How would you all do this?

[monterey]

Here's the situation.  Not calling it a problem, but something I'd like to change.

My current build is an RD 60" NTN with about 1.75" of reflex off an approximate 12 degree riser.  The FDC curve indicates a slight tendency to stack between 27 and 28 inches.  The tips have 4.5" wedges. There's nothing wrong with this bow (so far     ) and even a 28" draw shooter is probably not going to feel it.

But, as the builder, I'd like to see no stack right up to 29".  

My question is would it be effective to achieve this by increasing the wedges a few inches or go to 62" NTN off the same form.  If going to 62" should the tip wedges be increased along with the overall length.

Open to any and all suggestions.  

[Crittergetter]

Whats your taper rate?

[Crittergetter]

I had the same issue with my design, ( 3 piece- shorter working limb) increased the taper by .001 and bingo!! No stack till 29" on my 60" and no stack till 30.5" on my 64, havnt tested the 62

[Crittergetter]

Dp

[kennym]

I think Randy nailed it, if you have less than .003 taper.  My 58" with .003 PI will go to 30" before the lbs. start increasing. The string angle hits square off limbs just before that.

[monterey]

Originally posted by Crittergetter:
Whats your taper rate?

Taper rate is .003.  however, the limb profile starts at just over 1.4" and begins a gentle arc about 2.5" beyond the fades and toward the tips which are quite narrow.

I'll try to do some pics later.  Imgur Is not Android friendly!

[monterey]

Originally posted by kennym:
I think Randy nailed it, if you have less than .003 taper.  My 58" with .003 PI will go to 30" before the lbs. start increasing. The string angle hits square off limbs just before that.

I think that pretty much supports Randy's post.  Even though it's tapered .003 now, the differences in your limb profile and mine are pretty significant wherein yours holds full width to about half the working length and has wider tips.

Still not sure what to do but you guys have me thinking in broader terms.  

[Roy from Pa]

Geeze my head hurts...  

I think pics would be great... Unstrung, at brace and 28" draw...  It would be cool to see the DFC also...

   If I cannot add some advice to this post, I sure would like to learn something from it...

[monterey]

I'll put all that up later when I'm back at my desk.

[monterey]

Here's the pics.

 

 

 

 

[monterey]

and the FDC

 

[Bvas]

Please take this FWIW, as it is as much a question for myself as it is a suggestion.

But have you tried a slightly longer string?  To me, the 7.5" brace height seams a little high for a bow having that much reflex and what appears very little deflex.

[Bvas]

Also.....What draw length is the bow pulled to in the last pic?

[monterey]

Last picture is @28".

The string is just one off the wall and Is a bit short.  I could twist it up.  As far as the raw numbers at this point, do you think more brace will make a difference?

[Bvas]

Monterey, I'm def no expert. I've only made four bows. But what I'm suggesting is a longer string and less brace height.
I built a 60" r/d for my boy with about the same reflex, but a bit more deflex. I didn't use any tip wedges, and it is braced about 6-3/4".
I've never done a draw force curve on it, but it's pretty smooth to 29-30"

[Crittergetter]

The last third of the limb doesn't seem to be working much. Have you tried it without the tip wedge?  That would increase the amount of working limb and would increase the draw length.

She looks like she is bending pretty good...  I would say go to 62" but I think your limbs would be even straighter or even slightly recurved...   I prefer a little bend in my limbs (D-shape)...  I think it can make a bow quieter... What speed are you getting at 10gpp @ 28"draw??  If you are getting 180fps or more, Don't change a thing... What is your riser length from fade to fade???  Maybe a shorter riser with a power wedge may help...  These are just suggestions or some things that I may try...  Other experienced bowyers may have more definite answers for you...

  You need to download a DFC spreadsheet...  It is a lot easier than drawing it out...

[monterey]

Critter, This is the first off for this design and form so there is no reference to any other builds.

Now, help me with this cause we think differently in regards to the working of the limb.  My thoughts are that without the wedges and bending more towards the ends of the limbs would have the tips coming around even further and thus approaching the 90 degree angle earlier in the draw which would make it stack sooner?¿?¿   :confused:

[monterey]

Shredd, no speed reports at this point cause the riser Is not formed yet and it's not final tillered.  I'm not sure how I'm going to do the riser and grip yet.

I have a spreadsheet.  Probably the same one you have but it won't accept partial inch lengths for draw length.  I'm still playing with it.