Brian Manzella
Administrator
You could release any of the MULTIPLE Power Generators by total sheer effort.
Most good players do this in some way.
Release
- Thread starter mandrin
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You could release any of the MULTIPLE Power Generators by total sheer effort.
Most good players do this in some way.
mandrin
New
We are all familiar with pictures of Ernest Jones using a handkerchief to explain his ideas about the ideal golf swing. In effect many instructors have been / are using a small weight at the end of a tether to demonstrate centrifugal force in a golf swing. It is being taken to be representative for golf swing. However there is a large difference between a simple swirling point mass and a multibody dynamic system as formed by a golfer /club ensemble. This simple transposition is simply not correct.
It is an interesting to note here a two-fold paradox. On one hand there is a small fanatic group who simply denies centrifugal force to exist - the flat-earth people. And, on the other hand, those who do believe in its existence are wrong the way they think it acts in a down swing.
Fig1a shows a simple point mass M swirling at constant speed round a fixed center. In Figs1 b, c we have illustrated separately the action of the centripetal and the centrifugal force. Important to note that the line of action of the centrifugal force goes through the swing center and the point mass. If we imagine that the tether becomes stretchy than the point mass will move away from the swing center.
Let’s now look at a simple model of a golfer - shoulder, arms and club - as shown in Fig2. As long as the golfer comes down as one piece, the line of action of the centrifugal force passes though the inner swing center A. The centrifugal force results in a centrifugal torque. However as soon as the wrist starts acting more or less as a free hinge deeper into the down swing , the line of action of the centrifugal force changes drastically and passes through C, as shown in Fig3. There is indeed a centrifugal force which might be getting quite large but there is no centrifugal torque being developed..
The conclusion imposes itself now very clearly:
Centrifugal torque doesn’t play a significant role during the release phase of the down stroke.
So what on earth then is energizing the typical rapid release action?
Perhaps the earlier posts start taking on a new meaning.
More to come pending interest.
It is an interesting to note here a two-fold paradox. On one hand there is a small fanatic group who simply denies centrifugal force to exist - the flat-earth people. And, on the other hand, those who do believe in its existence are wrong the way they think it acts in a down swing.
Fig1a shows a simple point mass M swirling at constant speed round a fixed center. In Figs1 b, c we have illustrated separately the action of the centripetal and the centrifugal force. Important to note that the line of action of the centrifugal force goes through the swing center and the point mass. If we imagine that the tether becomes stretchy than the point mass will move away from the swing center.
Let’s now look at a simple model of a golfer - shoulder, arms and club - as shown in Fig2. As long as the golfer comes down as one piece, the line of action of the centrifugal force passes though the inner swing center A. The centrifugal force results in a centrifugal torque. However as soon as the wrist starts acting more or less as a free hinge deeper into the down swing , the line of action of the centrifugal force changes drastically and passes through C, as shown in Fig3. There is indeed a centrifugal force which might be getting quite large but there is no centrifugal torque being developed..
The conclusion imposes itself now very clearly:
Centrifugal torque doesn’t play a significant role during the release phase of the down stroke.
So what on earth then is energizing the typical rapid release action?
Perhaps the earlier posts start taking on a new meaning.
More to come pending interest.
Mandrin,
Ok - I'll bite. Why would the line of action pass through point C? I'm not sure I fully understand what you were describing. I could see the force acting through point C only if the rotational velocities at A and B were zero. I would have thought the actual line of force would act through some composite point determined by the rotations of A, B and C. What am I missing?
Jay
Ok - I'll bite. Why would the line of action pass through point C? I'm not sure I fully understand what you were describing. I could see the force acting through point C only if the rotational velocities at A and B were zero. I would have thought the actual line of force would act through some composite point determined by the rotations of A, B and C. What am I missing?
Jay
mandrin
New
Jay, your question is an important one. Basically it has to do with how forces are transmitted through slender beams connected together with convolute joints (hinges). If the force is transmitted along the longitudinal axis there can’t be any moment. If not, a moment exists around that particular member.
In our simple purely mechanical model, when only A is ‘free’, the line of action will be through A. As soon as B is ‘free’ than the line of action shifts to B. If C is ‘free’ it shifts to C. Hence the line of action of the centrifugal force acting at the distal end of the club will pass through the closest 'free' evolute joint.
Your question is basically why this is so. To help a more intuitive understanding look at the illustration, Fig 1 and Fig2, I put together. Pulling on the ends of a cord only a force along the cord can be transmitted between the two pulleys. In Fig 2 three slender rigid beams connected with two free convolute joints; similarly, force can only be transmitted along beam2.
Jay, if you have some spare time you can verify it yourself using the exact mathematical expressions I have developed for the vectorial centrifugal force components acting at the distal end of the club shaft. You will than readily see that it corresponds in all regard to the ideas put forward regarding the behavior of the line of action of the centrifugal force.
mandrin
New
Manzella matrix & release action?
There are not many golf instructors /authors who treat release specifically. I can think of Joe Dante and Homer Kelley and also some golf scientists such as Prof Jorgensen, Dr Cochran, Dr Nesbit and Dr Springings.
Brian, I am still awaiting patiently your opinion on this matter. There must surely be some interesting information on this subject neatly and succinctly defined in the Manzella matrix. I am all ears.
There are not many golf instructors /authors who treat release specifically. I can think of Joe Dante and Homer Kelley and also some golf scientists such as Prof Jorgensen, Dr Cochran, Dr Nesbit and Dr Springings.
Brian, I am still awaiting patiently your opinion on this matter. There must surely be some interesting information on this subject neatly and succinctly defined in the Manzella matrix. I am all ears.
mandrin
New
LiftOff,
It does not refer to force but instead to angular velocity; w2=0 means that the revolute joint is ‘frozen’, not allowing any rotation.
Mandrin-
I'm still a little hazy on this. Let me ask another question. If the angular velocities of A, B, and C are nonzero is the path of the point mass M only dependent on the rotation around C? That's what I'm gathering so far from the discussion and is not obvious to me. Maybe I need to understand the term "line of action".
As an example where I'm having a mental block - In your Fig 2 with the "free-wheeling" joints, it seems to me if you pulled outward on the bar on the right in the direction of the arrow, the middle bar would rotate counterclockwise on the joint on the left.
Jay
I'm still a little hazy on this. Let me ask another question. If the angular velocities of A, B, and C are nonzero is the path of the point mass M only dependent on the rotation around C? That's what I'm gathering so far from the discussion and is not obvious to me. Maybe I need to understand the term "line of action".
As an example where I'm having a mental block - In your Fig 2 with the "free-wheeling" joints, it seems to me if you pulled outward on the bar on the right in the direction of the arrow, the middle bar would rotate counterclockwise on the joint on the left.
Jay
birdie_man
New
mandrin I read this whole thread today.
You have me wondering and I have been up in front of my computer with a golf club making swings to try and get a sense of "what is going on." (this is a good sign, you see)
I don't yet fully understand all the work you have laid out and have no specific questions as of yet.
Basically- I am stumped but intrigued. (I'm sure I will be getting made fun of at work today...surely making my golf swings with a ruler at some point)
Anyhoo........that's all buddy.
...
.....just thought I would let you know so that you don't get too distraught over a lack of appreciation of your (quite apparent) very hard work...
You do work hard though.
-Paul
You have me wondering and I have been up in front of my computer with a golf club making swings to try and get a sense of "what is going on." (this is a good sign, you see)
I don't yet fully understand all the work you have laid out and have no specific questions as of yet.
Basically- I am stumped but intrigued. (I'm sure I will be getting made fun of at work today...surely making my golf swings with a ruler at some point)
Anyhoo........that's all buddy.
...
.....just thought I would let you know so that you don't get too distraught over a lack of appreciation of your (quite apparent) very hard work...
You do work hard though.
-Paul
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birdie_man
New
BTW I can't judge whether or not you are correct because I'm not really qualified to do so.........but what you have done (what I have understood of it anyhow) and where you seem to be going does seem to fit in with some intuitions I have. (how's that for a vague, general statement)
But good work nonetheless mandrin.
Sorry for calling you mandarin back in the day.
But good work nonetheless mandrin.
Sorry for calling you mandarin back in the day.
mandrin
New
The trajectory of M is a function of relative rotation of all three hinges, A, B and C.
The ‘line of action’ or ‘line of application’ is an extension of the force vector in both directions. It is the essence of the 'principle of transmissibilty’ used in structural analysis.
Correct. Nevertheless the line of action during rotation remains along the slender beam.
Jay, consider a cord. You can’t push with it and exert leverage. Only a pulling force can be exerted. And this pulling force is always directed along the cord. These arrangements are referred to as ‘two-force members’ in mechanics.
Now imagine a slender rod in which one inserts many small hinges between the two extremities. Similarly to a cord no pushing and no leverage, just the pulling force. Imagine next that we take away all hinges except two, one at each end.
We can now transmit a pushing force as well as a pulling force along the slender rod but still no leverage. It is this specific fact of having no leverage that determines that the line of action is along the rod - even if it rotates in space. Therefore the force is transmitted along the rod between the two extremes.
mandrin
New
Jim,
If you try to swing with the wrists locked (w3=0) you will likely in a full swing, break the shaft. The centrifugal torque building up when the shaft is not released gets really quite impressive.
Locking the shoulder joints (w2=0) is more appropriate for putting and partial golf strokes. On full swings all hinges should contribute.
Brilliant explanation a lay person, me, can understand!
Closer....
Mandrin-
Well, learning is sometimes a struggle of awakening out of the fog. I think I understand your example of the slender rods and force transmissability, but does the centrifugal force always act along that line of action independent of the path of the point mass? I thought CF was totally dependent on the path of the mass - so that's where I still have low hanging clouds in my way.
Jay
Mandrin-
Well, learning is sometimes a struggle of awakening out of the fog. I think I understand your example of the slender rods and force transmissability, but does the centrifugal force always act along that line of action independent of the path of the point mass? I thought CF was totally dependent on the path of the mass - so that's where I still have low hanging clouds in my way.
Jay
mandrin
New
Jay,
Concepts such as, for instance, mass and force, as we understand them now, are the result of a long and strenuous struggle of the very best minds over a long period of time, to finally come to cope with these notions. Definitely not easy subjects for the inquiring mind.
In general one can say that as soon as any object deviates in any way from a straight line motion, hence exhibiting curvilinear motion, there will be some centripetal/centrifugal force coming into play. Hence, yes, it depends critically on path.
On the club shaft there is at one end the outward centrifugal pulling force and at the other end, via the free wrist hinge, the centripetal inward pulling force. This is equivalent to the beam with two hinges and a force acting at each end. Perhaps now something starts clicking upstairs?
mandrin
New
LiftOff,
Leaning over backwards to explain is often quite a challenge. Glad to see it did the job.
Michael Jacobs
Super Moderator
Practical Aspects
Mandrin,
I just had the opportunity to read the whole thread...........
thanks for your hard work and contributions! Certainly you are in a league of a few......
As for the practical aspects of teaching "release" on a daily basis on the lesson tee....
No doubt there is individuality involved in each and every stroke - each and every golfer - learn styles and personalization takes improving a golfer's pattern beyond science and discussion.. with that said
In an individualistic "golfer" factors that effect "release" I will give a quick 5
1)the inner center (i believe Search for the Perfect Swing and others refer to it as a hub) anyway, the hub movement plays a huge role in speeding up or delaying the outward fleeing of the club which indeed leads to a lot of confusion amongst a lot of physics and mathematic models that create conclusions based on "models" with rods and fixed centers
2)Dr Zick's and Brian's Positive Torque - No Torque - Negative Torque descriptions are excellent - I think when the whole Academy's work is complete and inked it will be looked upon as scientifically satisfying and safe enough for a conversation at the kitchen table of an everyday golfer
3) The initial startdown - individualistic based backswing length and other factors...etc --- A definite 'pulling along the shaft'
4) As the downswing expands and the club flees from the golfer - a definite need to SWITCH from speed gathering to directional concerns - controlling the track of the handle and preparing for club face orientation
5) No question about the correlation of the handicap of a golfer and their
ability to manage the 'track of their hands'
So there is a quick synopsis of how I practically apply "release" on an everyday basis -
TGM Power Accumulators I use rarely as little examples if a student needs to clear up a confusion ... I use a 5th accumulator as does Brian
As for Barrels, needs a lot of amending, the concept of a 3 barrel pattern is outrageous.....
Mandrin,
I just had the opportunity to read the whole thread...........
thanks for your hard work and contributions! Certainly you are in a league of a few......
As for the practical aspects of teaching "release" on a daily basis on the lesson tee....
No doubt there is individuality involved in each and every stroke - each and every golfer - learn styles and personalization takes improving a golfer's pattern beyond science and discussion.. with that said
In an individualistic "golfer" factors that effect "release" I will give a quick 5
1)the inner center (i believe Search for the Perfect Swing and others refer to it as a hub) anyway, the hub movement plays a huge role in speeding up or delaying the outward fleeing of the club which indeed leads to a lot of confusion amongst a lot of physics and mathematic models that create conclusions based on "models" with rods and fixed centers
2)Dr Zick's and Brian's Positive Torque - No Torque - Negative Torque descriptions are excellent - I think when the whole Academy's work is complete and inked it will be looked upon as scientifically satisfying and safe enough for a conversation at the kitchen table of an everyday golfer
3) The initial startdown - individualistic based backswing length and other factors...etc --- A definite 'pulling along the shaft'
4) As the downswing expands and the club flees from the golfer - a definite need to SWITCH from speed gathering to directional concerns - controlling the track of the handle and preparing for club face orientation
5) No question about the correlation of the handicap of a golfer and their
ability to manage the 'track of their hands'
So there is a quick synopsis of how I practically apply "release" on an everyday basis -
TGM Power Accumulators I use rarely as little examples if a student needs to clear up a confusion ... I use a 5th accumulator as does Brian
As for Barrels, needs a lot of amending, the concept of a 3 barrel pattern is outrageous.....
tongzilla
New
which is? pivot?
Michael Jacobs
Super Moderator
No, I call it the "Security Accumulator"
right wrist only - bending then flattening can propel the ball alone - therefore can be labeled
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