davepjr71

This is also true. But that is overlooked because he has Dr in front of his name and his tests are the only ones that count. At least that's what they will tell you.

We can tell them until we are blue in the face that our arrows kill animals and it doesn't matter. theree will be some reason why it doesn't count.

quiksilver

Another list offactors that seem to have been ignored here is the frontal surface area of the projectile at point of impact, the broadhead's performance through bony, cartilagenous materials, arrow diameter, shaft drag through the viscous materials inside the body cavity, etc....

In sum, KE and Momentum are nice benchmarks for penetration potential, but it definitely doesn't end there.

To put it in its simplest terms, I'll demonstrate with a game of dodgeball. If I picked up a standard NCAA basketball (21 oz. = 9187 Grains), and threw it at your headat 40 Miles per Hour (59 Feet Per Second), you would have 71 pounds of Kinetic Energy hurtling at your dome, ready to slap you silly.

Now, if the ball would slam you in the earhole, it might knock your toupee off, but it surely won't decapitate you, orgouge a deep divotinto the side ofyour skull.

Now, compare that to a game of dodgeball where we're using a 400 grain arrow, traveling at 280 FPS tipped with a chisel-tip broadhead. Again, the same 71 foot pounds of kinetic energy - this time with the forceonly focused over a much, much smaller area. This game of dodgeball will certainly end badly if you're on the business end of that arrow.

KE and momentum are both worthless without considering these intangibles:cutting diameters, arrow diameters, fluid/bony penetration, broadhead structural integrity at high speed impact, etc...

fastpassthrough

Nicely put! here is a video of 1/2 plywood shot @ 40 yards
http://www.youtube.com/watch?v=VfLv2_hnfyg

davepjr71

[quote]ORIGINAL: quiksilver

Another list offactors that seem to have been ignored here is the frontal surface area of the projectile at point of impact, the broadhead's performance through bony, cartilagenous materials, arrow diameter, shaft drag through the viscous materials inside the body cavity, etc....

In sum, KE and Momentum are nice benchmarks for penetration potential, but it definitely doesn't end there.

To put it in its simplest terms, I'll demonstrate with a game of dodgeball. If I picked up a standard NCAA basketball (21 oz. = 9187 Grains), and threw it at your headat 40 Miles per Hour (59 Feet Per Second), you would have 71 pounds of Kinetic Energy hurtling at your dome, ready to slap you silly.

Now, if the ball would slam you in the earhole, it might knock your toupee off, but it surely won't decapitate you, orgouge a deep divotinto the side ofyour skull.

Now, compare that to a game of dodgeball where we're using a 400 grain arrow, traveling at 280 FPS tipped with a chisel-tip broadhead. Again, the same 71 foot pounds of kinetic energy - this time with the forceonly focused over a much, much smaller area. This game of dodgeball will certainly end badly if you're on the business end of that arrow.

KE and momentum are both worthless without considering these intangibles:cutting diameters, arrow diameters, fluid/bony penetration, broadhead structural integrity at high speed impact, etc...
[quote]


hahahaha That's a great analogy and well put.

I've tried this argument already. Ashby's tests were done with everything the same on the arrow but weight. I've tried to argue that if you go with a smaller diameter arrow and a different FOC that you can create an arrow that will have the same effects as the heavier arrow.

However, it always falls back on Ashby's report, Ashby's report, Ashby's report. Nothing ele matters.

quiksilver

So, I guess when you consider that, if you're shooting two otherwise identical arrows (same head, same speed, same weight, same friction coefficient on the shaft, same fletchings) - and arrow A is a lincoln log (diameter .5"), while Arrow B is pencil thin (diameter .3") - you're probably going to get better penetration with Arrow B, simply b/c the force is transferred over a smaller surface area.

Same goes with broadheads. If you have two identical arrows (same speed, same weight, same fletchings, same diameter, same friction coefficient on the shaft) - and you put a 125 grain muzzy on shaft A,while on shaft B, you put a 125 grain mechanical head with a cutting diameter of 2.75" - you're bound to get much better penetration from arrow A (provided that the blades are the same thickness/sharpness).

So, while a KE calculation is nice and handy, there are hiddenpenetration killers lurking (fat shafts, shafts that "drag" more than others once moving through the target, broadhead selection, etc..) Unfortunately, these are things that can't be easily quantified by a quick KE or Momentum calculation. Instead, we resort to field testing.

Good post and good discussionthough.

davepjr71

hahahaha That's a great analogy and well put.

I've tried this argument already. Ashby's tests were done with everything the same on the arrow but weight. I've tried to argue that if you go with a smaller diameter arrow and a different FOC that you can create an arrow that will have the same effects as the heavier arrow.

However, it always falls back on Ashby's report, Ashby's report, Ashby's report. Nothing ele matters.

fastpassthrough

Another great post!

davepjr71

Another very intelligent way of putting it.


Muzzy and other boradhead manufacturers realized that you have to have some sort of chisel tip to break through bone. But at the same time did not want a solid heavy broadhead design. So, they created the Muzzy with the chisel tip and replaceable blades. For years people have been proving that a broadhead like this will do the job.

Combine that with a smaller diameter arrow and maybe up the FOC and you have a dangerous combination.

In other's eyes all that matters is Ashby's test. However, all of Ashby's tests are done with everything being equal but weight. Yes, he switches broadhead design.And yes, he talks about FOC. However, he never compares arrows with thinner shafts to thicker ones. He states that a high FOC on a carbon arrow will dramatically improve penetration yet doesn't compare that to a heavy arrow with standard FOC.

He prefers extremely heavy arrows with heavy solid chisel broadheads and that is evident with the way he tests.

Arthur P

No, they haven't been ignored. The whole menu of those items was covered previously, and multiple times. It's just, for me anyway and I'm sure it applies to others as well, I've gotten tired of typing that "all else being equal" disclaimer at the end of every freakin' post.

Once again, IT WILL NOT SOLVE ANYTHING!

It MIGHT help reduce the overall wound/loss ratio by putting somewhat more effective arrows into the hands of the vast majority of bowhunters. You know, the guys who are totally CLUELESS when it comes to properly choosing and tuning their equipment. Like I said before, I'd much rather see the minimum set at 450 grains, but lookat how much whining and complaining I'm getting over 400. Sheesh!

I'm thinking about the possibility that such a change couldbenefit bowhunting as a whole.Reducing our wound/loss statistics would take a helluva lot of ammunition away from the anti's and a minimum arrow weight is the best, or at least most enforceable, way to do that.

You got a better idea on how to cut the wound/loss ratio than minimum arrow weight? One that's workable in the REAL world? Dude, I'm all ears.

gators37

Come on guys. everybody's comments seem to have some sort of truth to them, but KE is just an analytical measurement of the energy you have to work with (whatenergy the arrow has to work with at impact). Impact depth, pass thru. etc. are all effected, by "other things" (how efficiently the arrow transfers or does not transferthis energy to the target). Lets face it, if you have pasthru, strickly speaking all the energy was not transferred to the target, if this was good enough for a kill or not you guys would know better than me.
There is another item that I am interested in (which was briefly mentioned in some of the previous post)andwill be specific to a particular bow and that is if the bow "transfer to arrow" efficiency is indeed a curve (to a point where the slope changes which should indicate max. efficiency) or does the energy efficiency in the transfer just keep going up as you make the arrow heavier and heavier.