all the limb evenly. It might make a stable bow and it will be easy to string but for speed I would let the outer limbs work just a hair more than the inner which is why they are a bit tricky to tiller. They just dont look right sometimes :)   
"If you can find a path with no obstacles, it probably doesn't lead anywhere."
    --Frank A. Clark

Offline Kegan

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Re: Reflex/deflex questions
« Reply #2 on: December 27, 2008, 10:27:06 pm »
I was talking about a selfbow (is there a discrepency?), and more of a "radical" R/D then one with an inch or less of variance.

It seems you and I are talking about the same thing- with the bow bending more so in the outter limbs (the inner limbs jsut being heavy and deflexed). Similiar to the tiller shape in the PA article about gluing up a Bamboo backed hickory R/D. Smooth and even with the tips pulling out slightly at full draw.

Offline Jesse

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Re: Reflex/deflex questions
« Reply #3 on: December 27, 2008, 10:58:15 pm »
Yup same thing ;D The only discrepancy between a selfbow and a backed bow is that a backed bow will have more energy stored due to the glued on backing
"If you can find a path with no obstacles, it probably doesn't lead anywhere."
    --Frank A. Clark

Offline Jesse

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Re: Reflex/deflex questions
« Reply #4 on: December 27, 2008, 11:01:30 pm »
I should note I never made a r/d selfbow only backed :)
"If you can find a path with no obstacles, it probably doesn't lead anywhere."
    --Frank A. Clark

Offline Kegan

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Re: Reflex/deflex questions
« Reply #5 on: December 27, 2008, 11:08:58 pm »
Sounds good! Now I jsut have to go get a stave roughed out and drying :).

Offline Keenan

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Re: Reflex/deflex questions
« Reply #6 on: December 28, 2008, 12:13:27 pm »
Kegan, Personally I love the design for a self bow. My all time favorite and still my go to hunting bow is a R/D yew self bow that had about 3" of natural deflex right in the handle and so I just reflexed the tips with heat. It's hard to heat in allot of deflex at the handle so if you start with a deflexed stave the work is already done and the wood is not over stressed there.
 The profile of this one is close to what I think your describing. It's not a very prominate reflex so stringing is a breeze but the inner limbs are strong enough to aid in early draw weight.
  I had made this one for the ambush bow challenge to meet the criteria of a bow being strung for long hours even days without losing noticeable poundage. From my testings it seems to have worked.
  If I were to do this one again it might have just a hair more reflex at the tips. Full draw shows tips are no longer refelxed but working while the braced they are still reflexed. ;) So if more reflex is put in the profile at full draw would be less of a full circle. Hope that makes sense.

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« Last Edit: December 28, 2008, 03:10:10 pm by Keenan »

Offline Kegan

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Re: Reflex/deflex questions
« Reply #7 on: December 28, 2008, 09:14:52 pm »
That's a beautiful bow Keenan- and very inspiring! I got a stave roughed out for the most part today- and it already has a natural R/D shape (something I didn't realize until I alrady had it roughed out :D). I will add a bit more reflex on this one.

If I get the mid limbs working a bit more to give it a more circular tiller, will that wind up with a weak spot?

Offline juniper junkie

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Re: Reflex/deflex questions
« Reply #8 on: December 28, 2008, 09:52:05 pm »
Keenan, you da man!! I mean, who else hunts blindfolded??? ;D but, is that a rangefinder on your chest??? hmmmm may have to rethink that position ???

Kegan, the d/r design results in a smoother draw with less stack, I have done some and did not notice a performance difference, but I would flip the tips so that you have 1" of reflex past the handle when laid on the floor (back down) that way you get good cast. I would still leave the limb tips somewhat stiff.

Offline Keenan

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Re: Reflex/deflex questions
« Reply #9 on: December 28, 2008, 10:15:52 pm »
 JJ, that is a GPS don't. What Dave said is right on.

Offline Gordon

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Re: Reflex/deflex questions
« Reply #10 on: December 28, 2008, 10:52:50 pm »
I wouldn't give a r/d profile bow a circular tiller - it will overstress the outer limbs.
Gordon

Offline Kegan

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Re: Reflex/deflex questions
« Reply #11 on: December 28, 2008, 11:05:38 pm »
I wouldn't give a r/d profile bow a circular tiller - it will overstress the outer limbs.

What I mean, was more of a tiller like the one in PA about bamboo-backed hickory reflex/deflex bows. More, even over the entire legnth of the limbs.

Offline Keenan

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Re: Reflex/deflex questions
« Reply #12 on: December 29, 2008, 11:01:03 am »
 Kegan, the most important thing to keep in mind while tillering is to have as much wood bending as evenly as possible. Not so much visual appearance as it is considering the starting profile and how much it has bent from the original point. So what Gordon is saying is that if you have a heavy or fairly predominate reflex and are trying to get an oval or circular shape, then the reflexed portion will be bending considerably more at that spot.

Offline Kegan

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Re: Reflex/deflex questions
« Reply #13 on: December 30, 2008, 02:44:01 pm »
So, while tillering a R/D bow, I should also pay close attention to the taper? Make sure it's even and smooth, like on character bows?