Todd.

Hurry up and eat already, would ya?

Here ya go, hopefully you can read it ok. It may depend on your monitor size....

page 2...

page 3.

So Norb sees it as a "photo finish"- that either value is a good judge of penatration potential, but KE has the right unit label for his analysis of comparing penatration to work.

Sorry, but these debates remind me of my current workplace. All the engineering, mathematical calculations and Kaizan idea instituting has done nothing but got us behind in deliveries and made setups much slower, when it was supposed to be the opposite!

Proof is in actual bowhunting situations............not on paper! Calculations are a good starting point, but that is all they are. I find it more necessary in finding an arrow stiff enough and heavy enough to not be hard on the bow, making the bow quieter, and good accuracy.

If everything on paper worked, the Lakers would be the NBA champs and the Yankees have already locked up the World Series.[&:]

Good article, and kind of what I was trying to get at. At a certain point KE is just as good of an indicator of penetration as momentum is.

But also note while his tests compare arrow weight and velocity, that arrow diameter & differing material is not used as testing factor (all tests were done with "22XX" alums).

Easton did a ton of testing for the AXIS using equal weights vs. diameter (and I would have to think since they are the #1 sellers of alum arrows and I also believe Carbons, they would be loathe to skew their own testing in favor of one or the other shaft material). But it would be interesting to see an equal diameter, equal weight, different material test too.

I'd like to see Norb do an updated test using all these other criteria (diameter, material type) as well.

Excellent summation, Cougar Mag!

What great benefit is gained by possibly putting the setup on the edge of reliable and forgiving performance and durability by trying to increase the KE and momentum beyond what the appropriate setup naturally and best provides, and what is generally necessary? In the end, regardless of all of the computations, for most bowhunters it will still boil down to a common and long-established requirement; the shaft must be correctly matched to the specs of the bow and shooter.

Any compound that has a draw-weight suitable for hunting (specific) large game will do the job as long as the arrow is appropriately matched to the particular bow and shooter. Most "spine" guides will indicate the correct shaft(s) to use without having to engage in a lot of physics and math. From that point, you simply tweak the bow and arrow until flight and accuracy is good.

If your gear is tuned properly and your shooting skills are fitting, a shaft through both lungs will put the deer down, regardless of not getting full penetration and a blood trail

In the end, a scientific application of KE/momentum is an individual thing and does no harm unless the performance of the bow and arrow is adversely affected.

Good point. Problem is, the only one to do such a study under actual hunting conditions has been Dr Ashby, and the KE clan totally rejects his findings because the results didn't come out in their favor.

I think that was his intent of this testing was to eliminate those variables- strictly concentrating on KE and momentum for a given material.

And to me, the problem with doing test of "real hunting situations" is that there is very little, if any, consistency to the impact material. How do you get consistent material from an animal body to shoot shot after shot into for testing? Even if your 1/2" off from where the first shot went, who knows what sort of density differences you may encounter in an animal's body. I suppose if you had enough time and animal bodies to use, you could do lots of "averaging" to get some credible results.