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Old 11-01-2021, 12:22 PM   #1
enewman
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Default physics and Ashby

He missed a lot.

I put a paper together using physics and work-energy theorem. I used Joel Maxfield's test as my example.
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Old 11-01-2021, 01:19 PM   #2
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These comparisons make my head hurt!!

Ashby clearly states that he's not looking for lab results but real world outcomes into tissue not some man made material. Comparisons need to be apple to apple not apple to orange.
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Old 11-01-2021, 01:56 PM   #3
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These comparisons make my head hurt!!

Ashby clearly states that he's not looking for lab results but real world outcomes into tissue not some man made material. Comparisons need to be apple to apple not apple to orange.
Dr. Ashby stated THat with equal momentum but unequal mass the heavy arrow will out penetrate. Physics dictates this to be true.

That is not what physics tells us. His statement goes against physics.

Next. who tells us that we cannot use a different media to test in. The person that is also telling you that momentum built on mass will outperform momentum built on velocity. hahahahaaha

He also tells you that KE has nothing to do with penetration and momentum is force. That to goes against Physics.

The test done here was not a comparison to animals as I stated in the paper. The test was a physics test. Ashby's non-scientific outcome-driven tests are not scientific or physics.

To do a physics test you must receive variables. Animals have too many variables, making animals a bad test media to look at physics.

Last edited by enewman; 11-01-2021 at 02:00 PM.
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Old 11-01-2021, 02:06 PM   #4
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Originally Posted by Hardware View Post
These comparisons make my head hurt!!

Ashby clearly states that he's not looking for lab results but real world outcomes into tissue not some man made material. Comparisons need to be apple to apple not apple to orange.
Next, you say we need to compare. Let's look at some of Ashby's comparable testing.

Ashby shows that a 40lb bow will outperform a 82lb bow with arrow weight being comparable. Then he talks about how this shows that KE means nothing. What he doesn't say is that the momentum for that 82lb bow is also greater. how did the 40lb bow outperform? It was in the arrow build. He tells you this.

So, you don't like my post as you say it is not apples to apples. almost all of Ashby testing is not apples to apples. So, why would you accept a non-scientific test but not a physics test?

Not one test done by Ashby has been quantified. But the data I just showed was quantified by physics.

Last edited by enewman; 11-01-2021 at 02:10 PM.
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Old 11-01-2021, 02:20 PM   #5
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Insert popcorn eating deer meme here...
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Old 11-01-2021, 02:26 PM   #6
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My uneducated opinion- Ashby is geared toward traditional setups, not modern equipment. I do agree with some of the applications- but not all. To each his own.
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Old 11-01-2021, 02:27 PM   #7
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In for the discussion! I always enjoy a good debate about actual archery subjects on a bowhunting forum!
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Old 11-01-2021, 02:29 PM   #8
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In for the discussion! I always enjoy a good debate about actual archery subjects on a bowhunting forum!
lol those are few and far between these days
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Old 11-01-2021, 02:36 PM   #9
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lol those are few and far between these days
got to start debates.
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Old 11-01-2021, 02:46 PM   #10
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I believe penetration is greatly effected by having a well tuned bow in which the arrow flies straight and impacts the target straight on. When you do testes with different arrow weights it is hard to say that the arrows are tuned exactly the same. Thus, the flight of the arrow makes the tests very difficult to reduce variables.
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Old 11-01-2021, 02:49 PM   #11
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I believe penetration is greatly effected by having a well tuned bow in which the arrow flies straight and impacts the target straight on. When you do testes with different arrow weights it is hard to say that the arrows are tuned exactly the same. Thus, the flight of the arrow makes the tests very difficult to reduce variables.
agree
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Old 11-01-2021, 03:00 PM   #12
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Why do I always go to the bottom to look for the conclusions
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Old 11-01-2021, 03:11 PM   #13
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Old 11-01-2021, 03:11 PM   #14
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Why do I always go to the bottom to look for the conclusions
Haha, I don't know. The conclusion is in the first post. hahaha
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Old 11-01-2021, 04:56 PM   #15
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Quote:
Originally Posted by 98ag View Post
I believe penetration is greatly effected by having a well tuned bow in which the arrow flies straight and impacts the target straight on. When you do testes with different arrow weights it is hard to say that the arrows are tuned exactly the same. Thus, the flight of the arrow makes the tests very difficult to reduce variables.
Agree. Sadly this first hurdle is one that if I had to hazard a guess, 80% of bowhunters don't ever get past. The two most common things I see/hear as advice... 1. just shoot a mechanical, and 2. just move your pins.

As I've read/watched more and more on this topic, I think less and less of Ashby. In a way his whole methodology is constructed around reinforcing his theories, I feels a lot like confirmation bias. It gets even less "worthwhile" when its pointed out he contradicts physics. For the bowhunting academics its a fun topic to discuss and sure beats watching reality TV.
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Old 11-01-2021, 05:20 PM   #16
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Watching the videos Troy and Rocketman are cranking out it sure looks like they have stepped up their testing methodology and are producing some good data. My anecdotal evidence this year was impressive for what it's worth.
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Old 11-01-2021, 05:22 PM   #17
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Agree. Sadly this first hurdle is one that if I had to hazard a guess, 80% of bowhunters don't ever get past. The two most common things I see/hear as advice... 1. just shoot a mechanical, and 2. just move your pins.

As I've read/watched more and more on this topic, I think less and less of Ashby. In a way his whole methodology is constructed around reinforcing his theories, I feels a lot like confirmation bias. It gets even less "worthwhile" when its pointed out he contradicts physics. For the bowhunting academics its a fun topic to discuss and sure beats watching reality TV.
It's funny, not long ago I was all into Ashby. But I found a guy with a physics background. He showed me lots of things wrong with Ashby. I fought with him tooth and nail.

But one day I started looking at what he was telling me. I went deep into looking at physics. Then I went back to the Ashby papers. I cannot believe how stupid I was. What is worst is the number of people that I taught Ashby to.

It truly bothers me how much I taught Ashby. Now, I don't hate Ashby he is a nice guy. But I do think it's worth my time and even being beaten up over it to show people what is going on.

Are my papers for everyone, no they are not. But I am always willing to help where I can.
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Old 11-01-2021, 05:23 PM   #18
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Originally Posted by Gunnyart View Post
Watching the videos Troy and Rocketman are cranking out it sure looks like they have stepped up their testing methodology and are producing some good data. My anecdotal evidence this year was impressive for what it's worth.
Yes, I'm glad they are too. I have noticed they are now talking more about energy and work.

I do disagree with some of there data they put out. I did an arrow deceleration test. they call there's speed erosion.

They are showing at the bow at a distance. that's it. then they want to show you how much better a heavy arrow does. That's ok data but lacking.

My test and it's on this sight I showed every ten yards to 50 yards. then I showed based on the lab radar the time in seconds it took for each arrow I tested. then I showed a trajectory tape.

They want you to believe heavy is the only way to go. it is absolutely not.

Last edited by enewman; 11-01-2021 at 05:29 PM.
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Old 11-01-2021, 06:53 PM   #19
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Yes, I'm glad they are too. I have noticed they are now talking more about energy and work.

I do disagree with some of there data they put out. I did an arrow deceleration test. they call there's speed erosion.

They are showing at the bow at a distance. that's it. then they want to show you how much better a heavy arrow does. That's ok data but lacking.

My test and it's on this sight I showed every ten yards to 50 yards. then I showed based on the lab radar the time in seconds it took for each arrow I tested. then I showed a trajectory tape.

They want you to believe heavy is the only way to go. it is absolutely not.
Well they've yoked themselves to Ashby.... and are straight up fundraising for the foundation. So sadly any data they collect that directly contradicts Ashby.... I would be surprised if it came to light. Not saying its impossible, but I would be surprised.
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Old 11-01-2021, 07:28 PM   #20
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Not to derail the thread, but, wouldn't it be paramount to teach people to tune their equipment? A fine tuned bow with a straight flying arrow is gonna hit the spot aimed at and penetrate with less effort and friction. Honestly, most people don't get physics, but could learn to tune their bow. Don't get me wrong, I appreciate your efforts and all the info you post and some I understand, some I don't, but me not knowing physics doesn't stop my arrow from killing. Your posts are intriguing though.

You mean a lighter faster arrow is harder to stop than a heavier slower arrow? Do tell?

Last edited by lovemylegacy; 11-01-2021 at 07:38 PM.
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Old 11-01-2021, 08:30 PM   #21
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Not to derail the thread, but, wouldn't it be paramount to teach people to tune their equipment? A fine tuned bow with a straight flying arrow is gonna hit the spot aimed at and penetrate with less effort and friction. Honestly, most people don't get physics, but could learn to tune their bow. Don't get me wrong, I appreciate your efforts and all the info you post and some I understand, some I don't, but me not knowing physics doesn't stop my arrow from killing. Your posts are intriguing though.

You mean a lighter faster arrow is harder to stop than a heavier slower arrow? Do tell?
Yes, I agree. Teaching tuning would prolly be better.

The lighter faster arrow would only be harder to stop when matching momentum.

Shooting from the same bow, the heavy arrow will be.
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Old 11-01-2021, 08:54 PM   #22
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Ashby was given a very specific test to pass, so he catered everything he did in order to pass that specific test. That’s what I would do too, so not hating, just adding a bit of perspective. Also, he’s not wrong on a lot of things. Just no need to burn much brain power on this unless I’m hunting for bigger game.
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Old 11-01-2021, 09:16 PM   #23
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Ashby is a mighty fine fellow. He helped me put together the arrow i used to kill an elephant.

My humble opinion is any compound bow will kill deer sized animals with any arrow you want to shoot.

Ashby research was the best that had ever been done for folks wanting to kill silly big critters with recurve bows .

When i was talking to him he pretty much seemed to be the smartest fellow i had ever talked to

but that is just me

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Old 11-01-2021, 09:35 PM   #24
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Originally Posted by Buff View Post
Ashby is a mighty fine fellow. He helped me put together the arrow i used to kill an elephant.

My humble opinion is any compound bow will kill deer sized animals with any arrow you want to shoot.

Ashby research was the best that had ever been done for folks wanting to kill silly big critters with recurve bows .

When i was talking to him he pretty much seemed to be the smartest fellow i had ever talked to

but that is just me
What one of the problems is the people backing the ashby foundation is *******izing his work. They are preaching that you need a 650gr arrow to kill whitetail deer.

Some of the worst teachings I have ever seen.

But my post is not about arrows. Itís about how ashby screwed the pooch when looking at physics.
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Old 11-01-2021, 11:25 PM   #25
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Yes, I agree. Teaching tuning would prolly be better.

The lighter faster arrow would only be harder to stop when matching momentum.

Shooting from the same bow, the heavy arrow will be.
Iím confused, do you agree the heavy arrow is harder to stop? Isnít that what Ashby says?
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Old 11-01-2021, 11:27 PM   #26
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I think the important question to ask is: does more foc weight cause an arrow to fly straighter?
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Old 11-02-2021, 12:24 AM   #27
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Did Joel Maxfield test these two arrows out of the same bow, multiple times getting an average, or did he just throw some random velocity numbers up there? One can easily plug in numbers to the equation to give the lighter arrow more KE/P. I'm not preaching light or heavy, just pointing out that I could plug in numbers and it would show Mr. Maxfield to be wrong.
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Old 11-02-2021, 01:02 AM   #28
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Quote:
Originally Posted by Buff View Post
Ashby is a mighty fine fellow. He helped me put together the arrow i used to kill an elephant.

My humble opinion is any compound bow will kill deer sized animals with any arrow you want to shoot.

Ashby research was the best that had ever been done for folks wanting to kill silly big critters with recurve bows .

When i was talking to him he pretty much seemed to be the smartest fellow i had ever talked to

but that is just me

Canít argue with resultsÖ.


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Old 11-02-2021, 08:13 AM   #29
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Iím confused, do you agree the heavy arrow is harder to stop? Isnít that what Ashby says?
The test and what Iím talking about is physics.

Go back and read my paper. What Iím showing is that Ashby is wrong on what gives us penetration.

Dr ashby preaches that KE has absolutely nothing todo with penetration. Dr ashby states just that. In my paper the reference number one is his paper where he tells everyone in the world the KE has nothing todo with penetration.

Same paper and the statement about momentum is referenced in my paper, he states that two equal momentum arrows with unequal mass that the momentum built on mass will out perform. That goes againt physics. The test shows this. What Iím showing you and others is that ashby screwed the pooch.

Ashby spent to much time trying to prove that KE does nothing that he caused some testing to be skewed.

He talked about momentum but uses the definition of inertia.

There are so many flaws in the paper talking physics itís horrible.

Now. I just used a equation based on Newtonís second law and work energy theorem. I just showed that ashby was wrong.

Does this mean a heavy arrow will not out penetrate a light arrow. No. That was not the test. Heavy arrows will out penetrate. Why.

Because as you increase weight the bow converts potential energy to KE better. Thus the heavy arrow will leave the bow with either the same KE (very efficient bow) or it will be a little higher ( not as an efficient bow). Due to inertia the heavy arrow will retain its velocity better. So at impact the heavy arrow will have more KE.

Now at impact. When an arrow is moving through the animal we have resistance. As hunters we can control the resistance some what. We do that by the broadhead.

Ke is a major player in penetration. Momentum is also very important. Ke is what gives us the capacity to penetrate momentum is what makes it harder to stop.

This is why light arrow people talk about shot placement. A 450 gr arrow with the correct broadhead will perform just as well as a 650gr. But you must stay off the bone. Is it a for sure bone break using a heavy arrow. No.

So why is there so much talk about all of this. It comes down to trajectory. Long distance shooting trajectory is a big thing. Misjudging yardage is a big thing. It all comes down to what is best for you.

Again the test was looking at ashby comment on two arrow with equal momentum. When doing this the heavy arrow will have less KE. Thus its capacity to do work is less.
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Old 11-02-2021, 08:22 AM   #30
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Did Joel Maxfield test these two arrows out of the same bow, multiple times getting an average, or did he just throw some random velocity numbers up there? One can easily plug in numbers to the equation to give the lighter arrow more KE/P. I'm not preaching light or heavy, just pointing out that I could plug in numbers and it would show Mr. Maxfield to be wrong.
I can see you do not know joel maxfield. Look him up. When you do you may need to type in joel maxfield with Mathews.

Your question will be answers.

These test that Iím showing, are some I am working on. I am fixing tod a NEWTONIAN and NON-NEWTONIAN test.

Your question about same bow. No. You cannot test equal momentum doing this. Reason is thee is a big KE difference.

I have people tell me you cannot do a test like this, because I am changing bows. That normally comes from the ashby crowed. Funny thing is they seem to forget that ashby tested and compared to each other with a 40,54,70, and a 82 lb bows.

Funny is it was ok for ashby but not me. The difference is Iím showing different results and I using physics to support my test. Ashby did not.

Also a bow is just a machine. Itís purpose is to convert the energy you put in to drawing the bow into potential energy then convert it back to kinetic energy and transfer that energy to the arrow so the arrows has acceleration.

This is why I use a term I coined. K.E.D.D. kinetic energy delivery devise. That is all a bow is.

Ranch fairy calls it a kinetic energy spring. He is doing this I assume for the same reason I did. To show people when testing it doesn't matter what bow we use to reach what is needed to test.
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Old 11-02-2021, 08:27 AM   #31
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I think the important question to ask is: does more foc weight cause an arrow to fly straighter?
FOC. no FOC DOSENT. FOC is a static measurement to show you how much weight of the arrow is in front of the center given in percentage.

But if we look at what it really is we need to look at the center of gravity and the center of pressure and the static margin.

When we add weight or take it a way we move the center of gravity location. Does this change arrow stabilization. Yes but itís doing this because we are changing the static margin between the center og gravity and the center of pressure. So the location of the center of pressure is what is doing the stabilization.

Now for most including me itís just easy to use FOC. Itís a easy calculation for everyone to use.
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Old 11-02-2021, 08:31 AM   #32
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Canít argue with resultsÖ.


We can argue the results. We are now seeing people kill elephants, hippos, and Cape buffalo with sub 600gr arrows. Ashby could not get these results. Why, because he tested with low energy set ups.

Letís not forget Ashby stated on a podcast that he could not test with compound bows because he always got a pass through. He had no measurable data. That statment alone should trigger people into understanding what it takes to kill with a trad bow is not what we need to kill with a compound bow.
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Old 11-02-2021, 09:07 AM   #33
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I can see you do not know joel maxfield. Look him up. When you do you may need to type in joel maxfield with Mathews.

Your question will be answers.

These test that I’m showing, are some I am working on. I am fixing tod a NEWTONIAN and NON-NEWTONIAN test.

Your question about same bow. No. You cannot test equal momentum doing this. Reason is thee is a big KE difference.

I have people tell me you cannot do a test like this, because I am changing bows. That normally comes from the ashby crowed. Funny thing is they seem to forget that ashby tested and compared to each other with a 40,54,70, and a 82 lb bows.

Funny is it was ok for ashby but not me. The difference is I’m showing different results and I using physics to support my test. Ashby did not.

Also a bow is just a machine. It’s purpose is to convert the energy you put in to drawing the bow into potential energy then convert it back to kinetic energy and transfer that energy to the arrow so the arrows has acceleration.

This is why I use a term I coined. K.E.D.D. kinetic energy delivery devise. That is all a bow is.

Ranch fairy calls it a kinetic energy spring. He is doing this I assume for the same reason I did. To show people when testing it doesn't matter what bow we use to reach what is needed to test.
I could care less who maxfield, Ashby, or ranch fairy are just so we’re clear I’m not on anyone’s side. If you aren’t testing things out of the same bow or ,KEDD as you prefer, then you’re not comparing apples to apples. No matter who the tester is that is not a halfway sound experiment, it’s fishing for results to fit a narrative.

I could take an arrow from each end of the spectrum and make them out perform each other in ways that half the people would argue with and the other half would agree with.

All I know is I’ve witnessed real world results between what ~385gr arrows will do hitting bone vs ~500gr arrows. That cannot be argued.
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Old 11-02-2021, 09:37 AM   #34
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All you've done is compared kinetic energies of the two arrows with the lighter faster arrow having more kinetic energy.

Two more appropriate analysis would be to look at the situation from a conservation of energy perspective. In this analysis you'd take into account energy spent penetrating which would be greater for the faster arrow since the resistance a faster arrow would see is exponential to it's velocity. The other way it could be looked at is from a conservation of momentum perspective where you include the impulse to stop the arrow. In the momentum analysis you'll see that the impulse force the slower arrow sees is less (sees less resistance). The issue with this analysis is that arrow penetration is not an elastic collision.

Neither of these analysis is perfect since there are unknown variables involved.
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Old 11-02-2021, 10:01 AM   #35
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I could care less who maxfield, Ashby, or ranch fairy are just so we’re clear I’m not on anyone’s side. If you aren’t testing things out of the same bow or ,KEDD as you prefer, then you’re not comparing apples to apples. No matter who the tester is that is not a halfway sound experiment, it’s fishing for results to fit a narrative.

I could take an arrow from each end of the spectrum and make them out perform each other in ways that half the people would argue with and the other half would agree with.

All I know is I’ve witnessed real world results between what ~385gr arrows will do hitting bone vs ~500gr arrows. That cannot be argued.
then you don't understand testing. That is ok. most do not.

By the way, if you could care less then why are you on my post. hahahaha

as far as in the real world. the 500 will outperform the 385 all day every day. no one is disputing this.

as far as you saying I'm not comparing apples to apples. this alone shows me you do not understand. I did compare apples to apples. Momentum is equal. that is apples to apples.

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Old 11-02-2021, 10:04 AM   #36
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All you've done is compared kinetic energies of the two arrows with the lighter faster arrow having more kinetic energy.

Two more appropriate analysis would be to look at the situation from a conservation of energy perspective. In this analysis you'd take into account energy spent penetrating which would be greater for the faster arrow since the resistance a faster arrow would see is exponential to it's velocity. The other way it could be looked at is from a conservation of momentum perspective where you include the impulse to stop the arrow. In the momentum analysis you'll see that the impulse force the slower arrow sees is less (sees less resistance). The issue with this analysis is that arrow penetration is not an elastic collision.

Neither of these analysis is perfect since there are unknown variables involved.
yes because KE is involved. but the test was looking at physics and that two arrows of qual momentum but unequal mass. As I have already stated the test and physics were based on Ashby stating equal momentum.

the reason the lighter arrow wins is because of KE again Ashby states that ke has nothing to do with penetration. This physics test shows that Ashby was incorrect with both his statements.

I could have shown how much force was spent. I actually had all of that in the chart. but I was afraid it was to much. as we can see even what I did is to much.

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Old 11-02-2021, 10:07 AM   #37
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We can argue the results. We are now seeing people kill elephants, hippos, and Cape buffalo with sub 600gr arrows. Ashby could not get these results. Why, because he tested with low energy set ups.

Letís not forget Ashby stated on a podcast that he could not test with compound bows because he always got a pass through. He had no measurable data. That statment alone should trigger people into understanding what it takes to kill with a trad bow is not what we need to kill with a compound bow.

To each is own but I would never recommend to anybody that they should hunt dangerous game with less arrow than needed. You are going down a rabbit hole here that is ill advised. Forget about Ashby, FOC and all that stuff. Iíve spent time in Africa, no reputable outfitter would ever recommend what you are proposing. Itís dangerous, negligent and just plain silly. If a guy thats seen hundreds of Buffalo taken with archery equipment heís probably on to something. My guys wouldnít let you out of the truck with a sub 600 grain arrow chasing Buff, just because you can doesnít mean you should. There is just too much historical data showing what works and what doesnít with Buff, I donít know anybody thatís doing what you are stating and again anybody with any seat time in the Bush that would recommend it.


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Old 11-02-2021, 10:08 AM   #38
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then you don't understand testing. That is ok. most do not.

By the way, if you could care less then why are you on my post. hahahaha

as far as in the real world. the 500 will outperform the 385 all day every day. no one is disputing this.

as far as you saying I'm not comparing apples to apples. this alone shows me you do not understand. I did compare apples to apples. Momentum is equal. that is apples to apples.
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Old 11-02-2021, 10:14 AM   #39
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To each is own but I would never recommend to anybody that they should hunt dangerous game with less arrow than needed. You are going down a rabbit hole here that is ill advised. Forget about Ashby, FOC and all that stuff. Iíve spent time in Africa, no reputable outfitter would ever recommend what you are proposing. Itís dangerous, negligent and just plain silly. If a guy thats seen hundreds of Buffalo taken with archery equipment heís probably on to something. My guys wouldnít let you out of the truck with a sub 600 grain arrow chasing Buff, just because you can doesnít mean you should. There is just too much historical data showing what works and what doesnít with Buff, I donít know anybody thatís doing what you are stating and again anybody with any seat time in the Bush that would recommend it.


I would never recommend either.

Its funny how all Im doing is showing physics and you think Im promoting light arrows. come on muddy. I know you are smarter than that.
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Old 11-02-2021, 10:20 AM   #40
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Quote:
Originally Posted by BernieH View Post
All you've done is compared kinetic energies of the two arrows with the lighter faster arrow having more kinetic energy.

Two more appropriate analysis would be to look at the situation from a conservation of energy perspective. In this analysis you'd take into account energy spent penetrating which would be greater for the faster arrow since the resistance a faster arrow would see is exponential to it's velocity. The other way it could be looked at is from a conservation of momentum perspective where you include the impulse to stop the arrow. In the momentum analysis you'll see that the impulse force the slower arrow sees is less (sees less resistance). The issue with this analysis is that arrow penetration is not an elastic collision.

Neither of these analysis is perfect since there are unknown variables involved.
here is a test looking at the work energy using a foam test media. It to is quantified by physics. It this what happens in an animal. don't know as animals are not good test media if looking at physics.

dr Ashby was very smart when he stated I'm using a non-scientific outcome-driven test.

The test was not to see what we can do when hunting animals. it was to look at physics to see if the statement made by Ashby about equal momentum was correct. as you can see it wasn't. This is an issue in the archery world. people are being taught the physics of archery by people that read Ashby and it is WRONG.

here is looking at the force with matching KE. as you can see the net force between the two is equal. This would be that the equal momentum the heavy arrows force would be less.

Not sure why you brought up elastic collision. we know its not as the arrow is loosing energy
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Old 11-02-2021, 10:33 AM   #41
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Looking at the net force with equal momentum with a physics test into a foam target.

The question is why did it take less net force to stop the heavy arrow with equal momentum. The heavy arrow had less KE. Meaning it could not do the same amount of work. AGAIN I am only looking at the physics aspect of it. based on Ashby's statements.

As you can see he was wrong on the physics part. not what the arrow can do.
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Old 11-02-2021, 10:51 AM   #42
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I think the important question to ask is: does more foc weight cause an arrow to fly straighter?
No, your tuned bow will cause your arrow to fly straighter
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Old 11-02-2021, 11:02 AM   #43
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Looking at the net force with equal momentum with a physics test into a foam target.

The question is why did it take less net force to stop the heavy arrow with equal momentum. The heavy arrow had less KE. Meaning it could not do the same amount of work. AGAIN I am only looking at the physics aspect of it. based on Ashby's statements.

As you can see he was wrong on the physics part. not what the arrow can do.

So do you think that if you used a broadhead and say a deer instead of foam that your results would be different? Are the two arrows being shot into the foam the same diameter?
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Old 11-02-2021, 11:18 AM   #44
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I was told that I needed to explain better.

First, the test is a physics test. It was to look at what physics tells us, and I compared it to what Ashby stated. With physics, I showed that he was wrong. Not as what he did but what he is teaching that gives us penetration.

Now, as far as arrows. Suppose we shoot from the same K.E.D.D. Then the heavy arrow will out penetrate. We know this. We know this because physics tells us this.

I do not promote light arrows. I promote what works for you. If you are killing with a 425gr arrow, then there is absolutely no reason to change. When people come to me and state, the 425gr failed. my first question is not about mass (Dr. Ashby #6 in the penetration factors); I ask about what broadhead (#4 in the factors)

Ashby's studies are with low energy. He did this because he tested with high energy, and the arrows always passed through. No way to get measurements. That alone should tell you there is a point where a lighter arrow with the correct amount of Ke will perform just as well as a heavy arrow. We just do not know where that is.
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Old 11-02-2021, 11:37 AM   #45
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my first question is not about mass (Dr. Ashby #6 in the penetration factors); I ask about what broadhead (#4 in the factors)
My first question would be did you tune your bow or did you let the shop "tune" it?
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Old 11-02-2021, 11:46 AM   #46
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I'd like to see the momentum calculation at distances. It may be in the thread but I skipped all the arguments. This is a balance of trajectory versus momentum at the target point. It is my understanding that a lower mass projectile will not conserve momentum at the same rate as a higher mass projectile. At some point in the distance, the momentums will be equal and a lower mass but higher speed projectile will likely penetrate further than a higher mass projectile. After that point, the penetration switches. But there are other effects on the trajectory. Wind, primarily.

Ashby's methods were stated as unscientific. But unless his results were skewed, there may be something else going on from a physical standpoint that effects the equation. Foam, it appears to me, is a relatively consistent medium. Animals are not. There are other considerations than the physics of ballistics at source. Terminal ballistics in projectiles should be our driving consideration, including projectile orientation on impact.

I'm not supporting or defending anyone and it has been years since I studied terminal ballistics. I am raising questions in a true scientific manner. As I get time I will go back and read the posts before this one and see if this is addressed.
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Old 11-02-2021, 01:08 PM   #47
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My rig seems to put broadheads into one lung and out the other on deer and hogs. Not sure what else matters. I don't think I'll be hunting elephants or rhinos any time soon.
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Old 11-02-2021, 01:12 PM   #48
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My first question would be did you tune your bow or did you let the shop "tune" it?
since this data was from joel. no I did not tune my bow nor do I let a shop tune for me. hahaha

I use the HVPS tuning method. All my setups are tuned
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Old 11-02-2021, 01:13 PM   #49
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I feel like Iíve read this thread before
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Old 11-02-2021, 01:13 PM   #50
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I'd like to see the momentum calculation at distances. It may be in the thread but I skipped all the arguments. This is a balance of trajectory versus momentum at the target point. It is my understanding that a lower mass projectile will not conserve momentum at the same rate as a higher mass projectile. At some point in the distance, the momentums will be equal and a lower mass but higher speed projectile will likely penetrate further than a higher mass projectile. After that point, the penetration switches. But there are other effects on the trajectory. Wind, primarily.

Ashby's methods were stated as unscientific. But unless his results were skewed, there may be something else going on from a physical standpoint that effects the equation. Foam, it appears to me, is a relatively consistent medium. Animals are not. There are other considerations than the physics of ballistics at source. Terminal ballistics in projectiles should be our driving consideration, including projectile orientation on impact.

I'm not supporting or defending anyone and it has been years since I studied terminal ballistics. I am raising questions in a true scientific manner. As I get time I will go back and read the posts before this one and see if this is addressed.
miss read

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