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Spin Drift

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Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: January/06/2009 at 08:00
Bigdaddy0381 View Drop Down
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I have read that at a short distance under 600 yards you can't tell if it's a problem or not. I also know the its the bullet that causes it. What do you guys know about it. I have found very little on it. Is it a big problem? I don't shoot out far enough for me to worry about it but I would like to know more about it.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: January/06/2009 at 08:42
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Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: January/06/2009 at 08:42
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( I thought spin drift was something that flies off the ocean waves..........)    Eat and Drink
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: January/06/2009 at 08:55
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Thanks Dale. I'm going to read up on it more. I'm just trying to figure out what the cause of it is bullet out of weight / round. Or is it just the RPM's of the projectile or other atmospheric conditions. Or is it different in a more humid place or dose it stay about the same in a more dry condition. This is very interesting to me.

 

Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: January/06/2009 at 09:51
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the rotational moment of interia has been broken , so there is a small vector force that realigns the bullet in space-- rpm is given way to much topic-- say a bullet is shot from a barrel with a 1 in 12 twist it still must travel 12 inchs to turn 1 time. so even at 1000 yds or 3000 ft the bullet will only complete 3000 revolutions. even if the rpm appears to be astronomical on paper. however the second moment has the same value even though the velocity has dropped of substantially, giving it more importance than it would during the first part of the ballistic curve.

Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: January/06/2009 at 09:55
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X = 180 Y = 90 (X+Pyro)+(Y-Pyro) = ?

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Dale, you need to speak in working man terms. I get confused in all the technical jargon.  Bow
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: January/06/2009 at 09:58
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dont you just love it trigger!! i dont really understand it much either, but you gotta remember that dale is has scientific background, and he is eons ahead of our feeble minds!
no offense dale, but you are to damn smart for us!!
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: January/06/2009 at 09:59
Dale Clifford View Drop Down
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somewhat similar-- think of a curve ball thrown by a pitcher, it is useful because the ball doesn't start curving until it has slowed down substantially , hooks and slices in golf are somewhat similar.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: January/06/2009 at 10:00
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really, can you explain the golf thing a little to me i have a nasty tendency to hit the ball to the right off the tee.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: January/06/2009 at 10:00
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this is the easy stuff.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: January/06/2009 at 10:01
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Originally posted by Dale Clifford Dale Clifford wrote:

the rotational moment of interia has been broken , so there is a small vector force that realigns the bullet in space-- rpm is given way to much topic-- say a bullet is shot from a barrel with a 1 in 12 twist it still must travel 12 inchs to turn 1 time. so even at 1000 yds or 3000 ft the bullet will only complete 3000 revolutions. even if the rpm appears to be astronomical on paper. however the second moment has the same value even though the velocity has dropped of substantially, giving it more importance than it would during the first part of the ballistic curve.

 

I see as the bullet slows it is more likely to have "spin drift" but the twist will remain the same. So the slower RPM of the bullet will show flaws in the weight/ roundness of the projectile.

 

Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: January/06/2009 at 10:02
Dale Clifford View Drop Down
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your rotating your right hand back and opening the face of club to the ball, as the ball makes contact to the club it slides of the face which imparts spin, (in a slice)
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: January/06/2009 at 10:02
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X = 180 Y = 90 (X+Pyro)+(Y-Pyro) = ?

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Originally posted by Dale Clifford Dale Clifford wrote:

this is the easy stuff.
 
Thanks Dale. However now I really feel stupid
 
This is the easy stuff.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: January/06/2009 at 10:03
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why doesnt it work like a driveshaft?? if its out of balance from a shot u-joint the faster it spins the more it vibrates, where as if it spinning slowly it doesnt? to much stuff that i dont understand.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: January/06/2009 at 10:04
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you should have him explain bio engineering stuff
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: January/06/2009 at 10:04
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no the bullet doesn't lose rpm only forward momentum. -- so the effect of the rpm has more differential effect on the trajectory than it did at a higher velocity, because it has more time to work on the bullet,
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: January/06/2009 at 10:07
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Originally posted by pyro6999 pyro6999 wrote:

why doesnt it work like a driveshaft?? if its out of balance from a shot u-joint the faster it spins the more it vibrates, where as if it spinning slowly it doesnt? to much stuff that i dont understand.
it does somewhat, but the bullet isn't really deformed so your analogy becomes incorrect at that point.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: January/06/2009 at 10:09
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i know its not apples to apples, but i thought it was an intresting theory!
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: January/06/2009 at 23:46
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Dale,

Being the brain that you are, could you explain this spin drift and balance stuff in relation to a flying helicopter?  Maybe then they could understand it.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: January/07/2009 at 14:30
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Helo, helicopters do not fly, they beat the air into submission. That's why they don't understand.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: January/07/2009 at 14:44
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Dale, here is another analogy: when taking off in a propeller driven aircraft you have to apply more right rudder to counter the effects of the torque from the spinning propeller. As the aircraft picks up speed you need less rudder to keep it moving in a straight line.
In theory the torque will always move the aircraft to the left but is countered by the rudder being canted to keep the aircraft straight at operational speeds.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: January/07/2009 at 18:21
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( Bigdaddy has GOT to be using a spell checker............)      Coffee
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: January/07/2009 at 18:27
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Truly FASCINATING!..........    I'm so lost?
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: January/07/2009 at 19:18
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Originally posted by BeltFed BeltFed wrote:

Dale, here is another analogy: when taking off in a propeller driven aircraft you have to apply more right rudder to counter the effects of the torque from the spinning propeller. As the aircraft picks up speed you need less rudder to keep it moving in a straight line.
In theory the torque will always move the aircraft to the left but is countered by the rudder being canted to keep the aircraft straight at operational speeds.


On some helicopters you can see the same affect.  At a hover it takes a lot more left pedal (anti-torque) to stabilize the helicopter.  As you move into forward flight the airflow over the tail fin helps stabilize the helicopter and less pedal (or anti-torque) is needed.  The RPM is still the same, but the speed is stabilizing things, where slower speeds creates less stability.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: January/07/2009 at 19:19
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Originally posted by BeltFed BeltFed wrote:

Helo, helicopters do not fly, they beat the air into submission. That's why they don't understand.


I think they just vibrate so bad that the ground rejects them.
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