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-   -   Teach me FOC (https://www.huntingnet.com/forum/bowhunting/236875-teach-me-foc.html)

Kanga 03-11-2008 12:13 PM

RE: Teach me FOC
 
Jeff.

Pm me your phone number and I will give you a call tonight and answer any of your questions and hopefully put you on the right track;)

PA Hardwoods 03-11-2008 12:14 PM

RE: Teach me FOC
 


ORIGINAL: Ausie-guy

Jeff.

Pm me your phone number and I will give you a call tonight and answer any of your questions and hopefully put you on the right track;)
Ahh I wondered when Ausie-Guy was gonna show up on this thread. Russ were you actually working today? LOL[8D]

MO_Bowhnter 03-11-2008 12:14 PM

RE: Teach me FOC
 

FOC is all about stable flight. But you have to consider that the arrow's flight is not done until it comes to a complete stop. In other words, it is still in flight during the time it's penetrating that animal.

High FOC allows the arrow to remain more stable and resist deflection when it contacts ribs and such while passing through. A low FOC arrow can deflect off a rib, causing the shaft to have more contact with the surrounding tissues, causing extra drag and reducing the arrow's penetration. If the arrow can keep it's KE and momentum going in a straighter line - more stable flight path - while penetrating, it'll penetrate deeper.

That's my theory and I'm stickin' to it.

_____________________________
Just as I said in one of my previous posts...:D I'm sticking to it too.:)

NEW61375 03-11-2008 12:18 PM

RE: Teach me FOC
 
Jeff,

This might be kind of lazy but when I googled FOC, Arrow flight/penetration, Dr. Ed Ashby anything along those lines. There is a mountain of info and charts and graphs and arrow building calculators and comparisons between compounds / tradition set-ups and even links to hunting.net past threads about the topic. You coulf probably read forfew days on the topic. Some really good stuff on ke and penetration I just read by Ashby.

Rob/PA Bowyer 03-11-2008 12:24 PM

RE: Teach me FOC
 
Not to mention if the back end of the arrow is equal or heavier than the front end of the arrow it takes more fletch, "drag" to stabilize the arrow resulting in tailing etc...think of it this way, if the back end was heavier and there wasn't adequate stabilization, the back end would want to become the front end. It never happens but out of a poorly tuned bow, it could. A low FOC only compounds tuning issues.

Roskoe 03-11-2008 12:32 PM

RE: Teach me FOC
 
I can visualize an arrow, either when it is under load from the bowstring, or when the tip encounters resistance; wanting to bend under force. In the case of the arrow's tip entering an animal, the back of the arrow will want to try to overtake the tip if the weight is distributed more to the rear. So the arrow will bend or yaw and cause a loss of penetration. Having more of the arrow's weight distributed towards the front of arrow will cause it to be more prone to pushing straight through the animal. Makes sense to me.

Hoytail Hunter 03-11-2008 04:02 PM

RE: Teach me FOC
 
I've read and studied zero articles about FOC and how it affects penetration but I've got a decent sense of physics I think, and here's what I think Jeff:

I'm sure other guys have already said this (I didn't read all the posts) but maybe if put in a different way, it'll all of a sudden click... Your arrow in abest case scenario enters the animal perfectly square (straight). As soon as it hits anything with a consistency less than air, it'll want to deviate from that straight line. The more weight that you have towards the rear of the arrow, the greater the tendency to deviate from that straight line because there's more weight back there to steer the front of the arrow.When there's deviation, some of the KE in that arrow is spent by the shaft (not the tip) pushing against the walls of the hole that the arrow is creating. Resulting in more side to side push ratherthan forward push. Resulting in less penetration.

Another way to think about it is throwing a baseball bat into water like a spear. If you throw it handle end first you have low, in this case, negative FOC. It probably wont govery deep into the water before doing a flip. On the other hand, if you throw the baseball bat heavy end first, it'll penetrate through the water much better and probably wont do a flip at all.

Kanga 03-11-2008 04:04 PM

RE: Teach me FOC
 

PA Hardwoods
Ahh I wondered when Ausie-Guy was gonna show up on this thread. Russ were you actually working today? LOL[8D]
Shhhhhhhhh thats how bad rumours start:D

TFOX 03-11-2008 05:10 PM

RE: Teach me FOC
 
When shooting higher ke,you can shoot lower foc and still get good arrow flight,but if you are shooting on the low end of ke,you better pay attention to it.I always had best result when shooting 10% or higher for open class 3-d.

OHbowhntr 03-11-2008 05:14 PM

RE: Teach me FOC
 

ORIGINAL: Hoytail Hunter

I've read and studied zero articles about FOC and how it affects penetration but I've got a decent sense of physics I think, and here's what I think Jeff:

I'm sure other guys have already said this (I didn't read all the posts) but maybe if put in a different way, it'll all of a sudden click... Your arrow in abest case scenario enters the animal perfectly square (straight). As soon as it hits anything with a consistency less than air, it'll want to deviate from that straight line. The more weight that you have towards the rear of the arrow, the greater the tendency to deviate from that straight line because there's more weight back there to steer the front of the arrow.When there's deviation, some of the KE in that arrow is spent by the shaft (not the tip) pushing against the walls of the hole that the arrow is creating. Resulting in more side to side push ratherthan forward push. Resulting in less penetration.

Another way to think about it is throwing a baseball bat into water like a spear. If you throw it handle end first you have low, in this case, negative FOC. It probably wont govery deep into the water before doing a flip. On the other hand, if you throw the baseball bat heavy end first, it'll penetrate through the water much better and probably wont do a flip at all.
Funny analogy, I was thinking along the same lines. For anyone who has ever played yard darts, and lost the weight on one, the importance of FOC, especially in longer shots and slower bows become very obvious. But I think this may have been a rhetorical question, as I think he knows the answers long before he asks, he's just "testing" the rest of us!!! :D


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