a href="http://www.lancasterarchery.com/archery-classic-register/#header">
Results 1 to 15 of 15

Thread: Arrow Speed Calculator on Backcountry Bowhunting

  1. #1
    Join Date
    Nov 2009
    Location
    Clarksville, TN
    Posts
    38

    Arrow Speed Calculator on Backcountry Bowhunting

    OK, 1st,,, I don't need a lecture on arrow kinetic energy, broadhead selection or shot placement. I am trying to see what I will get from dropping grains but staying above 380 total. I just want to know if the arrow speed calculator on Backcountry Bowhunting is accurate. Here is the link if anyone wants to see. http://www.backcountrybowhunting.com/articles/tools.php
    Thanks, Dan

    Last edited by Medwc; November 25th, 2009 at 08:33 PM. Reason: had to fix link


  2. #2
    Join Date
    Mar 2009
    Location
    PA
    Posts
    4,155
    I have used it before, and it seems pretty close. Would like to see what others think.
    Even if it is not wholly accurate should help you find our "relative change" do to drop in arrow weight.

  3. #3
    Join Date
    Jan 2009
    Location
    North Carolina
    Posts
    725
    I just tryed it and it was surprisingly close! But you know you can do something very similar on Microsoft Excel. I set up a spreadsheet that works like this. First, I shot my bow through a crono several times to get an accurate reading, then weighed that arrow. Puting those numbers in the formula gives me my bow's KE. Then I just change the weight of the arrow while keeping the same KE and it gives me arrow speed! I think it's a little better than the online version because you don't have to worry about a lot of possible variables. If your draw length is set to 28" is it actually 28"? Are you sure about how much weight you have on your string? If your IBO is 300-308 fps, then where does your bow fall into that range? And don't forget about drop away rests vs. whisker biscuits. If you use your own bow's KE then that is a constant (for the most part, as long as you don't change anything) for your own individual set up. -Chris

  4. #4
    Join Date
    Nov 2009
    Location
    Clarksville, TN
    Posts
    38
    Well NOT having a chrono is my main problem. I don't want to cart all my stuff to a proshop to do what I am doing. I guess I could just buy a chrono. I figure if that arrow speed calculator is close that I will be close. Thanks for the info guys.
    Dan

  5. #5
    Join Date
    Oct 2002
    Location
    Ont Canada
    Posts
    1,604
    Quote Originally Posted by bowhunterprime View Post
    I set up a spreadsheet that works like this. First, I shot my bow through a crono several times to get an accurate reading, then weighed that arrow. Puting those numbers in the formula gives me my bow's KE. Then I just change the weight of the arrow while keeping the same KE and it gives me arrow speed! I think it's a little better than the online version because you don't have to worry about a lot of possible variables.
    Maybe I'm missing something, but how can you use a constant KE for different arrow weights when you have a constant draw length and weight? By changing the arrow weight, with constant draw weight and length your KE should change due to the lighter arrow...

  6. #6
    Join Date
    Nov 2009
    Location
    Clarksville, TN
    Posts
    38
    Well I finally found a couple of older threads on the Arrow Speed Calculator on Backcountry Bowhunting. Most of the 30 so poster said it is pretty close so I will use it for now. On a better note... I just talked the wife into another x-mas present (a digital Pro Chrono). Hopefully she will let me have it early.
    Dan

  7. #7
    Join Date
    Jul 2005
    Location
    In da "Show Me"
    Posts
    11,866
    I have 3 Chronys and this is the online calculator I use-

    http://utopiaprogramming.com/ke/KineticEnergy.html#

    I use 25 grains for the "wieght on the string" box (D-Loop, Peep, and BowJax on my Cables) and I am almost always within a couple of FPS from my Chrony.
    2010 New Breed Genetix- 60lbs. / 28.5" = 370 grains @ 282 FPS
    2012 New Breed Eclipse- 65lbs. / 28.5" = 370 grains @ 291 FPS

    2015 New Breed ??? - 65lbs/ 28.5"
    Carter's Archery- "Get Crackerized" , Starrflight FOBs- "Fletchings Only Better"

  8. #8
    Join Date
    Jan 2009
    Location
    North Carolina
    Posts
    725
    Quote Originally Posted by thunderbolt View Post
    Maybe I'm missing something, but how can you use a constant KE for different arrow weights when you have a constant draw length and weight? By changing the arrow weight, with constant draw weight and length your KE should change due to the lighter arrow...
    You're thinking of the KE of a moving arrow. I'm talkin about the KE put into the arrow by the bow. When you draw a bow, you put KE into the limbs which is then transferred into the arrow on the shot. So long as you don't change anything about your set up (draw weight, draw length ect.) your bow will store and transfer the same amount of KE shot after shot with enough consistency to use to predict arrow speed when you change the weight of the arrow. Does that make more since? -Chris

  9. #9
    Join Date
    Jan 2009
    Location
    North Carolina
    Posts
    725
    Quote Originally Posted by mdewitt71 View Post
    I have 3 Chronys and this is the online calculator I use-

    http://utopiaprogramming.com/ke/KineticEnergy.html#

    I use 25 grains for the "wieght on the string" box (D-Loop, Peep, and BowJax on my Cables) and I am almost always within a couple of FPS from my Chrony.
    Just played around with that link a little and it seemed pretty close. It works exactly the same as the Backcountry Bowhunting site.

  10. #10
    Join Date
    Nov 2009
    Location
    Clarksville, TN
    Posts
    38

    Bargain Bin


    Thanks bowhunterprime

  11. #11
    Join Date
    Oct 2002
    Location
    Ont Canada
    Posts
    1,604
    Quote Originally Posted by bowhunterprime View Post
    You're thinking of the KE of a moving arrow. I'm talkin about the KE put into the arrow by the bow. When you draw a bow, you put KE into the limbs which is then transferred into the arrow on the shot. So long as you don't change anything about your set up (draw weight, draw length ect.) your bow will store and transfer the same amount of KE shot after shot with enough consistency to use to predict arrow speed when you change the weight of the arrow. Does that make more since? -Chris
    I'm pretty sure it isn't quite that simple, but Hey! if it works for you

  12. #12
    Join Date
    Jun 2006
    Location
    Onalaska,Wa
    Posts
    1,628
    Quote Originally Posted by bowhunterprime View Post
    Just played around with that link a little and it seemed pretty close. It works exactly the same as the Backcountry Bowhunting site.
    I just ran my numbers and there was 3fps and 2lb. of ke difference. Pretty close enough for me.

  13. #13
    Join Date
    Jul 2005
    Location
    In da "Show Me"
    Posts
    11,866
    Quote Originally Posted by bowhunterprime View Post
    Just played around with that link a little and it seemed pretty close. It works exactly the same as the Backcountry Bowhunting site.
    It does except the numbers seem to be closer to my bows by a few FPS...
    Dunno why but, the other site gives me a lil higher speeds.
    2010 New Breed Genetix- 60lbs. / 28.5" = 370 grains @ 282 FPS
    2012 New Breed Eclipse- 65lbs. / 28.5" = 370 grains @ 291 FPS

    2015 New Breed ??? - 65lbs/ 28.5"
    Carter's Archery- "Get Crackerized" , Starrflight FOBs- "Fletchings Only Better"

  14. #14
    Ran my numbers and using low end IBO it was 12 FPS faster and useing high end IBO it was 20 FPS fast than the last crono. Closer than others I have used -

  15. #15
    Join Date
    Mar 2009
    Location
    PA
    Posts
    4,155
    What weight on string do people use for loop? I thought around 4-5grains...is that about right?
    Do speed nock count as weight on string? As I wrote that it seems obviously yes, but not sure if you are supposed to count them.
    Thanks.

Similar Threads

  1. Backcountry speed calculator
    By heilman181 in forum General Archery Discussion
    Replies: 46
    Last Post: July 2nd, 2010, 11:16 PM
  2. How close is backcountry speed calculator
    By Eric Everson in forum General Archery Discussion
    Replies: 13
    Last Post: May 30th, 2010, 09:34 PM
  3. Arrow speed calculator
    By DJO in forum General Archery Discussion
    Replies: 1
    Last Post: December 13th, 2008, 02:19 PM
  4. Arrow speed calculator
    By apostolis in forum F.I.T.A, N.A.A., Collegiate Archery, And J.O.A.D.
    Replies: 13
    Last Post: May 3rd, 2006, 09:55 AM
  5. Arrow Speed Calculator
    By apostolis in forum General Archery Discussion
    Replies: 0
    Last Post: May 1st, 2006, 09:26 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •