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Who has snorted the Fairy Dust?

Allegheny Tom said:
I didn't mean to imply that speed isnt a factor.
What I was trying to say is, in regards to penetration, there is more to be gained by heavier and slower than there is to be gained by lighter and faster. Dropping ~100 grains to gain ~50 fps for ethically realistic bow ranges is the wrong approach, not just in my opinion, also well proven by the vast testing and experiments done by Ashby.
This point has been discussed countless times and analogized (is that a word?) by comparing golf balls to ping pong balls and semi trucks to compact cars. Heavy hits harder than lighter.
The main issue is where is the hunter's threshold for trajectory?
Seems like too many guys have a threshold for a certain fps with little regard to arrow weight.
I have some friends like that..."I need to stay above 275 fps". Why? What is magic about the 275 threshold?
Now, there are (proven by Ashby) magic numbers when it comes to TAW and FOC.
Click to expand...

I think this is possibly the wrong approach, comparing archery hits to golf balls and semi trucks. These are collision problems (in physics).

While bullets can move fast enough to create shock waves upon collision that can cause catastrophic physical damage to game animals (KE is a sensible consideration there), arrows move too slowly.

What we want is for an arrow to slice through an animal, not to impart work on it. We don't want to move tissue/bone, we want to cut through tissue/bone with as little resistance as possible.

In this scenario, what we're up against is counter forces. When we launch an arrow, the bow imparts a force on that arrow. F=ma. Newton's 1st law tells us that arrow would stay in motion indefinitely unless acted upon by other forces, so we have an inertial force of....F=ma, yay! It's up to other forces to slow and stop that arrow.

Those forces include gravity and wind, but more importantly friction, suction, and pressure as an arrow traverses an organism, or attempts to do so.

Isolating the likely greatest counter force, friction, we have then two frictional forces, static and sliding. Considering those forces is a very different problem than the major forces in standard collision problems.
 
Weldabeast said:
Yeah.....and that's kinda why this thread is here and so long. Peeps either like the sarcasm or they don't but there is stuff to learn regardless if u like or not
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I’m a just say it already so we can go on kinda guy. I don’t have time for unneeded verbiage. I can not stand beating around the bush. I’m going to say it straight up where you can understand it. I don’t have time for all that noise. Boy I’m grouchy today. I had it out with a lady over bear population and hunting them. Psycho lady kept saying the university says we have 1000 bears and the governor sides with republicans. Couldn’t name a university and she had no clue who our governer was. She refused to believe I sit in front of one of North Carolina’s biologist at church and she didn’t know what he was talking about because he wasn’t the governer. Future reference we have a sickeningly liberal governer. 15,000 bears in 2014 growing at 6% a year. Shew now I feel better. Thank you for the moment to rant
 
Plebe said:
I think this is possibly the wrong approach, comparing archery hits to golf balls and semi trucks. These are collision problems (in physics).

While bullets can move fast enough to create shock waves upon collision that can cause catastrophic physical damage to game animals (KE is a sensible consideration there), arrows move too slowly.

What we want is for an arrow to slice through an animal, not to impart work on it. We don't want to move tissue/bone, we want to cut through tissue/bone with as little resistance as possible.

In this scenario, what we're up against is counter forces. When we launch an arrow, the bow imparts a force on that arrow. F=ma. Newton's 1st law tells us that arrow would stay in motion indefinitely unless acted upon by other forces, so we have an inertial force of....F=ma, yay! It's up to other forces to slow and stop that arrow.

Those forces include gravity and wind, but more importantly friction, suction, and pressure as an arrow traverses an organism, or attempts to do so.

Isolating the likely greatest counter force, friction, we have then two frictional forces, static and sliding. Considering those forces is a very different problem than the major forces in standard collision problems.
Click to expand...

Isn't it those counter forces that make mass more important than velocity in arrow penetration?

Screenshot_20220716-124203.png
 
GCTerpfan said:
Isn't it those counter forces that make mass more important than velocity in arrow penetration?

View attachment 67746
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From UglyJoe's post on AT I linked earlier in a different thread:

This is why it is wrong to state that arrow penetration depends on on arrow momentum. It simply does not. I've seen multiple threads on these forums where one poster shows a system built with a low mass, high velocity arrow and another with a high mass low velocity arrow; both arrows have the same momentum. The poster will inevitably conclude that both have the same penetration potential. A second poster will then—usually following Ashby logic—claim that "not all momentums with the same value are equal" or some such. That somehow momentum "built" from large mass and small velocity is different than momentum "built" from small mass and large velocity, and therefore the penetration potential of the two systems is different. This is nonsense—momentum is momentum, and quantities that truly depend on momentum do not care if the momentum describes a heavy system in slow motion or a light system in fast motion; once the momentum of a system is parameterized it "forgets" what factors went into defining it. The truth is that the heavier arrow penetrates better because it has greater inertia—greater mass—not because it has "mass-derived momentum". I will repeat myself for clarity's sake. Increasing momentum DOES NOT result in an increase in penetration.
 
GCTerpfan said:
Do you disagree with the statement below?
View attachment 67750
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yes.

Newton's first law says that an object in motion will stay in motion unless acted upon by forces. Momentum is just mass in motion (p=mv) . So if there is zero mass there is no momentum. If there is zero motion, there is no momentum.

The tendency to stay in motion belongs to inertia. TI=ma.
 
kyler1945 said:
From UglyJoe's post on AT I linked earlier in a different thread:

This is why it is wrong to state that arrow penetration depends on on arrow momentum. It simply does not. I've seen multiple threads on these forums where one poster shows a system built with a low mass, high velocity arrow and another with a high mass low velocity arrow; both arrows have the same momentum. The poster will inevitably conclude that both have the same penetration potential. A second poster will then—usually following Ashby logic—claim that "not all momentums with the same value are equal" or some such. That somehow momentum "built" from large mass and small velocity is different than momentum "built" from small mass and large velocity, and therefore the penetration potential of the two systems is different. This is nonsense—momentum is momentum, and quantities that truly depend on momentum do not care if the momentum describes a heavy system in slow motion or a light system in fast motion; once the momentum of a system is parameterized it "forgets" what factors went into defining it. The truth is that the heavier arrow penetrates better because it has greater inertia—greater mass—not because it has "mass-derived momentum". I will repeat myself for clarity's sake. Increasing momentum DOES NOT result in an increase in penetration.
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Translational Inertia. F=MA.

A given force applied to an arrow is the product of mass and acceleration. F=MA. Increase mass, and acceleration decreases, for that same force. Decrease mass and a greater acceleration is achieved.

A bowling ball moving .000000001fps isn't as likely to tear through me as a bowling ball moving 100000000fps.

m and a are proportional. v and a are related.

The question is what forces are necessary to overcome friction, suction, pressure of an organism.
 
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o_O My head hurts now. I will read over tomorrow lol. There is so much that can go into this that it could be mind numbing. I’ve considered testing out a 125 head on my set up to see how much it effects my single pin with no hood over at the same distance. My TAW would be at 413 and would probably slow 6fps for each 10 gr. So 274fps. Still may not make a difference but could help out on passing through.
 
Plebe said:
yes.

Newton's first law says that an object in motion will stay in motion unless acted upon by forces. Momentum is just mass in motion (p=mv) . So if there is zero mass there is no momentum. If there is zero motion, there is no momentum.

The tendency to stay in motion belongs to inertia. TI=ma.
Click to expand...

So you also disagree with this?

Screenshot_20220717-032340.png
 
Another from the AT thread.

“I surely wish you would stop taking everything as an attack on Ashby. Nothing I said above should be construed as such, with the exception of digging at the truth regarding momentum. I love Ashby the Data-Collector. It's Ashby the Data-Analyst that leaves much to be desired. I never set out to prove Ashby wrong or make him look bad. I just like for the community to have a resource for a real understanding of what is going on and why one arrow choice over another may be better from a hunting standpoint.”
 
“Nothing I am saying about this should be controversial. Most of you should be thinking, "well, duh!". The point of the thread is not to reinvent the wheel; its to explain—the right way—ideas that we already intuitively know. If you shoot a heavy draw, high energy bow with a heavy arrow you are going to have better penetration potential than if you shoot a light draw, low energy bow with a light arrow. Of course, no brainer! Someone who has never picked up a bow before could guess that. The point here is to get to the root of why this is true.”
 
From UJ

“I decided to start this thread while reading the other ongoing Ashby foundation thread. The Foundation posted a table of arrow masses vs. animal type and this table stirred great debate in that thread. Inevitably the thread decomposed into one set of posters arguing about a low mass arrow with high velocity having the same momentum as a high mass arrow with low velocity, and they argued that both arrows will have the same penetration capability. This exact argument is why you need to stop using momentum as a quantifier of arrow penetration.

The foundation itself has recognized this; they didn't post a table of arrow momentum vs. animal type. They posted a table of arrow mass vs. animal type. This thread was intended to help understand why the approach the foundation used, equating arrow efficacy with arrow mass, was the correct way to present their findings in as compact a format as possible.

PS—you don't have to "calculate" anything when calculating arrow mass; just put it on the scale. If you use momentum (incorrectly) you actually do have to do maths, then you constantly have to explain why momentum correlates to arrow penetration and what momentum actually is, then you have to differentiate between high mass momentum and low mass momentum, a distinction that isn't physical. Isn't it much easier to say "a heavier arrow is more difficult to stop"? Do you think you would be more successful in helping other archers choose a good hunting arrow with this simpler—and correct—approach?”
 
The debate is always interesting to a point. I think that if you come to it from the situation where you have lost animals, and the best buck of your life to that point, that it means more than if you come to it as a new bowhunter looking for what camp to put your tent up in. I went to "Heavy arrows", which I think is a misnomer, by the way, out of necessity. What I mean by that is that up until recently with the advent of carbon arrows most people were shooting wood or aluminum shafts and were running anywhere between 9 to 12 grains per pound of draw weight. That was normal. When carbon came along arrows got lighter and lighter and bow companies were (and are) in an arms race for your business and the benchmark they were and are still using to compete with each other is speed. How do you convince a guy the state of the art bow he bought 2 years ago is now woefully inadequate and he needs to spend another $1000 ASAP? Tell him it is SLOW! Tell him if he buys this new super duper whizbang bow that he can shoot deer at 70 yards all day long. I would dare say that 80% or more of bow companies market is guys who want to make one trip to the bow shop and get the bow, some arrows and a pack of mechanical heads and be done. They will shoot the bow a few times before season and call it good. If you can't buy it over the counter prepackaged, you've lost them. All of my bowhunting friends are like this. Everyone I know. When they buy a bow or crossbow the first thing, they talk about is "It'll shoot 380 feet per second, or my new crossbow will shoot 500 feet per second, and I can shoot deer to 120 yards now! They shoot about 20 shots per year in practice.

Personally, I got tired of my arrows not passing through 90 pound does so I looked for something better. I had that same light arrow with a mechanical stop cold on a big buck's shoulder and I never saw him again. Since going to heavier, more stoutly constructed arrows with good, razor sharp cut on contact broadheads, I haven't had those issues since.

My advice concerning arrows for anyone just getting into bowhunting would be to incorporate the first 2 Ashby factors of Structural integrity and Perfect arrow flight and then incorporate a good quality cut on contact broadhead. If you incorporate structural integrity and a good cut on contact head, you will be in that 500 grain total weight range. Sight you bow in with a single pin at about 25 yards and determine how far back you can get and not have the arrow drop more than about 2 inches. That is your maximum point-blank range. Then practice, practice, practice. Shoot from height and shoot from weird angles and get good.

Once you have the mechanics down, concentrate you time and energy on learning how to find and get close to deer. Think 20 yards and in. In the beginning, shoot a lot of deer. As many as you can legally. Get some experience shooting deer.
 
NMSbowhunter said:
How do you convince a guy the state of the art bow he bought 2 years ago is now woefully inadequate and he needs to spend another $1000 ASAP? Tell him it is SLOW! Tell him if he buys this new super duper whizbang bow that he can shoot deer at 70 yards all day long. I would dare say that 80% or more of bow companies market is guys who want to make one trip to the bow shop and get the bow, some arrows and a pack of mechanical heads and be done. They will shoot the bow a few times before season and call it good.
Click to expand...

This really annoys me. It comes from the belief that your customers are dumb. Because you think they're dumb, you think you can convince them that a faster bow will kill more deer. And this works. But because you think your customers are dumb, you are blind to option B: Telling your customers the bow is more efficient than a previous model/generates more KE. You still get the "I don't want to think about it" crowd, and the "my bow hits HARDER than your bow" crowd (which replaces my bow is faster than your bow crowd).

I know this will work because look how much money was made and spent on "my arrow is heavier than yours, and has 600 hours of design and testing time in it" in the last five years?

So, while I don't like the approach to business (or policy for that matter) that your customers are dumb, I then come back to the camp fire, and repeatedly hear the tribe say really dumb things, and show contempt for people who use big words or maths to help them, and outright ignore the truth because it would cause them to appear disloyal to the ingroup they've chosen.

It's a fun circle. And when viewed from a few feet away, is quite entertaining.
 
I don't necessarily think the bow companies think their customers are dumb, I think they know that to sell you have to keep the message simple. They are selling bows, not arrows. Speed numbers are simple and easy to market. Speed is sexy. Get to a speed that beats last year's flagship model and beats your competition and there you go. My friends put very little thought into bows and bowhunting. They go in and buy a full setup and then every couple of years drop the bow at the bow shop when it gets out of kilter, or the string looks like it is about to play out and then grab a few more arrows while they are in there. The bottom line is most people are not putting any thought into their setup aside from is it fast enough to kill a deer (according to mass marketing) and more importantly, how much more range can this new faster bow allow me to get when shooting at deer?

I don't have any numbers on this, but I believe from what I have seen personally is that most people buying bows are not bowhunters, they hunt with a bow because they are not legally allowed to hunt with a gun until later in the season. They throw the bow down the instant any legal firearm season opens. That is why crossbows got legalized recently here for general use. Guys really want to hunt with a gun because it is the easiest thing to use and a crossbow with a scope is the closest thing they can get to a gun that technically isn't a gun.

Don't get me wrong. If you need a crossbow because of some injury or impairment, I think that is fine.
 
GCTerpfan said:
How about a paper titled Momentum, Kinetic Energy and Arrow penetration?
www.dropbox.com

Momentum-KineticEnergy-ArrowPenetration.pdf

Shared with Dropbox
www.dropbox.com www.dropbox.com
Click to expand...
I will read a paper called Momentum, Kinetic Energy and Arrow penetration!

Thank you, GcTerpfan. I'll be honest I probably won't get to that until this evening or tomorrow evening.

I also see I'm the only one who went to bed early yesterday lol
 
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