[Deleted]
 

[Deleted by Admins]

RE: Speed is all you need! (?)
 

Earlier I indicated that speed is not all that is needed. If you were to equate mass to zero and solve the KE equation for your speed, you would get o (zero) KE so it would be obvious that you need more than speed to obtain a penetrating momentum. To take an animal you MUST HAVE SOME MASS and SOME SPEED; this alone disproves your initial premise " Speed is all you need!(?). Put your numbers into the KE formula, equating the mass to zero and you come up with zero KE. Without some KE (aka momentum) you would have zero penetration.

You have a given speed and a given mass and together they provide a Momentum (aka Kinetic Energy) to penetrate an animal; and what you have works. Fundamentally to gain any penetration at all . . . Kinetic Energy MUST BE GREATER THAN ZERO.

The numbers you give yield 81.8 ft-lbs of Kinetic Energy (aka MOMENTUM). So regardless of what others say you do have sufficient momentum. 20 ft-lbs more than I do and I nearly always get passthroughs.

RE: Speed is all you need! (?)
 

Dan, you have e-mail. Narf[8D]

RE: Speed is all you need! (?)
 

This looks like a good place to get my question answered. I am pretty new to bowhunting. I have a legacy 60# 28.5 draw and 29inch arrows weighing 350 with 85 tip or 365 with 100gr. Which should I use. And is this enough grains for whitetail? I haven' t shot is through a chrono yet. Also, someday I may hunt elk is this light of an arrow a total no no for elk?

RE: Speed is all you need! (?)
 

Woody....got it. All' s I can say is this will be good.......[>:]


Btw, SD, if you follow what a couple folks here are posting, beware!!! Stick to what Art, or Ak if he ever pipes in has to say. These guys know the theory behind penetration...the formula' s etc. I know whats going on and why, but cant shot it with some fancy physics numbers completely from A-Z......YET! I do have bits and pieces and a ton of info on it so far, but none of it jives, go figure. Some of them are even contradicting themselves. Kinda like Dick Cress. In which I will prove to him Momentum and Penetration are not one and the same!

Trying to change the thoughts of an industry is a giant leap. Will it happen, probably not. Will you even need to worry about it on your antelope or whitetails, probably not in a best case scenerio!

RE: Speed is all you need! (?)
 

better get those books out Dick....here is something for you to look at.

An important difference is that momentum is a vector quantity - it has a direction in space, and momenta combine like forces do. Kinetic energy is a scalar quantity - it has no direction in space, and kinetic energies combine like " regular numbers" .

The momentum of an object is proportional to the object' s velocity - if you double its velocity, you double its momentum. The kinetic energy of an object is proportional to the square of the object' s velocity - if you double its velocity, you quadruple its velocity. This has important consequences...

more to follow......

RE: Speed is all you need! (?)
 

I' m Irish . . . I love a good debate. But how do you debate Sir Isaac Newton????

Tell me why " It is the product of the mass of a moving particle multiplied by its linear velocity. {quoted from the following article}" isn' t the same as our Kinetic Energy Formula????

Momentum, also linear momentum, in physics, fundamental quantity characterizing the motion of any object (see Mechanics). It is the product of the mass of a moving particle multiplied by its linear velocity. Momentum is a vector quantity, which means that it has both magnitude and direction. The total momentum of a system made up of a collection of objects is the vector sum of all the individual objects' momenta. For an isolated system, total momentum remains unchanged over time; this is called conservation of momentum. For example, when a batter hits a baseball, the momentum of the bat just before it strikes the ball plus the momentum of the pitched baseball is equal to the momentum of the bat after it strikes the ball plus the momentum of the hit baseball. As another example, imagine a beaver jumping off a stationary log that is floating on water. Before the beaver jumps, the log and the beaver are not moving, so the total momentum is zero. Upon jumping, the beaver acquires forward momentum, and at the same time the log moves in the other direction with an equal and opposite momentum; the total momentum of the beaver plus the log remains at zero.
Conservation of momentum is one of the most important and universal of the conservation laws of physics; it holds true even in situations where modern theories of physics apply. In particular, conservation of momentum is valid in quantum mechanics (see Quantum Theory), which describes atomic and nuclear phenomena, and in relativistic mechanics, which must be used when systems move with velocities that approach the speed of light (see Relativity).
According to Newton' s second law of motion-named after the English astronomer, mathematician, and physicist Sir Isaac Newton-the force acting on a body in motion must be equal to its time rate of change of momentum. Another way of stating Newton' s second law is that the impulse-that is, the product of the force multiplied by the time over which it acts on a body-equals the change of momentum of the body.

" Momentum," Microsoft(R) Encarta(R) 98 Encyclopedia. (c) 1993-1997 Microsoft Corporation. All rights reserved.

Kinetic Energy, energy possessed by an object, resulting from the motion of that object. The magnitude of the kinetic energy depends on both the mass and the speed of the object according to the equation

E = 1mv2 [This is 1/2 X Mass X Velocity Squared the formula doesn' t come through correctly in a tex based system]

where m is the mass of the object and v2 is its speed multiplied by itself. The value of E can also be derived from the equation

E = (ma)d

where a is the acceleration applied to the mass, m, and d is the distance through which a acts. The relationships between kinetic and potential energy and among the concepts of force, distance, acceleration, and energy can be illustrated by the lifting and dropping of an object.
When the object is lifted from a surface a vertical force is applied to the object. As this force acts through a distance, energy is transferred to the object. The energy associated with an object held above a surface is termed potential energy. If the object is dropped, the potential energy is converted to kinetic energy. See Mechanics.


scalar (sk³" l…r, -lär" ) n.
1. A quantity, such as length, that is completely specified by its magnitude and has no direction.
[From Latin sc³lae, ladder.]


" scalar," (c) 1994 Houghton Mifflin Company. (c) 1994 INSO Corporation. All rights reserved.

kinetic energy n.
1. The energy possessed by a body because of its motion.

" kinetic energy," (c) 1994 Houghton Mifflin Company. (c) 1994 INSO Corporation. All rights reserved.

momentum (m½-mµn" t…m) n.
pl. momenta (-t…) or momentums
1. The product of a body' s mass and velocity. Also called linear momentum.
2. Impetus.
[Latin m½mentum, movement, from mov¶re, move.]

" momentum," (c) 1994 Houghton Mifflin Company. (c) 1994 INSO Corporation. All rights reserved.

RE: Speed is all you need! (?)
 

Dick you are making my head hurt:(.

Brian

RE: Speed is all you need! (?)
 

[X(]Wow, 6 pages of crap !!!!.Speed,shmeeeedddd.If your HUNTING a deer and not just going out to SHOOT a deer, speed comes further down the list of important things.I have never shot a deer past 20 yards.Hunting wood lots mostly, lends itself to close range hunting.
That is, if you do your home work ;)

[Deleted]
 

[Deleted by Admins]

RE: Speed is all you need! (?)
 

Krisken, I don' t disagree as I said earlier. You have mass, you have Kinetic, you have momentum and you get penetration; it works for you so use it.

The only place I disagree is the term " Speed is all you need! (?)" You need some combination of both mass and speed. So it is the term that is not correct.

I' d rather be hunting but a lively debate helps pass the time.

[Deleted]
 

[Deleted by Admins]

RE: Speed is all you need! (?)
 

I yield and stand corrected . . . Momentum and Kinetic Energy are not the same. I do apologize for the inaccuracy. I still believe that the term " Speed is all you need! (?) is not accutate though.

My physics book disappeared many years ago (around 39) and my math is as rusty as my logic. But I am studying a page that may support my ultimate conclusion on the values of momenta and kinetic energy.

The following website explains why Kinetic Energy gets my vote over Mpmentum. And it is kind of cute the way they describe it.

http://www.batesville.k12.in.us/Phys...TMomentum.html

[Deleted]
 

[Deleted by Admins]

RE: Speed is all you need! (?)
 

Dick,

I did see that one...even almost posted it for you but decided not to.....the reason why you ask. I do disagree that a truck hitting you at even 1mph will not bowl you over. I do agree though that a meat ball traveling at that high of a speed could and probably will inflict some serious damage. However our arrows are traveling no where near that ball park figure in difference....not even in a different ball park on the same block! or even city.

Well look at it as a blade of grass. I can pick one up and throw it at you, what happens, notta.

I can take a tornado and get that little blade of grass moving at some serious speed and quite possibly zip it through you.

Its exactly the same thing as that web page. However the speeds needed to achieve this a huge! one mile per second quite possibly could do this.

I have also seem some other pages that prove this and if I remember right they start talking about weight and the speed of light. It is relevant to its mass also. The higher the mass the less fast it needs to achieve to out penetrate.

I did however find one that proves what I was saying that you need both. And that there is at some point a minimal return of having to much mass or to much speed and actually had a number to go buy after you figure you stuff out for your own personal set up. Saying that X was the best of both worlds, anything higher or lower atleast at an extreme is back into the minimal gains department. Let me look the dang thing up again.

Now for the kicker on that web page. Take a look at the extremes for in which they are. 1000 times difference in KE and an exact even on Momentum. Now let me ask, are the two bows you and I shoot 1000 times different on KE? How about Momentum are we even close? probably not. In the bowhunting relm, probably not even close. Even the super light arrows coming out of Kriskens 340 some fps compound are not traveling twice as fast as my longbow and he is shooting at the very very top of the speed realm as we know it today coming out of archery gear today (thats if he is shooting through a chrono and not guessing, not to mention one that is showing an accurate reading to begin with). The differences are hardly a mac truck and a meat ball taveling at one Mile per Second! More to the tune of a knuckle ball and a fast ball in the major league. Or a wrist shot vs a one timer in the NHL. The problem is we are both not shooting exactly the same in mass so we have no constant!

I' ll dig up that web page here in a bit.....gotta get more arrows sealed.....

[Deleted]
 

[Deleted by Admins]

RE: Speed is all you need! (?)
 

Krisken

Actually, a man was killed by being hit in a fast pitch softball game, it was in the news in 2002. I remember it because I too play softball and thought it unusal.

As to the topic, does speed kill? Hell yes it kills. Is it imperative to MOST hunting situations, deer or elk, Hell no! elknut1.

RE: Speed is all you need! (?)
 

The differences between truck and meatball analogy and our arrows would be relative and I would think directly proportional.

[Deleted]
 

[Deleted by Admins]

RE: Speed is all you need! (?)
 

Dick,

Keep lookin at those momentum and Ke web pages you are pulling up.....you' ll find it eventually!

The factor is speed, Get enough of it and anything can be lethal, think I have proved that in my last post. You cant however compare even the fastest arrow going a humbly 345fps to something traveling 1 miler PER SECOND. Speed is however relative to the mass it carrys.

Everything is relative in its own right.....if you need some big drawn out equation, I have them! I however dont feel the need to confuze the people who may actually gain something from this.[&:] I do agree, you have to have weight....the real question is how much weight per how much speed is considered " acceptable" for the game you are hunting with the set up you are shooting (arrows, bheads, conditions of the hunt etc). These are questions only you can answer as each situation and style of bowHunter is different. The way we look at things is different, and quite frankly the outcome is vastly different. I am amazed at anyone shootin fixed blade heads at whitetails not getting complete penetration on a perfect hit.....it doesnt always happen. I am amazed also at a none complete penetration by the modern compound shooters when hitting 1 or both shoulder blades. Its obvious there are things at play that folks dont understand. There are two sides to the coin, without either, you have a defaced coin. In the penetration scheme, as you say one without the other is worthless as your KE figure is still 0. You are atleast right there.

The one problem with formulas is we can find other formulas that can and will give different results in the KE vs Mom scheme. Its not as simple as to every action there is an opposite and equal reaction. Hopefully you find the answer you are looking for..... Not to mention the constant with them in this type of industry...human error. The only way to get rid of it is with a shooting machine....but dang we have other factors we need to look at....does it end? Heck most dont even care to understand it. To each there own. But when they get that perfect hit with 3" es of penetration, atleast you and I will know why.

I will however tell you this. Stay away from the archery or bowhunting critics if you will. We all have our own beliefs. Some of which are closer to real life then others. And some of us can prove that time and time again (btw, have you ever heard of a easton 2440? Damn they are heavy [>:]) I will tell you a trip to your local physics department at a college who has no opinion either way on bowhunting would give you some great results. Being they dont understand the total penetration scheme you would either have to edumacate them or realize there are other factors at play then just KE, MOM, or even the combination of the two, which is atleast closer to reality then the bowhunting industry would lead you to believe.

I have never weighed a base ball to a soft ball. I do know they are pretty compareable. One other factor you need to consider is surface area. Hit something in one small spot, go figure its going to do more damage, then hitting something 2 or three times as big, all else being equal. The energy at hand will be focused all at one small area. It takes a genious to see that...not! Quite frankly I would rather not be hit by either lol.


This hockey game is getting good..I' ll be back!

RE: Speed is all you need! (?)
 

I shoot 67lb. at 270fps. I eat venison every year. PERIOD!

RE: Speed is all you need! (?)
 

Hi,

The difference between a softball or hardball isn' t just the weight and speed!

Some softball pitchers can attain hardball speeds,what about a golf ball?

What some of you failed too realize is a hard ball is a HARDER ball than a SOFT ball and a golf ball is harder than the others .

Granted the golf ball is traveling faster than than the other two, so what would you rather get hit by a golf ball traveling at 300' per sec or a ping pong ball at 400' per sec?

RE: Speed is all you need! (?)
 

I have never denied that speed is not needed . . . IT IS! But it is not ALL that is needed. If it was, one could equate the mass to zero and still kill a deer [in theory] with just speed alone and that just ain' t gonna happen.

Personally I shoot at 241 fps and 67# and 60 ft-lbs of KE and the only thing I regret every year is that I didn' t buy a bigger freezer.

RE: Speed is all you need! (?)
 

Dick,

are you having amnesia after 143 posts [>:][:o]

[Deleted]
 

[Deleted by Admins]

RE: Speed is all you need! (?)
 

heres a easy way to find out what arrow penatrates better light or heavy. also you will see what the driving force momentum will do in each case granted this is not a deer. two arrows shot out of the same bow at the same poundage one light going faster than heavy arrow. the target are you with me is a 2 by 6 kind of tuff on the arrows but it will show you what will happen. this should end the fast pingpong ball going fast compared to the golf ball bs.this test will surprise you on what you thought you knew.remeber this arrow and that arrow same diamater same bow weight. but differant weight and speed for the arrows this test should be done at 20 yards. common bow range check it out.

RE: Speed is all you need! (?)
 

Not that I know of. I accept that I erred stating that Momentum and Kinetic Energy are the same. But You' d need to refresh my memory some. I don' t recall saying that speed wasn' t needed. I believe in Kinetic Energy. If I am correct I have debated that we need both speed and mass to get the job done but that speed alone is not enough nor will mass alone get the job done. Nor have I said that Krisken' s arrow is too light or lacks the power to get the job done.

I am just not convinced that Momentum is what gets the job done.

RE: Speed is all you need! (?)
 

I found this on Martin' s site. I thought it fit right in with what we are talking about. Look about half way down at the " Arrow Penitration" section.

http://www.martinarchery.com/faq/facts.html#pene




60# Bow - 30" Draw

What do you think about this?

[Deleted]
 

[Deleted by Admins]

RE: Speed is all you need! (?)
 

ACLakey thats just what i was looking for. this is why i don' t think people with short draw lenghts and low bow poundage should be shooting logs.however heavy arrows have one thing going for them at longer ranges they don' t shed velocity as quickly as light arrows which means more momentum for heavy arrow. but they don' t shoot as flat as light arrows so if you shoot light arrows with plenty of ke i see a advantage with the lighter set up at normal bow ranges and farther.thats if you can hit with it.

RE: Speed is all you need! (?)
 

Well here it goes again.The age old debate and it keeps going on and on.I have been a member of this debate before and I am a middle of the road proponent.

There is one thing about the martin' s picture that I don' t like.It is a bit misleading,first it is most likely comparing thin walled aluminum against a thick walled aluminum and that will affect the outcome as well as the foc.I have tested these points and have found them to be true.I also would like to point out that they are using friction to stop the arrows and speed is what fights friction.Momentum is what will bust bone out of the way to let the arrow continue forward,or hide or whatever you may encounter in an animal but as long as all is being done is cutting then speed is a huge help.This is imo why when you look at traditional setups that are building huge momentum numbers they are also using 2 blade cut to tip heads.This is to eliminate as much friction as possible.


I have always hated the statements that heavier is better.There are just too many variables to make such a blanket statement.Or the one I always really hated is that a heavy arrow has more ke energy downrange than a lighter arrow.On paper this is true but when that lighter arrow is smaller in diameter and has 3" vanes and the heavy arrow has 5" helical fletching,drag will offset this and the lighter arrow will now have more downrange ke.I have never actually figured how much momentum is lossed but I would guess that it would be the same percentage loss as ke.Would most likely be a little more momentum but you can see how variables change things.


There are a couple things that bother me about your setup Krisken but i don' t have to use your bow to hunt with and I wouldn' t.If you like it then the choice is yours to make.I don' t even like that much speed for 3-d.I like to stay in the 270-280 range.

The biggest thing that would concern me is the durability of the the light arrow.Have you encountered a shoulder hit and did the arrow hold together?Also a lighter arrow will be knocked off course much easier by a limb or other object regardless of how much ke or momentum it posseses.Now don' t get me wrong,I use a light arrow,360 gr but I also have some over 420gr that I also use out of the same rig with the same pins.Or atleast I did,I just sold my hunting bow.


I actually considered going with a heavy arrow because of a point you made earlier.Hard to find your arrow when it travels 40 plus yards past your animal.A slower arrow isn' t going to travel as far after it passes thru an animal.

Use what you are comfortable with and be competent with it.

RE: Speed is all you need! (?)
 

Philosophically there are great argumentson each side of the fence on this one; I for one thank Krisken for geting it kicked off it has been a terrific debate and I don' t know about others but I learned from it and I' ve bowhunted since 1963.

I think each of us has a responsibility to develop an equipment package that performs well and does what we intend it to do then have the ethics not to push that equipment beyond those limitations.

I can' t think of a better way to pass the time while I wait for hunting season to roll around.

Thanks to all for the debate we' ve all won!

RE: Speed is all you need! (?)
 

TFOX friction is what stops the arrow or bone head on impact thats why i said try a 2by 6 and see what happens 2 arrows same diamater same bow same poundage the light one will be faster and heavy arrow will be slower. thr results will be simuler to the martin target the heavier arrow will penatrate about 5% deeper or less. there goes pingpong golf ball idea:D:D:D:D

RE: Speed is all you need! (?)
 

selway,I have done the test with wood behind a piece of foam and the heavy arrow in most cases would explode the board where as the lighter one would just leave a small hole.Now if you lower the foc way down on the heavy arrow then the lighter arrow always won out.I have shot at different distances and that plays a role.12% foc always yielded better results untill I tried a traditional stinger and it performed best at 18% but that is most likely due to the amount of foc that is already built into the shaft.

Yes all Of my arrows diameters were the same.I used weight tubes and points that were identical.

It always came down to how I put the arrow together and not the overall weight.When all things were equall,the light arrows would win out on foam and the heavy would win out on wood.Carbon would win out over aluminum and so forth.

RE: Speed is all you need! (?)
 

The following is a cut and paste of a response that Dr. Ed Ashby, as in PHD not MD, gave to a question regarding testing of penetration testing he conducted. It may surprise some people what he has to say.

[Deleted]
 

[Deleted by Admins]

RE: Speed is all you need! (?)
 

Krisken,

I shoot a longbow. Believe me friend I am not concerned with speed, albeit the longbow I have now is probably the quickest traditional bow I have owned to date and it is 4# lighter in draw weight than one recurve I owned, and which are supposed to be faster than longbows.

Two years ago I killed a buck which I hit a bit high and a bit back of point of aim. I thought the buck had stopped, and apparently he was continuing to walk up the power line I was sitting on.

The arrow hit him in the onside legbone, shattered it, went through the bottom half of the spinal column and lodged in the offside legbone. The impact, and the shock of his spinal column being hit I' m sure, knocked the buck off of his feet. He got up and headed back across the power line. He fell down three times before he got to the other side. Each time he got back up and continued on.

I didn' t see it because I was hunting from ground level, but my son was 35 ft up a tree about 50 yards behind me, and he saw the buck fall as it dropped down off the level of the power line to the forest floor on the other side. The deer never got back up after that, even though it did take another finishing shot an hour or so later when we gave him time to lay and calm down before we checked out the blood trail, which was massive, and trailed him to the end of it.

And what' s my point? Glad you asked! The point is my slow traditiona bow with a heavy wood arrow penetrated through two heavy bones and lodged in a third. The razor sharp SteelForce broadhead caused significant damage and did so without high speed to help it.

Insofar as the post above, the key element to which I would draw your attention is Dr. Ashby' s conclusion/postulation that Kinetic Energy has no correlation to penetration on a live animal. It is momentum that is the key measure that his tests have revealed to be the element to be directly relatable to penetration on live animals.

To be sure, there are lots of factors that come into play. A sharp/dull broadhead will have a significant influence, too. There are many a traditional hunter that routinely get complete passthroughs with their " slow" , i.e., sub 200 ft/sec, bows and heavy arrows. The real question is how far do you want to bury the arrow in the ground after it has passed through the animal?

A shooter wants to see how far away he can shoot an animal with his high speed equipment. A hunter wants to see how close he can get an animal so he can get a quick, clean and humane kill no matter what the speed is of his equipment.

Bil

[Deleted]
 

[Deleted by Admins]

RE: Speed is all you need! (?)
 

Krisken,

Let me ask a question. What is your average distance for a kill shot?

Bill