Binary Cam Allowances, BPF?

[Blodg]

It appears that the new Bowtech Binary cam does not calculate very accurately on
TAP for my draw length. I believe the Binary cam has a new level of
efficiency at short draw lengths and light draw weights that may have
never been seen before. For example; using the IBO rating as entered for
the 2005 Allegiance results in a BPF of 1.2807. When manually entering the
specs of a 27" Allegiance, 350 grain arrow at 295 FPS (off birth
certificate) I get a BPF of 1.3851. This appears to be quite a difference
and changes the recommended spine for my arrow from .475 to .440.

Another example - With the standard IBO rating I get an estimate for my
speed at 60 lbs./400 grains of 236 FPS while actual measurements show a
much higher speed of 256 FPS. I have read that using the IBO ratings from
the manufacturer usually results in speed calculations within a few FPS. I
don't think the problem is with TAP, I think the binary cam has a much
higher level of performance than "normal". I am using the BPF of 1.3851 based
on the birth certificate specs for my bow but I could see customers using
only the IBO rating and receiving suspect results.

I will be conducting an evaluation on the efficiency of the Binary cam
when my Allegiance ever arrives.

[TAP]

This phenominon is pretty common for short draw length specific cams! I have run some spirals in the 25-27"catagory that are in the mid 1.45 area!!!

That is why I have this feature in the program. Most bow companies have recognized the need to modify the draw force curve a little on shorter draw cams to get maximum performance. Can you imagine if they used the same curve on a 30" er!!!! WOWZA!

I am glad you figured out the use my own specs area. Once you have your BPF you are golden!! :D