Opinion & Analysis

Clark: Understanding The D Plane

Published

14 years ago

Jun 17, 2012

There is an ancient proverb which says: “May you live in interesting times.”

In golf instruction these are THE most interesting times. Like any other discipline we have come of age thanks to technology; things like radar and 3D capture systems have taken much of the guesswork out and replaced it with immutable laws of physics. We started out in the “dark ages” of golf instruction using only our eyes. We, the instructors, would watch the flight of the golf ball and infer from it what the golf club might have done to cause a shot. We helped some people but there was still something missing. Then came the video era and we got at least a better look at what the body was doing in the swing, but a certain ambiguity still surrounded impact. Now we have come pretty much full circle to the enlightenment era of Doppler Radar. This article deals with some of the new findings and how the data debunks certain long held myths.

If you are a fan of this or any of the other popular golf forums, you most certainly have heard of something called the D Plane. The D Plane was popularized by Theodore Jorgenson in his seminal work “The Physics of Golf” back in 1999. He used the term D Plane because it “described” the collision of the golf club and golf ball. His findings were somewhat controversial because he took issue with prevailing ball flight and impact theories; namely the initial direction of the golf ball and the role of the club face, path and angle of attack at impact. So let’s look into the D Plane and explain it in practical terms that you can understand and use to help your game.

D Plane definition — The wedge shaped plane between two three-dimensional directions:

The club head direction, which is a combination of the path AND the angle of attack; and
The club face orientation, which is a combination of dynamic loft and face angle.

Interpretation: The golf club swings up, down, reaches the very bottom of its arc, and travels back up. Because we all swing on an inclined plane (somewhere between 45 and 65 degrees) when the club is traveling down it is NOT swinging at our target (assuming we are aimed parallel left of our target line). It is in fact swinging to the right of the target. And when the club is swinging up, it is actually swinging to the left of the target (stand up and try it.) The only point in the entire arc of the swing where the golf club is swinging at our aim point is at the very bottom of the swing arc, what we call low point.

This might be a better way to understand it: If the golf club was swung on an entirely vertical plane (90 degrees) then ALL points in the swing, up and down, would be swinging at the target. This is physically impossible on an incline. So with that in mind, we learn something critical about the “true path: of the swing. It is not simply directional. It is a combination of the up and down in conjunction with the left and right. This is why video can NEVER show the true path. Video is a 2-dimensional representation of a 3-dimensional motion! The knowledge of this, thanks to Trackman, FlightScope, etc., has all but revolutionized teaching.

Here’s why…

Technically you cannot hit a straight shot with an in-to-in path aimed at the target. The more DOWN you swing, the more you need to aim or swing left. The more UP you swing (driver), the more you need to swing or aim right. It’s that simple. Because remember: If you hit the golf ball BEFORE you reach low point, which of course you should on any shot on the ground, at impact your path is in-to-out. This will give you a club face that is closed RELATIVE to the path, and curve the golf ball to the left (for a right handed player.) And if you hit a golf shot AFTER low point you are swinging to the left. This gives you a face that is open RELATIVE to the path. It is not the position of the club face relative to the target but RELATIVE TO THE PATH that gives the shot its shape. This explains quite categorically how a square face draw/hook or a square face fade/slice can be hit. Very often you can look at high speed video, see the face DEAD SQUARE to the target, and watch the ball curve. Maddening!

Finally all of the information above is based on hitting the golf ball on the center of the face (Which is rare by the way). Toe hits, heel hits, high or low on the face contact, twist the golf club. Here’s where the beauty of modern golf clubs comes into play. We have what is known as horizontal gear effect, which actually helps straighten the flight of the golf ball, when hit off center. When the toe of the golf club strikes the ball, the clubface opens, and when the heel of the club strikes the ball, the face actually closes. But … here is the where the integrated help I referred to comes into play: The toe hits have hook spin and the heel hits have fade spin. So … on a toe hit the flight actually starts to the right (open face) and curving a little back to the left. And on a heel hit, we get flight beginning to the left (closed face) and curving back to the right. So here we actually observe open face hooks and closed face slices! A real true draw is hit with a slightly OPEN face with a path from the inside. And a true fade is hit with a slightly closed face and a path well outside that face. Horizontal gear effect is more built more into woods than irons, but irons have it as well. And you think this is isn’t a crazy game!

It’s difficult to understand in words but there are plenty of D Plane videos on the net, and if you like I’ll do one here on the GOLFWRX forum as well.

Feel free to send a swing video to my Facebook page and I will do my best to give you my feedback.

Click here for more discussion in the ‘Instruction & Academy” forum.

Opinion & Analysis

5 Things We Learned: Thursday at the PGA Championship

Published

2 weeks ago

May 15, 2026

Ronald Montesano

Aronimink is not a storied club, but when Donald Ross himself proclaimed it to be as good as he can design and build, one had to take notice. Jay Sigel was the pre-eminent male amateur golfer from the mid-1970s to the mid-1990s. He might have called any number of Philadelphia clubs home, but he chose Aronimink. It served him well. Gary Player won a PGA Championship here in 1962, and was followed by the 1993 winner … nobody. Aronimink gave that event away to Inverness, for reasons of which it is certainly not proud. So be it. We had to wait sixty-four years for the PGA to return to Newtown Square, but here we are. Aronimink has been neo-restored by Gil Hanse and team, to return Ross features with an eye toward defense against the dark arts, errrr, high-tech equipment.

Day one saw Rory McIlroy and Bryson DeChambeau dig big holes, to the tune of plus-four and plus-six, respectively. Since the first-round lead will be minus-three at worst, many shots will need to be made up for the power couple to reach contention. By nightfall, seven golfers held the day-one lead at three-under par 67. Shots and sticks caught our attention, and we are proud to present Five Things We Learned on Tech Thursday at the 2026 PGA Championship. Thanks to InsideTourGolfer, Today’s Golfer, and GolfWRX for initial equipment research.

First, meet Min Woo Lee

Min Woo Lee, aka Dr. Chipinski, has once again thrust himself into the conversation of Can he, will he, when will he? Lee has so much talent, wins not nearly as often as we believe that he should, and has no major near-misses (much less titles) on his wiki. The young Aussie is getting older and wiser, but is he able to avoid the scarring that holds the older and wiser back from breaking through? Philadelphia offers another opportunity. Min Woo signed for five birdies and two bogeys on day one, and grabbed a share of the opening-day lead at Aronimink. Winners transcend history and the moment, and Lee will need that sort of ascent to lift the Wannamaker on Sunday.

Second, meet Aldrich Potgeiter

The young South African golfer can rip driver with the best of them. Aronimink tips out at nearly 7400 yards, but beyond the fairway bunkers that ensnare only the mortals, Potgeiter can take his chances with wedge from the rough. On Thursday, he spent plenty of time in the spinach. Like Popeye, he used his muscles to gouge and thrash and dig his way out. Six birdies against three bogeys on the card brought AP in a three deep.

Third, meet Martin Kaymer

Not a major event takes place without a where’s he been throwback moment. We know that Martin Kaymer left the PGA and DP World tours for LIV golf, but the two-time (US Open and PGA) major winner has a lifetime exemption into at least one major event, and he seizes the opportunity each May. Kaymer joined the six-seven brigade with four birdies and a solitary bogey on day one. Kaymer was never a long hitter, and the years are kind to no golfer. The German champion will need to uncork every bottle of guile and strategy in his cabinet to remain in contention. For today, though, he occupies a rung on the ladder of Tour Tech.

Fourth, meet Scottie Scheffler

Let’s see, he’s the defending champion at the PGA, and he found his way back to the top tier with five birdies against two bogeys. To be a favorite and then play up to that stature and expectation is quite difficult. Just ask Rory, Bryson, and some of the other pre-tournament heartthrobs. Scheffler’s game is complete, and to knock him off the OWGR #1 pedestal, one needs to defeat him at the majors. Aronimink is the sort of course that fits Scheffler’s game. Better yet, it unfits the game of many of his challengers. Don’t expect Scheffler to go away anytime soon. Come Sunday, he’ll be around.

Fifth, meet Stephan Jaeger

Clocking in for the unheralded players shift are Ryo Hisatsune and Stephan Jaeger. Hisatsune logged seven birdies on day one, but gave most of them back with four bogeys. Still, he’s tied at the top for a time. Jaeger pitched five birdies against two bogeys, including a run of three consecutive, from holes four through six. Odds are that one of the two will hang around through 36 holes. Odds also suggest that both will be gone by Saturday evening. Still, the PGA Championship has historically been the major most likely to be won by an under-known. Both Hisatsune and Jaeger feature on that list, so good luck, lads!

Club Junkie

Club Junkie’s Titleist GTS driver fitting results!

Published

2 weeks ago

May 14, 2026

Brian Knudson

On this episode of the Club Junkie Podcast, I head to the Titleist Performance Institute for a full driver fitting with the new Titleist GTS lineup. We dive into the fitting process, talk about what made the biggest difference in performance, and break down how the different GTS heads and shaft combinations compare on the launch monitor. If you are thinking about a new driver setup for this season, there is a lot to take away from this one.

I also get into Brooks Koepka and the gear setup he brought to the PGA Championship, including the putters that caught my eye during the week. There are some interesting equipment trends showing up at the highest level right now and we break down what stands out.

To wrap things up, I talk about reshafting a few wedges, what I learned during the process, and swapping an adaptor onto a new shaft for another build project in the shop. A gear packed episode from start to finish for anyone who loves golf equipment and club building.

Follow Club Junkie everywhere:
Instagram: https://www.instagram.com/clubjunkiepod/
X: https://x.com/ClubJunkiePod
TikTok: https://www.tiktok.com/@clubjunkiepod
Threads: https://www.threads.com/@clubjunkiepod

Club Junkie

Club Junkie WITB, week 16: New Titleist GTS woods!

Published

2 weeks ago

May 14, 2026

Brian Knudson

Excited for this week’s WITB as we get to add the new Titleist GTS woods to the bag! I was fit at Titleist’s TPI facility in Oceanside California a few weeks ago and my new clubs just showed up. I am also adding a cool set of irons that I built last year some wild custom wedges into a new golf bag. Speaking of the bag I have a new Ghost Anyday Black Ops stand bag that I will be using on my Motocaddy Remote M7 electric cart.

Driver: Titleist GTS3 (11 degrees @ 10.25)
Shaft: Fujikura Ventus Red 6s

3-wood: Titleist GT1 3Tour (14.5 degrees)
Shaft: Graphite Design Tour AD CQ-7s

5-wood: Titleist GTS (18 degrees)
Shaft: Fujikura Ventus Red 7s

9-wood: Titleist GT1 (24 degress)
Shaft: Fujikura Ventus Red 7s

Irons: Bettinardi CB24 (5-PW)
Shafts: KBS C-Taper Lite 110 stiff

Wedge: TaylorMade MG5 (50-09 SB)
Shaft: Mitsubishi MMT 125 Stiff

Wedge: TaylorMade MG5 (56-12 SB)
Shaft: Mitsubishi MMT 125 Stiff

Wedge: TaylorMade MG5 (60-08 LB)
Shaft: Mitsubishi MMT 125 Stiff

Putter: Dan Carraher ZT Proto

Ball: Callaway Chrome Tour

Bag: Ghost Anyday Black Ops Stand Bag