Author Topic: Pyramid vs everything else  (Read 1939 times)

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Offline upstatenybowyer

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Re: Pyramid vs everything else
« Reply #15 on: November 06, 2017, 03:40:16 pm »
I'm with Steve about there being more wood for making adjustments with parallel limbs. I used to try to get a bow roughed out as close as possible to the finished dimensions, but I've learned the hard way too many times that "you can never put wood back on." Well, at least not most of the time  :D
"Even as the archer loves the arrow that flies, so too he loves the bow that remains constant in his hands."

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Offline PatM

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Re: Pyramid vs everything else
« Reply #16 on: November 06, 2017, 03:45:21 pm »
  The stave probably wants width retained farther out the limb
I hate to do this but,"Why would it want this?"

  To have more width to take strain when your stave is not perfect.

Offline DC

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Re: Pyramid vs everything else
« Reply #17 on: November 06, 2017, 04:06:57 pm »
  The stave probably wants width retained farther out the limb
I hate to do this but,"Why would it want this?"

 
  To have more width to take strain when your stave is not perfect.

Got it, thanks
Vancouver Island

Offline DC

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Re: Pyramid vs everything else
« Reply #18 on: November 06, 2017, 04:22:58 pm »
I'm with Steve about there being more wood for making adjustments with parallel limbs. I used to try to get a bow roughed out as close as possible to the finished dimensions, but I've learned the hard way too many times that "you can never put wood back on." Well, at least not most of the time  :D

I've always done the front profile more or less to final size first. You guys are making sense. I'm going to rethink this. So you get the thickness to what, floor tiller, 20 inches?  Then work the front profile?
Vancouver Island

Offline mikekeswick

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Re: Pyramid vs everything else
« Reply #19 on: November 06, 2017, 10:42:41 pm »
No way! You need a front profile established first.
For fancy curves keep the width parallel. This means the outers limbs are thinner and will accept and hold reflex better than a thicker piece of wood.For a straight limbed bow pyramids can't be beaten. Even thickness = even bend = Equal strain....aka the holy grail of bow making :)
Of course all this is based on a stave that will allow you to make what ever design you want.

Offline Del the cat

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Re: Pyramid vs everything else
« Reply #20 on: November 07, 2017, 12:53:09 am »
Why would you do anything other than pyramid?
1. Wood doesn't grow wide and flat backed in easy to harvest sizes....
2. Easy to harvest sizes wouldn't be a consistent thickness along or across the limb if simple sawed out to a pyramid profile.
Next! ::)
Del
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Offline Sir Failalot

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Re: Pyramid vs everything else
« Reply #21 on: November 07, 2017, 03:08:48 am »
Very interesting!

I mean the wood gives the design, that's for sure. I've read that some wood wants a more flat but thin design and some wood a thicker, narrower. The characteristics of the wood would be the reason for it. So "some wood wants to be an ELB, some a flat bow". Is that somehow true or completely wrong?

Historically, we see that there are periods where ELB's where mainly common even in cultures where bows where not as massively produced as in england at the time of the famous english longbowman. The reason for an ELB design in england might be the simplicity of the design, and the fact that you can get more ELBs of a tree than flatbows. But the other cultures did not need that amount of bows (at least bot as high as in England). The bows of that cultures all have a very high draw weight and where made of hard wood.
That in conjunction with what I've read ("some wood wants to be an ELB") made me think that:
 (most) hard wood --> ELB

So.. what is true?

Offline upstatenybowyer

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Re: Pyramid vs everything else
« Reply #22 on: November 07, 2017, 03:09:54 am »
I'm with Steve about there being more wood for making adjustments with parallel limbs. I used to try to get a bow roughed out as close as possible to the finished dimensions, but I've learned the hard way too many times that "you can never put wood back on." Well, at least not most of the time  :D

I've always done the front profile more or less to final size first. You guys are making sense. I'm going to rethink this. So you get the thickness to what, floor tiller, 20 inches?  Then work the front profile?

That's not what I meant actually. I just meant that if I start with parallel limbs and I run into something in the wood that needs accommodation or modification I've got more wood to work with. Fundamentally, I'm with Mike. It's important to establish a front profile based on the design of the bow.
"Even as the archer loves the arrow that flies, so too he loves the bow that remains constant in his hands."

Nigerian Proverb

Offline Del the cat

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Re: Pyramid vs everything else
« Reply #23 on: November 07, 2017, 04:31:26 am »
...
 (most) hard wood --> ELB

So.. what is true?
No!...
If you mean hard as it physically hard.... well Yew is soft. It's also a "softwood". >:D
Osage is both hard and a hardwood! That'll make an ELB.
Hazel is a hardwood but it's soft, It's not best suited to an ELB, but can make one if allowances are made.
Ash is a hardwood and it's hard, It's not best suited to an ELB, but can make one if allowances are made.
Hope that's cleared it up ;)
Del
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Offline Sir Failalot

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Re: Pyramid vs everything else
« Reply #24 on: November 07, 2017, 04:52:41 am »
Okay, so not every hardwood is actually hard and not every softwood soft.  :o

So if we take osage and a stave that is as perfect for a pyramid as it is for an ELB.. will it perform better as an ELB or as a pyramid?
« Last Edit: November 07, 2017, 05:06:19 am by Sir Failalot »

Offline PatM

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Re: Pyramid vs everything else
« Reply #25 on: November 07, 2017, 05:04:46 am »
It will perform better as a static recurve. Haven't we already covered this? lol

Offline Eric

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Re: Pyramid vs everything else
« Reply #26 on: November 07, 2017, 05:32:29 am »
I think how well a pyramid design performs depends on how you define performance. If you only look at fps, then among straight-stave bows with no recurves or reflex, a pyramid is a superior design (in my opinion). My fastest straight-stave bows have all been pyramids. But with any design there are trade-offs. If you want a straight-stave bow and you choose to maximize fps, some other factor is suffering. For pyramid bows, in my mind one of the factors that suffers is the longevity of the bow. You're stressing the mid-limb of the pyramid bow so that it's about as efficient as it's going to get, but that means it's under more strain and the wood fibers will break down sooner from that strain.

Although they haven't been quite as fast, I've gravitated more towards paddle bows as of late because the wider mid-limb seems to buffer the bow against excessive strain a bit better. I'm willing to sacrifice a little efficiency in favor of a bow that maintains its performance longer.

But that's just me, of course. Others are free to make their own trade offs.
Eric Garza
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Offline stuckinthemud

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Re: Pyramid vs everything else
« Reply #27 on: November 07, 2017, 05:45:20 am »
so is a paddle bow widest at mid-limb, as opposed to parallel chord?

Offline Jim Davis

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Re: Pyramid vs everything else
« Reply #28 on: November 07, 2017, 05:59:53 am »
The only engineers that I know of who wrote about bows were Paul Klopsteg  and Clarence Hickman. Some of you need to read their works, since none of us is an engineer (as far as I know). You'd get lost in some of the math, as I do, but they draw their conclusions in plain words.
Jim Davis

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Offline Selfbowman

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Re: Pyramid vs everything else
« Reply #29 on: November 07, 2017, 06:15:12 am »
I like a sort of pyramid real close to a Badger bow. The better you
Have even diminishing . The better the performance . That is just
the way it works. Boat paddle Bows create wind drag. Swing a boat paddle
edge ways and then with the boat paddle flat into the wind. Just
facts of life. This is why I build long narrow bows  . The trick is to eliminate
set. We all strive for that. Arvin
Well I'll say!!  Osage is king!!