Kinetic energy

[pupper]

Who has calculated their bow/arrow setup in ft. lbs of kinetic energy?

The formula is: (velocity x velocity) X arrow wieght in grains / 450,250= ft. lbs of kenitic energy

my rig is a bowtech tribute 70# w/ 27.5" draw and I shoot 5575 gt xt hunters.

with a 100 grain tip I am shooting 291 fps, my arrow wieght is 361 grains.

make sure you chrono your shooting as my bow says it shoots 338 fps but through the chronograph it shoots 291.

so the calculation looks like this:

(291 x 291) x 361 / 450,250= 67.895

so rounding up my bow/ arrow set up hits with 68 ft. lbs of kinetic energy.

what type of punch are you packing?

[bochunk2000]

From what I gather I'm shooting about 270 fps.
We chrono'ed it 60# and got 245 and then dialed it up to 69 lbs.
27.5 in arrow with 125gr broad heads. I have a 28" draw length.
When I weighed the arrow a couple of days ago it weighed 429gr total. When I do the math that gives me about 69.5 lbs kinetic energy.

Could anyone please tell me what the minimum should be to hunt with. I'm pretty sure this is plenty I am just wondering the minimums. Thanks Steve.

[J_T]

Thanks for the post and the formula Pupper. I went looking for it in my stuff and couldn't find it.

I shoot a 64# recurve, 200 fps and a 750 gr wood arrrow. Works out to 67 ft lbs of energy.

I just made up some carbon arrows, thinking lighter (flatter trajectory) and I was able to build an arrow weighing 630 gr. This new arrow now gives me 56 ft lbs of energy.

If you want more KE >> go heavy.

JT

[Bow Walker]

Steve, there was an arrow site that I believe had the recommended KE for different game. Of course I can't find the site anymore. But from what I do recall, Elk was around 54 - 58 lbs per square foot. For Bear it was the same.

You don't have anything to be shy about or to worry about.

[road warrior]

(315x315)x415/450250=91.45669.Hoyt Cybertec 80lb 31"draw 27"415grn arrow.

[bochunk2000]

(315x315)x415/450250=91.45669.Hoyt Cybertec 80lb 31"draw 27"415grn arrow.

Wow! That sounds like you could take down a mack truck with good penitration. LOL.
Steve.

Thanks Dann I will have a look for that site.

[Bow Walker]

My main problem is that I haven't been able to chrono my new bow I don't know what the heck I'm getting from it.

I'm also in the process of building a couple dozen new arrows - starting with GT5575 camo shafts. I got the camo by mistake. I usually use the plain black shafts as they are a tad lighter overall.

I guess one side benefit from the slightly heavier camo shafts will be a bit more KE when I'm finished. We'll see when I'm done.

Maybe I'll make the long arduous trek over the 'Hat to see Sampson - he's got a chrono that I can most likely use if I get on my knees long enough

[willyqbc]

heres an online calculator that will take the math out of this...just punch in your numbers!!

http://www.iowabowhunters.org/KineticEnergyCalc.asp

My set-up this year will either be a 460 grain arrow doing 270fps or a 485 grain arrow doing 264fps... both yeild around 75 ft/lbs.

Chris

[Bow Walker]

Here's an interesting site. Ever wondered of fast you're really shooting that arrow??

http://www.calculateme.com/Speed/Fee...lesperHour.htm

[The Hermit]

Hey BowWalker! Franko has a chrono and we have been trying to tee up a time to get to the range with it. I need to sight in my new Weatherby, hopefully on Sat... maybe we can get Frank to come up and fling some arrows too! Hutch is also talking about the need to get out and fling a few too!