really crazy question....

[RC]

If you have two arrows of the exact same weight . One has say ...a 100 grain point and the other has a 300 grain point but both arrows total weight are the same.Will they both have the same trajectory or will the heavy in the nose one drop more? Told you it was crazy.RC

[sweeney3]

I dunno about trajectory, as in the arc of the arrow, or flight path, but the spine and therefor the flight characteristics will likely be very different.  That might affect the final trajectory.  Trajectory is the sum of internal and external ballistics and nonstandard conditions, for you artilerists out there.     Kinda similar with arras, but a lot less math.

[Encino Man]

My guess is that in theory, two arrows weighing the same would have the same trajectory. But in reality the arrow with the greater FOC would have better flight which means less resistance and that equates to a flatter trajectory. Just my humble guess.

[S.C. Hunter]

My belief is if the ratio for FOC is not exceeded for stability. The arrows in short distances may not differ much. We are only talking about flight and not penetration correct?

  The arrow that has the weight distributed more evenly will give better flight characteristics at distance. In windy conditions this would probably be seen more. Some say a heavy head pulls the arrow along for the ride? If this is so I guess the lighter head arrow is driven by the launch of the bow and the feathers help to steer the arrow.

  My point is at some point an increase in head weight will have a negative influence on flight. If the back end doesn't have a offset in weight or a bigger rudder, that being larger or more feathers. Just my thoughts. When I shoot my heavier head arrows I see a flight difference in the wind or at distance. I have wood arrows that weigh 550 grains with the 125 grain heads included. My carbons have the same weight overall but have 175 grain heads and I see a difference in the wind past 20 yds. My woods are more stable both may drift but my carbons will move more at the back end.

[Bjorn]

We are assuming perfect flight-right? If they weigh the same they will hit the ground at the same time.

[RC]

Let me clear it up. I don`t care about penetration. I just was wondering if the arrow with the high foc would drop faster being nose heavy. Both arrows fly like bullets.
  not being a smart axx but I have killed over 100 deer and more than twice that in pigs. I have never had any penetration issue and I have always shot under 60 lbs usually around 50. I can`t understand all the issue on penetration. Of course I`ve never hunted elk or cape buffalo but I have killed some BIG Boars.I think the reality of it is sometimes we hit shoulder blade and we just plain out made a bad shot. Superduper broadheads and arrows don`t make up for that ...better shooting does.RC

[BobCo 1965]

I believe that OL Adcock won distance records with very high FOC arrows.

I would assume that the higher FOC arrows would have a flatter trajectory.

[Apex Predator]

I haven't done the experimenting on this particular set-up choice Robert, but I've read lots on it.  The general consensus is that the higher FOC arrow flies flatter and is affected less by the wind.  That's contrary to what "common sense" tells us.  Most would figure the heavier point would cause a nose dive eventually.

[pronghorn23]

Interesting question. I would think (just my guess based on nothing) that the one with the heavier front would sink faster. I guess I think this because it's like the arrow is pushing the extra weight up front and therefore would lose more energy vs having the arrow evenly weighted throughout or with less weight up front.

This reminds me too much of math class story problems.

[Ryan Rothhaar]

Gravity is gravity.  Unless the air resistance of the two projectiles is significantly different they'll both "drop" the same, regardless of how the weight is distributed.  (See, I DID learn something in Physics class!)

And RC, I'm right with you on the penetration thing, bud!  What carbons with heavy points have done for me has more to do with increasing the spine range of arrows I can shoot out of my bow than penetration.  Of course I'm back to shooting XX75's now!

R

[lpcjon2]

A pound of bricks and a pound of feathers are dropped of the Empire State building which lands first?

 I would think that all weight being the same would not matter,as the heavier weight in front would cause it to drop faster due to wind resistance on the head. the heavy head once met with the resistance should allow gravity to take it down faster than an all balanced arrow of the same weight. The equally balanced arrow should drop at an even pull to gravity and the heavy front arrow will have more pull on the front lifting the rear and causing a faster drop.This is my un-educated hypothosis on the matter further testing will not be done by me.     JMHO

[Jeff Strubberg]

They will have exactly the same trajectory.  The arrow shaft doesn't provide enough wind resistance to matter, so mose up/nose down is pretty much irrelevant.

[Guru]

Robert, The only think I've noticed it they(lighter pointed arrows) seem to come out of my bows higher. In other words they seem to hit higher at close range...not sure why, and I may be crazy...but thats what it seems like to me. At long distance, not really sure.

I will say this thou...I really like the way a heavier point shoots compared to the lighter point weight arrow.

If choosing between the two, I wouldn't hesitate, my choice would be the heavier point    

[straitera]

One thing I do know is I can learn from anyone who's killed 100 deer & 200 pigs w/50# setup. Can't help you w/your question; but, I have questions of my own you can help me with. Worthwhile stuff Robert. Much obliged.

[Jim now in Kentucky]

Better to turn to science than philosophy for the answer. It's not what we think that makes a difference. It's what can be demonstrated and has been measured.

Paul Klopsteg did some extensive tests on the effect of center of mass for arrows back in the 1930s. It's all available in "Archery, the Technical Side."

I realize these forums would wilt without the flow of unsupported opinions, but if anyone really wants answers that can be trusted, they should consider a little research into Klopsteg's work and the field of flight shooting.

jm .02

[SveinD]

If FOC objects fly flatter than objects of equally distributed weight, wouldn't aeroplanes be FOC-heavy?

Of course, this would imply that arrows should have two larger feathers at center, or FOC-Zero, and two (3?) feathers at the back for optimal flight, at least while at low FOC values^^

Hm, I know it's getting late here, but ranting is more fun in dozy states of mind!    

Zzz...

[Hot Hap]

My head hurts. Hap

[Chris Shelton]

Hmmmmmm . . . arrows begin to drop as soon as they leave the string! The non-FOC arrow will not fly as smoothly as a FOC arrow.

Foc arrows have a more off-balanced placement of mass. Its like a water bottle filled halfway with water, if you push it that second wave of energy will push it again. With a fully filled bottle of water it only moves once.

The whole point of increasing FOC is to increase penetration. That penetration increase is due to the slower decrease in energy.

The higher FOC arrow will loose energy much slower than a lower FOC arrow . . . to me that says the higher FOC arrow will go further and drop slower . . .

[Rob DiStefano]

Originally posted by Chris Shelton:
... The whole point of increasing FOC is to increase penetration. ...

um, nope, not for me - higher foc arras just fly and track better, for me.  

dunno or care that much about the penetration factor 'cause all i'm interested in is an arrow that's about 10gpp and has good straight flight.  that equates to better accuracy for me, and as we all know too well, it's accurate shots with sharp coc broadheads that down the game best, not foc, gpp, lmnop or whatever.  so for me, it's consistent accuracy with straight flight that matters most.

 

Originally posted by RC:
If you have two arrows of the exact same weight . One has say ...a 100 grain point and the other has a 300 grain point but both arrows total weight are the same.Will they both have the same trajectory or will the heavy in the nose one drop more? Told you it was crazy.RC

dunno for sure, but if i shot both arras i'd probably see the high foc track better and that's what i'd wanna take hunting.

[lpcjon2]

Now Rob, I would have thought you would have already tested this theory.     I didn't think there was much you haven't tested or researched.