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  1. #1
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    Default I don't under stand how I hit that ball that low, with that much dynamic loft.

    I am a little confused by the numbers at the moment....

    Club: 7 iron, Ping I20, CFS Stiff
    Ball: Prov1
    Mat: Real Feel
    Launch Monitor: Flightscope (Indoor mode)


    Clubhead speed: 89mph
    Dynamic loft: 27*
    Angle of Attack: -3.5*
    Spin loft: 30.5
    Ball speed: 120mph
    Vertical launch: 19.1*
    Spin rates: 8500-9000

    Do these numbers make sense?

    Here is how I connect the dots....My spin loft is very big....which is underpinned by a high dynamic loft. This is what creates all that spin.

    Here is where I get confused....I don't understand how I hit that ball that low, with that much dynamic loft.

  2. #2
    ZAP
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    Senior Member ZAP's Avatar
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    Default

    It will be interesting to see the replies from the people who know a whole lot more than I do about this stuff.
    Just because I am not really afraid to be wrong I want to say impact was up a bit on the face. BUT I really have no idea
    because my experience with these things is limited at best.
    The easiest way to slay a dragon is to run up to it and shove a spear in it's throat.

  3. #3
    Senior Member Frans@France's Avatar
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    Quote Originally Posted by GeoffDickson View Post
    I am a little confused by the numbers at the moment....

    Club: 7 iron, Ping I20, CFS Stiff
    Ball: Prov1
    Mat: Real Feel
    Launch Monitor: Flightscope (Indoor mode)


    Clubhead speed: 89mph
    Dynamic loft: 27*
    Angle of Attack: -3.5*
    Spin loft: 30.5
    Ball speed: 120mph
    Vertical launch: 19.1*
    Spin rates: 8500-9000

    Do these numbers make sense?

    Here is how I connect the dots....My spin loft is very big....which is underpinned by a high dynamic loft. This is what creates all that spin.

    Here is where I get confused....I don't understand how I hit that ball that low, with that much dynamic loft.
    iron launch angle 75% Dynamic loft --> 27 * 0.75 = 20.25
    iron launch angle 25% AoA --> -3.5 * 0.25 = -0.875
    Total launch angle = 20.25 + (-0.875) = 19,375 so that 19.1* is very close.

    SpinRate [rpm] ~ 2.3-3.0 * ClubSpeed [mph] * SpinLoft [deg]

    3.0 * 89 * 30.5 = ~8143rpm
    Last edited by Frans@France; 06-05-2015 at 02:03 PM.

  4. #4

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    Default

    Clubhead speed: 89mph
    Dynamic loft: 27*
    Angle of Attack: -3.5*
    Spin loft: 30.5
    Ball speed: 120mph
    Vertical launch: 19.1*
    Spin rates: 8500-9000



    Vertical D-Plane (Spin Loft) 30.5°

    Ball should start 75% toward clubface normal (top of the D-Plane) 22.875° (of the 30.5)



    3.5° of that 22.875° is getting the ball "out of the ground."


    22.875° - 3.5° = 19.375°
    "All you have is the HUB PATH and the force and torque you apply to the club—that's the whole swing."

    Brian Manzella is Golf Digest's 37th ranked teacher in the USA and is a three time Golf Magazine Top 100 Instructor.

  5. #5
    Senior Member
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    Zap,

    Good theory....but it seems that both Frans and Brian are confirming that the numbers make sense.

    Looks like I just have to find a way of reducing the spin loft by 3-4* to get the spin rates down.

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