"sweet spot" physics- where are you?
 

I believe the "sweet spot" is aligned to the ball at fix to adjust your computer and thats IT. What are, if any, the Physics of the sweet spot? Like to hear an engineering - mechanical dynamics- reasoning on the "sweet spot".

Sweet spot is your COG. Plenty of physics there.

COG of the club head. The head being "heavier" than the shaft and the heaviest part of the shaft being in the grip. Suspension of the club from trhe butt of the grip will likely place the COG of the club head directly "below" the point of suspension. EVEN IF he shaft is bent like a "7" and hung on the edge of a table with the grip pointed NORTH- ( that would be southern cross for that part of the world where the blood rushes to your head). So the sweer spot is aimed by the computer??? Unless OTHER phisics can be added??? This is a valuable discussion due to HK emphasis on Sweet Spot I believe. Yes?, No?, Maybe?

Seriously:
We must add/change our vocabulary.
COG is a very specific and limited term- relates to weight- a mass within a uniform force, gravity. I would like to hear the physics discussed using MASS, ACCELERATION and FORCE, CENTROID com and MOMENT. (basic F=MA) because therein lies the physics of the golf club/swing.

HB

Interesting HB but according to Homer isn't it the LCOG? From the lowest point of contact on the aft of the shaft to whatever it plumb bobs? The sweetspot being a point without dimension and moveable depending upon where the lowest point of contact is (gripping up or down etc. )


Im no engineer so Ill just listen in..

The Golf Club has various balance points and the Clubhead also has a balance point (COG). The #3 PP senses and directs the Clubhead COG.

The Clubhead COG has an Orbital Path. The Ball has a COG.

It's important to note that the COG of the Ball always intersects the COG Orbit of the Clubhead unless you're hitting a specialty shot (i.e. Driver off the deck or sand shot).





Please note that the Impact and Separation points are for illustrative purposes only. Although Impact and separation points may be the same on the Horizontal Plane, it isn't necessary (or even possible, except during Vertical Hinging) on the Vertical Plane.

MY BOLD of quote;

Senses NO, Directs YES;
Lacking demonstrable knowledge of the Mechanical Dynamics. I start at the place that the "sweet spot" is a learned POSITION and is located by YOUR COMPUTER in a mechanical manner. Now, IF mechanical dynamics (physics) of the "sweet spot" (lets use Centroid or center of mass) can demonstrate a "sensable" effect we have something new. I have not found that effect.

HB

I recently learned about Center of Percussion.

It's the impact point where there will be no shock transmitted to the hands. This seems to be considered the sweet spot in baseball batting. And it is most certainly the sweet spot for a hammer.

Not that if impact happens below the COP, a forward force would be generated at the hinge pin. I guess that corresponds with the harsh feel of flipping and topping at the same time.



Then you have the Center of Oscillation. I often call this the Moment Of Inertia Center, but that term seems to not be used in English. Anyway, this is the inertia center as seen from the hinge. When the stick becomes a pendulum around the hinge, there will be as much velocity energy below this center as above it.Radius of gyration is the distance from the hinge to the Center of Oscillation so these two terms are often interchanged. For a clubhead with a given mass, the radius of gyration will correlate with how hard it is to swing the club. more radius of gyration means more inertia.

Until recently I thought this center had the same property as the center of percussion, but it doesn't. It sits higher on the stick. It will always be somewhere between the COG and the COP in the figure above.

Center of Gravity is the last term in the club.

Here's a patent dealing with how to get the COP in the center of the club head:http://www.ptodirect.com/Patents/5629475

This indicates that the COP is the true sweet spot. But perhaps there's more to it than just where the COP is.

coordinate system
 

First lets pick a coordinate system. Since this is going to be "hand waveing" rather than math lets us a Cartesian system - X, Y, Z. the "plane of the swing" defined as X,Y and any above or below plane defined a Z. A cylindrical system may be more appropriate but harder to understand. and polar system would become impossible. So the swing plane is a flat X,Y plane and deviation above or below this plane is +/- Z. (Just geting started) Any engineers object?

hb

I'm curious to see where you're going with this, hb.

Using a "test club" with the tip weighted to equiv. of club head mass and swinging this "club" flat on yhe X,Y plane , about the Z axis , with a "MACHINE" that either pulls or pushes as the TGM power package. The shaft will remain flat on the plane and the tip will either LAG or LEAD dependent on if it is accelerating or decelerating. (shaft will flex)this is due to tangential acceleration. And, there will be a SUBSTANTIAL radial force due to the radial acceleration.(shaft trys to stretch) A sensor located about where #3 would be can be used to sense the tangential acceleration but not the radial acceleration. AND the position of the TIP is unknown until PRACTICE has adapted the machine computer to compensate for variables. ie. the club becomes part of the machine. like any tool we use. pen, fork keyboard. sword etc. we just practice into automatic.

OK so far?

hb

HB