Would you Trade Speed for..
05-28-2006, 08:25 PM
#2
Join Date: Jan 2004
Location: Eureka, MO
Posts: 3,703
RE: Would you Trade Speed for..
The difference in the two arrows is prolly not much. The GT's are going to be lighter if you are in the 55/75 spine range but penetration will probably go down. You'll pick up some speed but lose some weight so I think they will perform about the same. I shoot GT XT hunters and am very happy with them but the super slims are excellent arrows as well.
05-28-2006, 08:29 PM
#3
Boone & Crockett
Join Date: Oct 1998
Location: Hughesville, PA USA
Posts: 18,322
RE: Would you Trade Speed for..
Your question/answer doesn't make sense. If your bow remains at the same weight and draw length your arrow will not increase KE...ever unless extremes are taken.
A bow has X amount of KE....going to a heavier arrow will slow your bow down however the KE will remain relatively exactly the same. Going to a lighter arrow will increase the speed of the bow but again, the arrow will retain relatively exactly the same KE. Your trading weight for speed but not for KE.
The only way KE will change is if you go to a heavier arrow and increase either draw weight or length.
I'm refering to relatively the same KE ie within a ftlb or 2 or less but not enough to be that concerned.
A bow has X amount of KE....going to a heavier arrow will slow your bow down however the KE will remain relatively exactly the same. Going to a lighter arrow will increase the speed of the bow but again, the arrow will retain relatively exactly the same KE. Your trading weight for speed but not for KE.
The only way KE will change is if you go to a heavier arrow and increase either draw weight or length.
I'm refering to relatively the same KE ie within a ftlb or 2 or less but not enough to be that concerned.
05-28-2006, 08:58 PM
#5
Thread Starter
Join Date: Sep 2005
Location:
Posts: 41
RE: Would you Trade Speed for..
well the reason I asked is cause it looks like I'll lose 8 lbs of KE by going to GT Pros
GT Pros 64 ft-lbs of Energy
A/C Super Slims 72 ft-lbs of Energy
Using this Formula:
and that's where that number comes from.
GT Pros 64 ft-lbs of Energy
A/C Super Slims 72 ft-lbs of Energy
Using this Formula:
Weight of an arrow; W=mg
where m=mass, g=gravitational constant 32.22 ft/s^2
where m=mass, g=gravitational constant 32.22 ft/s^2
Mass of an arrow ; m=W/g
but W is measure in grains, convert grains to lbs 1 lb = 7000 grn
but W is measure in grains, convert grains to lbs 1 lb = 7000 grn
m = W(grn)(1lb/7000grn)/32.22 ft/s^2
The basic relationship being used in all calculations is;
Kinetic Energy(KE) = 1/2 * m * v^2 (or one-half times mass(of arrow) times velocity squared)
Normally people just say KE = arrow weight divided by 451,000 something or other times velocity squared, here's where it comes from;
KE = 1/2 X (arrow weight in grains) X (1 lb/7000grn) X v^2 X (1/32.22)
2 X 7000 X 32.22 = 451,080 grn-ft/s^2
and that's where that number comes from.
05-28-2006, 09:06 PM
#6
Join Date: Mar 2004
Location:
Posts: 13,082
RE: Would you Trade Speed for..
Uhhhhh.........I have NO idea what all that foreign language is you have typed there....[&:]
KE= speed x speed x weight / 450,240. You can get pretty close by "guessing" but there's only one way to know for sure. Shoot through a chrono. I'll bet your KE will vary by only a couple pounds. So the question is......Would YOU trade for it??
KE= speed x speed x weight / 450,240. You can get pretty close by "guessing" but there's only one way to know for sure. Shoot through a chrono. I'll bet your KE will vary by only a couple pounds. So the question is......Would YOU trade for it??
05-28-2006, 09:13 PM
#7
Thread Starter
Join Date: Sep 2005
Location:
Posts: 41
RE: Would you Trade Speed for..
Ahhhh never mind I actually found the error of my calculation after I wrote it out.....[8D]
It actually is not as bad as it came out the first time ..lol
See some times just posting all this info down on paper instead of doing it in your head helps a ton
See In that calculation I didnt allow the drop in speed switching to the Heavier A/C Slim, thus in a perfect world shooting an arrow at the exact speed it would be a larger diffrence because you are moving more mass at a faster speed.
It actually is not as bad as it came out the first time ..lol
See some times just posting all this info down on paper instead of doing it in your head helps a ton
See In that calculation I didnt allow the drop in speed switching to the Heavier A/C Slim, thus in a perfect world shooting an arrow at the exact speed it would be a larger diffrence because you are moving more mass at a faster speed.
