Author Topic: Lying crono  (Read 4569 times)

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Offline PatM

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Re: Lying crono
« Reply #30 on: December 10, 2020, 06:34:00 am »
Just make the working limb less pure pyramid and your hooks more pronounced and a bit shorter.   

  As to how and why some designs shoot faster or farther despite what we may consider flaws, I don't really analyze that too much.  I'm not an engineer or mathematician.
   If something works, that's all that matters.

bownarra

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Re: Lying crono
« Reply #31 on: December 10, 2020, 06:54:43 am »
A recurve has the mechanical advatage of a lower string angle. This lower angle through most of the draw bends a thicker limb for a given draw weight, thus storing more energy per # of work. Thicker limbs also have an inherantly higher frequency of vibration : eg. return speed. Generally that is offset by having to use a bit wider and thinner limbs on the recurve...gain here....lose there....the search goes on haha
Short and as sharp as possible, kerfed if necessary to make them near 90 degs.

Offline Del the cat

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    • Derek Hutchison Native Wood Self Bows
Re: Lying crono
« Reply #32 on: December 10, 2020, 08:16:54 am »
I think to get the best result is to shoot a marble through the chrono instead on an arrow.

 How do measure marble slingshot bore velocity? With the same chrono in question or do you have a marble shooter you've tested in a shooting tunnel with doppler.

So, you got the fastest self 50lb bow on the flats. Another guy has one 20fps slower (tested with a real chrono). You shoot into teeth of a cross wind and get 200yds. He steps up later and wind is directly into his face and he shoots 220yds. Howd that happen?


HH~
What the wind is doing at face level and what it's doing 60 yards up may be entirely different...
Del
Health warning, these posts may contain traces of nut.

Offline HH~

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Re: Lying crono
« Reply #33 on: December 10, 2020, 08:54:05 am »
Tell me about it. Jumped out of high performance aircraft for a living! Got that right but in desert what you usually seen AGL is what you got at 1000ft plus a little from my desert ABN Ops experience.


HH
MAFA: Makin America Free Again

Long is the road, Hard is the way.

Mother Gue never raised such a foolish child. . . .

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 Selfbowman

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Re: Lying crono
« Reply #34 on: December 10, 2020, 09:22:35 am »
A recurve has the mechanical advatage of a lower string angle. This lower angle through most of the draw bends a thicker limb for a given draw weight, thus storing more energy per # of work. Thicker limbs also have an inherantly higher frequency of vibration : eg. return speed. Generally that is offset by having to use a bit wider and thinner limbs on the recurve...gain here....lose there....the search goes on haha
Short and as sharp as possible, kerfed if necessary to make them near 90 degs.

Got some pics of one of those fast recurves  . I seen DC’s bow last summer. I started out with 7” radius hooks but could not get the string on it so flattened out the first part of the hook near mid limb. Then decided to test it against my record longbow for comparison. The bows are the same length how did that change the string angle much? Are you not sure it moved the working limb out toward the tips more.  I will post a pic of the two bows side by side.
Well I'll say!!  Osage is king!!

Offline Selfbowman

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Re: Lying crono
« Reply #35 on: December 10, 2020, 09:32:30 am »
Here is pics
Well I'll say!!  Osage is king!!

Offline Selfbowman

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Re: Lying crono
« Reply #36 on: December 10, 2020, 09:34:34 am »
Pic
Well I'll say!!  Osage is king!!

Offline Selfbowman

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Re: Lying crono
« Reply #37 on: December 10, 2020, 09:44:44 am »
Stacking those bows reminded me of pic up sticks.😁😁😁
Well I'll say!!  Osage is king!!

Offline Morgan

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Re: Lying crono
« Reply #38 on: December 10, 2020, 10:05:36 am »
This is something I haven’t ever been able to wrap my head around, it’s an honest question, I have no trial and error experience on the subject, just the way my head understands bows.
Set robs performance. The more stress you can have in a design up until set happens the more energy is stored. All of the bows that I see that are built for performance have little working limb and stuff handles. The stiff curves add stress while their sole purpose is moving the limb tips forward? If you are going to limit working limb why would you not want the handle as part of the working limb? Would that not add a little energy without having to carry the limbs a long distance? Meaning if the handle doesn’t work till the last inch of draw, then it is pulling it’s weight to help, but not responsible for carrying the mass of the limbs. In my brain that would make up some for lost working limb real estate without adding length or limb mass.
I know you guys have made a science of this and been over everything with a fine tooth comb,  I am just asking these things not to challenge what you are doing but learn why a properly working handle would not benefit a super stressed design.

Offline sleek

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Re: Lying crono
« Reply #39 on: December 10, 2020, 10:05:47 am »
A recurve has the mechanical advatage of a lower string angle. This lower angle through most of the draw bends a thicker limb for a given draw weight, thus storing more energy per # of work. Thicker limbs also have an inherantly higher frequency of vibration : eg. return speed. Generally that is offset by having to use a bit wider and thinner limbs on the recurve...gain here....lose there....the search goes on haha
Short and as sharp as possible, kerfed if necessary to make them near 90 degs.

Got some pics of one of those fast recurves  . I seen DC’s bow last summer. I started out with 7” radius hooks but could not get the string on it so flattened out the first part of the hook near mid limb. Then decided to test it against my record longbow for comparison. The bows are the same length how did that change the string angle much? Are you not sure it moved the working limb out toward the tips more.  I will post a pic of the two bows side by side.

Arvin, recurring forces working limb to move towards the inner limb more, not towards the tips.
Tread softly and carry a bent stick.

Dont seek your happiness through the approval of others

Offline Selfbowman

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Re: Lying crono
« Reply #40 on: December 10, 2020, 11:07:26 am »
Sleek which part of the limb moves the most? The otter limb right. The otter limb work harder but the maximum compression  is at the fades. Yes or no? I think that the combination of both is where it happens. But what do I know this is my third recurve.😁😁😁😁
« Last Edit: December 10, 2020, 11:10:34 am by Selfbowman »
Well I'll say!!  Osage is king!!

Offline PatM

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Re: Lying crono
« Reply #41 on: December 10, 2020, 11:10:23 am »
How much narrower are limbs on the recurve?  I was under the impression that they were more your typical limb profile but they look quite narrow.

Offline Selfbowman

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Re: Lying crono
« Reply #42 on: December 10, 2020, 11:12:48 am »
Pat it’s a happy accident I guess. That’s all the stave had in it. 1/12” on the recurve. 2-1/8 on the longbow.
Well I'll say!!  Osage is king!!

Offline sleek

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Re: Lying crono
« Reply #43 on: December 10, 2020, 12:11:03 pm »
Sleek which part of the limb moves the most? The otter limb right. The otter limb work harder but the maximum compression  is at the fades. Yes or no? I think that the combination of both is where it happens. But what do I know this is my third recurve.😁😁😁😁

With your pyramid shape all parts should have the same bend radius. As far as what MOVES the most, would be the tips, but thays only because of the arc of circle it travels. The Fades have the most control as a result being nearest the center of the circle. Id give a more descriptive answer, but I only vaguely understand your question.
Tread softly and carry a bent stick.

Dont seek your happiness through the approval of others

Offline PatM

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Re: Lying crono
« Reply #44 on: December 10, 2020, 12:16:49 pm »
Pat it’s a happy accident I guess. That’s all the stave had in it. 1/12” on the recurve. 2-1/8 on the longbow.

  I think just a bit wider would cancel your set.