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whats the formula

headzilla97headzilla97 Member Posts: 6,445
For figuring out how much kinectic energy your bow has. I had a it speed tested today at the bow shop and its shooting a disapointing 249 fps. [:p]

Comments

  • shoff14shoff14 Member Posts: 11,994 ✭✭✭
    edited November -1
    249 out of your ultrasport? correct? that aint to bad with hunting arrows.

    for KE in foot pounds, you will take KE = 1/2 mv^2

    you need to change grains to pounds though. I don't know what the conversion is, maybe there is one on the internet somewhere
  • headzilla97headzilla97 Member Posts: 6,445
    edited November -1
    Thats what Im getting out of the ultra sport. the guy at the bow shop says it wasnt to fast but he said it was delivering a hell of alot of kinetic energy by the way it sounded when it hit the video wall. all u heard was wasoooohsh whack dead deer. "the dead deer part was added by me of course"
  • surekillsurekill Member Posts: 1,926 ✭✭✭✭✭
    edited November -1
    Vel x Vel x Weight devided by 280,000 something like that, I think.
  • shoff14shoff14 Member Posts: 11,994 ✭✭✭
    edited November -1
    quote:Originally posted by headzilla97
    Thats what Im getting out of the ultra sport. the guy at the bow shop says it wasnt to fast but he said it was delivering a hell of alot of kinetic energy by the way it sounded when it hit the video wall. all u heard was wasoooohsh whack dead deer. "the dead deer part was added by me of course"


    With my axis arrows my Ultramag was shooting low 260's. When I am done shooting 3d, am will be currious to see what the new string does for my speed. I should be shooting in the 285-290 range with my GT ultralights, but I haven't ran it through a crono. My guess is its on the low end of that range or just under.
  • taco413taco413 Member Posts: 2,504 ✭✭✭✭✭
    edited November -1
    I shoot 289 with my hunting arrows and 320 with my 3-d arrows out of my outback.
  • bang250bang250 Member Posts: 8,021
    edited November -1
    quote:Originally posted by taco413
    I shoot 289 with my hunting arrows and 320 with my 3-d arrows out of my outback.


    Do I need to say of course its a Mathews![:D]
  • dcso3009dcso3009 Member Posts: 2,350 ✭✭✭✭✭
    edited November -1
    The easiest way I have found is to go to www.goldtip.com and use their KE calculator. It is always right.
  • headzilla97headzilla97 Member Posts: 6,445
    edited November -1
    so i figure 400 grain arrow 100 grain for the head 20 for nocks and inserts and 15 for the vanes sound about right that gives me 72.98 lbs of thumping power. it says its high enough for moose nice. time to blow through some deer then
  • shoff14shoff14 Member Posts: 11,994 ✭✭✭
    edited November -1
    quote:Originally posted by headzilla97
    so i figure 400 grain arrow 100 grain for the head 20 for nocks and inserts and 15 for the vanes sound about right that gives me 72.98 lbs of thumping power. it says its high enough for moose nice. time to blow through some deer then


    400 grain arrow? what are you shooting logs?
  • headzilla97headzilla97 Member Posts: 6,445
    edited November -1
    Im shooting the new easton full metal jackets at 400 grains or 9.9 grains per inch
  • taco413taco413 Member Posts: 2,504 ✭✭✭✭✭
    edited November -1
    quote:Originally posted by headzilla97
    Im shooting the new easton full metal jackets at 400 grains or 9.9 grains per inch


    Uless you meant 400 grain total ya better weigh them arrows bro because at 9.9 per inch a 30 inch raw shaft weighs 297. So add 35 for insert vanes and nock+100 broadhead, you have 435 grain arrows. My arrows weigh 420 total with 100 grain head.
  • surekillsurekill Member Posts: 1,926 ✭✭✭✭✭
    edited November -1
    You also get more speed with less junk on your string.[;)]
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