Arc of Approach
 

Hi everyone,
I'm a newbie here and want to first say thank you, thank you, thank you. This site is the best golf forum on the internet. The obvious reason is it is based on TGM but as important are the friendly members and their posts.

I have (actually I should say attempted) to read and understand Homer's book. And as many others before me, have strugled in understanding all of the contents and nuances.

I do have my first question. Homer states that the Arc of Approach should always be negative (down toward the ball.) He does not differentiate between irons or woods that I saw. Everything I have read however regarding the driver says that the Arc of Approach should be positive, that being, hitting on the up stroke to minimize spin and therefore increase distance.

In the January 2008 issue of Golf Magazine, Charlie King wrote an instructional article titled, "The Easy Way to Add 20 Yards." What caught my eye was a table of data that showed driving distances of varying clubhead speeds and angles of attack with the driver.

What are everyone's feeling regarding this issue?

Thanks,
Wali

Trackman is showing that for extra distance, you need to hit very slightly up on the driver. Attempting to hit up with the driver can be tricky though. My best guess is to just move the ball up further with the driver.



3JACK

Welcome guys. Great question too. Obviously the long drive guys hit up on it to lessen the spin and increase the launch angle. On the other hand Tiger can often be seen to tee a driver kind of low and take it before low point.. Maybe he is not trying to maximize distance here but is hitting a shot of some kind.....probably the "lets just get it in the friggin fairway" shot.

Agreed on how to hit it on the up swing, tee it in front of low point.

This is a good question for our pros. Im thinking it is a special purposes long bomb shot not necessarily an every drive kind of deal but I could be wrong. Certainly the club fitting guys are always trying to get us to tee it high and hit it way up there. I personally dont like that as much as taking it around low point but with a 10.5 degree driver.

ob

2-J-2 is pretty clear......The ball should always be struck prior to the low point of the Downstroke, even when using a Driver,... This statement is what seems to contradict trackman and launch monitor data and seems to be a popular topic.

I've been wondering, is it possible to align the machine such that you can contact the ball just prior to low point but still have the clubhead be travelling "up" relative to the ground? In other words, can the machine be tilted such that the plane line is not horizontal (parallel to the ground) but rather rising in the direction of the target (sort of like a virtual uphill lie). The ball would be launched at a greater launch angle relative to the ground but still adhering to the words from 2-J-2 above. This tilt would not be possible for a ball played off the ground as the club would plow into the ground before the ball, but when teed up, there is some room to drop below the level of the ball.

I don't know if these words make any sense or not, nor do I know if its even geometrically possible. But I would like to table the thought.

3Putt

Swing Down Plane and Hit Up . . . Or Not.
 

Thanks to Homer Kelley, the Geometry of Low Point (2-N-0) has become more and more mainstream. The 'best' instructors -- read 'Top 100' in the popular magazines -- more and more make reference to it. Similarly, the Long Drive Guys benefit from its wisdom, i.e., post-Low Point Impact means less Backspin.

So, is Backspin the bad guy?

No.

Per 2-C-0, Backspin is not Compression Leakage; instead, it is a valuable component of Ball Control.

Years ago, Lee Trevino waxed eloquent on this point. Demonstrating, he arched his left wrist into an Impact condition and leaned the clubshaft forward. Said he:

"Give me a club with loft . . . I'll take it off!"

:mrgreen:

Swinging up and open faced drivers
 

Yoda and others. What do you think of my theory of the connection between trackman and launch monitor data showing more distance swinging up, and the growing demand of open faced drivers?

Interesting point Thom

You got me thinking about hinging and hitting up. Would angled hinging be superior to horizontal for the this? Or perhaps a clubface adjustment to a slightly more open position in fix?

ob

Just another point. Homer wrote his original book in 1969 (40-years ago). Although TGM is based on the laws of physics and circular dynamics, there have been many changes to the equipment. Metal drivers were introduced in the late 70s early 80s I believe. I think the first metal wood win was with a Taylor Made (could be wrong though). Today's exotic metals with unique characteristics are the norm. Every manufacturer has there "spin" on why their design is better but they all have one thing in common. Manufacturers have designed these heads to minimize spin and therefore increase distance. To minimize spin the ball must be hit on the upswing and the contact point (sweet spot) is above the center of the face.

If anyone has been fitted for a driver with a launch monitor, the data speaks for itself. Last year I went to Callaway's performance center here in my home town and was fitted for their FT-5 driver. I took several swings with my existing Big Bertha and was told that I had a negative attack angle and was getting too much backspin on the ball. I said that's the way I have always hit my irons and they said that is what I am supposed to do with irons. However with a driver, the manufacturers want you to have a positive attack angle to decrease spin and increase distance.

Could the new technology of the driver face warrant a different ball position?

Would luv to hear from a club manufacturer on this one.

Wali

Be weary of advice from club manufacturers. Think of irons as down and drivers as level. You are not a long drive guy. On the golf course, straight is long.

Track man and all the advanced science devices are wonderful for fitting as far as finding the optimal club and the optimal swing. What it doesn't consider is that you still have to find your bad ones. It's NOT all science. I'm sticking with Homer Kelley.

Kevin

Henny Great stuff.

How do the guys on tour adjust for an into the wind drive?

Some fitters would have us still hit up on it, the reasoning being the higher launch and the reduced spin into the wind.

Im old school and tee it slightly lower into the wind but am wondering about the extra spin this would add into the wind.

Thanks
ob

Hit down dammit!
 

Indeed, the data provided by Launch monitors and club manufacturers is to take into account.

However, the concept of hitting up with the driver is misleading the average golfer who understands it as an encouragement to scoop under the ball with the driver in an attempt to lift the ball in the air...:naughty:

But if you know your lessons and mix to your advantage:

• ball position relative to low point,
• the aiming point concept,
• the launch monitor's data,

you should end up with the ball positioned an inch up plane after low point and touch the ball on your clubhead's up travel.

Now, it is vital that you must not forget to direct your thrust DOWN even AFTER LOW POINT.
Low point is not the end of the DOWN because you should still have some right arm to extend untill the end of the follow through (both arms straight).

This is the only way to stay TGM correct (geometrically correct) and use the launch monitor's data to your advantage.

Yodeli your on fire and lighting up the whole board, keep going while your hot.

So the thrust, as directed through the pressure points 1,2,3 (4 being up in the arm/chest) is On Plane, Forward, Down, Out and towards the plane line after impact, after low point and until.......................when? Both arms straight? The club switches ends? The club points at the extension of the plane line on the horizon line?

Or am I getting mixed up, thrust being a straight line?

ob

Lotsa sidespin
 

I think that distance is less a concern into the wind than the imperative to stay on the fairway...
In such a case, launch monitor's data is useless because no guy on tour will risk seing the ball catch the wind and go anywhere.

A few months ago I saw Villegas hit low powerfull boring drives with lotsa draw.

I think that the "boring lotsa draw" is very important because the spin energy is not say 100% backspin but rather 50% backspin/50% sidespin.

100% backspin straight shot risks the ball to "lift" up (venturi effect) against the wind.
The 50%back/50%side directs the venturi effect sideways and the ball won't climb in the air where it risks to meet even stronger wind resistance.
Ice on the cake, the "lotsa draw" will help regain yardage on the fairway roll.

So, my bet would be a ball back, closed face, closed stance setup to execute a powerfull low boring shot with lotsa draw and lots a (side)spin!

Thermonuclear lava
 

You're right OB, I'm boilling like termonuclear lava :twisted: !
that's because I'm pasionnate about Golf and happy to help back others as they did with me on Lynn's wonderfull site! :salut:

Back to your question:
1-L-15: The club starts up and in after low point but the thrust continues Down Plane during the Follow-Through

6-C-2-A "...the Accumulators will not be released by this action until the Right Elbow can straighten (ie: both arms straight, the end of the follow through). Even then the Clubhead Lag is still maintained -- it has NO Release point."

Also, check this video (Hitting vs Swinging) on the Gallery and listen what Lynn says starting at 1:14.
This should answer your question about when the swich ends.

The direction of your Thrust and the direction your shaft is pointing are two separate things.
The more important is to put you mind on directing your thrust (ie: where is my PP#3 travelling?).
Your clubshaft/clubhead will follow all the time!
However, it is interesting to monitor where the clubshaft points at to check if the clubshaft lies on plane... (if not, it tells you that you're not moving PP#3 on the right track...... try again, look, look, look!)

As a result, the clubshaft should always points at the base of the plane line (either the clubhead or the but of the grip) to the horizon line.
Remember that after both arms straight, your left arm will swivel, allowing the shaft to "replane", the but end of the grip pointing now at the base of the plane.

But all this is a byproduct of sensing PP#3 :

• going down plane (aiming point) - yes, thrust is a straight line - spear a fish.
  OR
• tracing the base of the plane - tracing a straight line from the horizon to the horizon.

Two way to direct the thrust - two intentions - but funnilly enough, same travel of the hands! Your preference.

Hi Wally,

Just a technical note. Arc of Approach was used by Homer to describe the path of the club head as it appears to trace an arc on the ground. The angle that it descends on the Plane is the Angle of Attack. At least that is how I understand the terminology.

Thank you Yodeli. Ill save this to my LBG file. It is very, very good.

I love your "the direction of your Thrust and the shaft is pointing are two seperate things" and the "spear a fish" of the aiming point thrust.

As I work through 12-3, I realize I have issues around the geometry, delivery lines, arc/angle of approach etc, etc. I will figure this three dimensional puzzle out, damn it and the fairways of this land shall feel my wrath.

TGM is tough but thanks to people like you......... I will survive!


http://www.youtube.com/watch?v=Xv6lHwWwO3w

Sorry man its late here in Canada.

Salut mon ami

ob

Venturi? As in Ken Venturi?
 

Yodeli

Venturi? As in Ken Venturi? Surely you're not referring to the aerodynamic venturi effect (a decrease in static pressure_ which occurs in contracting duct flows situations).... which a golf ball is not... ever. Its the Magnus effect... circulation which causes lift just like on an airplane wing that you want to be talking about. And as far as the relative magnitudes are concerned... a 50 - 50 side v. back spin ratio would put the lift vector off a a 45 degree angle, in which case the ball would neither fly very far nor stay on the of the fairway... unless a gale just so happened to be blowing perpendicular the the fairway (at just the right speed) in which case the tournament would be postponed anyway.

Low boring flight on windy days? i.e. tee it low and de-loft accordingly .... yes ... there is less wind (aka graidient) close to earth's surface... makes sense in that situation but attempting to put a "counterbalancin" "english" side-spin on? That's messing with disaster imhop. Did Ken Venturi do that?

Don't know much about homer's theory but... Aerodynamics says this:

Spin is a function of "Dynamic loft" and clubhead speed. Dynamic loft equals face angle + increase in face angle due to shaft bend. A 10.5 on a soft flex shaft swung fast may infact be a 15 deg dynamic loft.

For each swing speed (which via smash factor becomes a ball speed) and spin (it can and does vary ball to ball) there is an optimal launch angle for maximum carry. That's what we're striving for... optimum launch angle for given ball speed and spin.

Long drivers have figured out they need to minimize backspin (which , while providing useful lift via the Magnus effect, also increases form drag) and maximize launch angle. They use low lofted drivers on stiff shafts (to minimize spin) and hit up on it (to maximize launch angle). Bubba hits up 5 degrees when "going for it". But we mere mortal should keep in mind they're he-men who swing really fast and have much practice under their belt. Most people (men included) should tee off with their 3 wood (15 degrees of loft or more.

Geometry of the stroke
 

Lol, :laughing9
Merci OB,!

If you need help with your geometry, I setup a blog with two articles you might find interesting.
These are reminders of the geometry of the stroke: you already know the concepts but seing pictures sometimes helps lighting some bulbs in the brain.
The drawings are a bit dramatic but exageration helps in seeing normaly unseen things!
Geometry of the stroke face-on: this one helps seing low point and will tell you a lot about what to do to achieve correct ball/turf contact.
Geometry of the stroke top-view: this one is my favorite - rarely seen - the best way to understand the requirement to hit out on the ball!
This drawing will tell you a lot about ball position relative to clubhead travel:
Say you play a wedge with a ball back in the stance. This drawing shows that your clubhead must still do a lot of travel out after impact in order to execute a perfect stroke.
On the contrary, with a driver and a ball positionned at low point, the ball is also at the outmost point of the clubhead travel. The clubhead will travel immediately in after impact.

Intuitively, we think about those two cats as two different strokes but it's really the same and unique geometric principle!

Isn't TGM cool? :thumleft:

You are right and it should not go unoticed!
 

Metal drivers were introduced in the late 70s early 80s I believe. I think the first metal wood win was with a Taylor Made (could be wrong though).
You are right! Taylor Made in deed. Fellow Okie, Ron Streck. 1981, or 1982 Houston Open. Great guy...great lag!

Thank you Yodeli

I like your blog, the graphics are very very good.

The "Hitter vs Swinger" Blakebuster free video you directed to me is great to see again. I also took another look at "Dowels and Wedges" and I finally have it figured out!

Two world class golf instruction videos that are available here for the cost of admission. Which is free. I had watched these videos many times before but now after some time the return to them helped to fill in so many blank spots in my knowledge. This stuff is precise but the ball demands precision doesnt it.

http://www.lynnblakegolf.com/gallery...ry.php?cat=517

I had confused/mixed the direction of thrust and the on plan motion of the pressure points or clubhead!!! No longer. I had not understood tracing to be the visual equivalent of the on plane path of the hands.

Cant wait to hit some balls tomorrow with the thrust going all the way down to both arms straight, full extension of the right arm. I know from experience there is magic to be had by getting to both arm straight but the direction of the thrust was confusing for me. Thank you.

Here are some jpegs from the "Dowels and Wedges" video


Spear the fish
ob

Edit; to get this back on track. So there is a lot of downward thrust required post low point, post impact, indeed all the way to both arms straight. For the person attempting the high launch low spin driver with the ball tee'd in front of low point..........the clubhead will be coming up and in (better take this in into account when addressing the ball) but the thrust is very much down and so there is no feeling of hitting up.

Brilliant post OB.
You got it 100% right! :salut:

Forever young
 

Hi no_mind_golfer.

I'm not an aeronautics engineer but I think Homer knew a bit about aerodynamics...
I was just using chapter "2-B TRAJECTORY CONTROL" as a reference. I might be wrong but Homer is talking about the Venturi Effect in there: "A speeding, spinning ball is subject to the Venturi Effect, meaning that an increase in the velocity of a flow of air decreases its cross-sectional pressure" etc...

Anyway, I've never heard about the Magnus effect and you could be right as well.
However, we all agree that a draw is giving the longest possible shot with a lower trajectory than a fade for example.
So it makes sense to use such a shot (a "punched drawing ball") while the wind is facing you (I never sait sideways).
But you are right; the configuration of the fairway should comply with such a shot: Dogleg left or wide enough to accommodate for the right to left ball flight.

Now, the only Ken Venturi effect I found doesn't relate to Trajectory Control but can keep you forever young :laughing1
http://www.youtube.com/watch?v=rSbDMqPI2Ng

Its the Magnus effect....
 

Hi Yodeli

click->Magnus Effect

I can assure you I'm right and Homer is wrong. He wasn't either an aerodynamicist or an engineer. He was QC technician who did the best he could given limited knowledge. If you're going to teach it... you have an obligation to get it right IMOP. Glad I could be of some help.

what is in a name?
 

Did Homer describe the phenomenon correctly, but misname it?

Yodeli,
I have one question regarding the links you provided for the face-on and top view swings.

In both cases it looks like the "Impact" point is in front of the right shoulder? Since everyone has discussed ball position as being no further back than between the feet (center).

The low-point being in front of the left shoulder (right hander).

Thanks,
Wali

Artistic license to get the point across. With the "extreme" it is easier to draw the diagram and show the "divot" and the "out".

Extreme drawings
 

Hi Wali, Golfguru is right: the drawings are exaggerated and not at scale. The purpose here is to put the emphasis on what happens between impact and low point and to see the role of the left shoulder as the center of the stroke.

The reality is less 'extreme' and, of course, the common ball position ranges from the middle of your feet to in front of the left shoulder.

However, you could choose to play a ball in front of your right foot with a wide stance...but to be geometrically correct, you would have to dig deep into the ground to low point and beyond with a divot the size of your stance - ouch!!! &H

This is maybe the reason why we usually shorten the stance with wedges :wink:!

Nice one
 

Good point no_mind, I was too lazy to check out what you wrote because I used to listen to Homer's words as a TGM fanatic monk(ey) :monky: !
But the link you provided is quite clear...
What Homer described as the Venturi effect is indeed the Magnus effect :shock:.

Aaaaah, at last, The Man made a mistake!
This TGM stuff was way too perfect to be true!
Homer was human: It makes me a believer monk :monky: more than ever!
Gimme a banana!