"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

"Radial" and "Longitudinal" reference (TGM) the Pressure Point (Senses and Directs) Alignment with the Clubface at Release (Pulley). "Radial" is termed to describe the PP at Right Angles to the Clubface and "Longitudinal" is termed to describe the PP which is Parallel to the Clubface.

The Pivot, Power Package and Pulley all contribute to Angular Acceleration regardless of Hitting or Swinging. The term "Throwout" is used to describe the Clubhead being moved around the Pulley by Centrifugal Force (Radial Acceleration) while "Driveout" is used to describe muscular effort propelling the Clubhead around the Pulley (same Radial Acceleration). Regardless of Method, it is the "Pulley" that creates Clubhead Acceleration and not the type of Thrust or how the PP is Aligned to the Clubface.

Physics term.
 

Daryl, we are speaking physics. I am slowly developing the physics of the "sweet spot" . At this point I have not assembled the club only a "test club" . Radial is a vector from the center -Z axis as defined and tangential is in the X,Y plane at a constant redius from Z=0, X=0, Y=0.
If you have the Physics of the "sweet spot" please contribute.

#3 pp is, as the word is. a POINT. with dimension. only sensing one dimension. The radial sensing is apparently accomplished within the "checkrein" response an I find no specific ref. in TGM to this sensor

HB

off topic
 

Off topic but I mention that the "tip" either lag or lead and lead is deceleration. No Lag! It has been talked about here, the forward bending shaft. I can see in many players what I will call a "faux lag" the right wrist does not maintain a fixed bend. It is easy to feel pp#3 by unbending the right wrist.

hb

Throwaway. :read:

Absolutely! More common than many would think.
hb

It's rampant - moving the hands independently of the pivot, or as Ben Doyle says, "adding". :(

Last piece of puzzel?
 

Now, lets displace the Center Of Mass of the club head from the axis of the shaft. 2 additional pieces of Physics are introduced. Toe up/down and torque.
1. with the COG thailing and on the plane we have toe up when accelerating and toe down when decelerating.
2. as the COG leaves the plane of the shaft we have toe down equated to radial force and torque- laging (tending to lay the COM back-open if above the shaft plane) when accelerating and leading(tending to have the COM pass the shaft- close of above the shaft plane- Roll under if COM is below the shaft plane (Driver as example)) when decelerating.

All making the dynamics a computer learned event.
ie. learn a motion then let the computer learn how to hit the ball.

I include some shaft dynamics data as illustration.

http://www.tutelman.com/golf/shafts/ShaftLab.php

See "Lessons from the Data".
Interesting stuff!

HB.


PS.
This data shows that the pro's have a forward bend in their shaft at impact- Throwaway- I think so, Also a loss of effective Club Head mass. But lets hold that analysis for another post.

Had the sweetspot passed the hands though?

Can you point to golfers that don't unbend the right wrist?

Your question requires more information on dynamics.
If you are questioning forward lean- maybe, maybe not but forward lean is not the critical factor.
If you are questioning COM vs. hands on grip, the answer is yes. The shaft will be bent forward- lag gone, effective mass decreased. Mass is developed from the ground or the last lagging component closest to the clubhead.

HB

ps. Quick reply Huh?- just happened to be here editing.

Well- not off-hand, but, I paraphrase- " Throw or drive the right forearm, not just the clubhead, into impact with the selected degree of right wrist bend.." and then "Drag that wet mop" and also Impact fix.
I see so many video's where the elbow-stalls and A faux #3 can be easy to hold because the unbending right wrist is almost automatic and can even chase a NO LAG forward bent shaft and feel like LAG is still there.

Just the way I see it but I am still in the TGM envelope- I think??

hb

http://www.youtube.com/watch?v=AqShg...eature=related

The right wrist can't unbend if you roll an arched left wrist through impact. :thumright

In my case I can point to the "lazy" factor.
Everything, once put in motion should continue in motion. I have to remind myself that the shoulders must continue, with effort, and the elbow and the forearm, into and beyond impact.

This is "way off" the sweet spot topic but, and this is how I think about it. There ar a lot of synchronized planes involved. The club shaft plane ( the one everyone talks about) which "changes", the shoulder(s) plane, The hands plane (which I place on the shoulder plane). AND THEY ALL MUST BE IN SYNC , The left wrist only cocks and uncocks, that is the only thing happening at the "GRIP-hand wrist" part of the assembly -until follow through. This is a very BIG topic well beyond present topic other than how it effects COM "manipulation".

HB

Not to get off track and this may seem needlessly precise or small but... There's something that isn't talked about often which is Id say critical to a powerful , free flowing flail with correct on plane , Hand Motion. Namely: The re forming of the Bent Left , Flat Right Hand Condition post Finish Swivel.

Its not a Right Hand Release, capital R, a source of power but it does promote a full, free flowing and Aligned flail and in that way allows for full power. Its as if the flail needs some room or a place to go post impact, like a sprinter running another 30 yards past the tape.

Fix; Impact Hands (Flat left , Bent Right)

Adjusted Address: (B Left, F Right)

Top: Impact Hands

Impact: Same

Follow Through ; Same

Finish Swivel ; Same often, ideally .

Post Release Swivel ; Not the same, ( Bent Left , Flat Right.)

Finish: Impact Hands

The condition of the left hand post Finish Swivel is Cocked, Turned to Plane and Bent. Hogan did it, Moe did it, Bobby Jones did it........Lynn does it!

Sure you can do otherwise; Angled Hinge a three quarter shot for instance with a Bent Right Hand at your cut off Finish but for the normal shot , so to speak, the flail is full , free wheeling , on plane and the Wrists are tension free. Firm grip , free Wrists with a Bent Left Hand past Finish Swivel.... if only momentarily.

Not very many flat left hands post finish swivel out there on the tour.

That said the cure for Throwaway is still the Rolling of the Flat Left Wrist through the ball. Absolutely. As opposed to holding on to a bent right hand. If you Roll the Flat Left you will reduce the throwaway pressures placed upon the Bent Right. Steering is the enemy of the Flat Left Wrist.

Here's a rare discussion on this subject.

http://www.lynnblakegolf.com/forum/thread6100.html

Jason Day gets close.

What is cool is learning to keep it Flat all the way to the Finish as a drill and then taking the Flying Wedge back over your head and back to impact fix location. Its not necessarily what all players can or will do, but it shows it can be done with a correct Finish Swivel and re-cocking of the left wrist.

Ben Doyle does that on his "how to build a GOLF swing" video. Hes says somthing like "Smith and Westfield" but thats not the correct words. What does Ben Doyle say?

HB

I overlooked the somewhat contentious nature of my post. My apologies HB that probably should have been a new thread. Don't want to take you off course.

If the moderators want to rectify this by starting a new thread thats fine by me.

ob


PS Lynn does the from Finish to Address move thing too when describing the Wedges.

Wonderful, extremely important and clarifying post Mr. O.B. with another important link from YODA. :salut: :salut: :salut:

Kevin

Somewhere In Time
 

Great stuff, O.B. Thanks.

Re my post URL above, newbies should note that my archived posts from Jan-March 2004 were brought on with a 1970 date. Plus, all my post titles were lost, Maybe some day we'll be able unscramble all that, but for now, that's the way it is.

:golfcart2:

No problemo- I have said what is to be said about the "sweet spot"- and what i said was what it does or doesn't do.

I figured out what Ben was saying. "Fastest Gun in the West" He has a drill.

HB