jesserichard
New Member
Or a broadhead issue
kjohn15
Member
I actually just switched to a heavier arrow for more KE. Shooting rage broad heads. I'm not a world class archer and I don't shoot a lightning fast bow. Shot placement is obviously key, but why wouldn't you prepare for a possible mistake and equip yourself just in case. If you catch the shoulder blade, you will wish you had more KE
HuntNFish
Member
Nope you would be wrong...
Momentum is what delivers the KE. Double the speed and you double the Momentum of the arrow, but double the speed you quadruple the KE, so I don't understand a lot of the comments on trading speed for KE - in Iowa it don't matter on whitetails...
KE Example (What Kills)
350 grain arrow at 320 FPS = 79.8 ft.lbs KE
430 grain arrow at 280 FPS = 74.8 ft.lbs KE
Momentum Example (What Carries)
350 grain arrow at 320 FPS = .497 slug ft / sec
430 grain arrow at 280 FPS = .535 slug ft / sec
So in Iowa speed is what delivers out to 40-50 yds. on whitetails. Now with that being said if you shoot through brush, trees, concrete, or have a shot at an Elk at 70 yds (not likely in Iowa) a heavier arrow would work better.
Heavier arrow cost speed which cost KE you want more KE and less guessing distance go lighter. By the time my lighter arrow slows enough to match the KE of your heavier arrow they will be out of sight.
Huge misconception that need to be corrected, when bows were slower heavier might have carried more KE, but times have changed...
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hoosierhunter
Active Member
Your saying the increased speed offsets your lighter arrow correct?
So for example a fmj arrow and a axis will produce pretty much the same KE numbers out of the same bow.
That I can agree with, but the lighter arrow loses energy on impact far greater than the heavier arrow thus decreasing penetration.
HuntNFish
Member
Yes increased speed offsets the weigh carried, but to a distance because the lighter arrow is shedding speed quicker and in Iowa that distance is outside ethical whitetail range.
Would have to know the set-up to make second assumption check the charts.
lighter arrow does not necessary lose more energy on impact more KE the more likely the deeper penetration.
So... Shooting same bow 340 IBO into foam deer target. lighter arrow will have more penetration at the shorter distances than the heavier arrow. From my experience if you shoot same bow - at 5 Grain / LB draw you will see better penetration than a 7-8 grains / LB arrow out to distances conducive to whitetail hunting in Iowa. 3D shooter should be able to contest and the preceding is the science behind it.
Would have to know the set-up to make second assumption check the charts.
lighter arrow does not necessary lose more energy on impact more KE the more likely the deeper penetration.
So... Shooting same bow 340 IBO into foam deer target. lighter arrow will have more penetration at the shorter distances than the heavier arrow. From my experience if you shoot same bow - at 5 Grain / LB draw you will see better penetration than a 7-8 grains / LB arrow out to distances conducive to whitetail hunting in Iowa. 3D shooter should be able to contest and the preceding is the science behind it.
hoosierhunter
Active Member
I'd be interested to know that break point, but my guess is it's probably 50-60 yards.
It's a tough concept because your logical side says it's not possible, but I can say I have a very limited sample from last summer and my lighter arrow did out penetrate my heavier arrow at 30-40 yards.
150 Class
Well-Known Member
Bows have changed but all of them still do a better job of getting the energy into a heavy arrow. Same bow shooting two different weight arrows... the heavier arrow will ALWAYS have more KE in it, even though the lighter arrow will ALWAYS have more speed leaving the bow. I do not think it is a significant concern for most of us but some of you are misinformed on how a bow works.
It is sort of like getting closer to a dry fire. The lighter the arrow, the closer you are to a dry fire. The energy is still in the bow, rather than in the arrow. That is also why a heavier arrow will quiet down the bow (because they absorb more of the energy).
It is sort of like getting closer to a dry fire. The lighter the arrow, the closer you are to a dry fire. The energy is still in the bow, rather than in the arrow. That is also why a heavier arrow will quiet down the bow (because they absorb more of the energy).
Crimson Arrows
Well-Known Member
KE is takes velocity squared
Momentum takes weight x velocity
Easier to get lost in the KE with velocity carrying more of the end result. End game ,though, shoot a decent weight combo in the right place on whiteys and all will be well
Momentum takes weight x velocity
Easier to get lost in the KE with velocity carrying more of the end result. End game ,though, shoot a decent weight combo in the right place on whiteys and all will be well
HuntNFish
Member
Study it then, it should help u better appreciate Speed as it relates to KE. If not explain why weight is better on whitetails in Iowa...
http://archeryreport.com/2009/12/arrow-kinetic-energy-quick-reference-chart/
http://archeryreport.com/2009/12/arrow-kinetic-energy-quick-reference-chart/
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HuntNFish
Member
Spot on...
HuntNFish
Member
No seems you may have been misinformed once the arrow leaves the bow its all about weight and speed - see the link to the chart I think it will give everyone a great resource for better understanding all of this. You want KE you will go with speed. Your above comment is true ONLY if the speed does not change and we all know a heavier arrow will be slower out of the bow.
http://archeryreport.com/2009/12/arr...ference-chart/
I agree with almost everything here. The only point I would argue is that heavier arrows will have more KE. I believe they will have more momentum. Which is different than KE.
150 Class
Well-Known Member
I do agree that when the arrow leaves the bow it is about speed AND weight. I also said that the lighter arrow is faster, which is the same as your comment that the heavier arrow is slower. When talking KE or momentum, your heavier arrow wins after it leaves the bow. This is for hunters shooting broadhead tipped arrows into live animals. Shooting into foam is apples and oranges when debating KE, momentum, or penetration.
http://archeryreport.com/2011/02/bow-efficiency-care/
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JasonF
Member
These new bows put out so dang much ke it's not like your gonna have problems. I don't know that I've really ever shot a deer that I didn't blow right through and stick in the ground 8 inches. Guess I can't say that bout my targets it pretty much stops them every time. So I don't understand why you couldn't do a penetration test on a target. Gonna be the most consistent test there is. Yea the light arrow may lose speed a little quicker but it's goin so much faster it makes it gain ke from the speed. If you find a arrow that's not super light and so heavy that it slows it way down it's gonna have more ke, I don't understand how that doesn't make since. Them super fast arrows fly farther a lot faster, don't drop near as fast, and gives you more room for error on a whitetail.
HuntNFish
Member
I do agree that when the arrow leaves the bow it is about speed AND weight. I also said that the lighter arrow is faster, which is the same as your comment that the heavier arrow is slower. When talking KE or momentum, your heavier arrow wins after it leaves the bow. This is for hunters shooting broadhead tipped arrows into live animals. Shooting into foam is apples and oranges when debating KE, momentum, or penetration.
http://archeryreport.com/2011/02/bow-efficiency-care/
Yes I agree but starting at very different points (initial speed out of the bow) this initial difference in the bow give the advantage in KE to the lighter arrow, but as the graphs show the heavier arrow will pass the Lighter arrow in KE over time which equates to distance - so i believe with most set-ups out to say 40-50 lighter arrow still wins.
But look at the difference in momentum there is something to be said also about the ability for that to buffer outside forces such as wind, rain drops, etc. shows heavier arrow will not deflect off limbs t the degree of the lighter arrow. that could be important on an displaced shot.
as far as apples to oranges if the arrow, the material being penetrated and the tip the same this should be a fair test. mechanical broad-heads would have variance as they perform differently with different speed and KE.
Let's think about this concept using bullets. A 7 RUM shooting a 160 grain bullet at over 2950 fps gives 3030 foot lbs of energy. Yet a 375 H&H shooting a 270 grain bullet at 2600 fps gives over 4000 foot lbs energy. Why? The 375 has more mass. Basically, heavier and slower will have a greater ability to do work i.e energy
This why I always try to shoot the heaviest arrow I can. Its a trade off though, you lose speed to gain penetration.
This why I always try to shoot the heaviest arrow I can. Its a trade off though, you lose speed to gain penetration.
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150 Class
Well-Known Member
Please look at the graphs again. One shows the efficiency of the bow. The other shows the KE and momentum of the arrow as it leaves the bow with different weight arrows, same bow. Nowhere does it show the downrange speed of the arrow, nor the changes of speed, KE, or momentum. What it does show is that the heavier arrow has more KE and momentum as it leaves the bow. Heavier arrows absorb more energy from the bow at the shot. They will carry their momentum better so they will penetrate better. The one downfall is that they are slower and will loose their trajectory faster.
As stated in my original post, I do not think any of this is a significant concern for most of us. If you like fast, go for it. I am just trying to stop more of you from becoming misinformed.
A better comparison is different weight bullets from the same gun, not different guns, but your point is spot on.