physics and Ashby

[enewman]

Yes, FOC helps control arrow flex on hard impacts.

https://www.facebook.com/grizzlystik/videos/128298182436058

[100%TtId]

Eric, are you testing out of a Hooter Shooter? Just curious about removing more variables.

[enewman]

Eric, are you testing out of a Hooter Shooter? Just curious about removing more variables.

Some times I do. But I need to work on my hotter shooter. It is not always repeatable. I just need to work on it.

Doing the arrow deceleration test I did I didn’t use it. Not needed.

Joel maxfield doesn't use a hooter shooter. But that man can shoot.

[cbd10pt]

[QUOTE=enewman;15916861]If you have any data or testing that FOC improves penetration for a compound bow, I would love to see it.

Doesn't matter what the arrow comes out of,
" Wobble can start with bad form, twigs, grass, bone etc."

I enjoy solid math, but sometimes you just have to get your hands dirty to understand how things work.
I've been on about 300 blood trails myself, all sorts of different arrows, all sorts of critters.
The ones with holes in their lungs didn't go very far.
Wild animals are fast, that's why speed is important.
Speed, moderately high FOC, and medium sized mechanicals = more short blood trails.
Don't believe me ask Waddell https://youtu.be/knEeH2WyQaE

[enewman]

[quote=cbd10pt;15924481]

If you have any data or testing that FOC improves penetration for a compound bow, I would love to see it.

It doesn't matter what the arrow comes out of,
" Wobble can start with bad form, twigs, grass, bone, etc."

I enjoy solid math, but sometimes you just have to get your hands dirty to understand how things work.
I've been on about 300 blood trails myself, all sorts of different arrows, all sorts of critters.
The ones with holes in their lungs didn't go very far.
Wild animals are fast, that's why speed is important.
Speed, moderately high FOC, and medium sized mechanicals = more short blood trails.
Don't believe me ask Waddell https://youtu.be/knEeH2WyQaE

I like what he is saying. I agree 100%. Im heading to the diamond c Friday. Im hunting with a 449gr arrow. The lightest I have been in for years. Im testing the new veteran broadhead that will be shown at the data show.

Yes, it's mechanical. I shot a goat not long ago at the diamond c with a combat veteran. Again it has a new tip design that took this head to 200gr. It to will be shown at the ata.

I got too deep into Ashby. I dug my way out. It's crazy to see what I'm seeing. Because this is not what Ashby teaches, it's not what the rf teaches, yet we see success every day with setups that we are told will not work.

The foundation or its members push that if you do not get a pass-through, that setup fails. I have several videos by dave holt killing African games with rage broadheads with no pass-throughs.

I actually wrote a paper on using your energy up and getting big cuts for lots of blood with no pass-throughs. People freaked out over it. why, because we are told we must have a pass-through.

I like what was presented in this video—lots of good information.

[Duckologist]

Stop shooting bone.

Sometimes it's incidental. This past Saturday I shot a deer from high up at 20 yards that was quartering away pretty hard. So I shot just below the spine and at the back of the rib cage. The arrow exited the offside armpit then enter the shank portion of the leg shattering the bone then exiting the leg. Messed up my dang ossobuco

[Gunnyart]

Given the choice between a passthrough and a large diameter shallow cut I'll take the passthrough.

[enewman]

Given the choice between a passthrough and a large diameter shallow cut I'll take the passthrough.

that is how most people think. I know I did.

but what gives us greater blood trails. a 1" two blade with a pass-through or a 1.75" cut that stops in the off-shoulder?

[Hardware]

that is how most people think. I know I did.

but what gives us greater blood trails. a 1" two blade with a pass-through or a 1.75" cut that stops in the off-shoulder?

Depends on shot placement!!!!

[Gunnyart]

Even assuming it makes it to the off shoulder. I’ll still take the pass through rather than an arrow plugging the hole.

[StrayDog]

Honestly, I haven’t read everything in detail. However, the momentum, kinetic energy, weight, etc. of the arrow is only one part of “the physics”. The other part is more or less Newton’s 3rd law (i.e. the force imparted on the arrow by the target, animal, etc.). This is similar to saying my hot rod has 400 hp & weighs 3500 lb is better than your hot rod that makes 300 hp & weighs 3,000 lb. Maybe so maybe no depending on which hot rod can transfer that power to the ground most efficiently. There are a lot of variables. In the arrow example many things will also affect penetration and lethality: cutting surface area, sharpness of blades, center of gravity, contact angle, deflection angle throughout the penetration. To take it a step further, there are then many factors that affect the first set of factors: broadhead geometry that can result in varying contact area as the broadhead penetrates the target/animal, stiffness of the broadhead and/or arrow that affects the path of the arrow and/or efficiency of using the energy contained in the arrow to penetrate the target/animal, etc.. I don’t write testing procedures everyday for my day job but I’ve dealt with a ton of them and one thing I can say is that it can be extremely difficult to conduct an honest comparative test like you’re trying to do. Not say you “experiments” don’t have merit, just saying it’s actually more complicated than most people realize due to the shear number of variables. Some test variables don’t make a lot of difference and some make huge differences when comparing objects that aren’t exactly the same. Bottom line - I’m on the side of testing things to show they preform to meet the intended requirements and will leave the comparative tests to the PhD.’s who sit in dark rooms and argue over every conceivable detail they can come up with.

[enewman]

Honestly, I haven't read everything in detail. However, the momentum, kinetic energy, weight, etc. of the arrow is only one part of "the physics". The other part is more or less Newton's 3rd law (i.e. the force imparted on the arrow by the target, animal, etc.). This is similar to saying my hot rod has 400 hp & weighs 3500 lb is better than your hot rod that makes 300 hp & weighs 3,000 lb. Maybe so maybe no depending on which hot rod can transfer that power to the ground most efficiently. There are a lot of variables. In the arrow example many things will also affect penetration and lethality: cutting surface area, sharpness of blades, center of gravity, contact angle, deflection angle throughout the penetration. To take it a step further, there are then many factors that affect the first set of factors: broadhead geometry that can result in varying contact area as the broadhead penetrates the target/animal, stiffness of the broadhead and/or arrow that affects the path of the arrow and/or efficiency of using the energy contained in the arrow to penetrate the target/animal, etc.. I don't write testing procedures everyday for my day job but I've dealt with a ton of them and one thing I can say is that it can be extremely difficult to conduct an honest comparative test like you're trying to do. Not say you "experiments" don't have merit, just saying it's actually more complicated than most people realize due to the shear number of variables. Some test variables don't make a lot of difference and some make huge differences when comparing objects that aren't exactly the same. Bottom line - I'm on the side of testing things to show they preform to meet the intended requirements and will leave the comparative tests to the PhD.'s who sit in dark rooms and argue over every conceivable detail they can come up with.

It is very hard. Im 54 years old. I have no physics background. So, with the help of a few, I have been learning and researching. Some of it comes easy to me. Some do not. Force, for some reason, just kicks my ***.

When looking at these tests, I want to keep them as simple as possible so most can understand. But bt doing it this way also means I'm making some mistakes. Variables are the biggest problem with all of this.

Most people will have no clue about SI. The last few years of putting out data, I have always just done it in imperial. But one of my last papers, I had a guy with a physics background tell me I needed to be doing it in SI. So now I'm working on showing both. I am also depending on what Im doing is in the last part of the papers, I'm beginning to show the ANOVA.

I am looking at force. I have been calculating it, but most of the time, I leave it off. I feel it's too much. It's not that people won't understand, but If I struggle with it, why should I make it where people also struggle with it. At that point, the paper is just trash.

I have a test I'm looking at. I should be able to show fluid drag. Equal momentum. Then equal KE. The media will be a Newtonian target (water) and a non-Newtonian (starch). I have looked at this for a while.

I'm going to have to get very efficient at shooting bare shafts, as I do not want the vanes to hang on the milk jugs. Trying to remove that variable. I don't have a way to remove the variable of the milk jugs.

[enewman]

stray dog.

Force is different to look at. Now the test I have been using (joel maxfield The lighter arrow (more KE) seems to be always out penetrating. (sliding friction)

also using the equal momentum unequal mass and the lighter arrow will be harder to stop doesn't mean it will out penetrate.

This is where force will need to be looked at or why I think so.

here I show based on some of Joel's testing where the light arrow out penetrated. As we see it has more force. so it's easy to see why the lighter arrow outperformed.

But what if I reverse the penetration. most are going to say see the heavy out penetrated. But this is where looking at force will come into play. as you can see the Force is almost doubled. So the test even though the lighter arrow didn't out penetrate it does show the same results. it was so much harder to stop.

Now, are people going to understand this? I don't know as it was hard for me to understand for a while.

All I can do is just keep showing the data. try to remove as many variables as possible.

I do appreciate your post.

[enewman]

stray dog.

This brings up a question I do not understand. When looking at F=ma we look at time. In all of Ashby, testing time is never used. he uses displacement. Why would he not use F=w/d. Now I'm assuming is because he thinks by how he posts that momentum is force. I also think he spent a lot of time trying to prove KE has absolutely nothing to do with penetration. His words.

so to use the F=w/d he would have had to accept KE.

This is just my opinion only

[Duckologist]

that is how most people think. I know I did.



but what gives us greater blood trails. a 1" two blade with a pass-through or a 1.75" cut that stops in the off-shoulder?

2 holes are bettern 1. Ask the dog trackers

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