2 arrows of different mass but the same KE = same penetration????

[ozy clint]

is it possible to have 2 identical arrows, differing only in mass, that have the same KE, yet they penetrate exactly the same amount.

apparently some guy has the backing of NASA on this. ?????

any rocket scientist out ther who can share their view?
i don't completely understand so what's going on here?

[lpcjon2]

George,George,George we need you...LOL IMO It would have to be done in an extremely controlled environment,And the target would have to be identical,the draw,ect. in every way I doubt that it could be done.

[Longbow338]

Hard to argue with physics.

[vermonster13]

Backing by NASA? Were they shooting in space?    :p

[Orion]

From what I understand about all the stuff that's been bandied about re kinetic energy and momentum on this siute, it would be possible to get the same KE out of two arrows of different mass by varying the speed. However, the different mass of the arrows would yield different momentum results (and momentum, being the better predictor of penetration in critters, according to Dr. Ed's research),  the heavier mass arrow would penetrate more than the other.

I'm certainly not a rocket scientist, but that's my story and I'm sticking to it.  What does NASA know about arrows anyway.  Arrows aren't rocket science.  

[Tater]

Foghorn Leghorn


 Quote " It's mathmatechics son, you can't argue with mathmatechics!"

[ozy clint]

that's what i figured orion.

[lpcjon2]

If NASA has the money and time to do that, what the heck is next!Testing the G Force and  resistance  and KE that a sperm encounters when leaving the ----- well you know what I mean.Federal dollars at work.

[Buckeye Trad Hunter]

Originally posted by Orion:
From what I understand about all the stuff that's been bandied about re kinetic energy and momentum on this siute, it would be possible to get the same KE out of two arrows of different mass by varying the speed. However, the different mass of the arrows would yield different momentum results (and momentum, being the better predictor of penetration in critters, according to Dr. Ed's research),  the heavier mass arrow would penetrate more than the other.

I'm certainly not a rocket scientist, but that's my story and I'm sticking to it.  What does NASA know about arrows anyway.  Arrows aren't rocket science.      

Couldn't be said better.  Force equals mass times velocity, therefore a heavier arrow at the same speed cannot have the same penetration.  If this guy has NASA backing him we need to end our space programs.

[Ragnarok Forge]

The testing could be done and it actually would not be that hard to set up and run the testing.  There are so many factors in penetration and the two different arrows that I can say the odds of both penetrating the same are about as likely as me convincing my wife I need another boat to add to my boat collection.

Is it possible, you bet,  it is likely, not at all.  KE is not a measure of penetration, never has been, never will be.  KE is the measure of energy stored in the arrow during flight.  Impulse determines penetration.  KE is just numbers used by the industry to sell fast bows.

It sounds to me like another industry wonk who worked a test or worked the date to find some numbers to prove a point they wanted proved.  I wouldn't believe anything they are saying until I saw a report with testing data and the signature of someone you can identify as a rocket scientist. That way I could look over the report and determine if their assumptions, math, and testing all support their thesis and conclusions.

Pretty much I am call bunk on this one without some proof.  Possible yes, probably no.

George, where are ya man?  I think you and I singing the same tune for once.

[ChuckC]

Ozy  I am gonna guess that you will never encounter that in the real world.  If they are truley identical in all things except mass they are not gonna pass thru the shoulder blade of a wildebeast at the same exact level.
ChuckC  

[ChuckC]

actually, your statement is a bit vague.  HOW MUCH difference are we speaking of ?
ChuckC

[Longbow338]

Has anybody seen video in sponsor classifieds where the 150 gr head blew through two bull scapulas while the heavier heads penetrated one and stuck in the other.  Still not an identical shot because certain parts of the bone are thicker than others but will make you think.

[Jeff Strubberg]

It's more likely that two arrows of different mass and the same KE would show differnet levels of penetration.

KE is a pretty good measure of how well you can get a projectile going, but for my money momentum is a much better predictor of how they will stop.

[McDave]

Obviously, the real world adds a lot of variables that are difficult to account for, so probably a simple formula such as MV, or MV(squared) is not going to give you the correct answer.  But I'm sure that if you had an old water buffalo carcass and shot a 600 grain arrow into it at 180 fps, you would be able to find arrow speeds at which a 500 grain arrow would penetrate less than, equal to, or more than the 600 grain arrow.

You up for that, Clint?

[Buckeye Trad Hunter]

I miss read.  I mistook the KE for speed.  As stated before the KE has no bearing on penetration.  However a formula such as f=mv will 100% give you the correct answer.  A 600gr. arrow @ 180 fps will penetrate better than a 500gr. arrow @ 180 fps.  We're not talking about what if I hit a shoulder on a cape buffalo.  If that happens you're gonna get poor penetration no matter what.

[Brook Trout]

Yes, Force equals mass x velocity, but that is not the only factor in penetration.  Other factors such as broadhead sharpness and arrow material determine resistance after impact.  So yeah a heavy arrow with say a dull broadhead may penetrate the same as a light arrow with a sharp broadhead.  Thats why its important to have your heads sharp.

[ArkyBob]

Man when I read these kind of threads, my head starts hurting.  I think I'll go drink a glass of muscadine wine!!!!!

BOB

[Richie Nell]

"Man when I read these kind of threads, my head starts hurting. I think I'll go drink a glass of muscadine wine!!!!!"

DITTO
...and I think I will dull my broadheads and shoot an UNtuned arrow.  Nothing is a given anymore.

[Don Stokes]

A swallow cannot carry a coconut. However, TWO swallows...

The single most important factor in penetration is a tuned bow and arrow, regardless of mass, KE, momentum, single or double bevel, angle of fletching, or anything else we can dream up. A perfectly flying arrow will penetrate well. An imperfectly flying arrow will not. Everything else is window dressing.

Please pass the wine.