Theory, you can guess but it must be tested.

[Widowbender]

Originally posted by Biggie Hoffman:
3 pages so far... I bet George is blowing coffee thru his nose this morning.

       

[NorthernCaliforniaHunter]

It's all about the angle of the dangle. I think I'm going to go back home and crawl into bed.

George, yer killin' me!  

[frank bullitt]

My question to Terry is, when will there be a  Science, Theories, and other Black Magic forum?

   And Tom, is there alot of oaks and hickorys near that rock? And how many squirrels have played dead to your arrows this month?

[HATCHCHASER]

I'm with you Biggie.      I still haven't seen any takers.  

[HATCHCHASER]

Sorry Rick.  I skipped over your post.  Let us know what you find.

[Dustin Waters]

Gravity will have the exact same effect on both arrows.  If you drop a golf ball and a shot put at the same time from the same height, they will hit the ground at the sametime.  I remember that experiment from a physics class in high school.  So given all is the same for both arrows, weight, and angle being shot both arrows will hit the ground at the sametime. One will fly further than the other, but they will hit at the sametime.  its very difficult to comprehend in your head, because logic says thats impossible, but a slug from a 12 ga fired at the same angle and a .22 fired from the same angle will hit the ground at the sametime given no outside influences, the only difference is the distance in which they will fly.

[Chuck Wyatt]

Tom,

I hope you and yours are doing fine under your rock.  

[Jesse Peltan]

That's right Dustin. The high foc arrow will have more momentum therefore going further than the low foc arrow, but dropping at the same rate.

[p1choco]

Wondering where some of you guys went to school?        Well, must have been a LOOONG time ago.

[SlowBowke]

No offense but...
" perhaps 35 percent, the other is exact same weight, but  more like 17 to 20 percent FOC.">>>>>?

Not a bad idea to compare the two, however, a couple questions come to mind.

Perhaps? More like? Numbers please?

Why compare two that are BOTH considered HIGH in the FOC dept? Just wondering your reason for choosing these numbers is all. No offense meant.

Plus......HOW in the world did you get 35 percent FOC???? and what is the arrow weight in the examples? and the bow weight, draw length, type?. Are both arrows flying perfectly?

More than a little curious on the answers to the above. I've shot up to 400 grains up front on carbon and never got much above 27 percent and this raises a question of HOW MUCH weight it took to get 35 percent?

Even on shafts of 9 gpi I cannot come close to 35 percent without losing spine WAY before then.

If we are going to compare, let's make all the facts known then others can take this information and compare it to their own,  should they choose to do so.

For the record, the consistancy of gravity effecting any arrow, posted above, is accurate.

All drop at the same rate, regardless. Only the speed of each determines how FAR it will go before it hits the ground. With identical force behind them and identical weight, they will have identical trajectories. At least that is the laws of physics taught.

Will the higher EFOC make much difference when the only resistance is air?  I honestly dont know but I suspect that what difference that EFOC has ONLY against air, might be very little and unlike what this same momentum will do when it meets a more solid object.

It's  possible  the higher EFOC wil fly flatter and Ill have to give that a go myself, but doubt the difference will be very "measurable" and may be SO small it's not really noticable for the short time the arrow is in the air.

Any "gain" like say being able to shoot 35 yards and the identical weight arrow shoots 30 yards, shot from the same bow, same angle?  I'd be greatly surprised.

I do know however, that the EFOC arrow will fly AT LEAST as far and NOT drop faster like some may think.  The effect of a flatter trajectory, is however, a plausable deduction that has me wondering myself.

Great post!

I'd personally like to see comparison more in line with comparing an easily reachable 25 percent FOC to say 10 percent, out of the same bow, same arrow weight and is why I am doing so this fall hunting. The reason I am testing has nothing to do with trajectory, (but I will admit that perhaps I should take a look at that as well), only penetration.

Its almost impossible to have ALL factors identical. No two shots taken hunting are identical nor are the areas the shot connects to so the testing I am doing for my OWN personal choices in what I use will take more than a few animals to make a solid choice that one is better .....or not. I fully expect my own testing to take more than a season or two.

Common sense tells me that regardless of WHAT factor you are testing, there IS a point of no return yet I am finding the EFOC (20 percent or higher) arrows MUCH more easily tuned to great arrow flight and with the information available to us on the EFOC / penetration subject I thought it worth my time to try myself.

I'm sure, along the line, I'll be posting any information I find that definately shows a pattern and I'll watch this post too for everyone elses imput.

Hoping all have a great season.
Slowbowke

[George D. Stout]

SlowBowke, you gave a nice treatise, but the 35% was just given as a generality, not a number that was necessarily attainable.  Dramatic factor only.  So to keep you happy, let's say 27%, as opposed to 15%.

I'm not interested in patterns from casual testing, anyone can do that.  And it really will fall to the mindset of the one testing.  Accuracy demands constants.  So does concrete proof.

"Flies like a dart!"   You hear that all the time.
Well darts are so front heavy that they have to be launched at a higher arc to begin with and quickly succumb to front end weight.  That's what they are supposed to do.  I want my arrows to fly like arrows, not darts.

At some point, there will be diminishing returns, where arrows will be too heavy and slow, or too light and fast.  Somewhere betwixt and between, there is an area of efficiency that can be optimized both by speed and weight (as long as arrows fly well)...and within that area the differences in fronts-of-center will have an impact.

Now...with that said, that is not really what I asked.  And, all the semi-educated guesses won't answer the question.  At best the only thing offered at this point is hypothesis.  That, as we know, is not a real answer and must be followed by real testing through controlled means.

So far....four pages of hypothesis.        

[Russ Clagett]

math and science make my head hurt. Once the arrow goes through the deer it doesnt matter to me.

Or the deer.

[Tom Leemans]

Well, I can tell you that I've shot the same arrows with the difference being 125gr. head vs 160 gr. head. Same hold on the shot, the 160 gr. head definitely drops further over, say, a 35-40 yard range.

[Terry Green]

Originally posted by JimB:
OL says the perfect arrow would have 100 % of the weight up front.

 

Nope....that would be called a bullet.     :D  

The perfect arrow is bloody from one end to the other reguardless of the FOC.  

[Jeremy]

A couple of concepts are being knocked around here and some misinformation.

Gravity will not effect either arrow differently.  Each has the same mass, the same initial velocity and the same initial momentum.

What George is concerned about is the rotation about an axis at the center of mass.

While gravity won't affect the arrows differently, air resistence of the fletching will.  The higher %FOC arrow increases the lever arm for the fletching, meaning the fletching will have a greater effect on how the arrow flies for the higher FOC arrow.  That's the whole principle behind how high %FOC stabilizes an arrow quicker than a lower %FOC.

It's been pointed out that if you drop two arrows parallel to the ground the one with the higer %FOC will go point-down first.  That's just illustrating the effect of the increased lever arm.  Now try it with bareshafts    

So you have two forces in play here affecting the rotation about the center of mass: the drag created by the fletching in the horizontal plane and the drag created by the fletching in the vertical plane.

The arrow will start to rotate (nose dive) only after the force in the vertical direction overcomes that in the horizontal direction.  So you start of with an equation where F1=F2 for each arrow.  The length of the lever arm is included in both sides of that equation and cancel each other out.  The main components left are the forward velocity and the downward velocity.  If the two arrows start out with the same initial velocity and decelerate at the same rate they will start to nose dive at the same time.

That's not the case though.  The arrow with the higher %FOC stabilizes quicker off the bow, so while the initial velocities are the same, the higher %FOC expends less energy in stabilizing the arrow and is going faster.  Really, it should start to nose dive after the lower %FOC arrow.

All you need to do is look at flight records to see the benefits of a higher %FOC.

[Biggie Hoffman]

You guys are killing me!!!

         

[robtattoo]

If I'm on a spaceship, travelling 1 mile an hour faster than the speed of light & I turn on the headlights, will the light shine out the front or the back?

 

[jeff w]

How can something have "initial monemtum"?

"Increased lever arm"?

Nevermind, the reference to modern javelin records clears up evrything.....................

[frank bullitt]

Did someone say BULLITT?


I'm not the sharpest arrow in the quiver, but I will shoot straight for you!

[Jeremy]

How can something have "initial monemtum"?

"Increased lever arm"?

The formual for momentum(p) is just the mass(m) times the velocity(v): p=mv
An arrow has mass and an initial velocity when shot.  When in motion, it has momentum.  Since the arrow is decelerating after the shot, it's momentum decreases as well.

If I said "increased the length of the lever arm" does that help?  Is it easier to turn a nut or bolt with a wrench with a long handle or a short handle?  The rotation (torque) is directly proportional to the length of the lever arm.

I had a few minutes earlier and decided to play     I was wrong on the javelin reference