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^^ ATA EC Target Speed ^^

Discussion in 'Uncategorized Threads' started by Pocatello, Nov 13, 2007.

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  1. Pocatello

    Pocatello Active Member

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    My Trap & Field is at home, but I did browse it a few days ago, and think I can account for the differences. First, on the singles targets, a radar gun picks up the target a few feet out of the house, while most chronograph setups are picking up the target right in front of the machine. I would think that the fact that air resistance is in play would account for the slower reading on radar. On the doubles targets, my recollection of the recommendation for the chronograph was that the target speed be set with a single target thrown straight down range, then without changing the spring, reset the machine to throw pairs. That would account for the higher target speed compared to the radar gun, where the pairs are thrown and one target's speed measured.
     
  2. quicksand

    quicksand Guest

    From the speeds quoted in the first thread, all of the speed conversions are based on the conversion from mph to fps by using (x_mph)*(88_fps)/(60_mph)=x_fps.

    42mph=61.6pfps, 39mph=57.2fps and 67fps=45.68mph

    However, 76fps=51.82mph....big difference from 57.2mph?

    Does this help?

    Dave
     
  3. Neil Winston

    Neil Winston Well-Known Member

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    Pocatello, think adjacent over hypotenuse for both case.

    Neil
     
  4. Ray Brasser

    Ray Brasser Member

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    Radar gun readings are taken with the gun at the 16 yardline, which picks up the target as it clears the roof of the house... well after it has left the trap machine. Chronograph readings are taken right from the machine, which picks up the target speed immediately after it has left the throwing arm. Hence the difference. It's either 42mph once it's cleared the roof, or 45mph coming right off the arm. Same target.

    Radar gun readings for doubles measures the right-hand target. Since the chronograph is attached to the trap machine, and mounted to read a straightaway target as it leaves the throwing plate, it cannot read the right-hand target. So you set a very fast single straightaway target and then switch the machine over to throw doubles. It's just another way to set the main-spring tension for doubles. I'm sure you've seen a machine that screws up and only throws a single target when you're shooting doubles. It goes straightaway and very fast. It's coming off the arm going about 57mph.

    Ray
     
  5. BigM-Perazzi

    BigM-Perazzi Well-Known Member

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    "good ol' hypotenuse"

    I know him well...
     
  6. Shooting Coach

    Shooting Coach Well-Known Member

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    You are forgetting the "angle of the dangle". LOL

    I am quite happy with the chronograph. If the rear sensor is in the shade, just get out your trusty Surefire!
     
  7. Neil Winston

    Neil Winston Well-Known Member

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    Here's what's going on, Rich.

    The speeds given for the chronograph assume the use of either:

    Either: The neat ProChrono mount sold by Stuart Patenaude or

    Or: A chronograph on a tripod tilted to (about) match the flight-angle of the clay target. That means the speed indicated by the chronograph is the "speed through the air" which is not "speed over the ground" which is less.

    The radar gun measures the speed at which the target is receding, which is "speed over the ground."

    The difference between the two is: (stta) - (sotg) = sine (the angle between the two) * (stta)

    Got it? They are reading different things, but the two can be reconciled by multiplying the chronograph reading by the cosine of the angle the chronograph is set at, which gives the "adjacent" side, which is what the radar gun reads.

    Neil

    I hope this is right; I can't edit my posts anymore. Do others have this trouble?
     
  8. JBrooks

    JBrooks TS Member

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    Yeah, I can't edit your posts either, Neil.
     
  9. Ray Brasser

    Ray Brasser Member

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    Rich -

    With a radar gun at the 16 yardline, you set the machine for doubles and then measure the speed of the right-hand target... 39mph.

    With a chronograph you set the speed of a single straightaway target at 57mph and then set the machine to throw doubles.

    That, plus the angle of the dangle and the hypotenuse of the square.

    Ray
     
  10. hmb

    hmb Well-Known Member

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    This is all BS. Set the targets so they look good, then shoot them. HMB
     
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