Trad Gang

Howdy guys!
I haven't been online much cause of poor internet connection. However, I have a question for you guys that know more then I.

Heavy Vs. Light for penetration......oh boy

Test that I did:
50lb Recurve,
405 Grain Arrow,
530 Grain Arrow,
Same arrow Dia.
Same tip Dia.
Same distance from target.

Target being 1/2" ply board stood up on fence.

The 405 Grn. arrow way way way OUT penetrated the heavier 530 Grn. arrow.

The 405 had around 24" of penetration through the board!
While the heavier 530 grn. arrow only had around 12"  of penetration.

I have read Dr. Ashby's articles and believe what he writes. I just can't figure out why the lighter won. I shot at least 5 shots with both weights and the lighter won every time. Once it even went through the ply wood 15" then 1/2" into a 2x4.......I am baffled guys, Can someone explain this???!!!!

My guess is one arrow is tuned for the bow and one isn't.

howdy woodslinger!!!
Yes actually the 530 grn. is tuned (bare shafting) while the 405 grn. is alittle bit stiff.

Waaaaaay too many variables when shooting into wood.

In no particular order, you've got; different densities, grain orientation, broadhead rotation in relation to the grain, moisture difference, broadhead sharpness, bevel pitch on the broadheads, broadhead tip shape + probably a ton of stuff I can't think of!

If you want to test penetration comparisons, do it on meat. That's what you're shooting at & that's what broadheads are designed to hit.

The reason heavier arrows penetrate better in general is the the transfer of energy is more efficient into the heavier object.  Example at 500 grains your getting back 80% of the energy you put into the bow and at 400 grains your only getting 75%.  The lighter arrow may be flying like a bat out of hell but the heavier arrow is carring more energy.  There can be exceptions to this though depending on bow design and how far in extreme you go.  At some point a heavier arrow won't gain you any more efficiency and you'll lose energy.  KE is a decent representation of penetrating ability but momentum is probably a better way to measure penetrating setup.  This can be a difficult topic for anyone without some physics background.  Dr Ashby's study is a great resource and very sound science from what I've read.    Clear as mud for most folks.

Thank you guys for yall's posts.

Sloaf, I also agree momentum is the better way to measure penetration. I've done the math with both momentum and KE and it proves the heavier arrow should be better. However, I can't wrap my mind around why the lighter arrow did better on the board. How could one know when too much is too much on weight?

Robtattoo, Yes Sir, I understand that the board isn't "consistent" enough for a scientific study and that meat would be way better. If I can get a chance I will test that as well. However, I do not see that the board's variables would create such a consistent outcome. Not one set did the heavier arrow win. I am using field points by the way not broad heads sorry, I forgot to mention that.


Keep um coming fellows!!!! Thanks, HH

Don't want to take the wind from your sails but I don't think a sheet of 1/2" plywood speaks for penetration. The faster/lighter arrow, as it breaks through the plywood, has less time for the vibration of the sheet to stop your shaft. The heaver/slower one has more time to do the same thing. That's That! IMO

... mike ...

huh....that's interesting.
Well, lets look at this. What if I shoot at game (hogs, dogs, and deer) and place a not so perfect shot and hit bone......maybe rib or one of the shoulder bones. Wouldn't that be alittle closer like 1/2" plywood vs. meat? IF that's the case, and wood is closer to bone then meat is.......even if it is a "timing" issue........I'd like to know.

Maybe if you tried single beveled fieldpoints you'd get better penetration!    

I kinda agree with Robtattoo. Density of plywood can change in fractions of an inch. You probably need to be shooting into something that has more of a uniform density...Like the tailgate of your brothers truck.  Doh!

See ya in 3 weeks!

Shoulder bones will stop an arrow quick. That's why "timing the shot" is a big issue. Arrows are not bullets. Shot placement is key. Relaxed, feeding game will let a well placed arrow pass thru them. From a quiet bow mind you. Where a deer looking at you will move like lightning as you loose an arrow. THIS may become a poor hit with little penetration whatever the arrow weight.

... mike ...

Hey, Camo! What's up bud?
Yeah, tail-gate not a good idea, everyday all day. lol

And I agree too about plywood not being consistent. BUT.....wouldn't the lighter arrows have to hit the same variables as the heavier arrows? AND......if that's the case how could the lighter arrows not ONCE hit a variable in the plywood that would cause it to LOSE to the heavier???? Huh??? uh??? HUH????? lol You're dad fixed up now with this GT's?

I had a simular expierience as HH. My son and I shoot identical bows with the same carbon shafts.  Mine have weight tubes glued in the front half, brass adapters and are shot full length. Weight 740 grains.  Son's are shortened for tuning and he uses aluminum inserts. Weight 550 grains.
When shooting together into a foam block target, my arrows would make a loud thump and rock the target, his would just zip into it, but when we went to pull our arrows they would be stuck in the foam just about the same. Both of us had our arrows flying well.
I had been trying to convert Son to the Dr. Ashby inspired way of doing things but have been unable to prove that the practical difference amounts to much.
I know that I tend to shoot the heavier arrows more consistantly but Son usually outshoots me so the debate goes on.

if you shot both arrows into a 1 in. plate steel and the both bounce off does that mean they would penetrate the same on an animal ? If you shoot two arrows into a block target and 1 out penetrates the other by 1 in. does that mean it will penetrate the same on an animal?  no i don't thinks so.

experiments like this are fun to do but aren't very practical in compared to what happens on meat and bone.

just curious what kind of arrows are you shooting and diameter of the arrows, diameter of the field points

HH the only way to know how you can maximize your efficiency is to add arrow weight in increments and graph your KE with each one. You'll see it peak and then drop off at a certain point.  I haven't done this personally because I don't want the slower arrow speed and haven't had any penetration problems with whitetails.  I've been shooting 500 grains with a 53# recurve.  As for your test results I think you need a ballistic gel to reproduce tissue penetration.

Plywood is probably more consistant then a animal carcass - or even a live animal.

Until someone can come up a consistant test medium replicating the various tissues found in an animal, all tests can show are what happened with that individual that day.

Ballistic gel is not the answer either, because it enters drag into the equation nothing close to what living tissue does.

Steve

Just a thought --- Is it possible that the greater speed of the lighter arrows caused a bit of a "blow out" of the plywood on impact thus reducing the drag on the shaft (similar to the effect of a single bevel broadhead splitting a bone)?

WOW, got some attention now... Keep um coming guys, I greatly enjoy getting different opinions and experiences other then mine!!! Keep it up fellows!

Thanks to all who replyed!!!!! HH

The heavy arrow is hitting the plywood and the front is slowing down at such a fast rate that the back is oscillating to shed energy faster. The heavier arrow has more retained energy to shed. Once you get to 8-10 grains per pound I think heavier leads to poor energy transfer without stiffness to help keep your arrow straight upon impact.

Foam,layered and 3-d targets are all being designed to stop very fast, small diameter arrows by the use of excessive friction.

I shoot in an open 3-d club and all the wheelie guys get deeper penetration in the targets than I do shooting 9-11 grains per pound. Speed kills with a decent weight to it. The key is not being to lite to make penetration suffer. Less vibration/oscillation directly impacts penetration. If you could watch your test on high speed video I think you will see how much this plays into the results

i have for 35 years been doing these kinda experiments at first when i was a wheel bow shooter i wanted to prove the liter arrows would out penitrate  heavier arrows, and i shot and destroyed more arrows than i could count! found that at close range( out to 20 yards) the liter arrows did drive deeper but not much, but as the distance increases the heavier arrows took the lead every time!  now that i'm trad the same tests applied, the heavier arrows take home the meat every time~!  i shot at every thing for these tests, plywood, 1/8" alum sheets, steel drums,concreat blocks, but the best tests were hunting for 35 years and keeping logs of of every hunt,every little detail!i know there are way to many variables to all these tests, so from hunting experience i will choose heavy over lite for way to many reasons to list!! just my own opinion!

If maximizing penetration is a major goal for the game you seek, I look at it like this:

If you want to test maximum penetration for a water buffalo, you should probably test on a water buffalo with your hunting head and not on plywood with a field point.

If you want to test maximum penetration for an elk, you should probably test on an elk with your hunting head and not on plywood with a field point.

If you want to test maximum penetration for a deer, you should probably test on a deer with your hunting head and not on plywood with a field point.

But, if you wanted to see how far your field pointed arrow would penetrate through plywood, you probably should test on the plywood and not on a water buffalo:)

If it makes you feel better, way back in the '40s Fred Bear built a frame filled with calf's liver and using a shooting machine tested various combinations of draw and arrow weights both light and heavy for maximum penetration. These tests convinced him of his theory that 60pounds draw with an arrow of 600grains(10gpp) was near ideal for maximum penetration. The minimum arrow weight for this tested best penetration was to be no lighter than 10% less than the ideal 10gpp weight, which would be 540grains(9gpp).

later,
Daddy Bear

Since most shots on deer sized animals are close it really don't matter.A heavier arrow will retain more energy longer but most stickbow shoots don't take many long shots so does that really matter?I do feel if shooting a large broadhead a heavier arrow helps compensate for the extra drag of the bigger head or multiblades but since most that go for the heavy arrows tend to shoot skinnt little two blades it is just a waste of what could be used to get a flatter trajectory.Personall I like big blades so will shoot heavier arrows for that reason or to quiter a noisy bow.If a bow is quiet enough with lighter arrows and I am shooting a skinny two blade there is no way I want to shoot a heavy arrow for no good reason.jmo of course.   :)

i think TNstickn has got something with his comments, and his explanation also explains why the higher the FOC the better the penetration, the less weight to oscillate and the more energy transfer into the animal.

When you do try it on MEAT, Please "DONT" shoot the neighbors "DOG"... But anyway, Good Post !!

What kind of arrows?

Howdy Jeff,
I'm shooting CX's Heritage 90's at full length. They fly great with the 250 up front. Alittle stiff with 125's. I think CX arrows with the buff tuff finish is hard to beat in my opinion. I've shot these arrows into concrete slabs with no damage. Tough tough tough.......Anyways, thanks guys HH

Plywood is a wonderful thing.  If you do the same test using blunts, it is very likely the blunt will out penetrate the field point and the broadhead.

Maybe we should be using blunts on big game ?
ChuckC

X = down range = depth of peneration    

in several of the older  ( years back ) discussion it has been shown that a heavy arrow gets much more increase in peneration than a light arrow. Now speed ( light arrow ) will have a flat projection from the bow to the target. The heavy arrow will be more like a bell curve, the longer the target to the shot of the bow the higher will be the aim point.

Now what that means to me using carbon arrows at 530 gr, my poor ability  as a archer is I will keep the shot to under 20 yards...pick a spot

Bill

HH, DO THIS..

FASTEN THE PLYWOOD IN A WAY WHERE IT IS SOLID AND CANNOT MOVE

DO THE TEST AGAIN !

Fast arrows have an advantage when the target is fairly lightweight and moveable can be "pushed" back by the arrow.

Let us know

Jacob

I would like to see the results with about 6" of foam glued to the back of the board, for continued resistance after penetration.

Eric

Any test can be changed until it yeilds the desired results.

The only test that will ever answer the light/heavy/speed question for HUNTING penetration will come after a test medium is found that will replicate a living animals ribcage/lungs.

Until then, these "tests" are interesting but will never yield conclusive results.

Steve

I don't have any good foam or I'd had already tried this behind the board. I looked around prior to the test and didn't have any. What I'd like to do is shoot an animal with a rifle and then set it back up quickly and hit it with broadheads with different weights behind em. HOWEVER, I cannot do that at this point. I also have another set up that is a 650 grain arrow out of a 55lb long bow, strickly a 15 yard and under arrow. I shot this rig (different bow and arrow) into that same board from the same distance and it had very little penetration. However the shaft size is a bit larger which automatically makes for less penetration. BUT MY GOSH, that's a heavy set up out of a decent weight bow. I saw a kill picture once of a young woman who killed a medium sized pig with a 25 lbs recurve. She used a 650 grn arrow. SO, I think both are set ups are probably lethal "enough".....but I'd like to know which is "better" then the other..........tough call.

Thanks fellows and keep um coming.....HH

HH

FASTEN THE BOARD !

Whump Sez; beats me dude--I can shoot light arrows into styrofoam and heavy arrows into the same foam and the heavy will out penetrate the light arrows every time. Your acid test will be on game---if the light set up works for you I see no reason to over do it on weight. However weighter set ups are usually a lot quieter. Some things are stranger than fact but I can't see how a well tuned heavy set up is getting less penetration than a well tuned light set up, unless your heavy set up is not out of paradox when reaching the board.    :saywhat:   Hunt safe.

Howdy Whump,
That makes sense if the arrow is still in paradox that it'd lose penetration. Thank bud!

J, I have had a wisdom tooth removed and won't be up to shooting for a day or two I imagine. BUT, when I get a chance I will fasten the board.

Hope you have a quick recovery HumbleHunter, Look foward to these test!

Here are some basic generalizations.

These are based on changing one thing at a time keeping everything else equal except for the one thing changed.

If you want to increase your penetrating capability.

In no specific order.

#1. Use a heavier arrow.
#2. Increase your arrow's speed.
#3. Choose a broadhead that has less blades and has near a 3 to 1 ratio (make sure it's very sharp).
#4. Increase your arrow's FOC.
#5. Choose an arrow with a smaller diameter.
#6. Utilize a broadhead that matches your helical or off-set of your feathers.
#7. Teflon coat your broadhead and arrow.

Those are just a few that come to mind.

And the easiest and most important aspect that an bowhunter can do to increase his arrow's penetrating potential...is to tune your equipment for as near perfect arrow flight as you are personally capable of doing.

Ray   ;)

IMO it's about trajectory and arrow paradox on impact w/ this test.The arro w/ the most arch in his trajectory will have greater paradox at impact,causing more friction when striking a flat surface.Take a arro and push it from the knock into a hard surface at a horizonal.Then take the same arro and add some angle to that plane and the arro will flex easier in one direction.
With game being of different medium and not a flat surface,reducing deflection IMO is the key to heavier arros for penatration.Just my thinking.

makes sense guys, thank ya!

Thanks TNstickn, I appreciate it!