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Did DC hit 200 fps @ 10GPP after all??
Badger:
Alan, I should probably ship the bow back to you.
simk:
--- Quote from: avcase on December 06, 2022, 05:22:16 pm ---95% of the time there is a testing issue with high speed claims.
--- End quote ---
Thanks Alan for being critical :) ..and getting me off my comfy couch!
I checked my shooting machine again - and of course the drawlength wasn't set according AMO standard. It was measured from the pivot point what means my measurings weren't "shy under 28" but pretty percise 29" drawlength. All other variables were correct. The speeds in fact were measured @ 9.2gpp, not 10gpp (taken in account higher drawweight at 29").
I'm still very happy with these longbows which I did not design for max. speed. I will maybe make one with heat treated belly laminates; seeing some more potential in there.
cheers
mmattockx:
--- Quote from: bradsmith2010 on December 06, 2022, 04:14:03 pm ---Mattock,, the bow was about 54 inches,, sometimes when trying to do that,, some of the reflex pulls out and its a wash,, shooting about the same,, but you could be right,, I think a little longer bow would hold the 28 draw a bit better,, since my draw is about 25 or 26,,
--- End quote ---
I think you're right on a bow that short. I always make mine around 66" and I draw close to 28", so they have some draw length leeway, but that one is designed around your draw and probably should stay that way.
Mark
bradsmith2010:
Mark, sometimes I am shooting the bow through the chrono as I tiller,, and an increase in draw usually increases the speed, if I tiller it out another inch and no speed increase,, I know im not gonna get much more,, if any,,,kind of readched the limit of the bow,, then I keep in mind where that happend and design my next one accordingly,, I have pushed the limit on some longer bows even to 32 inches,, but the speed doesnt go up as much as you would think,,
maybe if I adjusted the proportions,, but as we know,, getting to 180 and above is pretty tricky,, when I make a bow for my draw,, say 25 inches and its in the 170 or high 170,, I feel pretty good about,,it,,
these are mostly sinew backed,, I made a bow for Jeffer,, and his draw was close to 29 inches,, the stave was great and had some reflex,,self bow, it was close to 180 fps,, arrow little lighter than 10gpp,,, ok looked at my notes,, shot it at 28 inches about 56# and 512 grain arrow,, 181 fps,, I think thats my best self bow I tested,,I never tested it at 29,,, it was not heat treated at all,, no corrections,, just like the stave came out,, osage
willie:
--- Quote from: avcase on December 06, 2022, 05:22:16 pm ---
I believe this bow was a legitimate 200 fps at 28” draw with 10ggp arrow bow. I very carefully followed how the bow was tested, asked many follow up questions, and I couldn’t find any obvious issue to say otherwise. I couldn’t find any fault with DC’s bow. I consider DC’s 200 fps bow legitimate and an incredible achievement!
Alan
--- End quote ---
Alan
How was the28" drawlength measured? AMO? to back of bow?
@all
was there a spec to measure the 28" in the original challenge?
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