Tip string grooves

[pierce_schmeichel]

Today I tested a 60 inch nock to nock moose  sinew backed Osage bow that has one, and quarter inches of string follow. The bow is 31lbs, at my draw, and has a  14 strand FF 652 string. With the regular limb nocks the bow shot through the chrony at 140 fps. Ten shot average. With the cut in V nock the bow shot through the chrony 140 fps. Ten shot average. Really confused, but that was my honest results of the test.

That is really odd! I don't understand what would cause that one to have no change. It should have at least gone 2-3fps faster because of the mass reduction alone. I guess best thing to do is more testing haha!

[pierce_schmeichel]

Just finished testing on a 40in 40lb @19.5" draw sinewbacked buck thorn bow. It shot my 400gr arrow 131fps with the traditional side nocks and then I did the conversion. Same weight same ntn length same draw length but it now shot the arrow 139fps on average. So only an 8fps increase this time.

[bassman211]

That is still a good increase in speed. Maybe it works best with shorter bows. I will be testing another short bow soon, and post results.

[mmattockx]

Maybe it works best with shorter bows.

That's a thought. If you have the set up for it, comparing before/after full draw pictures or the full draw limb bend traced onto a board or paper on a tillering tree might give some more hints as to what is going on. Normally I would say that if you are gaining speed you must be adding extra strain into the bow somewhere. I don't know where that is happening here, but comparing full draw shapes might make it more apparent.


Mark

[GlisGlis]

I dont know if it's relevant but if you have the exact same brace height the tip grooved bow is less tensioned and there is also a smaller angle with the string at brace
I's a small difference but in shorter bows is more pronounced

[pierce_schmeichel]

It's not that. When I do these tests I cut off the tips so that it's a comparison of a ntn bow of the same length.