CP/CF release

[mandrin]

I misunderstood Mandrin. I thought the rightmost graph showed the total momentum in the entire system, not just of the 3rd and fourth segments.

drewyallop,

You didn't misunderstand.

“The solitary curve sticking out on the right represents in each case the sum of the angular momentum of the 4 disks, hence the total angular momentum of the system.“

My question on reference point was badly phrased. As you know angular momentum is always calculated from a given reference point. I am curious to know the point since my experience is limited to relatively simple calculations e.g. single mass, orbits, projectiles. Maybe it would be better if you could show me your more detailed calculations in a pm, if you have time.

In this particular analysis the situation is straightforward. There is one common axis for the rotation of the four disks. The matter is however still a bit more involved than for a single particle. There are four linked differential equations which have to be solved for a set of particular torques chosen.

 

[bluebird]

"CP/CF release implies a centrifugal or a centripetal force acting on the club through the release phase of the club through the bottom part of the swing. In either swinging or hitting this is not the case. The only radial force playing a significant role in the release is the centripetal force acting on the hands/arms. It is much smaller than the radial forces associated with the club yet produces the most significant release torque."

Mandrin,

Is the acceleration increase provided by a cp force solely accomplished by the shortening of the length of the lever?

If this is true then the resultant acceleration would be pale in comparison to the enormous velocity multiplication made possible by the application of massive amounts of torque applied thru the simple first or third class levers, applied with the hands and wrists.

Here is what I see. The so called CF swing uses the L wrist as the flying fulcrum and the R hand applies the torque in the CF direction, away or outwards. A third class lever.

The so called CP swing uses the R wrist as the flying fulcrum and the L hand applies the torque in the CP direction, inwardly. A first class lever.

Both swings have a CP force that needs to be applied to hold the lever length and possibly to shorten the lever length.

So another question arises, Is any force applied in a CP direction considered a CP force?

Please critique.

John

 

[drewyallop]

drewyallop,You didn't misunderstand. “The solitary curve sticking out on the right represents in each case the sum of the angular momentum of the 4 disks, hence the total angular momentum of the system.“

The question you didn't answer Mandrin is what happened to the external force that was applied to the system in the first iteration.

 

[mandrin]

"CP/CF release implies a centrifugal or a centripetal force acting on the club through the release phase of the club through the bottom part of the swing. In either swinging or hitting this is not the case. The only radial force playing a significant role in the release is the centripetal force acting on the hands/arms. It is much smaller than the radial forces associated with the club yet produces the most significant release torque."

Mandrin,

Is the acceleration increase provided by a cp force solely accomplished by the shortening of the length of the lever?

If this is true then the resultant acceleration would be pale in comparison to the enormous velocity multiplication made possible by the application of massive amounts of torque applied thru the simple first or third class levers, applied with the hands and wrists.

Here is what I see. The so called CF swing uses the L wrist as the flying fulcrum and the R hand applies the torque in the CF direction, away or outwards. A third class lever.

The so called CP swing uses the R wrist as the flying fulcrum and the L hand applies the torque in the CP direction, inwardly. A first class lever.

Both swings have a CP force that needs to be applied to hold the lever length and possibly to shorten the lever length.

So another question arises, Is any force applied in a CP direction considered a CP force?

Please critique.

John

John,

I realize that it is all rather confusing. The main reason is that intuition and feelings are not of any help here. Only a detailed analysis shows the actual force(s) responsible for generating the release torque. The 'shortening of the length of the lever' to produce centripetal acceleration in a golf swing, is a minor contributor. There is a centripetal force associated with any object following a curvilinear path such as for instance a circle where the the length of the lever is perfectly constant and yet a very large centripetal force can be generated.

I will soon go in details but for now let's suggest another way how torques are generated through the arms, hands and wrists. Forget about levers for a moment. Torques can not only be produced by direct twisting action, Fig1, but also by a linear force, Fig2. The latter is actually the main mechanism for the release torque acting on the club.

​

Typically, centrifugal and centripetal forces are referring to forces when a body undergoes circular motion. However strictly speaking they occur as soon as any moving body deviates from its straight line motion. If one uses a force, for instance to reduce the length of a cord of a twirling mass, one would probably usually refer to it with some other term but yes this is also a centripetal force when using the meaning of centripetal literally.

 

[SteveT]

mandrin... all those pretty pictures of dynamic and static elements is fine for simplified science, but can you occasionally superimpose them on the human body executing the golfswing? I believe that will be helpful for the scientifically unwashed golfing masses.

I assume you have a golfswing and can separate the "feeel" from the "real"... but in a real-life image of the golfswing.

 

[mandrin]

The question you didn't answer Mandrin is what happened to the external force that was applied to the system in the first iteration.

drewyallop,

There is no external force applied. In the various experiments there are only internal torques applied to various disks.

“We will do 6 experiments. There are three internal torques successively applied..............”*

“Also it should be clear the funny way the ground force comes into the picture as an external force. For every internal torque, especially proximal torque, an associated reaction force is generated, between golfer and ground. Thereafter this ground reaction force acts on the golfer as an external force and it is only this external force which can generate any net positive angular momentum.”*

 

[SteveT]

Here is what I see. The so called CF swing uses the L wrist as the flying fulcrum and the R hand applies the torque in the CF direction, away or outwards. A third class lever.

The so called CP swing uses the R wrist as the flying fulcrum and the L hand applies the torque in the CP direction, inwardly. A first class lever.

Both swings have a CP force that needs to be applied to hold the lever length and possibly to shorten the lever length.

So another question arises, Is any force applied in a CP direction considered a CP force?

Please critique.

John

John.... are there "flying fulcrums" in a dynamic system because a fulcrum is defined as something that is anchored in the ground to support a lever? Perhaps you are thinking about "force couples" that do occur between the hands during the golfswing. Please help me on this one.

 

[bluebird]

John.... are there "flying fulcrums" in a dynamic system because a fulcrum is defined as something that is anchored in the ground to support a lever? Perhaps you are thinking about "force couples" that do occur between the hands during the golfswing. Please help me on this one.

SteveT,

I would be glad to rename them to (double pendulum, hinge pins with perpendicular accumulators) that can be fired at any angle on the fly at any speed. Thanks for the response.


Although telling folks that you can see something that is not visible to others is not a great thing to have in ones resume, it's pretty clear to me.
The point is that if the hands can achieve a 25 mph swing speed at a 150 inch circumference , and the clubhead circumference is 401 inches, that is a multiplier of 2.679 . Without a fulcrum and an applied torque , your clubhead speed will achieve the velocity of 66.9 miles per hour.

Since the speed gain of shortening the radius is small, that leaves us two possibilities . Accelerate all the speed early in the swing, or accelerate all the speed early in the swing plus add everything under the sun that one can store and apply at the exact time necessary. The multiplication factor available at the hands is at least ten to one. If anyone could just muster a two to one increase that would yield 133 mph.

John

 

[bluebird]

John,



I will soon go in details but for now let's suggest another way how torques are generated through the arms, hands and wrists. Forget about levers for a moment. Torques can not only be produced by direct twisting action, Fig1, but also by a linear force, Fig2. The latter is actually the main mechanism for the release torque acting on the club.

​

Mandrin,

Thanks for the reponse. What confuses me is the appearance to me that adding some of Fig1, would seem to only enhance the speed of Fig2's arrival. I will as much as humanly possible forget the lever. Thanks again

John

 

[mandrin]

It is interesting to analyze side by side CF and CP release, comparing the torques acting on the club. They have more in common that perhaps expected.

 

[grahler]

Mandrin,

You said... Analyzing the matter however they seem to have in common the same dominant releases action due to the centripetal acceleration of the upper segment.

This is one of the more accurate things I have read lately.

Nice work there.

 

[SteveT]

The centripetal release torque is proportional to the angular velocity squared of the upper segment (arms). In golf there are auto-regulating mechanisms which make golf possible. Produce more velocity and automatically there will be a greater release torque.

Where is this "release torque" generated in the golfer's body, where can it be seen, felt ??

 

[mandrin]

Where is this "release torque" generated in the golfer's body, where can it be seen, felt ??

SteveT,

You make it sound like forces are to be seen, can be put on a table and being examined. Not quite. We can't see forces. But we can observe the effect they have when acting on objects. I can't see gravity but definitely am aware of its effect on me. Even so. I remember having read somewhere, probably in a golf instruction book, that when pros where asked what they felt in the down swing they said feeling very little. The better the swinging the less they felt or something to that extend.

A two segment planar math model of a golfer can't be used to predict the intricacies of a real golfer, but is quite adequate to analyze the forces/toques acting on the club. You want to know the physical location of the releases torque somewhere in the golfer's body whereas the double pendulum model does not even have a body.

The essential merit of a simple 2d analysis is to show the fallacy of the commonly accepted erroneous believe of centrifugal force acting outwards on the clubhead being responsible for the release of the club. It is not and instead it is the much smaller centripetal force associated with the motion of the lead arm with generates the bulk of the release torque, for both swinging and hitting.

If we want to pinpoint a precise physical location one could say that the wrist joints are a prime candidate. Two parameters are important. The velocity of the hands and their trajectory in space. The latter is mainly defined by lead arm and the lead shoulder joint. Hence velocity is the only main parameter, readily under control by the golfer. Just like Miura's parametric acceleration, Nesbit's interest in hub path is related to the trajectory of the hands. However by far the velocity of the hands is the most important factor in generating the release torque.

 

[SteveT]

mandrin:

Thank you for your response which helps clarify the new term "centripetal release torque" in the downswing.

You say in your response: "...by far the velocity of the hands is the most important factor in generating the release torque."

Perhaps you meant "velocity at and of the hands" and not the hands themselves applying a 'release torque' in an efficient swing.

However, the source of "generating" the velocities and release torque is still not clear. Perhaps you could help clarify that for me by extending the 2D hub model into the full golfswing for a full analysis.

And yes, you are correct; the forces and torques cannot be "seen", and perhaps I should have said "sensed".... sensed by the observer and felt by the golfer. I and perhaps others are still wondering about your full involvement with the golfswing, and if you try to test out your analyses on yourself... swinging a club. Do you.. can you...

 

[bluebird]

It is interesting to analyze side by side CF and CP release, comparing the torques acting on the club. They have more in common that perhaps expected.

Mandrin,
Thank you for that analysis. The torque charts, Fig4a and Fig4b are very interesting.

The first thing that stood out to me was that our nomenclature for the two are reversed. After a little searching it became clear that some camps do not agree on the names. No horse in the race here so I will switch to your nomenclature, and apologize for any confusion this may have brought forth.

Several questions.
Would there be a way to impose the hand speeds and club head speeds into those charts?
Would it be possible to impose the torque delivered to the ball into these charts?
Thanks again, excellent work!

John

 

[mandrin]

Mandrin,
Thank you for that analysis. The torque charts, Fig4a and Fig4b are very interesting.

The first thing that stood out to me was that our nomenclature for the two are reversed. After a little searching it became clear that some camps do not agree on the names. No horse in the race here so I will switch to your nomenclature, and apologize for any confusion this may have brought forth.

Several questions.
Would there be a way to impose the hand speeds and club head speeds into those charts?
Would it be possible to impose the torque delivered to the ball into these charts?
Thanks again, excellent work!

John

John,

From your PM and your post it appears to me that you feel that I use centripetal and centrifugal force different from some standard way. This is really not the case. Let me try to explain where I think you are going astray.

The usual way in golf is to relate to the simple image of a small mass twirling about a center. An image frequently been used and actually still is in golf instruction. One assumes the clubhead to behave like the small object twirling around a center. Not quite correct.

There are two segments in the model, representing respectively arms and club. The upper segment rotates around the inner pivot, whereas the lower segment during release primarily rotates around the joint between the segments. Both segments have their own centrifugal and centripetal force associated with them.

The common erroneous believe is to assume a centrifugal force, acting on the clubhead, being responsible for the release. This is not true. It is the centripetal force of the upper segment which is the major factor in the release torque.

It is indeed counter intuitive but it is an inward force acting on the club which causes the clubhead to be propelled outwards. However, the centripetal/centrifugal forces associated with the club itself, even getting very large, don't play a role in the release.

John, I can arrange the hand and clubhead speed into the torque graphs. Conveniently I can use the same vertical scale. With regard to the torque delivered to the ball you have to explain a bit more what you mean.

 

[bluebird]

Mandrin,
Please forgive me for my lack of communicating skills.

My personal golf swing history was that there was a effort to drive my hands to the ball and from a DTL view, the hands separated from the body midsection. Since forsaking that pattern my current hand-path stays closer to the body and the hands appear to disappear in front of my body, from a DTL view. The little knowledge that I have has come from reading and studying internet forums. On another site, the hands disappearing style was described as a CP release.

Since forsaking the drive hold and implementing the Ideas Release my clubhead velocity has increased and improved my distance and lowpoint control. I believe we are on the same side of which swing / release is best.

Since previously describing the drive hold as a CF release, I felt a need to explain, that my nomenclature must be switched from yours. As I observe in your Fig 4a chart, the combination of the decrease in torque applied in the latter half of the swing, at the lower part of the upper section and the increase in centripetal force, is that your description of the New Ideas release is labeled a CF.

So in a search to determine where I had picked up this misnomer, low and behold, on another forum, came the forth the fact that different camps, name their styles as they see fit, and that is possibly is how I picked up my erroneous nomenclature. I take full responsibility for any misinformation and was simply trying to relay what my observation was. It was also explained that it is possible to intermix parts of both styles and this may also factor into the fold. There is no appearant standard.

Those charts are awesome. Thanks again

John

 

[bluebird]

John,

With regard to the torque delivered to the ball you have to explain a bit more what you mean.

Mandrin,
As to the torque at the clubhead. There has been several threads recently that suggest that delivering a velocity without ball contact is somehow different then the same velocity occurring during an actual hit. How could this be true?

Please allow me to suggest this theory.
With a golf swing where the only centripetal force applied is to maintain the radius length, the clubhead mass is considered to be free floating unaffected by any torques. Now let us consider that the loft is not normal to the arc. when there is an increase CP the shaft is now actually being pulled skywards. Would not this apply an actual torque unto the ball?
Thanks

John

 

[mandrin]

Mandrin,
As to the torque at the clubhead. There has been several threads recently that suggest that delivering a velocity without ball contact is somehow different then the same velocity occurring during an actual hit. How could this be true?

Please allow me to suggest this theory.
With a golf swing where the only centripetal force applied is to maintain the radius length, the clubhead mass is considered to be free floating unaffected by any torques. Now let us consider that the loft is not normal to the arc. when there is an increase CP the shaft is now actually being pulled skywards. Would not this apply an actual torque unto the ball?
Thanks

John

bluebird,

I have added the speed of hands and clubhead (black). It so happens that the numerical vertical scale for the torque is also valid for the speed curves. Units however have to be taken as m/s instead of Nm. Notice the behavior of the centripetal torque (red) and the hands speed curve (black). They are nicely correlated.

​

Forget about any action during the impact interval. Only the clubhead speed at onset of impact is important in addition to path and orientation of clubhead.

 

[dbl]

Sorry, but does anyone else see basically a link to "Forex Rainbow" when hovering over Mandrin's image above? If not, I've got to get my machine checkedd out.