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Author Topic: "The Study" - need YOUR ideas NOW!  (Read 1033 times)

Offline Dr. Ed Ashby

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"The Study" - need YOUR ideas NOW!
« on: March 27, 2003, 07:48:00 PM »
Hello all,

Please put on your collective thinking caps.  Most of the study data base work and protocols are done.  I'm developing an "idea and questions" list now.  This is a sort-of 'wish list' of things we would like to know about hunting arrow performance on real animals.

So far, I have about a page and a half of typed questions I want to look for the answers to, but I wish to "pick the collective brains" of the dedicated hunters of the Trad Gang.

I don't want to list all I have - 'cause it would just confuse the issue - too much to think about.  I'll just give a couple of examples from the list, and then I'd like for ya'll to just think about things YOU would like to have answers to - besides the performance levels of the different broadheads being tested.  So ... here are a few examples of some I already have on the list.

(1)  A look at the relationship of IMPACT kinetic energy and momentum as predictors of penetration, with arrows of equal 'broadhead design and structural integrity'.

(2)  The effect of the 'Moment of Force' on penetration.  A comparison of 'similar' arrows with EQUAL IMPACT FORCE, but with one having greater mass at lower velocity, and the other having lower mass at a greater velocity.  How important is the 'rate of disipation of force' as a factor in penetration?

(3)  Is there any quantifiable difference in the degree of blood trails that can be related to type of broadhead/cut width/number of blades/sharpening angle/broadhead cut blade profile(s)/type of edge sharpening method used.

(4)  What effect, if any, does the percentage of weight FOC have on penetration when all else is equal.

Ok, now, ya'll give me ALL you can think of!  :readit:

Lets try to keep this post 'at the top of the list' until I've milked everyone of EVERY IDEA ya'll can come up with.  If I need to add any 'data collection' items, I need them NOW ... BEFORE the study formally commences.

Ed

Online paradocs

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Re: "The Study" - need YOUR ideas NOW!
« Reply #1 on: March 27, 2003, 08:27:00 PM »
Ferrule diameter vs shaft diameter, as it relates to penetration?

Offline Douglas DuRant

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Re: "The Study" - need YOUR ideas NOW!
« Reply #2 on: March 27, 2003, 08:31:00 PM »
The effect of the “speed of impact”, if any, on the penetration achieved by a broadhead. Ron Le Clair showed a picture of a shoulder blade penetrated by a light carbon arrow in a thread a while back. If I understand him, he thinks you don't need high weight with fast light carbons to get good penetration. Stiffness, frequencies of modulation (is that real), small diameter are all things I have heard stated as reasons carbon arrows seem to penetrate well.

Consideration of the arrow concerning penetration seems as important as the broadhead, which rides the shaft. Factors such as arrow diameter, speed, weight, material, foc, are all potentially important to penetration.

The arrows path through the animal, with bones on impact, and exit, full stomachs ect being considered.

Repeatable bow energy, arrow speed, and draw length data. Accurate arrow spine, length and weights measurements are also important.

Distance, angle, elevation, and alertness of the animal at the shot are also relivent factors to consider.

From what I have seen you seem to have considered all these things already. I think some more on it, and if I come up with something I'll add it later. Good Idea asking, you never know what someone will think of.

Offline Ray Lyon

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Re: "The Study" - need YOUR ideas NOW!
« Reply #3 on: March 27, 2003, 08:35:00 PM »
How does shaft material affect penetration, if at all, with other factors being equal.

Is there a corelation between number of blades on a broadhead and the length of blood trail do to the "shock" to the animals system of more blades.(Initial thoughts would be more blades, shorter trail because of quicker blood loss, but my memory seems to say otherwise with my personal experiences).
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Offline Van/TX

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Re: "The Study" - need YOUR ideas NOW!
« Reply #4 on: March 27, 2003, 08:58:00 PM »
Dr. Ed, I remember reading your study in the late 1980's.  You are so far ahead of most folks I'll just take at face value what ever you come up with.  You're a good'un.  Thanks!  :cool:
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Offline Dr. Ed Ashby

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Re: "The Study" - need YOUR ideas NOW!
« Reply #5 on: March 27, 2003, 09:05:00 PM »
Paradocs ... Douglas ... got 'ya covered on those.  Keep them heads working!  I'm sort of isolated here, and really need a 'sounding board'.

Ray ...  Have shaft materials in there.  Also degree of blood trails as related to type of hit, presence/absence of exit wounds and their location(s), type(s) of broadhead, number of blades, blade profiles (several parameters), total cut area of the broadhead (an am considering adding 'cut volumn' - any thoughts here?), edge sharpening angle, edge sharpening technique, and 'alert level' of the animal to the shot.  Any more?

Ed

Offline herb haines

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Re: "The Study" - need YOUR ideas NOW!
« Reply #6 on: March 27, 2003, 09:33:00 PM »
Dr. Ed ,
this might not even have any bearing on any thing but what about angle of hit and distance traveled .
    what i am wondering is from what i have read that a shot from a tree stand with exit low down on body would bleed out better than a a shot from the ground with a through and through shot .don't know how clear i am on this ,hate treestands ,hunt from the ground wondering which is better .----- herb  :confused:
"Heaven is just over the next ridge......"

Hello Darlin'

Offline Dr. Ed Ashby

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Re: "The Study" - need YOUR ideas NOW!
« Reply #7 on: March 27, 2003, 09:41:00 PM »
Herb,

It's in there!  Keep up the thoughs though.  I REALLY do appreciate everyone taking time to think about these things.  I hope to have a data base that I can keep going even after 'phase one' of the study is completed, hoping that factors which are 'indeterminate' can be cleared up as the data continues to accumulate.  I want the information collected to be as 'complete' as I can get it.  This 'input' of other bowhunters really helps me out!

Ed

Online paradocs

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Re: "The Study" - need YOUR ideas NOW!
« Reply #8 on: March 27, 2003, 09:44:00 PM »
Hmmm, how 'bout moving vs stationary target, mud-encrusted hide vs "clean" hide, male vs female within the same species, wet vs dry fletching(assuming feathers from a well-tuned setup), all in relation to penetration?  I'm sure I'll come up with some more; just give me a few more beers.  ;)

Online Kevin Lawler

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Re: "The Study" - need YOUR ideas NOW!
« Reply #9 on: March 27, 2003, 09:48:00 PM »
I think you got yourself 2 studies there. I for one would like to see an independent study on the camparison of penetration of different shaft materials and a thesis on why one out pentrates the other.

Offline Buckeye

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Re: "The Study" - need YOUR ideas NOW!
« Reply #10 on: March 27, 2003, 09:50:00 PM »
I would like to see the shaft material test go even a bit further in specifics. In other words same broadhead (weight, design) on equal weight arrows of carbon alum. and wood. Seems there has been more than a bit of speculation the last few years as to whether carbons in fact out penetrate other arrows. I remember your original study did speak to diameter of shaft as it related to the ferule/broadhead ferule diameter. At least it figured into the TPI. I would be interested in that test result. Thanks

B
...all to often technology is substituted for skill and knowledge, guess that is why I married a teacher and shoot stickbows!

Offline Buckeye

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Re: "The Study" - need YOUR ideas NOW!
« Reply #11 on: March 27, 2003, 09:53:00 PM »
Sorry bout the cross post Kevin!
B
...all to often technology is substituted for skill and knowledge, guess that is why I married a teacher and shoot stickbows!

Offline Dr. Ed Ashby

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Re: "The Study" - need YOUR ideas NOW!
« Reply #12 on: March 27, 2003, 10:00:00 PM »
Paradocs ... are there any breweries near where you aree?  If so, most have 'hospitality rooms'.  Great place for 'thunk'n'.   :scared:    :scared:    Thinking of naming it MOABS (Mother Of All Broadhead Studies - any name suggestions for the study out there?) Have had to divide the data bases up into three 9so far) and cross-link 'um, 'cause it got too big to work with!

As for shaft materials, I hope to be able to answer the 'what' part, but the 'why' will just be my speculation of why I THINK the results show what they do!

Ed

Offline Dr. Ed Ashby

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Re: "The Study" - need YOUR ideas NOW!
« Reply #13 on: March 27, 2003, 10:02:00 PM »
Buckeye ... that is exactly what I intend to do, but it will only come after what broadhead to use is determined.

Ed

Offline JRW

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Re: "The Study" - need YOUR ideas NOW!
« Reply #14 on: March 27, 2003, 10:42:00 PM »
Please also break down some of the data by brand/model of broadhead. Not all 2, 3, or 4 blades are created equal.

Thanks, in advance.

JRW

Offline Russ

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Re: "The Study" - need YOUR ideas NOW!
« Reply #15 on: March 27, 2003, 10:52:00 PM »
Dr. Ashby, Thank you for the opportunity to provide input. As already mentioned, carbon arrow penetration as related to total arrow weight and compared to other shaft materials. Carbon arrow penetration as related to added nock weight. Lots of nock weight or weight tubes may, theoretically, take away the alledged carbon benefit of lack of noodling on impact. I assume the critters down under are smaller than Africa's and I'd like to see data on penetration with lighter bows. I hunt, in my old age, with 55-65# bows. What arrow combinations work well in this weight range on deer, caribou, moose and such? How does one compensate for these relatively light bow weights and what is it's importance on thin-skinned North American big game? Lastly, I'm fascinated by your previous findings that penetration is more important than shot placement and would like to see it addressed again in this new study. Thansk again and I look forward to the new study!

Offline Russ

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Re: "The Study" - need YOUR ideas NOW!
« Reply #16 on: March 27, 2003, 11:59:00 PM »
Forgot to mention front loaded carbons. It seems to be all the craze right now. Does it work?

Offline Dr. Ed Ashby

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Re: "The Study" - need YOUR ideas NOW!
« Reply #17 on: March 28, 2003, 12:09:00 AM »
JRW ... consider it done!

Russ ... All the data this time will be related to the force at impact (I'll revisit the Kinetic Energy vs Momentum argument first, to see which I use, but the existing data I have is pretty overwhelming that there is NO consistant correlation between Kinetic Energy and penetration, so it will most likely be momentum.)  This 'impact force' format will allow for one to use their own set-up, a chronograph and one of the 'on line' down range ballistics calculators to get an idea of how their equipment should perform relative to the study's results.  There will be a fair amount of testing done with lighter bows too.  That should help.

The idea that so many hold that only 'big' animals were used in the Natal Study is wrong.  Most of the testing was done on warthogs, impala, bushbucks and nyala - animals VERY consistant in size and structure with the hogs and deer of North America.  It was only as we began to 'push' the broadheads that we couldn't fully evaluate the performance level of on the smaller animals that we moved up to larger animals, those of wildebeeste, kudu and zebra size.

There's plenty of 'big stuff' down under too - feral horses, bantang, scrub bulls, Asian buffalo and camels - so we will, no doubt, end up with some 'push' stuff here too, as the field begins to narrow.

Initial testing will begin with feral goats, pigs and deer.  Only the things that pass the testing at this level unscathed will 'move up' to the next level of testing.  There will be an attempt to segregate or 'rate' the broadheads for the level they perform to.  (Although I never adhered to that theory.  If it's adequate for the largest, then it darned sure is adequate for a smaller critter.  Ain't no such thing as 'over kill' with an arrow.)

There will also be some data collection on North American game, but season and bag limits severely restrict the amount of data that can be collected there.  Aussie has no season or bag limits on the feral animals!  Now that offers the potential for reasonable data collection, but it still pails in comparison to the shooting opportunities of Africa.

Broadhead selection has to be 'weeded out' before I can start to definitively look in the data base for other factors, or do any studies focused on a specific factor, such as the effects on penetration of shaft size relative to shaft diameter.

Hope the information that eventually comes from this study will be of some help to you Russ.

Ed

Offline Dr. Ed Ashby

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Re: "The Study" - need YOUR ideas NOW!
« Reply #18 on: March 28, 2003, 12:11:00 AM »
Thanks again Russ.  The front-loaded carbon is one I'm anxious to look at too!

Ed

Offline Russ

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Re: "The Study" - need YOUR ideas NOW!
« Reply #19 on: March 28, 2003, 04:13:00 AM »
Dr. Ashby, I'm sure you are aware of this but thought I'd mention it anyway. There is a theory that carbon arrows do not "noodle" or oscillate wildly upon impact like wood and aluminum arrows. Therefore, carbons are thought to penetrate better than other types of arrows, even though they may be much lighter, because they better maintain their sectional density. It is further theorized that this lack of noodling transcends momentum theories. Weighting the carbon shaft with excessive nock weight, with or without point weight, or weight tubes is thought to interfere with this inherent property and decrease penetration, despite increased arrow weight. I'd love to know if experimentation proves this out. It would change the arrows I hunt with.

Lastly, the momentum versus kinetic energy arguments have always seemed a bit hollow to me. Both equations use mass and velocity and differ only in their mathematical relationships. As I remember from undergraduate school, a thousand years ago, Newton's original solids equation for momentum was changed later by an engineer, for his particular experiments, and remained so. In your Tissue Penetration Index, mass and velocity figures were held subject to arrow shaft diameter relative to broadhead diameter and the mechanical advantage of the broadhead. This relationship seemed to de-emphasize mass and velocity to a large extent, yet you seem intent on studying it further. What is your perspective of all this?

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