limb-tip mass and speed

[gringol]

Bowyers spend a lot of time, energy, and thought lightening limb tips to improve cast.  Then we do things like adding tip protectors, horn overlays, etc and increase tip weight.  Has anyone done any testing to determine when added weight to the limb tips becomes significant?  I'm sure most of these additions are not noticable to the naked eye, but in theory all added mass makes a difference...

[swampthing]

The idea applies to the tapering of the limb out to the tips. If the limb was square all the way out, like a 2x4, it would be a lot slower than a tapered one. That said, for every 10-15g on a limb tip you "could" loose 1-fps.

[onewhohasfun]

Yes all added mass makes a difference. Don't forget  carbon and foam limbs, skinny strings, string silencers, etc.
My limited testing shows a very slight gain in speed ,but only with very light arrows.
Heavy hunting arrows will probably negate any small percentage of speed gain.

[ddauler]

I only know this from my days building self bows from hickory. I built a bunch originally started making mehre heath replicas. Later I built pyramid style bows and wow! I went back and tapered the limbs more on the originals and double wow! Of course with modern glass bows we are talking very little mass in the tips anyway.

[gringol]

swampthing,  is that 1-fps loss per 10-15 grn added based on empirical data or just an estimate?  

Everything I've read says lighter limbs (and especially limb tips) = more speed, but I'd like to see some apples to apples comparisons.  For example,  bow #1 shot 500 grn arrow 180 fps, horn tip overlays were added and bow #1 shot same arrow 177 fps.  (not that 3 fps is a deal killer, I'm just curious)

[swampthing]

Highly scientific, empirical, and tested. Seriously though, I have seen that speed change pretty consistently, based on added mass, weather it is on the string, on the arrow, on the bow, etc.. etc..  Some bows are affected more, especially with light arrows.

[LEWIS VADEN]

Lighter tips also reduces handshock in the few bows I have built.

[Stumpkiller]

Wider tips and limbs also generate more air drag when snapping forward on release.

[The Whittler]

Besides looking like a glob on the end of the limbs, I also read/heard they contribut to hand shock.

[tradlongbow]

Blacky Schwartz did a comparison test on three different limb lengths from the same manufacture, and the limb with the smaller limb tips was faster by a few feet per second.

So then he did an experiment to see if the smaller tips made a difference, he tapped a penny on the limb tips and it slowed the limbs down.

[Bjorn]

I just threw a penny on the gn scale-50 gns so two would be 100 gns. That's pretty significant! Careful though guys we could be accused of talking about that "S" thing-I can feel the hackles starting to stir all over the internet.   :D

[Sixby]

A brass nock point on the string of a compound will drop 3 fps consistantly off of the bow speed. I have never actually tested heavy tips on a stick bow because I build light tips and there is no need to prove that heavy tips would be detrimental to performance all else equal. Its just a fact that they are.

God bless and Merry Christmas to you all, Steve

[legends1]

You cant measure the effect because the amount of effect is so small adding a tip protector. Manuel shooting (with fingers)though a chronograph will very 2-3 fps. That's why we shoot 3-4 arrows to get a average. Most bowyers today I know have tapper limbs with small tips. More important is the protection of the bows tip on the lower limb.