Author Topic: Pyramid vs everything else  (Read 1934 times)

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Offline DC

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Pyramid vs everything else
« on: November 06, 2017, 01:25:09 pm »
I generally layout my bows in a pyramid. Even taper from the fades to the tip. Aesthetics aside, is there a performance reason for doing it any other way?
Vancouver Island

Offline Jim Davis

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Re: Pyramid vs everything else
« Reply #1 on: November 06, 2017, 01:50:42 pm »
If you mean side taper and little or no thickness taper, then yes, that's what is called a "pyramid" design. And I know of no physical reason to make a wood bow any other way.

All these "flipped" tips and such are just for the eye or to keep string angle within practical limits or twho overcome some defect in materials or workmanship.

I would rather shoot bows than make them, so I almost always make a "pyramid" bow, though I hate that term. They look NOTHING like a pyramid, even in front or back view. Now if there were some good reason to use an architectural term, then "obelisk" is a whole lot closer to the look. I suspect  the person who plastered the pyramid moniker on the design had never even heard of an obelisk. The language grows from the bottom.
Jim Davis

Kentucky--formerly Maine

Offline PatM

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Re: Pyramid vs everything else
« Reply #2 on: November 06, 2017, 01:55:01 pm »
How many flight and speed records are held by pyramid bows? That might be the answer.

 Pyramid bows are ugly though so I wouldn't make one even if they were better. ;)

 Flipped tips and recurves are often put in to  take advantage of superior material, not overcome defects in inferior material.   Not that people don't try the latter.

Offline DC

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Re: Pyramid vs everything else
« Reply #3 on: November 06, 2017, 01:59:41 pm »
How many flight and speed records are held by pyramid bows? That might be the answer.
Where's Badger??


Because I'm usually using small diameter staves(high crown) and the "pyramid" doesn't come to a point I always have some thickness taper. It's the even side taper that I'm asking about.
Vancouver Island

Offline PatM

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Re: Pyramid vs everything else
« Reply #4 on: November 06, 2017, 02:07:51 pm »
 I know. I just wouldn't do that.  The stave probably wants width retained farther out the limb so why not do that?

Offline Badger

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Re: Pyramid vs everything else
« Reply #5 on: November 06, 2017, 02:11:45 pm »
  As far as I know a pyramid will keep up with an equally reflexed parallel limb bow. I prefer the parallel limbs because I feel it works better when heating in gentle curves and reflexing. I find the biggest difference has to do with how much reflex and not so much design. Even the elbs seem to be about the same speed. I always start mine off as parallel with the last 14" tapered, by the time I am done it is more closely resembling a pyramid most of the time anyway. I think the parallel gives me more options during the build if I need a little more bending limb, if I don't need it I end up shaving it off most of the time.

Offline Jim Davis

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Re: Pyramid vs everything else
« Reply #6 on: November 06, 2017, 02:18:05 pm »
The most that can be asked of any material and any design is that as much material as possible should contribute to the draw force and that as little mass as possible be moved during the shot. Your version of that concept will determine the relative efficiency of the design.
Jim Davis

Kentucky--formerly Maine

Offline PatM

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Re: Pyramid vs everything else
« Reply #7 on: November 06, 2017, 02:22:03 pm »
I know, that's why light tipped recurves are better. ;)

Offline Jim Davis

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Re: Pyramid vs everything else
« Reply #8 on: November 06, 2017, 02:30:11 pm »
...but...the mass at the tips of a recurve is much more than the mass at the tips of a "pyramid...."
Jim Davis

Kentucky--formerly Maine

Offline PatM

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Re: Pyramid vs everything else
« Reply #9 on: November 06, 2017, 02:48:55 pm »
   Not to  the degree that it isn't offset by more optimally straining the rest of the limb, which is designed to take advantage of that by carrying width farther out the limb.

Offline DC

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Re: Pyramid vs everything else
« Reply #10 on: November 06, 2017, 02:52:36 pm »
  The stave probably wants width retained farther out the limb
I hate to do this but,"Why would it want this?"
Vancouver Island

Offline DC

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Re: Pyramid vs everything else
« Reply #11 on: November 06, 2017, 02:56:47 pm »
  I feel it works better when heating in gentle curves and reflexing.
As in easier to do or better performance wise? Maybe recurves don't tend to twist on a wider limb? I think I've heard that.
Vancouver Island

Online bradsmith2010

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Re: Pyramid vs everything else
« Reply #12 on: November 06, 2017, 03:00:58 pm »
I very rarely cut the front profile,, I just shape it as I go depending on the bend,,, sometimes it turns out a bit pyramid, and sometimes a bit more parallel... especially white woods might need to be a bit wider,,,  especially heavier bows too,,,,
there is a reason most Native bows are not all pyramid,, right,, (-P

Offline DC

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Re: Pyramid vs everything else
« Reply #13 on: November 06, 2017, 03:07:32 pm »

there is a reason most Native bows are not all pyramid,, right,, (-P

When you are using a sharp rock it's easier to taper 1' than 3'???? Did I get it, huh, huh.
Vancouver Island

Online NonBacked

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Re: Pyramid vs everything else
« Reply #14 on: November 06, 2017, 03:29:38 pm »
Look what you got started, DC! I love the levity of experienced bowyers!

It’s actually a very good question about limb design and performance. Esthetics aside, I won’t say pyramids are ugly or pretty…they’re “cute”. And, I agree with Jim – if you want a quick-build, pyramid is the way to go and they have good shooting characteristics. My first consideration when deciding on a specific design is the quality of the stave, and then the available width. Some staves will only work with an ELB or a pyramid design. When using narrow staves, (you already know this) you will have more flexibility with the draw weight by using parallel sides – more wood, more power. The next variable is adjusting the length of the parallel sides…again, stave quality is the first priority, and then the intended use (hunting, target, kid’s bow, etc.) is factored-in to achieve the intended draw weight.
H