How to Hit an Iron Shot Straight-D Plane Style

November 13th, 2009 by John Graham Leave a reply »
This blog will talk about the necessary physics required for the ball to actually fly straight. It will talk extensively about the D plane and how it explains the requirements necessary to do it.

With irons or any shot with the ball on the ground:

According to D Plane information, in order for the ball to fly straight, the normal to the clubface(the 3d location of the where the clubface is pointing) and the club path must point at the target at the hit. It is also a requirement that the ball is hit absolutely solid(right in line with the CoG). This location is basically a point and any mistake left or right will alter the shape of the club during the hit.

I mentioned in a previous blog that I am having some research done on this topic but hopefully it confirms my thoughts and trackman’s claims.

Back to the topic. Because the ball is hit with a downward angle of attack on a crisply struck iron shot, the club is still traveling downward and outward after hitting the ball until it reaches low point. Because the club travels to the right after the hit the path of the club(relative to the ball) is inside out. The impact path is right of the low point swing path.

This Picture will help you picture this is it doesn’t make sense.

D Plane Iron Impact for Straight Shot
D Plane Iron Impact for Straight Shot

It is for this reason that you must either aim or swing a little left for the ball to actually fly straight. Even though the club is swinging left, relative to the ball the club path can now point exactly at the target.

Keeping the club constant, the more down angle you have in your strike the more to the right the clubs actual path becomes. Thus, you will have to aim more left. The amount of left you aim depends on your angle of attack and what club you are using.

There’s a relationship between the shape of the swing plane and the amount the club is moving out after the strike. As the swing plane get’s more vertical the amount of out becomes less all while the amount of down is increasing. Ferris wheel would have all down and no out.

As the swing plane get’s flatter, the amount of out is increasing while the amount of down is less. A merry-go-round would have all out and no down.

Depending on a persons impact angles, it will depend on whether or not they aim/swing more left with shorter clubs or longer clubs. If someone hit all clubs with the same angle of attack, they would have to aim/swing more left with a 3 iron vs a wedge.

If the player’s angle of attack get less by more than 1 degree from wedge to 3 iron than that player would aim/swing more left with the wedge.

Most player’s will fit into this second category where they aim/swing more left with shorter irons than longer ones.

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14 comments

  1. Parshooters says:

    Is your illustration correct? With an outside to an inside swing plane your showing. At the point of impact your cutting directly across the path of the target line. There can only be one end result depending how the golf ball was struck, and that would be a cut fade to a slice.

  2. John Graham says:

    Parshooters,

    I wish the illustration used some better and more clear labels but if you keep the colors and words of the same color together it makes sense. The blue words and arrow are talking about the 3d path of the club at the strike.

    The green line is the direction of swing based on a tangent of where lowpoint is. This is not the same direction of the swing when the ball is struck. This is explained in my D plane videos on the D Plane page: http://johngrahamgolf.com/blog/the-d-plane

    To answer your question, yes the illustration is correct but it shows a 2d illustration of a 3d event so it’s hard to see correctly.

    Let me know if you have any further questions.

    JG

  3. Daniel says:

    What if I hit the ball in an upward manner. (like many many amatures) Because the lowpoint of my swing is before the ball – would that mean that I would have to aim a little more to the right of the target, to hit it “straight” at the target? Right now I hit the ball solid. Swingplane is great. Contact inside/out but I pull many shots a little. Sometimes a pull draw. I may have my head a little to closed when I hit the ball “to late”. If I just opened the clubhead a little tad I may hit it straight? Can not wait to try things out on the range.

  4. John Graham says:

    Daniel,

    Yes, that is correct. If upward strike than should aim right.

    Yes, you’re other statement is likely to be correct also.

    JG

  5. D. says:

    If this isn’t shades of —->

    “Groove Your Golf Swing My Way” by Lee Trevino,
    then I don’t know what is!!

    Ya know, for the recent Irish crew –
    the secret seems to be in the black water (Guiness).

    For the Canadian long-drive crew –
    it’s in the water & the letter ” J ” also –
    Jason, Jamie, Jeff …. and who else ?

    And for the Texas crew –
    what else? — They dug it outa the DIRT !!!

    Ben, Byron, Lloyd, Jimmy, Lee, et. al.

    Seriously – Lee dug his way out of the Dirt –
    and he did it in HIS way,
    which IS the swing as described here,

    but guided by his impressions
    of what he learned from watching Hogan practice.

    Yes ma’am, I’m proud to be a Texan ;)

  6. John Graham says:

    D,

    Not really sure what you are getting at here.

    JG

  7. Jp says:

    Hi John,

    Great work.
    Thats really helping me understand my over-cooked draw.
    Can you please expain the ball flight of the following CP and FA combo…..
    CP 3° in-out FA Square to target (3° closed to CP)
    I know the ball finishes left buy why?

    Look forward to your reply.

    JP

  8. John Graham says:

    JP,

    The ball finishes left because the face is closed to the path. This tilts the spin axis of the ball to the left which causes the ball to lift in that direction. Combine with a little gravity and you get a curve to the left.

    The main way to picture things is the ball starts close to the face and curves away from the path if it is different than the face.

    Your above example, starts just right of target and curves to the left.

    Hope that helps.

    JG

  9. Marcos says:

    Es correcto pero a mi modo de ver solo es posible pegando Con la mano derecha y el swing de un plano

  10. Jp says:

    Hi John,

    Thanks for that.

    I have a couple more questions,

    To hit a perfect drive which starts slightly right and has a slight draw finishing on target. What would the CP, FA and predicted spin axis be and why?

    Do you have or know of an accurate chart that predicts spin axis according to CP and FA for 1 or all clubs?

    Look forward to your answers.

    Regards

    JP

  11. Glen Kirk says:

    John, does D-Plane have anything to do with putting? If so, how. Does swinging the putter shaft instead of the putter head make any difference?

  12. John Graham says:

    Glen,

    D Plane does have a little to do with putting. It has the same influence in terms of idea as any shot. There are some that have upward and downward angles of attack so there will be some adjustment needed but I don’t think it is very large. I don’t think it’s large because of the fact that the plane angle is very steep so there won’t be much adjustment from reality and devices that measure path like SAM.

    JG

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