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Main Boards => The Dark Continent => Topic started by: Bowlim on February 25, 2004, 02:17:00 PM
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What kind of longbow ser-ups give 105 Ft.lbs as required in SA for Elephant. Anyone have any numbers?
Let's say you had a Hill style LB at 100# what kind of velocity would such a bow give with the 1-2000gr arrows that might be required?
With a 2000 grain arrow it would seem to require about 112 fps to get 105 Ft.lbs, so what kind of bow would do that.
Also you easily get it with a standard IBO popgun with a 350 grain arrow at 305.
Hav I got the devisor right, is it 240450?
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I once tried to shoot a 2000 grain arrow from one of those high percentage let off compounds.,,,,,The bow stayed at full draw!
Regards,
Dan
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wrong divisor it's 450240
2000 grains at 150 fps = 100 ft-lb KE
350gr @305 = 72 ft-lb KE
I hate the use of KE as a measure of killing power as a .22 long rifle (90 ft-lb) has more than the 350grain arrow.
a 600 gr arrow at 175 fps has the same momentum but about half the KE of the 350 gr@305
Arrows don't kill by energy transfer they kill by blood loss, blood loss being obtained through penetration which is better measured as a function of MOMENTUM. Momentum being weight(grains)xvelocity(fps)/7000/32.2 measured as lb-ft-sec.
I have a simple spreadsheet .xls that calculates energy and momentum based on aluminum, arrow length, size etc... send me a pm and I'll send it to anyone who can use it
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Thanks guys.
Dan stop Dik Diking around with my bow and sell it!
The other issue is how fast does a 100 pound lb pump out one of those arrows, in general. to get 105 I would need over 150 fps. There has to be an easier way to kill a Jackrabbit.