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Wednesday, December 15, 2010

Yes, Jonny... There Could Be a Problem

Recently I mentioned an email I got from Jonny Barber a few weeks ago. Jonny ran across some posts on other sites that may indicate a problem with a post I did earlier in the year called "Understanding Your Shot Shape." I'm glad he did, because I don't know everything -- please wipe that look of shock off your face! -- and I really do appreciate it when you guys catch things that I've got wrong. (Like when Rob Roth tweeted me to let me know some of my info on Stack and Tilt was out-of-date. Thanks again, Rob.) I want people to be able to trust what they read in this blog, and sometimes things change and I don't know about it.

The post Jonny referred to focused on how shot shapes -- that is, the path your ball flies on after you hit it -- can help you figure out what you're doing during your swing. He sent me all the links he found, which I'll give to you in a minute, and asked if it would change what I said in that post.

I wish I could say "No, it doesn't change what I said." But in all honesty, I'm not sure now. I know some of it's right -- specifically the shots labelled 4, 5, and 6, which are also the way I generally recommend hitting shots. Those three assume you're swinging the club on a straight path and simply hitting the ball with a closed, square, or open face. But the other shots... According to the posts Jonny sent me, using the traditional method of hitting a push-draw (path 7 in my post) would actually produce path 4, a straight draw.

In other words, if you tried to hit a push-draw around a tree using the traditional guidance, you'd actually hit the ball directly into the tree!

What Jonny found is some really important information that's starting to get more attention... and it's not always made clear that the speaker is referring to what is now being called the "New Ball Flight Laws." You need look no farther than Sean Foley's appearance on Golf Channel's recent 12 Nights at the Academy series, where he described the "preferred shot" as one that flies straight and then "falls off" to one side or the other at the end, rather than as a fade or draw.

So I want to bring you up to speed on this paradigm shift in the golf world, about which the folks who make the TrackMan ball flight monitor say "All the scientific people in the golf industry know that this [the old beliefs about ball flight] is very wrong."

These new rules focus on one simple, unquestioned truth that I've mentioned before. In fact, I used this illustration in the post about fixing path problems that immediately followed the post mentioned earlier:
Diagram of putter and ball contact

I mentioned Dave Pelz's statement that face angle has five times the effect on ball direction that path does -- or, to put it another way, if you swing on line but your club face is aimed 6° right, the ball will actually go 5° right. (Make sure you understand that. It's not 1° more than the club path, but 1° less than the face angle. Essentially, the ball is going where the face is aimed, not where you're swinging.) Of course, that makes sense for a putt where friction eliminates most of the effect of sidespin imparted by that open face and the ball speed is fairly slow.

But suppose the ball is in the air?

This is where that "paradigm shift" is happening. The belief has always been that the ball started out in the direction of the club path, then veered off as the sidespin took effect. My own thinking was that the ball behaved as Dave says if you were swinging at a slow speed (say, for a chip or pitch), while a drive smacked at 120mph traveled along the swing path for a while before the sidespin made it turn.

The new thinking is that swing speed doesn't matter -- the ball always heads off at an angle as soon as it leaves the club face, no matter how hard you hit it. Increased speed simply makes it curve more. Now, this clearly has some serious implications for the weekend golfer -- like smacking the ball into a tree rather than around it! If these new rules are accurate, we need to understand how they affect our strategy around the course. If we're losing shots because we're aiming incorrectly, that's a relatively easy problem to fix... and a quick way to shave some strokes from our score!

Jonny sent me three links:
Since I'm mostly interested in how this affects shotmaking for weekend golfers, I'll give you some time to look over these links Jonny sent me and then I'll pick it up again tomorrow.

5 comments:

  1. Thanks for the credits in this article, Mike. I hope they are of use to my fellow subscribers. I really appreciate your desire to be correct in any information you disseminate; I think that's what has drawn me to your blog in the first place. Looking forward to tomorrow's post - perhaps finally I will have the tools to be able to shape the ball around that tree!

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  2. When the path is straight at the hole but the face is open (or closed, I assume) - the ball goes FURTHER off line ? I'm sorry - but that's just dumb. It sounds like there is a greater force of repulsion against the ball if the club path is going toward the hole. The ball won't come off the face of the putter any more or less off line no matter what direction the path is going. It's just basic physics and geometry.

    These aren't "new laws" of ball flight. Foley never pretends that he is teaching anything new, only what he has learned from other great teachers. Butch Harmon and his father have talked about the straight ball with a little fade or draw at the end. Nicklaus talked about it.

    Again - it's basic physics that work when you can hit the ball hard enough with enough spin that the fade or draw spin can't take over until the ball loses enough velocity for the air pressure to affect the ball. Most of us can't do it because we don't hit the ball hard enough.

    The same physics apply to bowling when you see a pro throw a ball that goes out straight and breaks late. You also see it with baseball pitchers who can make the ball break closer to the plate.

    While I understand the marketing aspect of calling these "new laws", they aren't new, and they won't apply to most golfers who can't strike the ball with enough force to make the ball overcome spin and air pressure.

    Of course the ball starts off in the direction in which it is struck. Again - basic geometry. The ball has no choice but to start off in that direction...which is why teaching pros try so hard to get us to square the club face at impact. Then the spin takes over as air pressure against matches up.

    You can't change the laws of physics - just draw different pictures around them.

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  3. Jonny -- You're welcome. Credit where credit is due. ;-)

    Court -- I understand your objections. Part of the reason I waited so long to do these posts was so I could get my mind wrapped around these things myself. Initially it seems to go against logic. Let me try to give you some common examples that may help you see where this comes from.

    But first, it's not so much that Foley talked about hitting it straight and letting it fall off at the end, but that he didn't use the terms "fade" or "draw" to describe those shots. That seems to be more common among the people using these "new laws."

    Here's a basic law of physics I think you're familiar with:

    Angle of incidence = angle of reflection

    Remember that one? If a ball approaches a flat surface at a 90° angle, it bounces off at a 90° angle (that is, straight back).

    If it approaches at an 80° angle to the surface (10° from vertical), it bounces off at an 80° to the surface. The angle between these two angles = 20° (10° from vertical both ways). It doesn't come in at that 80° angle, than go back out on the same line and then curve... yet that's what we've been saying happens when we hit the ball with the club.

    You used the example of a pitcher throwing a ball; I used to describe it using the trajectory of a ball out of a cannon. I think the problem is that we're comparing ball flights created in different ways. You and I are thinking in terms of a ball directly launched in a certain direction with spin, while in a golf swing the ball gets its spin and direction by bouncing off another surface. These aren't the same phenomena at all.

    With a golf ball it doesn't work out quite this neatly, probably because the ball deforms against the flat surface of the club. That extra friction has an effect -- 1/6 of the combined vertical angle of incidence/reflection, as Pelz points out.

    If you hit a shank, you see this in action. The club is moving straight ahead, but the ball doesn't start straight ahead then curve. No, it immediately shoots off at an angle -- just like a puck on an air hockey table bounces off the round "stick" you use. (Because they're both round, apparently you don't even get the benefit of a little friction from the ball flattening. It behaves just like the equation says.)

    Now, as long as your path is reasonably straight and the club face reasonably square, the ball starts out reasonably straight. (Obviously, if you open the face several degrees, you're going to get a big slice or hook. That hasn't changed, but now they say the path is bit off-line as well.) In fact, as long as you get the face reasonably square, this takes a lot of pressure off having a perfect swing path because the face angle is the most important aspect of shaping a shot.

    Where this really changes things is when you're trying to manufacture shots around things. I'll try to explain it better in the next post.

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  4. BTW, in my putting book I used the trajectory of a thrown ball to help explain how you read break on greens. That was a proper application of similar principles, so these "new rules" don't change the book. I used Pelz's explanation (which conforms to the "new rules") throughout the putting book, so you don't have to worry about changes if you've already bought it.

    And if you did buy it, thanks!

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  5. Just because Foley didn't use time honored terms like fade and draw doesn't mean he's trying to change physics.

    How is a thrown ball the same as a putt rolling on a green ? A putt is controlled by velocity and angle, like a cannonball. A thrown ball also has air resistance and spin - two things a putted ball don't have. (geez - now I have to dig into the book again) :-D

    I think I'm having a problem with this new "law" because all of the drawings used to explain the usage show the ball in motion and not the club, and things like velocity and gravity are ignored. The ball isn't reflecting because it isn't moving until it is struck.

    Hitting a ball that goes straight and drops off one way or another isn't new.

    You know as well as anybody, and better than most, that slice, fade, hook, and draw are basic principles that are caused by varying degrees of face angle (open or closed) and path.

    These "new laws" are not new - they are more like Jim McLean's 17 "new theories" that he releases when his book sales slow down. He repackages the old with a new title and people go out to buy this "new" swing, which is the same as all the others.

    The math will tell you that hitting a ball that goes straight and breaks late has more to do with the squareness of the strike and path combined with enough velocity to override the spin until the ball slows enough for the ball to turn. (unfortunately for me, I understand the principles, but can't write down the x / y / z of the puzzle.

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