Watching Tiger @ Memorial Skins game today

[jake2]

I think the Trackman boys screwed up the Dynamic Loft definition.

They inter-mixed a FACE variable with a PATH variable. Those suckers are independent.

In actuality, I think they were trying to get at "shaft lean" when they said "attack angle."

I do not think there's anything wrong with the definition (read my post above), problem is their rule of thumb, which is being mistaken as definition.

Edit: They do seem to simplify in the rule of thumb that
forward lean angle = negative AoA angle

 

[mgranato]

Any estimations on the variance and or tolerance here?

With a driver, the potential for added loft from forward shaft flex depends on how far back from the face the head's CoG is located. As the club is released the arms slow and the head speed increases. That force causes the head's CoG to line up with the shaft's CoG through the grip end (forward flexing of the shaft). How much of this influences loft depends on the location of the heads CoG, the bend profile of the shaft, and the golfers release point. It takes one heck of a swing to get the max forward flex loft (around +2.5*) at the ball, and is the exception not the norm. Keep in mind that additional loft from a true forward flexing of the shaft is often "confused" with a rearward leaning shaft at impact. Both can add loft, but they are not the same thing.

 

[jake2]

"It turns out that if you hit down or up on the ball with the same club, the spin rate will be more or less identical if you impact the ball on the same spot on the face. This is in contradiction to the myth saying that hitting down on the ball increases the spin rate."

Yeah...but...One little problem with that—the LAUNCH ANGLE!!!!!!!

It is all about the LAUNCH ANGLE!!!!

YOU HAVE TO HIT UP ON IT!!!!

Here we go...

10° lofted driver, hit down 2°, no shaft lean/sweetspot strike—so 10° of dynamic loft, 8° of spin loft.

That's really low, and will produce low spin.

One clarification for this:
if SPIN LOFT = Dynamic ("delivered") Loft —(minus) Attack Angle
then 10 - (-2) = 12 (down 2 is -2 right ?)

Still low but higher spin?

Great!

Right?

Ah...

Not so fast...

The LAUNCH ANGLE on that example would be about 6.5°.

Total and complete UNUSABLE JUNK!!!

So....

This guy would—at let's say Tiger's swing speed of 120ish—would need to have a 10° driver with backward shaft lean of 2° & a sweetspot strike (12° of dynamic loft), and hit up 4° to get the same 8° of spin loft at a usable 10ish° launch angle.

Get it?

Of course, for simplicity sake, I left out forward shaft kick, and hitting the ball higher or lower on the face.

So, there is a way that I guy could ADD LOFT to his driver, and spin it less.

How?

Hitting up with MORE FORWARD LEAN.

Which to me, is easier.

Do the math, bro.

 

[Ringer]

[media]http://www.youtube.com/watch?v=7zCgkXvJYlw[/media]

Increase the angle of approach but keep the dynamic loft down by keeping the hands ahead. Ball will take off with a higher trajectory and less spin. I think it is easier to do with a less lofted club, but it can still be done if the swing is adjusted.

 

[mgranato]

Last year, He had the 16th lowest launch angle (out of 189), and the 34th highest spin rate - he aint doin' none of that stuff.