Trad Gang

Two arrows, both tuned well to the same bow.  One is Extreme Front of Center...perhaps 35 percent,  the other is exact same weight, but more like 17 to 20 percent FOC.

My theory is that the EFOC, will drop more quickly on a horizontal plane than the one with less FOC.  I'm thinking this because of the overbalance of weight toward the front end would be affected by gravity (and inertia) more quickly.  

Only way to find out is horizontal shots with both at a given distance.  It would almost have to be machine shot to be a good scientific model.

George, George, George. What the heck are you doing? You are one of the last ones I would have thought to get dragged into this kind of discussion.

Ah yes, the end of another era. Gonna grab an old bow and quiver full of arrows (have absolutely no idea what the FOC is on any of them) and go play with some squirrels. I can always depend on squirrels to stay the same.   :)

I'm going to say that conditions being equal the EFOC arrow will out fly the same distance or maybe a little further.  I think the major effecting factor would be drag.  Being the same weight, I think gravity would effect both arrows in an equal manner.  

I can visualize your theory, but I think EFOC has a step up due to efficiency.  Less drag.  It would be interesting to see the results.  I think indoors off a machine at about 20yds would yield good results.  Who's going to put the theory to test?

Tom,

Ain't got my reading glasses on, but did you just say you "Hunt squirrels in Depends" or "Hunt squirrels with Depends"?

If so, so what?  All that would prove is that the more extreme FOC arrow would be a poorer choice for a flight arrow.

Tom...did you just compare George to a squirrel?  I think the lighter FOC would stay flatter.

Chuck, yes.    :)  Good to see you in here, been a long time.

Chuc, yes. And George will take it as intended...a compliment.

My limited physics says that gravitational force is equal on objects of equal mass - as such they will fall at the same rate.

Gravity,, will effect both arrows differently.

They may weigh the same but both do NOT have the same mass. Mass including the inertia imparted to both arrows.

I would guess that the more weight forward (in turn getting more inertia) will fall first.

Somebody needs to test this...!!

John III

If the efoc arrows fall faster how come Ol Adcock is setting new (breaking his previous) world records with them. Efoc arrows have more momentum and recover out of the bow faster therefore the actually fly flatter. Once you account for the fact that you don't need as much fletching your arrows will be a lot flatter than low foc arrow(ps 17-20% foc isn't low 19% is efoc). I'm sure Ol has a better explanation.

Well any takers?   :coffee:

You drop a bowling ball and a golf ball from the same height and they land at the same time(less a little more wind resistance for the larger bowling ball). Remember your physics classes folks. Gravity isn't the deciding factor in flight.

Is this all about pre-season reasons for missing later on- during the season?

You guys have NOT figured in gravity swells !!    :readit:

Vermonster, that only hold true for a vacuum. If you have two objects of equal wind resistance and different weight the heavier one will have more momentum to fight against wind resistance therefore hitting the ground sooner.

Jesse you jump ahead to far in the lesson. Momentum wasn't going to be for a little bit yet and lead into why High FOC isn't a detriment to distance in flight.    ;)

Tom...I just came back from shooting arrows, and I felt the need to release some pent-up astringent vibrations that had somehow penetrated my aura....perhaps osmosis.    :saywhat:   And where have you been all this time?  It's been awhile.

Physics, schmysics...Vermonster 8^).  This is in need of real world experiment, and not dropping two items in a vaccuum.  I say that the EFOC will begin to arch more quickly due to inertial issues and gravitational pull....kinda like our first rocket tries after Sputnik to to the air.  It has to be done to prove yea or nay.

Flight shooting is done with a totally different arrow, and shot at angles that are far from horizontal, so that's not apples/apples either.

George, I've been under my rock. Probably should have stayed there.   :)

The bow one uses makes a big difference in the outcome. For most bows the normal laws of physics apply. However, for those few of us who shoot Hill bows the curvature of the earth also needs to be taken into account. Regardless of FOC, EFOC, PMS, etc., when an arrow is shot parallel to the earth from a Hill bow it takes days for it to hit the ground. Takes even longer if you shoot from the east towards the west.

Explains why I go through so many arrows each season. Well, OK, one of the reasons.    :)

See what you started George?

Even though I don't believe in Newtons theory of gravity I'm pretty sure that a 'D' shaped long bow will launch the efoc arrow flatter.

What an interesting topic for discussion!

I believe both arrows shot at/from horizontal will fly the same for the first 20-25 yards, however, the higher FOC projectile will most likely drop quicker...becoming very noticable as they approach 35-40 yards.

Why?  

Heck if I know.

Blackhawk....I like your style.    :thumbsup:

The high FOC shaft should be thinner and have less drag when using a brass insert and same broadhead to make weights match.

I'm glad deer can't read...   :D

I just don't want to think this much....lol.

I will be interested to find out what the real world testing says.  Let me kow if no one else plans to test this.  I am building a firing system for testing the speed differences between skinny and fat strings.  I could always work up some arrows for standard, high, and extreme FOC and test them at various yardages to see if there is a difference in drop off.  

I have to agree with the earlier posts that point out that physics says the extreme FOC should fly the flattest.  They recover more quickly and fly truer to the target, thus loosing less energy to shaft modulation.

Anyways, let me know if I need to add this to my list of testing to do.  Note with hunting season starting in a week it will be winter before I start the testing.

for those few of us who shoot Hill bows the curvature of the earth also needs to be taken into account. Regardless of FOC, EFOC, PMS, etc., when an arrow is shot parallel to the earth from a Hill bow it takes days for it to hit the ground. Takes even longer if you shoot from the east towards the west.
 :biglaugh:    :biglaugh:    :biglaugh:  
Tom , only Hill shooters understand the truth !!!

Ben...[Physics deprived Hill shooter ]....

An efoc arrow will  have less mass behind the point/weight, which normally would mean the shaft would be less stiff. That would mean the shaft would actually bend more and recover more slowly than a more standard arrow. But the lighter shaft behind the heavier head/weight would indeed stabilize somewhat quicker because the wind force on the side of the feathers could more easily move the smaller mass back in line with the arrow's flight.

Inertia and momentum are the same for both arrows because they have the same mass. Placement of the mass has nothing to do with these forces.

The efoc arrow would nose down faster if the arrows were simply dropped in a horizontal position from a great enough height to allow nosing down--say 20 or 30 feet. But flying at 160 fps, the drop is so small in comparison to the forward motion that the difference would probably be immeasurably small.

Most of what is reported these days though does seem to favor the very foc weight distribution.

I know I don't shoot well enough to notice a difference!

Jim Davis

OL says the perfect arrow would have 100 % of the weight up front.

I would think you would need arrows of identical material and diameter to make a fair comparison.With this,it would be hard to come up with 2 that would have the same overall weight because one would have to have more point weight,thus you have to start with a stiffer static spined shaft and it would be heavier as would it'd head.You lower FOC arrow and higher FOC arrow would always be different in overall weight(I think).I have played with this a little with 2016's+2018's and 55/75's + 75/95's and that's the way it always plays out.

You might be able to make one arrow aluminum and one carbon but of the same diameter,fletch,etc and have them come out the same overall weight? That would take some brainstorming and my head is hurting already.

I understand it's very hard to get 30-35 % FOC unless the bow has vertually no shelf or sight window(way far from center cut)and then very weak,light shafts with a lot of point weight.

I think the theory of relativity applies here. If it is me or my relative who is shooting the arrow, we will claim it did not drop as fast. If the person shooting the arrow is not a relative, then we will claim that arrow dropped faster. Gravity also comes into play. The gravity of the harm done by cheating for my relatives is much less than the gravity of the harm created by someone else cheating for his relatives. I hope all of you now understand relativity and gravity and their impact on the drop of arrows.    :readit:    :knothead:

Actually, an 26% EFOC arrow has been conclusively and scientifically determined to drop half the width of a gnat's eyelash less at 90 meters than an otherwise identical arrow that has a 11% FOC. The testing was conducted in climate controlled governmental installations within Cheyenne Mountain and corrected for temperature, altitude, humidity and every other variable factor, all in accordance with ASTM 30-2804.157(B)(3)(g)(iii), the most stringent scientific engineering standard for flight testing of arrows from traditional bows.

Allan

Grammatical errors corrected:

I think the theory of relativity applies here. If it is me or my relative who is shooting the arrow, we will claim it did not drop as fast. If the person shooting the arrow is not a relative, then we will claim that arrow dropped faster. Gravity also comes into play. The gravity of the harm done by cheating for my relatives is much less than the gravity of the harm created by someone else cheating for his relatives. I hope all of you now understand relativity and gravity and their impact on the drop of arrows. [readit] [knothead]

Actually, a 26% EFOC arrow has been conclusively and scientifically determined to drop half the width of a gnat's eyelash less at 90 meters than an otherwise identical arrow that is 11% FOC. The testing was conducted in climate controlled governmental installations within Cheyenne Mountain and corrected for temperature, altitude, humidity and every other variable factor, all in accordance with ASTM 30-2804.157(B)(3)(g)(iii), the most stringent scientific engineering standard for flight testing of arrows from traditional bows.

Allan

I am in no position to test it, though I'd like to see it, though I'm pretty sure amar911  is right!    :smileystooges:    

IMO
The portion of the arrow with more mass will hold more energy, thus staying truer to its course than the low mass portion its dragging greatly stabilizing flight.  In the instance of EFOC, the more of the mass that is located in the very front the more stable will be the flight and the more efficient the energy stored will be used.  If that mass is in the rear, the arrow will want to jackknife, with it in the front the rear portion is smoothly drug.

The EFOC will also retain its energy longer as its is stored in a smaller area, giving stable flight for a further distance than the one with it's mass spread out.  Eventually the front will indeed dive , but that time of final instability will have been reached a significant distance after the arrow with homogeneous mass gave out.  This is precisely the reason OL's flight records are broken, and the same thing that will cause this test to be moot.  

Moot because, though it did indeed dive it reaches that point long after its brother who didn't dive had already died.  


     (http://www.clipartof.com/images/emoticons/xsmall2/1243_arrow.gif)

It's possible to have same diameter shafts, same lengths in different spine to work right with heavy and light heads respectively.  Using thin rope or plastic tubing could make up the weight difference in the lighter arrow keeping the weight and diameter equal.  It might take a lot of experimenting to get it right though.  I'm still interested to see how George's arrows fly regardless of the other variables.

George,

If you consider a javelin to be a really long arrow without fletching you'll have your answer.  People began throwing javelins out of the stadiums - literally.  The answer was to move the weight forward, closer to the tip.  

Your from PA where they still throw these in high school, go and ask some track coaches what their old records used to be prior to moving the plug forward.  I bet that you will be surprized.

Scott

3 pages so far... I bet George is blowing coffee thru his nose this morning.

Obvious you guys don't shoot large 5 1/2" to 6" fletched arrows "around" your handle. Sorry, this topic may not apply to use primitive types.   :biglaugh:

Should be easy enough to test without a machine if you use a bow with sight pins.A centershot compound would be easy because you will have less effect with spine changes when loading the arrows for weight.If it was not raining here today I would test it for you.  :)

Equal weight means equal effect from gravity.   The only thing that could cause the EFOC arrow to drop faster would be drag from the shaft not being parallel to the direction of travel.  

I'm betting the drag effect s so slight it's hard to even measure (given the diameter of an arrow shaft), and disappears completely with fletching.

Yesterday I was shooting my 50# Super Kodiak at 70 yards (aiming with the point) with arrows from two sets. One set (5) weighed around 580 grains, and the other set (2) weighed around 670 grains. Theory tells us that the heavier arrows would drop out first. They didn't, in several trials. 5 of 7 in my last group would have fit in the mouth of a 5 gallon bucket. One of each set was outside the group, low.

That has nothing to do with the subject at hand, but it shows you where theory can lead...

I remember reading about a similar FOC test from "Archery- The Technical Side". An aluminum arrow was made with a sliding weight, and no fletching. It was shot with the weight in different positions from extreme foc to reverse foc (boc?). As long as the weight was at the middle or forward, it seemed to make no difference in cast. Too far back and it would tumble. Drag was the same, since it was the same arrow. This test could be done in a similar fashion using a finished aluminum arrow with a positionable weight inside it, to eliminate the variable of having two different arrows with different fletching, points, etc.

I might try it, but I don't have any tubular arrows.   :)

It's Monday, I have read this thread 3 times now and I am still smiling and laughing! What a way to start the work week, thanks for the thread George.

Allan, you are hilarious!  :)

George, I'll take on your question.  I want to know this for myself anyway and have been setting aside some fir shafts to test with.  It's gonna take a while to get things set up but I'll keep you all informed as I progress.  The likely test bow will be a Griffin Tsunami set up with a sight and a clicker.

Sorry, Tom.

Rick

QuoteOriginally posted by Fletcher:
George, I'll take on your question.  I want to know this for myself anyway and have been setting aside some fir shafts to test with.  It's gonna take a while to get things set up but I'll keep you all informed as I progress.  The likely test bow will be a Griffin Tsunami set up with a sight and a clicker.

Sorry, Tom.

Rick

My hero's of the past are dropping like flies.

Time for me to go back under my rock????

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

:biglaugh:    :biglaugh:    :biglaugh:

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!   :knothead:

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?

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

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

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.

Tom,

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

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.

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

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

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.     :readit:    

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

Or the deer.

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.

QuoteOriginally 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.   :readit:

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.

You guys are killing me!!!

 :biglaugh:    :biglaugh:    :biglaugh:

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?

:biglaugh:

How can something have "initial monemtum"?

"Increased lever arm"?

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

Did someone say BULLITT?


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

Quote 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

QuoteI'm glad deer can't read...  :D  

My favorite post right there   :biglaugh:

Man, you guys and gals are great!

I think it all depends on the color of the turbulator.    :D

Jason.....and my 'flight record' for GA whitetails since 1985 with Zwickey Delta 4 blades is STILL under 40 yards!!!!!   :jumper:    :jumper:    :jumper:

Terry...Yes, but you mount them vertically so they slip between the ribs.   :saywhat:

:biglaugh:    :biglaugh:    :biglaugh:

QuoteOriginally posted by Widowbender:
I'm glad deer can't read...    :D  

I'm sometimes sad that I can.   :saywhat:

Tom....

QuoteOriginally posted by Terry Green:
 :biglaugh:      :biglaugh:      :biglaugh:  

Oh no Jason! Not the "T" word!!!

It's no joke, Biggie. This is serious business. If you ever mess up and hit a deer in the gizzard you'll wish you had one.   :readit:

Robtattoo, neither. It will squirt out the sides, like stepping on a packet of mustard.

And speaking of mustard, I've been trying to figure out how to work Spam into this, for the benefit of you long-timers.

thanks to this thread, someone now owes me a new keyboard.....  and my nostrils are hurting from the rapid exit of coffee.

QuoteOriginally posted by 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?

 :biglaugh:  

Now this is a REAL test question.

Anybody got this figgered out yet??...Huntin' seasons almost here and I need to know which of my arrow to put the broadhead on....

FYI...already been down that road. When I used to shoot 3d with compounds back 10-12 years ago we tested everything imaginable fletching drag, vanes vs. feathers,etc. etc. Also tested arrows that were 5% FOC vs ones that were 20% FOC...These arrows had same impact point out to fifty yards. The reason for the test was because people were saying you could only use about 12 to 15 % FOC, any more would cause the arrow to nose dive. That's a big part of the reason they were pushing the 85 and 100 grain broadheads for carbon arrows was to keep the FOC down under 12%. That was a load of bull then and its a load of bull now. Just because we have fun with it doesn't mean that we haven't given any thought to the process or tested things out. I don't take to the woods with anything that I haven't given full thought and consideration to. For the record I shoot a carbon arrow with a 125 grain adapter and 125 grain glue on woodsman for and FOC of 23%. Does it fly like a dart? No, it flies like an arrow. Is it the perfect arrow? Only when its bloody from one end to the other...    :D    :D    :D

I still think my idea of a sliding weight inside an aluminum shaft is the perfect solution for the test method. Same arrow, different FOC. No other variables to deal with. All the way forward gives maximum FOC, stuck in the middle or thereabouts gives minimum, much easier than trying to build two matched arrows with different FOC's.

I agree with Jeremy!

QuoteOriginally posted by Don Stokes:
I still think my idea of a sliding weight inside an aluminum shaft is the perfect solution for the test method. Same arrow, different FOC. No other variables to deal with. All the way forward gives maximum FOC, stuck in the middle or thereabouts gives minimum, much easier than trying to build two matched arrows with different FOC's.

By changing the length of shaft behind the weight (i.e. sliding the weight within the shaft) you will be changing the dynamic spine. This would change the tuning, thereby effecting arrow flight and nullifying the test.

Okay guys. Stop having fun. Let's turn this into work!

I'm sure everyone here is interested in finding out the result of George's testing, but can't we enjoy ourselves a little along the way? Having fun on this site while learning from others seems to be the charm of our little community.   :campfire:    :campfire:

Allan

jason....easy man.    :)

I think, 'knowing' george (as much as one can get to know someone from reading his posts over many years)....I, and I think most of the jokers understood that george started the thread in FUN....not so much poking fun at those who like play around with the 'scientific method'...and more than seriously looking for an answer to the question.

Jason, it seems that every alteration changes dynamic spine. Best I could come up with. Still fewer variables.

Got close to the test this morning. I chose two sets of my barreled shafts and put 145 grain Snuffers on 4 arrows and 190 grain Ribteks on three. Final weight of all was within 5 grains of 600. The shafts with the heavier heads were stiffer (90# vs. 85#) and lighter in weight before putting on the broadheads. I didn't attempt to calculate FOC, but it was obviously and noticeably different. 28 1/2" BOP.

I shot them first at 20 yards from my 50# Super Kodiak to make sure the arrows shot well. Backed up to 65 yards, which was just shy of my point-on distance with field points. My point-on with the broadheads was less, closer to 60 yards based on where my arrows hit the ground in front of the target. I could tell no difference in the two sets, pulling all the way to the head. I'm not good enough at that range to be specific, but if there had been a distinct difference in their performance I think it would have been noticeable.

I know this is not the test George wanted (different heads, not horizontal), but it accomplished my objective. I don't have to shoot the two sets differently, which is what I wanted to know. I'll be hunting with them. Within 40 yards I'm sure I won't be able to tell the difference.

Don,

Just a thought, but those Grizzlys are considerably longer than the Ribteks, aren't they?  Going to play heck with "point on"...


Here's a parable about testing.


A scientist wanted to learn about the leaping abilities of frogs. To do so, he placed a frog on his laboratory table, stood behind the frog and shouted, "jump, frog, jump!" The frog jumped. The scientist carefully measured the distance of that first leap. He consistently repeated this procedure a number of times to provide reliable and valid statistical research.

He then surgically removed one of the front legs of the frog.  Placing the frog on the table, the scientist once again stood behind him and yelled, ,,jump, frog, jump!" Again, responding to the noise, the frog leaped forward and the scientist carefully measured the distance. The scientist had the frog jump with three legs a number of times to gather his scientific data. He then surgically removed another leg of the frog and repeated the experiment. He repeated each step of the experiment, measuring the ability of the frog to jump with four, then three, then two, then one leg. Finally, the scientist cut off the last leg and placed the frog on the table, stood behind the frog and yelled, `jump, frog, jump!" Not surprisingly, the frog did not leap. The scientist yelled again but there was no response. The scientist finally stomped his feet, clapped his hands, and screamed as loudly as he could, but still the frog did not move.

The scientist reflected on what he had seen and contemplated the meaning of this experiment. Finally, he sat up straight in his chair, and with an excited expression on his face that disclosed his discovery of new scientific insight, he wrote down, "After amputation of all four legs, frog became deaf."

Maybe the frog was too tired from all the jumping ?

QuoteOriginally posted by Jeff Strubberg:


Here's a parable about testing...

The scientist reflected on what he had seen and contemplated the meaning of this experiment. Finally, he sat up straight in his chair, and with an excited expression on his face that disclosed his discovery of new scientific insight, he wrote down, "After amputation of all four legs, frog became deaf."

Was this the same "scientist" who came up with the global warming theory?

No, the global warming scientist"is the son of the scientist that warned everyone about the dangers of soil wind erosion in southwest Kansas and the Oklahoma panhandle in the late 1920s.

Where is Krister when we need him?? He likes these ones. While you guys are deliberating this one I'm headed to Oz to do penetration tests on everything that moves. See you in three weeks! Get this figured out will ya.

somebody mentioned SPAM. SPAM is the perfect medium to gauge penetration on! it contains a homogeneous blend of muscle fiber, arteries, and adipose material to simulate an animals actual
structure.
the thin recycled beer cans that constitute the covering SPAM is contained in perfectly imitates the strength of the bone expected to be encountered in north american game animals.
the lubricity afforded by the adipose material simulates the blood that bathes the head and arrow shaft during penetration.
the problem i have with doing the test is that i can't find SPAM.
i can find a manufactured meat product that also contains pork skin and other contaminates, "light spam", whatever that is, "chipotle spam" and other abominations.
perhaps someone that has access to SPAM can do the test.

Not sure I wanna be that close to SPAM...

Particularly not after the great SPAM cake incident in Ohio...

Jeff, it was Snuffers and Ribteks, and yes, they are different lengths. I compensated as best as I could. Regardless, I know now that I don't have to shoot the two types of arrows differently.

I spent some years designing scientific experiments professionally at a university, and I can tell you this one is tough. Almost impossible to change only one variable, which is crucial to accurate testing.

George, you are a baaaad boy.

You fellers are a LOT smarter than I thought you were....

Not to highjack the thread, but, larryh, you're right, Spam is perfect for testing penetration. I think the can is a little too tough, so I wrapped it in deer skin that was soaked to get it back to the original texture. It took quite a few cans to get enough for a decent target.

It was a waste of time, though, because I kept getting pass-throughs. Not to mention that the target mysteriously disappeared in the night... and that smell!!

Jeff, Ohio Spam cake??

Gotta be someone else here who remembers the Ohio SPAM retirement cake...

You think SPAM is ugly?  Try SPAM with frosting...

You need a knife of good quality and someone who knows how to keep it razor sharp to cut one of these babies. Both were lacking at this event. And that's all I'm gonna say about it.   :saywhat:


(http://tmuss.tripod.com/spamcake.jpg)


  The Spam Wars (http://tmuss.tripod.com/spam/spam.html)

It was the oil dripping out of the bottom that made it so funny, Tom !

"Man this knife is dull!"

 :bigsmyl:

That looks suspiciously like Dean "Haggis" Torges' beard... I knew somebody would remember. Ahhh, the good 'ol days...

One fellow who's name escapes me showed up at the Howard Hill World Championship with a Spam can attached to his quiver.

Thanks for that link, Tom.

I just reread the whole Spam thread. Took an hour and a half, and had me laughing out loud.

I was there Jeff, but had the good sense not to ask for a piece.

Was it maple syrup icing? Yum! OK, back to the topic.

Topic? Was there a topic?

:goldtooth:

widowbender's post is good enough for me. compound bow with sights, peep, stabilizer, and release aid = shooting machine  ;)