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Q & A for Supertiller build along

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Q & A for Supertiller build along

Postby jwillis » Sat Nov 15, 2008 3:24 pm

Let's do our discussion in here, then when the build along is finished, it will be nice and clean and Gino can move it into the build along archive.
Thanks, Jim
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Re: Q & A for Supertiller build along

Postby wantoknow » Sat Nov 15, 2008 3:57 pm

Great job Jim.
Thanks
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Re: Q & A for Supertiller build along

Postby kcbrown » Sat Nov 15, 2008 6:04 pm

Looking good man, I like it.
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Re: Q & A for Supertiller build along

Postby tjdeerslayer37 » Sun Nov 16, 2008 12:07 pm

alright jim, you've put your riser right into the program and ive always plotted from the fades out. when you put in your thickness taper you start your thickness at point 1 correct? which is the bottom. if you're starting your thickness taper at point one, that means its starting while you're still in the riser. right? how does the program make the bow not bend at that point, or did you specify somewhere in there that the riser is thicker than your .345 or whatever it was, and i just missed it?
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Re: Q & A for Supertiller build along

Postby stagmitis » Sun Nov 16, 2008 6:21 pm

Wow!

That last pic looks like Hickmans 100% efficient bow model!
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Re: Q & A for Supertiller build along

Postby jwillis » Sun Nov 16, 2008 9:03 pm

tjdeerslayer37 wrote:alright jim, you've put your riser right into the program and ive always plotted from the fades out. when you put in your thickness taper you start your thickness at point 1 correct? which is the bottom. if you're starting your thickness taper at point one, that means its starting while you're still in the riser. right? how does the program make the bow not bend at that point, or did you specify somewhere in there that the riser is thicker than your .345 or whatever it was, and i just missed it?

TJ, You are very observant. I told it to start calculating at point 4 which is 6" from center. You do that at the "Start Point" in "Design Operations" (at the top of the screen). I did start the thickness taper manually from bow center because that is the way I measure my lams and grind them that way, too. Now that you mention it, I forgot to add the thickness for the riser...doah! I should have done that manually after copying in the figures for the thickness taper. I'm not sure it will change anything, but it might. I'll experiment with that and see if it does. Good catch. Jim
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Re: Q & A for Supertiller build along

Postby jwillis » Sun Nov 16, 2008 9:12 pm

stagmitis wrote:Wow!

That last pic looks like Hickmans 100% efficient bow model!

It does! Mine must not be 100% efficient because it only shoots a 10 gpp arrow 181 fps with a release aid...lol. :( Kenro said it is bending too much near the fades causing that small area to move the entire limb as a lever. He may be right. However, if you look at the limb stresses chart (located in the upper right hand portion of the Supertiller window) the limb has pretty much equal stresses it's entire length. He suggested a power lam and more taper on the next bow. Jim
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Re: Q & A for Supertiller build along

Postby tjdeerslayer37 » Sun Nov 16, 2008 9:47 pm

wait, so if you told it to start calculating 6" from center, its bending in the program as if it has a 12" riser? if thats true, maybe that tells you why ST says you have equal stresses along the whole limb when really, if kens right :roll: , youre bending too much at the fades?

if youre putting in a riser extension in the bow does that mean you tell the program to start calculating from where that wedge ends or will the program recognize the extra thickness enough to not bend in that area?
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Re: Q & A for Supertiller build along

Postby jwillis » Mon Nov 17, 2008 9:16 am

tjdeerslayer37 wrote:wait, so if you told it to start calculating 6" from center, its bending in the program as if it has a 12" riser? if thats true, maybe that tells you why ST says you have equal stresses along the whole limb when really, if kens right :roll: , youre bending too much at the fades?

TJ, you are right. The program needs the correct thickness for each of the coordinate points. I should have entered the thickness of the stack plus the riser at 6" and 8" but I forgot to do it. It will make a difference but I'm not sure how much. Ken was actually looking at a photo of my real bow when he made that observation at the WTT thread. I already cut and ground the fadeout lam and tip wedges last night for my next bow trial. :)

if youre putting in a riser extension in the bow does that mean you tell the program to start calculating from where that wedge ends or will the program recognize the extra thickness enough to not bend in that area?

Again, you are right, we should enter the correct thickness of the riser, plus the fadeout lam, plus the lam stack at each coordinate point so the program can use that data for the calculations. Obviously, the more coordinate points you choose, the more closely the model should simulate a real bow.

Jim
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Re: Q & A for Supertiller build along

Postby stagmitis » Mon Nov 17, 2008 12:46 pm

Fun Fun JWillis!


I guess the powerlam would create a shorter working limb and the faster tapers would allow the tip to bend further back creating more of a power stroke....?

Any reason for adding a powerlam instead of a longer riser other than the visual aspect?
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