Author Topic: arrow speed and release?  (Read 8175 times)

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Offline loefflerchuck

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arrow speed and release?
« on: September 05, 2014, 04:26:22 pm »
Just tested the last sheephorn bow I finished. 35" nock to nock. 55-57# at 19.5". I know that's not a long draw for a 35" horn bow, but it has a huge amount of reflex and 19.5 feels like full draw on this one. I tested the bow with a 550 grain cedar target arrow. No special flight arrow. All shots were between 175 and 181 fps. I am pretty sure I was pushing my hand forward on release. I tried hard not to and got shots around 150fps, but I may have been recoiling. These horn sinew bows are heavy in the hand and I know that slows them a bit. at 30 yards arrows drop more in flight than from a slower early release osage bow. The questions.... 1- Can a highly reflexed high early draw weight bow have a faster arrow a few feet from release but a shorter cast?
  2-How much faster does pushing your hand forward on release send the arrow? I feel like I must have been doing it on the osage bow too.
Thanks
I'll post the bow in the horn bow page

Offline steve.b

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Re: arrow speed and release?
« Reply #1 on: September 05, 2014, 04:41:58 pm »
An arrow, as with any projectile has a kinetic energy defined only by its mass and its velocity. Given the same arrow, at the same angle in the same environment, it will always go the same distance for a given velocity.

Offline Badger

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Re: arrow speed and release?
« Reply #2 on: September 05, 2014, 04:44:34 pm »
  At that short draw length it sounds like a faulty test even if you were pushing your hand forward. I think if you calculated out the force draw curve you would find it was not storing enough energy to shoot that weight arrow that fast even at 100% efficiency. Might be  a bad test. If it was fast out of the bow it would have good cast and not fall off.

Offline loefflerchuck

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Re: arrow speed and release?
« Reply #3 on: September 05, 2014, 08:04:29 pm »
Steve- thanks. I know this only from a bullet fired from a gun.  I was looking for some variable, but when you put it that bluntly scientific the only variables are bad arrow, wrong release. Badger- The arrows were 26". I was probably overdrawing the bow at the last second. Shooting a 550 grain arrow at 60+? pounds. and underdrawing at 30 yards. The shots were 175, 152,177, 180, 148, and 180.7. Keep in mind the bow had 10" of reflex. and a non bending still reflexed handle at full draw. I was expecting 150-155fps. I didn't measure the curve till after shooting it. 28# @ 10" and 38@ 15. Goes to show unless you have a mechanical hold and release a chrono is not a good test.
 

Offline loefflerchuck

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Re: arrow speed and release?
« Reply #4 on: September 05, 2014, 08:29:12 pm »
And yes I do know that most of the mystery of bow design is gone now and a simple wood bow will shoot as well if not better than complex composites if both are made right. But not if both are 36" long.

Offline Marc St Louis

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Re: arrow speed and release?
« Reply #5 on: September 05, 2014, 08:35:10 pm »
Unless you have a shooting machine with some control over draw length the best thing to do is keep the arrow length to no more than the draw length of the bow when testing it for speed.
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Offline Del the cat

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Re: arrow speed and release?
« Reply #6 on: September 07, 2014, 04:52:11 am »
A good loose makes a huge difference and it's surprisingly hard to get a good clean consistent drawlength and loose when chrono testing.
I find if I'm too busy watching the point of the arrow to make sure I'm getting full draw I can do a poor loose.
It's easy to gain 20yards with a crisp loose and a full draw, on guy at the club was coplaining his tired old bow didn't have much cast, I had a go and got 20 yards further, same arrow :laugh:
back to the Q.
Once it's left the bow, it doesn't matter what it was shot from... same arrow at same speed and angle of elevation will go same distance.
Del
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