are you serious ???
09-30-2007 | 01:18 PM
#1
Thread Starter
Typical Buck
Joined: May 2007
Posts: 996
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From: Belgium
are you serious ???
ok, I have just installed my new G5 optix sight and it kicks @$$ !
but on the little piece of paper the add as a manual it gives the pin position for several different arrow speeds...
Since the chrono still has to be invented in Belgium,has anyone have an idea how fast my arrows are travelling....
I'm shootinga bowtech tomkat a 55#, DL is 28,5"
arrows are easton axis 400 spine, 29,5" length andtopped with 125gr tips, blazer vanes....
shooting a WB
need more info, just ask....
thx guys.....
Frank
Belgium
215 fps ??? are you serious ???
but on the little piece of paper the add as a manual it gives the pin position for several different arrow speeds...
Since the chrono still has to be invented in Belgium,has anyone have an idea how fast my arrows are travelling....
I'm shootinga bowtech tomkat a 55#, DL is 28,5"
arrows are easton axis 400 spine, 29,5" length andtopped with 125gr tips, blazer vanes....
shooting a WB
need more info, just ask....
thx guys.....
Frank
Belgium
215 fps ??? are you serious ???
09-30-2007 | 05:04 PM
#3
Joined: Jun 2007
Posts: 1,020
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From:
RE: are you serious ???
I'm glad you like your sight frank. I ran into the same problem as you when I was setting mine up. I opted to just go and by the chronograph and get the accurate measure of how fast my bow was shooting. I figured I would want/ need it eventually anyway. I bought a cheaper one thoughbut it works great. Im gonna use it on some of my rifles as well for some costom loads.
09-30-2007 | 05:42 PM
#4
Fork Horn
Joined: Nov 2003
Posts: 313
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From:
10-01-2007 | 07:45 AM
#6
Nontypical Buck
Joined: Feb 2003
Posts: 3,625
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From: Middletown PA United States
RE: are you serious ???
For those wanting some detail it asks for the weight of stuff on the string. FYI that includes the center serving
10-01-2007 | 10:29 AM
#8
Giant Nontypical
Joined: Dec 2004
Posts: 7,876
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From: Ohio
RE: are you serious ???
Here's something I've saved from here. Sylvan jump in if ya care too.
Thanks for the lesson!
Actually, I just noticed a dumb mistake in the explination. It's not 20.25 x 1.69 but rather it should have been 70 x 1.69 = 118.42 ft. lbs. Sorry about that!
Thanks for the lesson!
ORIGINAL: Sylvan
Actually it's pretty straight forward. If the bow is a 30" draw and an 8" brace height then the power stroke is 20 1/4 inches or 1.69 ft. If you pull 70# over the entire power stroke which gives the absolute maximum stored energy possible you get 20.25 x 1.69 = 118.42 ft/lbs of stored energy. Now if the bow transfers 100% of it's energy to the forward motion of the arrow, the amount of kinetic energy on the arrow is also 118.42 ft/lbs. Now since KE = 1/2mv^2 and we know the KE and the mass of the arrow you simply solve for the unknown v = (2KE/m)^.5 So in the example I used for a 350 grain arrow it comes out to 390.3 ft/sec and a 600 grain at 298.1 ft/sec.
Nope, not even if you could manage all that. At least not at 70# peak, 30" draw, 8" brace and 350 grain arrow.
I think that is called a firearm. that's not true either. Turtelshell is correct, you can't create energy, the best you can do is carry a bunch of it with you. That's what we do with a firearm. We carry the stored energy in chemical form in our ammunition. In archery, we carry it around in chemical form in our muscles. Unfortunately, even the strogest of us are pretty limited.
I'd love to see how you calculated it, but it matches what I have seen elsewhere
Even with a 0% letoff bow, which climbs to max poundage very quick and stays there, it MIGHT be doable, but would be unshootable.
UNLESS some new technology comes along that actually creates energy during the shot.
Actually, I just noticed a dumb mistake in the explination. It's not 20.25 x 1.69 but rather it should have been 70 x 1.69 = 118.42 ft. lbs. Sorry about that!
10-01-2007 | 12:35 PM
#9
Thread Starter
Typical Buck
Joined: May 2007
Posts: 996
Likes: 0
From: Belgium
RE: are you serious ???
ok, I had my arrows weighed at a pharmacist, so it's accurate.
They weigh 29,43 grams so that should be 452,7 grains, if I'm correct...
I'm just a dumb belgian guy, I tried the calculator link but no results came up close to be an arrowspeed.
what does IBO speed mean ???
F.
They weigh 29,43 grams so that should be 452,7 grains, if I'm correct...
I'm just a dumb belgian guy, I tried the calculator link but no results came up close to be an arrowspeed.
what does IBO speed mean ???
F.
10-01-2007 | 02:45 PM
#10
Fork Horn
Joined: Nov 2003
Posts: 313
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From:
RE: are you serious ???
From another site...
A.M.O.(Archery Manufacturing Organization) and I.B.O. (International Bowhunters Association) both have a method for testing arrow speed from bows and although they are different both can be used to compare equipment for relative speed. Both of the speed testing standards use a constant drawlength, arrow weight and bow weight to test bowspeed. These are the way the two differ.
A.M.O.
Under this standard the bow being tested will have a maximum pull weight of 60lbs. The arrow will have a grain weight of 540(9 grains of arrow weight per pound of bow weight). The draw length will be set at 30 inches. The chronograph used for measuring the speed will be placed at point blank range for testing.
I.B.O.
Under this standard the bow being tested will have a maximum pull weight of 70lbs. The arrow will have a grain weight of 350(5 grains of arrow weight per pound of bow weight). The draw length will be set at 30 inches. The chronograph used for measuring the speed will be placed at point blank range for testing.
What is important about these two speed ratings is that they are only to be used to compare bows speed tested under the same standard. They should NOT be used to tell you what you will personally shoot for speed.
For example lets take an average archer……Bill Bowshooter……..Bill has a 29 inch draw length shoots his bow at 65 lbs and shoots a 455 grain aluminum arrow. In our example neither the A.M.O. or the I.B.O standards will accurately reflect the speed of Bill’s bow. Since Bill is shooting a shorter draw than both standards, shooting an arrow that weighs 7 grains of arrow weight per pound of bow weight, and is shooting 65 lb peak weight he will shoot at a speed very different to either standard.
If we try to make some generalizations about the two different ratings we could say that the I.B.O. speed rating is much faster than most archers could achieve, and conversely the A.M.O. speed rating reflects a speed that is less than what most shooters could achieve with the same bow. If a bows I.B.O. speed rating is 320fps and its A.M.O. speed rating is 245fps that would mean the average archer would shoot that bow somewhere in the middle of that range
A.M.O.(Archery Manufacturing Organization) and I.B.O. (International Bowhunters Association) both have a method for testing arrow speed from bows and although they are different both can be used to compare equipment for relative speed. Both of the speed testing standards use a constant drawlength, arrow weight and bow weight to test bowspeed. These are the way the two differ.
A.M.O.
Under this standard the bow being tested will have a maximum pull weight of 60lbs. The arrow will have a grain weight of 540(9 grains of arrow weight per pound of bow weight). The draw length will be set at 30 inches. The chronograph used for measuring the speed will be placed at point blank range for testing.
I.B.O.
Under this standard the bow being tested will have a maximum pull weight of 70lbs. The arrow will have a grain weight of 350(5 grains of arrow weight per pound of bow weight). The draw length will be set at 30 inches. The chronograph used for measuring the speed will be placed at point blank range for testing.
What is important about these two speed ratings is that they are only to be used to compare bows speed tested under the same standard. They should NOT be used to tell you what you will personally shoot for speed.
For example lets take an average archer……Bill Bowshooter……..Bill has a 29 inch draw length shoots his bow at 65 lbs and shoots a 455 grain aluminum arrow. In our example neither the A.M.O. or the I.B.O standards will accurately reflect the speed of Bill’s bow. Since Bill is shooting a shorter draw than both standards, shooting an arrow that weighs 7 grains of arrow weight per pound of bow weight, and is shooting 65 lb peak weight he will shoot at a speed very different to either standard.
If we try to make some generalizations about the two different ratings we could say that the I.B.O. speed rating is much faster than most archers could achieve, and conversely the A.M.O. speed rating reflects a speed that is less than what most shooters could achieve with the same bow. If a bows I.B.O. speed rating is 320fps and its A.M.O. speed rating is 245fps that would mean the average archer would shoot that bow somewhere in the middle of that range
