Easy KE calculator

[Bow Walker]

Follow this link http://www.goldtip.com/calculators/kinetic.asp?rnd=197743665 to use Gold Tip's KE calculator.

Here's their recommended KE for various types of game. Anything 50 ft lbs and up and you have nothing to worry about.

Although if you're going after Grizzlies with your archery tackle - not only do you need your noggin examined - but you might want to ensure a KE in or around 70 - 75 ft lbs of energy.

20 ft. lbs.Small Game - Birds, Rabbit, etc.. lbs
30 ft. lbs.
40 ft. lbs. Medium Game - Deer, Antelope, Bear
50 ft. lbs. Large Game - Elk, Moose, Caribou
60 ft. lbs.
70 ft. lbs.
80 ft. lbs.




This one will give you youe FOC on your arrows. Recommended here is anything between 10% and 14%.........some folks go as high as 15% or as low as 8%
http://www.goldtip.com/calculators/foc.asp

[bochunk2000]

Thanks Dan Those were helpful. I seem to be about 11.9 on the FOC when I am using Lumenoks.
Steve.

[.270boy]

415 grain arrow at approx. 260 fps = 62ft lbs

yup im ready to shoot an elk this year, i checked my dads setup and hes making 82 ft lbs.... :0 same arrows as me but there flying 40fps faster

[daycort]

thanks bw. I am 10.75 foc. not quite sure what that means.... if some one could fill me in. I am @ 67 ft lbs

[Tinney]

Although if you're going after Grizzlies with your archery tackle - not only do you need your noggin examined - but you might want to ensure a KE in or around 70 - 75 ft lbs of energy.


Why? If I was the grizzly shooting type I'd have no issues tackling one with my current setup. And I damn sure ain't over 65 ft lbs.

[Bow Walker]

Steve - how do you like the luminocks? Does it change the way you shoot at all?

dayort - F.O.C. is an arrow and arrow flight tuning tool. Here is an article that explains something about the principle behind F.O.C.

How to determine front-of-center (FOC) for arrows.

F.O.C. Guidelines
http://www.socalarchery.com/Informat...f%20center.htm (http://www.socalarchery.com/Information/front%20of%20center.htm)

Fine tuning arrow flight by using FOC. (Front of Center). This method of fine-tuning is something that not everyone knows about, but should. By determining your arrows FOC percentage, you will be able to make changes/adjustments to help increase arrow flight stability and range.

In order for an arrow to fly correctly, with the point in the lead and the fletching following, the center of mass must be located somewhere between the tip and the middle of the arrow shaft. If the center of mass is located close to the tip, the arrow will have good stability but will drop quicker because of the heavy nose. However, if the center of mass is located close to the center of the shaft, the arrow will have good range, but arrow flight may be unstable. As you can see the trade offs here are stable arrow flight vs. arrow range. The object is to find a happy medium that will allow you to have the best of both worlds.

The balance of an arrow can be modified by adding weight to either the front or the rear of the shaft as needed. Heaver vanes, for example, increase the weight of the rear portion of the arrow. Changing points can add weight to the front of the arrow.

There is no perfect F.O.C. for each setup. Here are some starting points.

FITA 11-16%

3-D Archery 6-12%

Field Archery 10-15%

Hunting 10-15%

[Eagle1]

Thanks Dan Those were helpful. I seem to be about 11.9 on the FOC when I am using Lumenoks.
Steve.
Luninoks are cool, can see the arrow go right thru the animal.
I feel it adds weight to the wrong end of the arrow so you have to go with a heavier tip to bring the FOC back up, other than that it;s a great way to see your arrow in flight and for a vid cam.
Dan should 3 - D with Steve and his luminoks so he can see where the kill is, LOLOLOL :evil:

[Bow Walker]

8) Just 'cause you don't need glasses to shoot yet!! It's comin' wait for it.8)

[bochunk2000]

Steve - how do you like the luminocks? Does it change the way you shoot at all?

Dan I find they work great. They don't add much weight and I shhot 125gr braod heads so they seem to make my foc better. They are awesome to watch. They can help wth tuning too...see the arrow wobble or not etc.

You can watch some vides of how they work at:
http://www.lumenok.net/photo.htm
Steve.

[The Hermit]

I estimate that my bow is set around 55 pounds. My arrows are travelling at 228 fps as measured with a cronograph. They weigh 369 grains with broadheads as measured on my scale. Using the linked calculator they have a kinetic energy of 42.6 foot pounds.

In order to achieve the magic 50ft/lb KE for big game I need to amp up the velocity of the arrows to 247fps.

Will I gain the needed 19 fps by cranking up the draw weight to the max 60lb for the bow?

Is the recommended KE game chart assuming the velocity was measures as the arrow leaves the bow or at point of impact? I assume velocity as the arrow leaves the bow??

[J_T]

Hermit, while many will argue that speed is the key, I would move up your arrow weight.

Keep in mind, the KE component we all refer to is being calculated at the bow. Your arrow must keep it's KE when it hits the mark. A heavier arrow will assist in penetration at the point of impact.

My rule of thumb matching an arrow to a bow, is 10 gr of arrow for each pound of bow. By that calculation, your arrow should be approximately 550 gr.

I shoot a 63 pound recurve, my arrow weighs in at 630 grains.

JT

[Bow Walker]

Will I gain the needed 19 fps by cranking up the draw weight to the max 60lb for the bow?

Is the recommended KE game chart assuming the velocity was measures as the arrow leaves the bow or at point of impact? I assume velocity as the arrow leaves the bow??
Bill, if you are comfortable at the poundage you are shooting now you may want to consider upping your arrow weight to gain some more KE.

If you feel that you can comfortably handle the 60# pull on your bow, then crank 'er up and test shoot some arrows. You will have to re-sight your bow, but you should just have to do a 'gang adjust' on your sight.

The key here is being able to draw your bow COMFORTABLY when in a hunting situation. That is, when it's cold out and your muscles are cold, or you are in an awkward position such as sitting, kneeling or bent over.

You've got to be able to draw back quietly, and without excessive movement.

So some testing is in order. Testing is fun though - just means you have a reason to go out and shoot!

As mentioned above - KE is usually measured within 10 yards of the bow. Downrange is, of course, a different story. I think it is important to start out with the maximum KE you can comfortably achieve at the shot, so as to maintain the greatest amount of KE downrange at the moment of impact and penetration.

[The Hermit]

Given the expense of building new and heavier arrows with broadheads I am going to try turning up the draw weight on the bow first. PUlling the 55 pounds is easy for me so I think the full 60 pounds will be okay but will test it out this afternoon. :-)

[J_T]

Hermit, what kind of arrow are you shooting and what is the inside diameter? If you can get the tip out, slide a piece of polyprop rope up the inside. It will add about 100 grains and stiffen the arrow just a bit.

JT

[Bow Walker]

But - add a drop or two of glue........you don't want the added weight sliding around on there during the shot.

Let us know how it went when you increased the #'s of your bow. That might just be satisfactory.

Another easy fix is to go up to a 125 grain head and increase the weight a tad at the nock end.

[BowSitter]

Bill, you also must keep in mind your arrow spine.
A little stiff is good but a little weak is not.

[Bow Walker]

Bill, you also must keep in mind your arrow spine.
A little stiff is good but a little weak is not.
can be said of a lot of things:shock:

[J_T]

I spent the Easter weekend with my girlfriend that I hadn't seen in two months. Believe me, a little stiff was good.:twisted: :lol:

[Nails]

JT, I guess you found the bunny??

Hermit also with lower KE, it can be good to use a cut on impact type broadhead.

[The Hermit]

Yup I bough 100 gr Montecs adn Slick tricks. I tuned up the draw weight and adjusted the sight. Can't readily tell much difference...

[Bow Walker]

You probably gained about 8 - 10 fps ?? You should be darned close to where you want to be.

If your arrows are travelling at 237 fps you're right in there at 49.4 KE.....that's nothing to be ashamed of.

[The Hermit]

Ha! I was at the range breaking in the barrel on my new Weatherby yesterday and a fella let me put a round through his chrono... 200gr partition zippin along at 2740 fps equals 3334.93 ft. lbs. of KE.

[Bow Walker]

Yesyerday (sunday) I built 6 arrows and then went to the range to test them....I had a couple different options built into them. All in all a great day!