Ball Flight Laws
For decades golfers have employed an incorrect understanding of why the ball flies the way it does. Science has set things straight, but many golfers remain unaware.
For decades, the PGA Teaching Manual has contained some incorrect information pertaining to a golf ball's flight. That information can be summed up as follows: "The golf ball starts on the direction of the swing path and curves back to where the clubface was aimed at impact."
Put another way, the Manual has stated that the swing path is the primary, over-riding determinant in the golf ball's initial starting direction. This information is wrong. It's been updated (slightly) within recent years, yet many golfers - famous or otherwise - and instructors - famous or otherwise - still believe it.
Mike Bennett and Andy Plummer discuss the ball flight laws on Charlie Rose on December 23, 2009.
The (Non-)Debate
The debate over the nature of a golf ball's initial direction of flight is, unfortunately for generations of golfers, a relatively recent one in golf. Only within the past few years have instruments which can measure the moment of impact in precise detail been developed, and those instruments have just recently started to see data that contradicts the decades-old (incorrect) information about what governs a golf ball's launch and flight.
When I first started playing golf, I never considered the possibility that the ball could come off the clubface in any direction other than nearly perpendicular. It seemed like common sense. Though I realized a golf ball-golf club collision was not elastic, I didn't think that a ball could be "carried" very much in the .000045 seconds the ball is compressed on the face - not enough to determine where the ball went, anyway.
Eventually I changed my mind. I'm sad to say that this change was not based on science but rather the fact that awesome instructors and world-renowned players all seemed to say the same thing. "I aim my feet where I want to start the ball and I aim my clubface where I want the ball to go, then swing along the line of my feet" they'd say. During this phase I even went so far as to point out that pool balls, collisions between which are almost as elastic as we see in real life, can be "thrown" off-line due to friction between colliding balls.
It turns out I should have trusted what I felt was common sense in the beginning: that the clubface has a much larger effect on the ball's initial path than any amount of "carrying" on the clubface by the swing path. Even though it's in another plane (vertical rather than horizontal), consider which direction a ball travels when you properly strike it with a descending blow: upward, because the loft of the clubface is pointing that way.
The Science
Though The Physics of Golf shared the information years ago (the second edition is dated 1999). The information is available elsewhere too (like here and here - thanks to John Graham at Richie3Jack's for those links). All of those works are fairly scientific, and though widely read and understood among the scientific component of the golf industry, the average golfer (and golf instructor) remained unaware.
One year ago marked a turning point in the battle of current, correct information versus "the way we've always told people to do it." In January, 2009 Trackman - makers of a popular launch monitor - publicly released information in their newsletter which shared the information in an accessible, easy to understand format. Again, while the scientific community - and a few instructors and golfers - knew this already, the Trackman newsletter was significant simply because of the easy digestibility.
From the January newsletter's article "The Secret of the Straight Shot" here (emphasis added):
The horizontal launch angle is determined by only two parameters, the club path and the face angle. As a rule of thumb, the horizontal launch angle is 15% determined by the club path and 85% determined by the face angle. For example, assume a club path of +6.7 degrees (6.7 degrees inside-out for a right-handed player) and a face angle of -1 degree (1 degree closed for a right-handed player). This would result in a horizontal launch angle of 0 degrees (ball starting at the target line).
In other words, you are saying that the face angle is by far the most dominating factor for the initial direction of the ball. Is this not in direct contradiction with the "Ball Flight Laws"?
Yes it is. According to the "old" ball flight laws, the initial direction of the ball (HLA) is 100% dictated by the club path. All the scientific people in the golf industry know that this is wrong, yet still a lot of PGA professionals use the incorrect 'old' ball flight laws in teaching. And many PGA organizations around the world do not teach their apprentice and member professionals according to the 'true' ball flight laws.
Fredrik Tuxen, Trackman January 2009 Newsletter
The science gets a bit headier beyond that - the downward angle of attack and its effect on the "true swing path" is considered - but the key piece is fairly clear: 85% of the ball's initial direction is determined by the clubface angle and only 15% of the ball flight is determined by the path.
These numbers vary little. You might think long drivers, who compress the bejeezus out of the golf ball, flip the ratio, but they don't even get out of the 80s, reaching roughly an 80/20 ratio at best. In fact, the ratio is much more easily pushed in the other direction: a putter, swung at a relatively slow swing speed, can generate ratios approaching nearly 100% clubface oriented.
So How'd They Do It?
During a recent telecast at the Sony Open, Nick Faldo - a six-time major winner and one of the best golfers in the history of the game - shared this advice, captured in the screen shot you see here:
Nick Faldo in the process of giving advice that's clearly based on the old - and very much wrong - ball flight laws.
So how on earth did Nick Faldo shape the ball - and break par let alone win six majors - if he had the wrong information? The power of his subconscious mind. Science tells us that if Nick Faldo set up with his clubface at the tree in the picture above and his shoulders aimed just to the right at the escape route, he would either:
- return his clubface to the same angle as it was at address and swing along his shoulder line.
- subconsciously return the clubface open to (right of) where it was at address and swing even more inside-out than his shoulder alignment.
Shot #1 is what Nick said you should do. If Nick followed his own advice and performed #1, he'd hit the ball right into the tree. If Nick was on a golf course with no trees, the ball would start just right of the target and hook well left of it.
If Nick subconsciously manipulated both the clubface angle and the swing path to produce #2, he'd start the ball to the right of the tree and hook it back towards the target - the shot he wants to play.
What are you going to believe - science or Nick Faldo's feel? Even Nick Faldo's subconscious mind didn't trust his feel, favoring the reality of science (or the instincts of having been a great golfer for a long time) instead!
Ball Flight Laws and Their Effects on Teaching
Consider a student who's hitting a straight-fade or a straight-slice. A straight-fade starts straight at the target and then, for a right-handed golfer, peels off to the right.
If this golfer visits an instructor who believes the old ball flight laws, he's going to have the student trying to square up the clubface. After all, the instructor believes that the ball starts on the swing path, and then reacts based on the face. So the instructor will believe that the student's swing path is fine and that his clubface is open.
This instructor will spend a lot of time trying to get the student to "square up the club at impact" when he's already doing so! Best case scenario? The student starts hitting pulls. Hey, at least they won't slice…
The reality is that this student needs to work on his swing path. His clubface is already awfully close to square at impact - the ball is starting at the target. It's purely his outside-in swing path that's causing the fades or slices.
During the Bob Hope Classic, Michael Breed used what appeared to be the old ball flight laws in helping actor Michael Peña. Peña was hitting a pull-fade - not a bad shot if you can hit it repeatedly because the fade works back to the target - and Breed gave him the advice to swing more from the inside (which is fine if you want to hit a draw) and to release the clubface (oof).
The result? A nasty duck-hook. Peña's clubface was already closed - that's why he was hitting a pull-fade. If he was to start swinging more from the inside, he'd need to open the clubface, not close it more aggressively. Breed's tip only really "makes sense" if you believe the old ball flight laws.
True Ball Flight Laws
One thing is not up for debate and never has been: a ball curves based on the clubface angle at impact relative to the swing path. A closed clubface relative to the swing path always draws/hooks and an open clubface relative to the swing path always fades/slices:
With arrows representing the swing path, the balls in these images will fade/slice, travel straight, or draw/hook from top to bottom.
You can combine these three basic clubface positions with the three basic swing paths:
The combination of the two triplets result in a combination of nine possible ball flights:
This diagram demonstrates every possible shape a well-struck golf ball (we're not talking about tops and shanks here, people!) can have. The true ball flight laws tell us that a pull (B) is a combination of an over-the-top (outside-in) move with a closed clubface that matches the amount of outside-in swing path.
The true ball flight laws tell us that a push-draw (G) is a result of an open clubface with a swing path that's more inside-out than the clubface is open. For example, if the clubface is 3° open at impact but the swing path is 6° inside-out, the ball will start right (open clubface relative to the target) and curve left (closed clubface relative to the swing path).
How would the old ball flight laws tell us to hit a push-draw (G)? They'd tell us to swing in-to-out while keeping the clubface square to the target. Basically, they'd tell us to hit shot D. Ouch.
In the chart above you'll notice that the straight shots - B, E, and H - are italicized. These shots are each hit with a clubface square to the swing path and are the only shots on which the "old" and "true" ball flight laws agree.
I've also marked in bold the "good" shots: a pull-fade, a straight shot, and a push-draw. The straight shot is good for obvious reasons, but as you can see the pull-fade (C) and the push-draw (G) work because, though they start away from the target, they curve towards the target.
(Side note: That's not to say the other shots aren't good. Lee Trevino and Jack Nicklaus both played a push-fade. On my graph, that's shot (I), the farthest right. How could they win majors or even break par hitting that shot? Take the whole graph above and rotate it counter-clockwise (to the left). Imagine Lee Trevino: he aims his feet and swings his club 20° left, pushes the ball 10° right, and lets his fade take the ball the remaining 10° back to the target. That's how shot (I) can win a major - when you play for it.)
Where Do we Go from Here?
If you're like most golfers, having toiled under the old, incorrect ball flight laws, you may feel energized reading this. Perhaps you've been battling a persistent slice by trying to "release the club." It's a common suggestion, but if your ball starts at the target before slicing, you should have gathered that you need to work on your swing path, not your clubface angle at impact. That's even more important if the ball starts left before slicing two fairways over.
Armed with the proper knowledge, you're going to be amazed at how often you hear advice based on the old, incorrect ball flight laws, and from whom you hear it. Magazines, television, respected teachers, and accomplished players will all dish out advice that's potentially damaging to your golf game because it's based on the "old" laws.
The ball flight doesn't lie. Now that you know how to read it, you can spend your time working on the right things.
Photo Credits: Black and White Illustrations: Unknown Origin; Color Diagram, Screen Capture © The Sand Trap .com; Video © Golf Channel.
Sensational article. Make this a sticky on the front page. Required reading for anyone who plays or plays with others. Very concise and easy to understand.
As a high handicapper I struggle with squaring the face at address. The soles of most drivers want to roll the face out of square if you ground them before gripping, so I must focus on my grip being square to the club face so the club face can be square to the target at a square address. While alignment markings on heads are considered less than elegant I think we would benefit from some help in squaring the face now that we understand how important it is.
An excellent well written piece. Very good work. You'll still find among instructors that know the correct ball flight disagreements between how to help that straight fader. Some will still say face first, then rotate the whole thing around so it points at the target. The debate comes from the golfers perception. Does the golfer feel/know face relative to path or face relative to target. Depending on an instructors belief, they will attack the issue differently.
The other thing coming down the pike is the fact that the ball flight does lie unless there is centered contact. Trackman has discovered that gear effect occurs in irons also.
Oh, I don't think that's so much a lie. I think - though perhaps I shouldn't make the assumption - that most people know the ball flight laws only work with good contact. They don't apply when you top or shank the ball, or toe it badly, of course. Maybe it needs to be said, though, so thanks for mentioning it.
I also think every decent player has hit a shot with an iron (typically off the toe I'd imagine) that draws a little more than you'd expect. So I have no doubt that the gear effect exists with an iron.
I'm curious how Draw biased clubs play into this. If you're hitting a pull slice or pull fade, won't a draw biased driver cause you to hit a bigger pull/ or perhaps just a straight pull?
Draw biased clubs move the center of gravity towards the heel. This does a few things: it makes it a bit easier to rotate the clubface to get it square at impact, and it moves the sweet spot so that anything hit on the center of the clubface acts like a toe-hit - giving you a bit of draw spin from the gear effect.
But, to answer your question, if you come over the top, you could hit pulls or just a ball that doesn't slice quite as much due to the slight offsetting draw spin from the gear effect (or a combination of both).
So we could say that the only time the club face should be pointing towards the target is when we intend to hit a straight shot.
So, feel golfers have got a big advantage over the ones following the "old rules'. I knew it. Hmm. Anyway, is it possible to hit the same shot with 2 completely different set ups if theyre the exact opposite? like an open stance and in to out SP with an open club face compared to a closed stance and out to in SP and closed face? Id give it all up to just hit it straight consistently.
Great article. The Breed footage was a good find!
I made myself a chart almost identical to your 'Ball Flights for Right Handed Golfers' graphic just a couple weeks ago. Having only been clued-in to the 'new' science of face vs path, I needed something visual to help me keep it straight.
I second the comment that this post be made sticky on the front page of the site. It'll certainly find a place in my bookmarks.
"The true ball flight laws tell us that a push-draw (G) is a result of an open clubface with a swing path that's more inside-out than the clubface is open. For example, if the clubface is 3° open at impact but the swing path is 6° inside-out, the ball will start right (open clubface relative to the target) and curve left (closed clubface relative to the swing path)."
Great article Erik! I am also delighted I took your advice and purchased the S&T Swing book. I have already read it three times since Christmas and immediately put the method in play. In just four rounds I have already experienced a huge difference in my ball striking. However, there is one thing I just cannot seem to comprehend and that's the quote above. I just don't get it! Is there a visual to demonstrate what you are explaining above as perhaps seeing it will make it clear? Thanks again for taking the time to put this article together. I am already spreading the word...
The shot that most emphasises the path versus angle theory has to be the bunker shot, open stance, out to in swing with club face laid open but pointing at the target with a small allowance for spin on landing.
I like the article and agree with it. One point I didn't see made was that the degree of carry must alter relative to ball compression? A squash ball would stick to the club face much longer than a marble for example. I would think the marble would always travel in the direction of the club face and not curve?
Good information. Where does clubhead rotation fit into the laws? You could have a square clubface at impact which is rotating closed. What effect does this rotation have on the ball flight?
Uh Guys.......... this is more than just "good information". This is a "Game Changer" for all of us who have learned the wrong ball flight rules. Essentially this gives us the Right Information to use in order to diagnosis our swing flaws; it also explains to me why I cannot create Draws / Fades on command even when I am "Certain" that I executed according to the old rules....For example - I hit the tree consistently when trying the Faldo example shot! Bombastic Information! Now, I must get back to work transforming my Pull, Pull Fade into a nice Push/Draw!.
While I am not sure I totally understand all that is written here, it did inspire me to play with my swing a bit today. No matter what I do I tend to square the club face at impact - fades and draws are awkward for me. Today I decided to play with my feet to try and get more consistency figuring the rules might be what is messing up things. On long irons/driver I dropped my rear foot back slightly, after aligning to the target - not away and back, but just slightly back. The result was excellent. Then on short irons I dropped the front foot back, after alignment. The ball flight and contact was great, getting through the swing was smoother. The crazy thing is the divots were a aiming little left or right, but the ball was straight on the target line as referenced by my shoulders.
I guess the default line "well if the pros don't (or do) do it then it must be the law." Everyone repeats what they are taught, peer pressure, industry, misinformation all create limitations that may not be necessary.
The push draw? Let me see if I can use the existing red/green/blue thing to exaggerate the point(s).
Let's assume your target is the Green E at the top of the graphic. To hit a push-draw, you'd align your clubface towards Blue H and contact the ball when the clubhead was swinging along a path pointing towards Blue I. You should get a shot like "G" - one that starts right of the target (which is roughly where the clubface is pointing) and draws back (because the swing path is more in-to-out than the face, or the face is closed relative to the swing path).
In the book the "in to out" part is hitting on what Mike and Andy like to call the "back side of the circle." So you may be able to do this from a square stance pointing at Green E.
Also, remember that the graphic exaggerates things so it's easier to read. A 5-yard draw doesn't require a clubface/club path difference of 20 or 30°. Realistically, most people who shape the ball a small amount look pretty square - 3° is a small angle.
Yes, that's true. You can see it with some of the foam practice balls out there, too. But golf balls all fit within an awfully small range. After all, the rule applies almost as well to a quarter swing with a wedge as it does with a full driver swing by Jason Zuback, so… that's why 85% is the rule of thumb, with it more likely to be 90/10 than 80/20.
Almost none. 45 millionths of a second is not a lot of time. We do see a change in behavior with the gear effect, but if memory serves the clubface is contacting the ball for something like five to ten times longer when you hit the ball well off-center (because while the clubhead is twisting out of the way it's still touching the ball).
Great article. I remember seeing the ball flight charts a few years ago. I use the rules to analyze my swing both at the range and on the course. What I didn't know was the 85-15 ratio.
I know that a slice/fade is from swing outside-in because it puts side spin on the ball, while a push is from having the club face open because that is the direction on which the ball starts. And the opposite, of course, for the hook/draw and the pull.
And if I practiced more, my swing would be more consistent so that the theory that I know would become the reality for which I strive.
Fantastic article, after a couple of readings it makes complete sense. Like Phil I had a problem understanding how an open clubface can create a draw but then I remembered all the scratches on the bottom of my driver seem to suggest the face is open at the time it touches the tee/turf and my usual shape is a push draw - How could this be - then the light switch went on.
To phil just think of it like this; if the swing plane is more in to out (in degrees) than the clubface is open (as per example) it will draw - just believe. My son wisely says the path to happiness is not asking questions!!
Thanks Chris, all help on this matter is greatly appreciated. I'm a golf instructor and my world has just been turned upside down! I needed to have it crystal clear before standing in front of a student again. In the space of a couple of weeks, I have gone from the conventional swing to Stack & Tilt and now this! Fortunately, the students are being very understanding, it's the other instructors that are not too happy and prefer to remain in the dark.
Phil, if you are an instructor, I'd count you among the good ones even without seeing you. Too many instructors these days are unwilling to accept that they may be wrong or that there may be a better way of doing things. Kudos to you for being open to new information.
Thanks for your kind words, Erik. I'm always learning and studying the swing so I can help improve my students' games. Although English, I am based in Madrid and nobody (including pros, both playing and teaching) appears to know the correct ball flight laws. And I only found out via your website with your articles on Stack & Tilt. Why hasn't a bigger deal been made out of these new findings?! As embarrassing as it may be teaching the wrong things for 10, 20, 30+ years, surely any self-respecting teaching pro would switch over immediately to avoid total humiliation.
Keep up the great work on the website, you have no competition as far as I'm concerned and I check in daily to make sure I'm abreast of the very latest developments. And thank God I do!
According to the old way. To hit a fade you align your body towards the left of the target and aim the face towards theh target, this would produce an open face in relation with the body, and that would be the reason of the "high fade".
According to the right way, to hit a fade you wouldnt need to open the face and aim at the target, you aim the face and body left and swing inside out.
So what would be the reason of the "high" fade?
As I think it,in theory, a good executed fade should fly as high as a good draw, because we are not closing or opening the face.
Any comment on this?
Yes - a fade that started at the target (or the tree that was in the way, perhaps) and then faded to the right of the target.
No, you've misread something along the way. Bear in mind that when people say "stance" what they truly mean is "swing path" because, give or take, golfers make impact pretty much on the same line as their stance line.
So the correct way is this: aim your stance well left, aim the clubface a bit left, and swing. The clubface is open relative to the swing path so it will fade, but the ball starts left of the target so it has the room to fade.
I am 100% clear on the angle of the clubface (the ball starts in the direction the clubface is pointing), however how can you tell the swing path from the curve of the ball thereafter? Take for e.g. a ball starting right and spinning further right. It is clear the clubface is open at impact. No problems there. But it could spin further right due to an out-to-in swing path or due to the clubface being open relative to an in-to-out swing path. Is that correct or am I getting confused again?
It could. All you can tell from the spin is the swing path relative to the clubface. If the clubface is 10° open but you swing from the inside 5°, that's still a push-fade (or a push-slice).
But even then, that ball won't fade/slice as much as a ball that's hit with a clubface that's still 10° open but with a swing path that's square to the target or 5° from the outside. Obviously those shots will curve much, much more.
Hi Erik,
Thank you for a fantastic article! My brother and I have been swinging golf clubs since before we could walk, but just recently found 'The Sand Trap'. Every article is very well written and you can be sure we'll both be coming back to check out new articles on a regular basis.
Please keep up the great work!
My only complaint is that I live in Michigan, so I have to wait a couple of more months before I can try this out! I've always hit a consistent draw, but whenever I tried to hit a fade, it would turn into a push-fade. This really clears everything up, so I'll stop trying to use just my hands to hit the shot. Thanks!
Is this thinking correct? Please comment on swingpath for each of these. Having trouble associating your clubfaces and swinpaths above to get the results on the colored chart. Thanks.
Clubface
Target Swingpath
closed closed ----------> pull draw
closed square ----------> pull
closed open ----------> pull fade
square closed ----------> strght draw
square square ----------> straight
square closed ----------> strght fade
open closed ----------> push draw
open square ----------> push
open open ----------> push fade
I am having trouble visualizing what the swingpath is doing on each of these. So all shots that start left of the where you are aiming your body result from over the top swings? So, if I am over the top more than the clubface is closed (relative to target) the net result is a pull fade?(makes sense because of the spin generated) And if I am over the top less than how much the clubface is closed (relative to the target) the net result is the pull hook? (unless the clubface ends up being square to the swingpath) Thanks.
Yes, you've got it.
The ball will always spin based on the club's path relative to the clubface. You can swing out-to-in, for example, 3°. If the clubface is square to the target, you'll fade the ball. If it's 3° closed, it's a straight pull. If it's closed 6°, it's a pull-draw.
I think you've got it. If you get confused, keep things simple: the ball starts where the clubface is aimed (essentially), and curves based on how the club came into the ball along that line.
This video makes it very clear:
http://www.playbettergolfblog.com/2009/11/understanding-the-new-ball-flight-laws/
Glad I read this. I was fitted for new irons last year, which was my first "lesson" in 25 years. The pro pointed out that I was setting up with my club face several degrees open (about five). And he told me with my new, slightly flatter irons, I wouldn't need to set the clubface so open because the flatter lie should straighten out my hook.
Well, they did take a little of the curve off my ball, but I found that I couldn't hit a consistent push-draw unless I set the club open to the target line. Once I went back to opening up the clubface, my push-draw ball flight became much more consistent.
I love it. I get all tingly just thinking about the day Manzella rolls out the ME PLANE!
Just think, he just invented the game of golf 5 years ago.!
If my memory serves me, didn't Jack Nicklaus' book Golf My Way describe the way to hit fades and draws in a similar manner to Faldo's video lesson (i.e., pointing the club face at the target and swinging along a different path)? And how many current amateurs (and pros?) learned how to play using Jack's book as a guide? Amazing to think how many trees were hit attempting to escape from trouble using the old view of cause and effect (and we just thought we didn't execute!).
Yes, he points that in the very beggining of his book. The idea is that you
aim your body to the left part of the hole, an the clubhead toward the target, that way is an intelligent move he says. because if the ball goes straight it ends up left to the hole on the green, if it fade nicely it goes directly to the hole, and if fades too much it will end up slighty right of the hole.
Funny how he was well known by the high fade when he actually didn't know how he was doing it.