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Straight bow, optimal tiller profile (VirtualBow)?

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willie:

--- Quote from: Tuomo on December 16, 2025, 04:18:20 pm ---Also, the more whip-tillered the bow is, the more efficient it becomes (the reason here being lower tip mass)


--- End quote ---
Although the tip area with the steep taper is somewhat lighter, I dont think those FPS are attainable because the max strains in bow 9 are 73% higher than bow 4

Tuomo:

--- Quote from: willie on December 16, 2025, 09:28:18 pm ---
--- Quote from: Tuomo on December 16, 2025, 04:18:20 pm ---Also, the more whip-tillered the bow is, the more efficient it becomes (the reason here being lower tip mass)


--- End quote ---
Although the tip area with the steep taper is somewhat lighter, I dont think those FPS are attainable because the max strains in bow 9 are 73% higher than bow 4

--- End quote ---

Of course not! Those are only theoretical values within given boundaries; there is no set, for example. When modelling bows made from natural materials, it is important to interpret the results correctly – what is realistic and what is not. This is where practical experience in making natural-material bows becomes essential. You can learn a lot from theory, but you should not believe everything.

Mo_coon-catcher:
#4 is closest to what I would want for that profile. I would want it a smidge stiffer in the outer where the tips Eiffel Tower. Still some bend but just noticeable when sighting down the limb. And just slightly stiff the first few inches coming out of the fades, not much but just enough to tell it’s not bending as much as the rest of the wide portion of the limb.

Kyle

willie:

--- Quote from: Tuomo on December 17, 2025, 02:27:46 am ---
--- Quote from: willie on December 16, 2025, 09:28:18 pm ---
--- Quote from: Tuomo on December 16, 2025, 04:18:20 pm ---Also, the more whip-tillered the bow is, the more efficient it becomes (the reason here being lower tip mass)


--- End quote ---
Although the tip area with the steep taper is somewhat lighter, I dont think those FPS are attainable because the max strains in bow 9 are 73% higher than bow 4

--- End quote ---

Of course not! Those are only theoretical values within given boundaries; there is no set, for example. When modelling bows made from natural materials, it is important to interpret the results correctly – what is realistic and what is not. This is where practical experience in making natural-material bows becomes essential. You can learn a lot from theory, but you should not believe everything.

--- End quote ---

Virtualbow is a nice tool for modeling theoretical bows.  The properties of natural materiels is of course, much more complex.

(From the other thread)

--- Quote --- viscoelastic material properties are time-dependent. A well-known example of this is that with a fast release we obtain a higher arrow speed than with a long anchor at full draw. Thus, the main reason lies in the intrinsic material properties, which we do not know well enough and which are difficult to model accurately. In practice, we must rely on measured data. For example, the measured difference between hickory and bamboo backing is both interesting and important.
--- End quote ---

I find operating virtualbow to be much easier than determining a working stress to design to.
Has having access to a thickness sander made your materiel testing any easier?

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