Definitive Club Face Angle & Swing Path on Ball Flight Thread

[Williamevanl]

Yup. Now let's stick to the topic, please. If you want to talk about something else, please start a different thread.

It seems really important to me. I hit balls 4 days a week and I've never had lessons. If the ball starts straight and slices right and I think that its because of the club face angle then I would just strengthen my grip. Having played golf for a few years now I know/think thats not the solution.

Thinking that b) his clubface was pointing five degrees left of the target and his swing path was 10 degrees inside-to-out (15 relative to the clubface) made me think that I should shut the face down more which resulted in a pulled shot. 'swing path determining initial path etc...' But thinking that a) his clubface was 10 degrees right and his swing path 25 degrees inside-to-out (15 relative to the clubface) allowed me to actually learn how to work a ball. 'As in I actually fixed my swing and came ~25 degrees from the inside and I can hit that buttery push draw that I could never hit before. The club face feels open to the target line but my swing is so far from the inside that the ball is fairly straight with a little right to left. I believe, and I could be wrong here, that the ball's ending behavior with a sound setup and solid fundamentals is primarily determined by the swing path and yes its the hardest to fix.

[CalBoomer]

My first try at engaging this thread was unsuccessful. I'm going to take a Mulligan.

1. My golf authority = 0
2. No data
3. Understanding of physics and geometry = very good
4. Read both Trackman articles in detail

For the moment, let's leave the target line (TL) out of the discussion and concentrate on the clubface angle (CFA), the swing path (SP), and the starting line of the ball (SL). Assume that the club strikes the ball with an open CFA angle of 10* relative to SP. In a perfectly elastic collision (no friction and no deformation of either object), the ball would indeed fly at 10* to the right of the target line. In other words, its SL would be totally determined by the CFA relative to the SP.

In the real world, especially golf, perfectly elastic collisions do not exist. The golf ball deforms substantially and there is friction between the club face and ball. This friction and ball deformation have the effect of "dragging" the ball along the SP, resulting in a net angle for SL of something less than 10* relative to the SP. Determining how much the angle would change would require precise physical measurements, a la Trackman.

What could one conclude from this "thought" experiment?

1. The ball would never fly with the SL along the SP unless the club-face angle were 0.

2. Simple analysis of the physics involved, strongly supports the general Trackman argument. But only hard data could determine the real world "net" angle for the SL relative to the SP given a specific CFA angle, and would obviously differ from club to club, especially in regard to loft.

[iacas]

In other words, its SL would be totally determined by the CFA relative to the SP.

And according to the most recent data, that's what happens. CFA is something like 85% responsible (give or take) for the starting line (SL) of the golf ball.

Hey, I used to think the way you did - after first thinking the way I do now four to six years ago or so.

This friction and ball deformation have the effect of "dragging" the ball along the SP, resulting in a net angle for SL of something less than 10* relative to the SP.

Yeah, more like 8.6°.

If all the golf ball did was "get dragged" along, it wouldn't spin, or wouldn't spin nearly as much as it does. It still tends to rebound awfully close to perpendicular to the clubface. The more deformation you get (lower lofts, more speed, less glancing angles) the more the ball is carried and the further below 85% you go, but you apparently never really get below about 75%, and that's with some long-drive guys hitting 6° drivers. Again, according to the science - empirical data - we now seem to have.

Determining how much the angle would change would require precise physical measurements, a la Trackman.

So if you read the Trackman articles, you know where I'm getting that 85% number from (or was it 86% or something? Anyway...).

2. Simple analysis of the physics involved, strongly supports the general Trackman argument.

You lose me there. You seem to argue for the ball being carried by the SP, while the Trackman article says that's bunk and that CFA is by far the primary determinant.

[CalBoomer]

In using the term "dragged," I was being colloquial. In effect, the compression of the ball and friction with the clubface (which imparts the spin) will cause the SL of the ball to travel along a vector somewhere between the SP vector of the club and the 10* angle of the club face. The Trackman data claim that the SL vector is much closer to the clubface angle (CFA) than to the original SP vector--as you said, an 8.5* angle. So the empirical data suggest that reality is closer to a perfectly elastic collision than one might have anticipated. I would suspect, however, that that data more likely came from a driver than a pitching wedge, because the greater the friction with the clubface, the more the SL angle should be shifted toward the SP vector and away from the CFA vector.

[iacas]

In using the term "dragged," I was being colloquial. In effect, the compression of the ball and friction with the clubface (which imparts the spin) will cause the SL of the ball to travel along a vector somewhere between the SP vector of the club and the 10* angle of the club face. The Trackman data claim that the SL vector is much closer to the clubface angle (CFA) than to the original SP vector--as you said, an 8.5* angle. So the empirical data suggest that reality is closer to a perfectly elastic collision than one might have anticipated. I would suspect, however, that that data more likely came from a driver than a pitching wedge, because the greater the friction with the clubface, the more the SL angle should be shifted toward the SP vector and away from the CFA vector.

And a driver creates way more compression and "friction" than a pitching wedge... so now you believe clubface angle is by far the primary determinant.

Don't confuse backspin with evidence of "friction." Hit down on your driver as steeply as you hit down on your wedge and you'll get an awful lot of spin. The more glancing the blow the more the ball will roll on the face (in any direction), which is why we see backspin AND sidespin... not significant changes to the starting line.

[14ledo81]

How about the effect swing speed could have? If we have agreed that ball compression has the tendency to carry the ball slightly along the SP, then swing speed should make a difference. Slower swing speed equals less compression, which would mean the CFA is even more dominant when swinging slower, especially when pitching and chipping.

[The Recreational Golfer]

Re David_Wedzik's question 1: Where can we see the Trackman data on this? Conventional thinking is that path determines initial direction and clubface angle determines curve (or not) thereafter.

[uttexas]

Here's some trackman data on Adam Scott http://www.butchharmondubai.com/blog...2f2%2fAdam.pdf

[iacas]

Averages

Swing Path (SP): 3.0 Horizontal Swing Plane (HSP): 0.7 Club Face Angle (CFA): 2.8 Horiz. Launch Angle (HLA): 2.8 Spin Axis (SA): -2.9 Note: The "club path" is in three dimensions. For horizontal launch angle, the comparative part of "in to out" or "out to in" is horizontal swing plane (or path). This page explains it more: http://thebrandingengine.com/WAMUser...DataReport.pdf Horizontal swing path measures deviation from a straight line down the target line. Positive is in-to-out, negative is out-to-in. Face angle measures just that - positive is open at impact, negative is closed relative to the target line. Spin axis is negative for draws. Individual Results

None

[The Recreational Golfer]

This issue was addressed over 40 years ago in the book The Search for the Perfect Swing. On page 124 the question is asked, “Which is more important in determining the direction the ball starts off on: the direction in which the clubface is pointing or the direction of clubhead travel?”

Answering, it says, “A ball will always leave a clubface somewhere between these directions; but usually nearer the direction along which the clubface is pointing than that along which is being swung.”

On page 134 where putting is dicussed, it says, “Experiments show that the direction on which the ball sets off is governed very largely by where the face of the putter is pointing, and only a little by the direction in which the head of the putter is moving.”

Regarding the full swing, I don't believe an individual golfer can honestly say one way or the other because of the high speeds involved and exceedingly short time span in which the event in question occurs. Lab testing and high-speed photography would be required.

We might be fooled by with putting, though, when a putt misses right and we clearly pushed the putter head. When that happens, though, I would surmise the putter face went right, too, so the putt was squarely struck and went where the putterface was pointed.

To throw in some random facts, SPS says that impact lasts one-half millisecond on a driver swing and the ball is in contact with the club for three-quarters of an inch of travel. An approach putt is in contact with the ball half a millisecond also, and three-quarters of a millisecond for a tap-in, or a fortieth of an inch of its travel.

[iacas]

This issue was addressed over 40 years ago in the book The Search for the Perfect Swing.

I realize that, but at the same time, it was also "addressed" over 40 years ago by the PGA manual, and still seems to be a topic of discussion and confusion.

[The Recreational Golfer]

It's clear that when you putt, the angle of the clubface determines the direction the ball will go to a much greater degree than the club path. Dave Pelz did that research. It's also clear that when you pitch with the face of your wedge open, the ball will go off to the right of your swing path. That's why you have to open your stance as well if you want the ball to straight toward something.

Club face angle has a greater affect on the direction the ball leaves the club than club path does regardless of what kind of stroke we are making, unless it can be shown that at higher club speeds, different physics apply.

Pelz researched it in the lab, the Golf Society of Great Britain researched it in the lab. Both came to the same conclusion. What is the basis of the PGA Manual's conclusions? If it isn't testing where all variables are strictly controlled while one variable is isolated for change and the results recorded in an unmistakable way, I would be skeptical of whatever they had to say on the subject.

[JaY_B]

I thought it was all about extremes, if the clubface is square to the target line and the clubhead is moving from inside to out then the ball will start right and draw back but if the clubface was fairly closed to the target with the same swing path then the ball would start left regardless?

[The Recreational Golfer]

The physics of the matter says it's all about angles. In your first example, say the club path is in direction X and the clubface is closed to that path by four degrees. The ball will start of in a direction between X and four degrees left of that but closer to four degrees left than to X, because clubface angle has a greater affect on the initial direction of the ball than club path does.

The more the clubface is closed relative to direction X the more to the left the ball will start, so your second example would be true depending on the size of the angles.

It is not true that the ball would start along direction X regardless of clubface angle then swing one way or the other--that clubface angle has NO effect at the start. The truth is that clubface angle does affect the initial path of the ball and to a greater degree than club path.

Open the face of your wedge and swing along your body line, and the ball starts off to the right doesn't it?

The way to make this easier to understand this all is to not think at all about where you intend the club to go, but where it actually is going and the relation of the clubface to that path. Physics doesn't deal with intention.

[iacas]

The physics of the matter says it's all about angles. In your first example, say the club path is in direction X and the clubface is closed to that path by four degrees. The ball will start of in a direction between X and four degrees left of that but closer to four degrees left than to X, because clubface angle has a greater affect on the initial direction of the ball than club path does.

You're stating as fact the very thing which this thread discusses.

[shortgamewiz]

I've been having interesting experiences related to this topic recently. There is a new concept of impact now (or maybe it's not that new and there must be plenty of folks here that probably know it well) that has the hands way ahead of the ball with the clubface rotated wide open, at impact... at least thats how it looks. JB Holmes talks about doing this with his coach who is a TGM guy I think --saw the vid on youtube. I've also been checking out the Taly Williams site that I've become quite keen about, where he talks about this impact position extensively and how to achieve it. Anyway, so the first time I tried this approach, I was quite surprised that I didn't hit one slice-- in fact the shots were absolutely the straightest things I ever hit, with a slight draw that started slightly to the right. It was almost spooky how consistent and straight they went. Wild stuff. At least to me. And I've hit plenty of draws before, infact my usual ball path is right to left, but those things had a completely different character and shape to them. They were kindof like.. dead straight. Solid - straight. uhh..*struggle to describe*.. anyway... I can't help thinking.. hey.. this must be the RIGHT way to do it. So now I'm rethinking everything. According to Taly Williams since the clubhead path is curved and your clubhead is lagging, at a hundred miles per hour, and your body center is at that point facing at an angle significantly rotated left at impact, then this "open" position is actually square to the path. But it feels sooo friggin wierd..

[iacas]

Some more handy links:

http://books.google.com/books?id=MnC60GN8PJ4C&pg;=PA535
http://books.google.com/books?id=bmVk8BkOLH4C&pg;=PA490

Thanks to Richie3Jack's place for these.