Is this Kinetic Energy Calculator on the web accurate?

Home Forums Technical FAQ Is this Kinetic Energy Calculator on the web accurate?

This topic contains 19 replies, has 12 contributors, and was last updated by l-o-s-t-arrow L.O.S.T.Arrow 2 years, 7 months ago.

Viewing 15 posts - 1 through 15 (of 20 total)
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  • August 17, 2006 at 10:42 pm #495144 Back to Top REPORT
    symo
    Symo


    Joined: 6/29/2004

    Is this K.E. calculator accurate? It tells me that I can get more KE out of a lighter arrow than a heavier one with my bow.
    http://bucklemke.com/ke/ke.php[/url:229htnbw][/quote:229htnbw]

    This KE calculator is an estimator, and is known to be inaccurate for heavier arrows. It is by no means a 100% accurate instrument. It makes some generalized assumptions for added weight on the string, the number of pounds away from 70 your are, etc etc. If you want to know KE, all you need is the mass of your arrow and its velocity. This calculator will not give me KE without entering my draw length, draw weight, etc. We’ve been through this many times on this forum.

    With that said, if you take the same bow, and change nothing except arrow weight, the heavier arrow will ALWAYS have more KE than the lighter one.

    Here is an accurate example:

    A bow at 70.7lb draw weight with a 29″ Draw

    Arrow of 350 grains: 298.8 FPS KE=69.4 ft-lbs
    Arrow of 400 grains: 281.5 FPS KE=70.4 ft-lbs
    Arrow of 450 grains: 266.9 FPS KE=71.2 ft-lbs
    Arrow of 500 grains: 254.4 FPS KE=71.4 ft-lbs
    Arrow of 600 grains: 233.8 FPS KE=72.8 ft-lbs
    Arrow of 800 grains: 206.4 FPS KE=75.7 ft-lbs

    Anybody can run the “math” on those numbers and see that the KE is correct. :thumbup

    January 12, 2007 at 1:10 am #503673 Back to Top REPORT
    mq1hunter
    MQ1hunter

    Joined: 1/9/2007
    I got to find my stuff I made a program in JAVA a while back doing the same thing and I also have some numbers from the Wisconsin Bowhunter Assc. Neceda shoot…
    I don’t see the need for them to lie…
    And in another post it is a pandora’s box with arrow speed combo. The general princeable would be that the heaveir arrow retains more KE then the lighter faster. Which in turn would make the bow quieter and more efficient.
    Then again I still shoot a MQ1
    :D
    I run what they have to what I got and see…
    be back
    January 10, 2009 at 8:19 am #503674 Back to Top REPORT
    ordoublelung
    ORDoubleLung

    Joined: 1/3/2009
    What is the fps of the arrows down range say at 30…40…50…60yds. To me that would be the numbers we should really be dealing with…the energy at the target. [=}=] [=}=]
    January 11, 2009 at 2:53 pm #503675 Back to Top REPORT
    striperday
    striperday

    Joined: 9/29/2008
    KE is the measure of energy in motion. PE (Potential Energy) is the measure of energy capable. #-o You have good question and good point! My Engineering degree will always haunt me. ;)
    May 5, 2009 at 4:34 pm #503676 Back to Top REPORT
    elkhunter130
    elkhunter130

    Joined: 5/4/2005
    What is the fps of the arrows down range say at 30…40…50…60yds. To me that would be the numbers we should really be dealing with…the energy at the target. [=}=] [=}=]

    Mathews LX results

    Easton Pro Chrony:

    Peak Draw Force – 68.9 lbs
    Arrow Speed – 271 fps
    Arrow Weight – 405.00 grains
    Arrow Length – 29.00 inches
    Calculated K.E. at Bow – 66.06

    Results over distance:

    Yards / K.E.
    20 / 61.4
    30 / 59.3
    40 / 57.2
    50 / 55.1
    60 / 53.1

    This is what having to much time on your hands produces. Oh yea, the bow shoots just great and kills everything it shoots at. :X :shock:

    May 27, 2009 at 4:44 am #503677 Back to Top REPORT

    Innova

    Joined: 3/16/2005
    Hello everyone,

    Just to let you all know, I wrote the calculator that is linked to in the first post.

    I decided to post for a couple reasons. First, a brand new calculator has just been put up. The link will now redirect to http://utopiaprogramming.com/ke/index.html. If you have bookmarks, you can update them. The numbers the calculator outputs will still be the same, but it is now easier to use.

    I welcome any suggestions you have for improving it.

    Secondly, as you have noticed, the speed calculations are an estimate. But I have found them to be very close. The most likely thing to cause the speed estimate to be off, is weight on the string. Weight in the center of the string (nock, loop, etc) will slow the arrow down. However, the further you move out on the string, the less impact the weight will have. It can even cause the arrow to increase speed up if it is far enough out.

    Thanks,
    Innova

    PS, if for some reason, you still like the old version better, it is available at http://utopiaprogramming.com/ke/ke.php

    June 16, 2009 at 7:33 pm #503678 Back to Top REPORT
    klemsontigers7
    klemsontigers7

    Joined: 9/1/2006
    Thanks for providing the older link. I think it is easier to use if someone tells you a speed, arrow weight, draw length and weight… for figuring out a bow’s IBO.
    June 16, 2009 at 7:42 pm #503679 Back to Top REPORT

    Innova

    Joined: 3/16/2005
    No problem.

    I just noticed that my url tag is wrong above…it has an extra period at the end.

    Here is the link for the new version again: http://utopiaprogramming.com/ke/index.html

    May 24, 2010 at 3:35 am #503680 Back to Top REPORT

    davidquinones

    Joined: 12/11/2008
    I noticed you guys are calculating kinetic speed and ya’ll might know a little something on spped. Having a hard time deciding on which bow to get. I currently shoot a 70# MQ1 and it is a great bow. The action on the Z7 is excellent but it is similar or slightly better speed to my MQ1. Comtemplating on upgrading and the decision on which bow to get has been very difficult. I shot the new Z7 and it is an awesome bow. My biggest dilema deciding is speed vs Z7. I want the action of the Z7 with monster speed. Any recommendations or opinions would be appreciated…
    May 24, 2010 at 3:37 am #503681 Back to Top REPORT

    davidquinones

    Joined: 12/11/2008
    I noticed you guys are calculating kinetic energy and ya’ll might know a little something on speed. Having a hard time deciding on which bow to get. I currently shoot a 70# MQ1 and it is a great bow. The action on the Z7 is excellent but it is similar or slightly better speed to my MQ1. Comtemplating on upgrading and the decision on which bow to get has been very difficult. I shot the new Z7 and it is an awesome bow. My biggest dilema deciding is speed vs Z7. I want the action of the Z7 with monster speed. Any recommendations or opinions would be appreciated…
    May 26, 2010 at 10:16 pm #503682 Back to Top REPORT
    l-o-s-t-arrow
    L.O.S.T.Arrow

    Joined: 5/16/2006
    Location: Alberta
    I noticed you guys are calculating kinetic energy and ya’ll might know a little something on speed. Having a hard time deciding on which bow to get. I currently shoot a 70# MQ1 and it is a great bow. The action on the Z7 is excellent but it is similar or slightly better speed to my MQ1. Comtemplating on upgrading and the decision on which bow to get has been very difficult. I shot the new Z7 and it is an awesome bow. My biggest dilema deciding is speed vs Z7. I want the action of the Z7 with monster speed. Any recommendations or opinions would be appreciated…

    :D Your may have to wait ….your talking two cam hyper speed and solo cam smoothness…someday…we are already speed and smoothness combined with the Z7 over bows that are only a few years old…

    JMO

    Neil

    January 11, 2011 at 1:15 pm #503683 Back to Top REPORT

    Innova

    Joined: 3/16/2005
    Hello, I wrote the calculator in the first post (with help with the details, from posts I found on this site). I would like to let everyone know that I have made a version of the Kinetic Energy Calculator available for Android phones. If you are interested, you can click the following links (on your android device) to download the app:

    Free, ad supported version

    No ads, $1.00 version

    Thanks, and let me know if you have any questions!

    January 11, 2011 at 1:19 pm #503684 Back to Top REPORT

    Innova

    Joined: 3/16/2005
    Sorry, the links should have been:

    Free ad supported version[/url:22at30fh]

    $1.00, no ads version[/url:22at30fh]

    October 30, 2011 at 10:43 pm #503685 Back to Top REPORT
    legacy80
    legacy80

    Joined: 12/23/2010
    just curious , i calculated my kinetic energy at 64.5 ft/lbs , is that good or average or what ?
    October 30, 2011 at 11:20 pm #503686 Back to Top REPORT
    legacy80
    legacy80

    Joined: 12/23/2010
    just read a good right up on this subject and im all dialed in , arrow weight , bow speed , all that is in good shape so nevermind , and ive got an 8 pointer to prove it , this article shed light on the expandible /fixed question i had too , so im all Muzzy all day
    my dad has been using em for as long as i can remember and he has a few 10s on his wall so , thanx anyways , father knows best
Viewing 15 posts - 1 through 15 (of 20 total)