Penetration Kinetic Engery

[M.E.B.]

For those of you who have read my previous posts I have experienced a few penetration problems. Bisch was nice enough to send me some arrow weight tubes.

The additonal 60 grains slows my arrows down around 10 fps. The decrease in speed and increase in weight according to the arrow calculator puts my kinetic engery at the same as with my lighter faster arrows.

I'm gonna try them and see what happens. If it were you and the kinetic engery was going to calculate out the same would you go with the lighter faster or heavier slower?

Thanks.

Mike.

[GUT_TRAIL]

For pure penetration, I believe the heavier arrow setup will do better. The old getting hit by a 100mph ping pong ball vs 100mph base ball type scenario. Im shooting a 455g arrow at 200pfs and getting pass throughs on deer and medium hogs. But 200 fps is cooking.

[Reedimus]

Your momentum will be greater with the heavier arrow. Momentum is the key to better penetration not necessarily kinetic enegery.

[WKH2213]

And razor sharp broadheads!!!

[Reedimus]

http://www.tuffhead.com/education/formulas_momentum.html

[moe monsarrat]

Heavy is the way to go.

[Buff]

I have spent countless hours working on this problem.
A recurve has X amount of power, there is nothing you can do to change that energy factor.
Dr Ashby has written volumes of data that is as good as any data ever written.
KE is a good number for a 30/06 but has little to do with archery equipment.
The heavier your arrow is the deeper it will penetrate.
The arrow leaves the bow with pretty much the same energy whether it weighs 300 grains or 600 grains. The 300 grain shaft is a lot faster but can't maintain the energy as long as the heavier slower shaft.
Dr Ashby has proved with his years of tests that the more of the weight that is on the front of a arrow the deeper it will go.

Most of my stuff is of little or no use to you as I was worried about killing silly big animals with very heavy bows but I did work up something for the pass around bow a year or so ago.

When they sent me the pass around bow, it came with a half dozen arrows.
If I remember right it is a 40 pound bow. The penetration on targets confirmed my fear that penetration on game was going to be a problem. I was worried as one of the folks that had the bow before me had shot a couple of hogs and not recovered them.
I had some 425 grain broad heads left over from the elephant hunt.
I took those and put them on a carbon heritage 350 shaft.
They were very slow. VERY slow.
Any shot past 15 yards was going to be tuff as the arrow really dropped off But the penetration on my targets was 4 times deeper.

I killed a black buck with it and penetration was not a problem.

I know that was a little long winded but this subject is near and dear to my heart.
The heavier your arrow is the better it will penetrate 100% of the time. The problem is it has to be light enough that you can hit something with it.

[SAVIOUR68]

Your momentum will be greater with the heavier arrow. Momentum is the key to better penetration not necessarily kinetic enegery.

Bingo we have a winner
A shaft that also has a higher FOC will also help .

[triffnix]

good info right there! I also noticed that with two arrows of the same weight the oe with thehigher foc will penetrat deeper but also drop off faster.
About 3 year agoi also was very worried about KE and Momentum because my first trad hunt was coming up and i didnt have any experience and didnt know if i should shoot fast light or heavy slow arrows.. I rea the ashby reports, got alot of good info here and so iwent with heavy slow arrows with high FOC and that worked pretty well!
Will never go back to fast light arows with my trad stuff. the next advantage is that heavier arrows make the bow quieter.
but this is just my experience...

Daniel

[Bisch]

Your momentum will be greater with the heavier arrow. Momentum is the key to better penetration not necessarily kinetic enegery.

This is a key point that a lot of folks overlook!

Good explanation, Buff!

Bisch

[SamHarper]

I dunno. I suspect that after a certain point, you'd begin to get diminishing returns with a heavier arrow. I mean just think about it. Imagine you try to shoot a telephone pole out of a 40 lbs bow. You'd have no momentum at all because your velocity would be zero.

p = m*v

If velocity is zero, then momentum is zero, no matter how high the mass is.

On the opposite extreme, if your mass is zero, then it doesn't matter how high your velocity is. Your momentum will still be zero.

So somewhere between these two extremes is a sweet spot--an ideal mass that will give you the greatest possible momentum, above which or below which, momentum decreases and so does penetration.

If you graphed momentum/penetration (on the y axis) against arrow weight (on the x axis), the graph would probably look like an upside down 'U' or maybe a bell curve, with the peak being the weight as which you'd get the maximum momentum/penetration.

And I suspect that peak would change with bow weight and draw length. With higher bow weights, the peak would shift up and to the right. With lower bow weights, the peak would shift down and to the left.

This is all theoretical, of course, but it makes good sense to me. It would be interesting to test it.

[Bowhunter1994]

Momentum buddy... KE means nothing in archery!

[Bisch]

Sam, I'm sure you are correct here! There has to be a certain arrow mass for any given bow that will produce the most momentum. You go away from that point in either direction, and you will lose momentum.

I'm just guessing here, but maybe that has something to do with where the magical, mythical, 10gpp rule came from?

Bisch

[RickBarbee]

There has to be a certain arrow mass for any given bow that will produce the most momentum. You go away from that point in either direction, and you will lose momentum.Bisch

Wisdom.

[M.E.B.]

Penetration Kinetic Engery

I was shooting 500 grains at 160.

Now I am shooting 620 at 150. Pretty close to that with 560 grain arrows. Gotta do more shooting I did a little last night. 200 and 250 grain heads.

Both have about 30 KE. Using the KE as it is the easiest calculator to find on the net.

It's surprising the drop at 20 yds with 10 fps less. Gonna give it a try next week. Hunting will be fine. Shooting under limbs at 3 d might be tough.