Release action

[SteveT]

@mandrin..... no use feeding the troll who is obfuscating endlessly with mendacity... either due to ignorance or devious intent.

What is puzzling is why others on the forum are drawn to supporting him... just to attack me (but not you)... "the enemy of my enemy is my friend"???

 

[footwedge]

@mandrin..... no use feeding the troll who is obfuscating endlessly with mendacity... either due to ignorance or devious intent.

What is puzzling is why others on the forum are drawn to supporting him... just to attack me (but not you)... "the enemy of my enemy is my friend"???

That's not puzzling, it should be a revelation for you.

 

[SteveT]

That's not puzzling, it should be a revelation for you.

Ignorant people hate the scientific truth.. and the messenger too...???!!!!!

 

[footwedge]

Ignorant people hate the scientific truth.. and the messenger too...???!!!!!

No, wrong revelation, sort of backwards you have it.

More like this... smart people like the scientific truth, but hate the ignorant messenger, the messenger of course would be you.

 

[OLIVER1]

@mandrin..... no use feeding the troll who is obfuscating endlessly with mendacity... either due to ignorance or devious intent.

'NO USE FEEDING THE TROLL WHO IS OBFUSCATING ENDLESSLY WITH MENDACITY'!?!?!?!? - What the devil!?!?!
So you failed science AND English at school, Steve?
Just joking, of course. I actually enjoy reading much of your stuff Steve, but you can get a little naughty at times...
Don't you think that if Mandrin and BerntR were to get together they could iron out their differences in a jiffy? It's a little harder on the forum, of course.

 

[SteveT]

So you failed science AND English at school, Steve?

Don't you think that if Mandrin and BerntR were to get together they could iron out their differences in a jiffy? It's a little harder on the forum, of course.

Did rather well at "science" and ended up with an engineering degree maximum cum laude .... and even my scientific and vernacular vocabulary excels above most... even though I take poetic liberties with my grammar, but you obviously get the point...!!!

mandrin and BerntR are irreconcilable ... better believe it.

 

[BerntR]

The sound of one hand clapping

I have explained my point of view at all crossroads and from various angles. Mandrin has had ample opportunity to explain his paper as well as the shortcoming in my arguments. He hasn't addressed the arguments. Neither his own or mine.

It is typical for his style that he makes a big deal out of the non existence of figure 35 c-d - instead of explaining why the forces in figure 36a (which I mistook for 35c, which I'm sure he understood) have the wrong direction. Such has all his responses been. Full of obfuscating comments and no effort to bring clarification to the table.

I don't have to prove where Mandrin is wrong to prove him wrong. I only need to justify my own point of view. So far there hasn't been any substantial response to my point of view. Mandrin just keeps saying that I don't understand his "sophisticated" paper. I don't agree with that and I question whether he understands what he has done himself.

Mandrin has obfuscated a very simple problem by decomposing the CP/CF force pair and regrouped them with other inertia and non inertia internal forces. And then ignore the CF contribution to the wrist torque that is a significant part of diagram 35b. He is just too happy to get rid of CF and doesn't see that its footprint is still there.

When you cut through all the obfuscating complications and the cheap rhetoric, the situation is as simple as it has always been - as far as centrifugal force goes. You have a centripetal / centrifugal force pair that is pulling away from each other here as in any orbital motion. These forces can only be carried by the levers. A cocked wrist joint will be outside the line of action of these forces. This offset leads to a wrist straightening torque, and that's the main thing here. And this torque is the major contributor to the release.

Mandrin was whipped by nmgolfer a couple of years ago in another release discussion. Mandrin was the defender of centrifugal force in the release, but was brought to his knees by Nmgolfer's counter arguments (as usual). But that discussion was really about the swing speed created during the release and not the wrist uncocking as such.

A "centripetal" force without the centrifugal opposing force is never going to happen.

Here is mandrin's own conclusion, as rephrased in one of his responses. His tribute to the sound of one hand clapping. I just hope I am not the only one who sees the absurdity of his statements.

Centrifugal force does not play a role in the releases action.
.....
The centripetal force up the arm constitutes the major force in the releases action.

 

[TeeAce]

BerntR,


Wrong.
The centripetal force up the arm constitutes the major force in the releases action. You have the simple picture in your mind of a single mass whirling around a center. With linked bodies the situation is a bit more complicated.

I just wonder if it can be effected or is it just biggest force measured at that point? The last one I can accept without any questions, but I would put the question mark to the first one.

 

[JonWil]

No, wrong revelation, sort of backwards you have it.

More like this... smart people like the scientific truth, but hate the ignorant messenger, the messenger of course would be you.

 

[leon]

I just wonder if it can be effected or is it just biggest force measured at that point? The last one I can accept without any questions, but I would put the question mark to the first one.

Isn't the point of the new information that you can optimise your release to maximise your clubhead speed, which would maximise the force, but at the point of impact you have no chance of influencing the force.

 

[leon]

Well I was finally bothered to read Mandarin's original essay and the latter parts are pretty good. The first bit is overly wordy for me and there are a few statements which aren't fully correct (e.g. "Inertial forces only exist for as long as there is motion" - technically they require acceleration, whereas motion only implies movement which could be constant velocity, but I understand what you are getting at). I think the whole section could have been summed up by just showing figure 16. And I think this is also at the crux of Mandarin and Bernt's argument. This is exactly why I don't like either centripetal or centrifugal as a term - it is just a convenient label for forces which happen to be aligned with some instantaneous radial direction. They are just forces, one "applied" and one a "reaction" in the sense that they are commonly understood, and the fact that most people think they understand them but really don't just adds to the confusion. If you really want to get to the crux of the problem, you should take the approach Mandarin uses later on (e.g. fig21) and define everything in a global cartesian system.

I admit i got a little bored and skimmed the last bits (its been a long week) but I like the graphed forces and accompanying conclusions - it makes sense and ties up with what Brian has been saying recently. Oh and it pretty much boils down to what was shown back in fig 16, i.e. if you apply a force that is not aligned with the clubshaft, it will tend to align the shaft to the force direction. do it right, and the line up will be at impact = speed! That's about as simple as it gets, and I like simple.

 

[leon]

And while I'm at it, I still have no idea why Mike and Brian decided to call it "Going normal" - normal to what?! Normal implies perpendicular to some reference line (2D) or plane (3D), so where is the reference? Along the shaft might be termed radial, or axial, but normal?

 

[SteveT]

This is exactly why I don't like either centripetal or centrifugal as a term - it is just a convenient label for forces which happen to be aligned with some instantaneous radial direction. They are just forces, one "applied" and one a "reaction" in the sense that they are commonly understood, and the fact that most people think they understand them but really don't just adds to the confusion.

..... if you apply a force that is not aligned with the clubshaft, it will tend to align the shaft to the force direction. do it right, and the line up will be at impact = speed! That's about as simple as it gets, and I like simple.

And while I'm at it, I still have no idea why Mike and Brian decided to call it "Going normal" - normal to what?! Normal implies perpendicular to some reference line (2D) or plane (3D), so where is the reference? Along the shaft might be termed radial, or axial, but normal?

Yes, there is a "reaction" to centripetal force generated by rotation and there is a stress reaction found in the arms and even the club shaft!. The "pulling out" feeling your body experiences is just the resistance to centripetal force, and the reaction force is found beneath the feet as ground reaction forces. If you use your non-inertial feeeelings, you will conclude with an erroneous force determination.

Feelings trump physics with the rationale: "I know what I feeel." ...and... "golf is a game of feeeel."


As for "going normal", that's sort of complicated to put in the context of what happens approaching impact. One of the GTE associates suggested that 'going normal' should be thought of as originating from the curvature of the hands coupling point path.

The perpendicular aspect of 'going normal' is the rotating radius from the tangent of the hands coupling path approaching impact. It's a line that goes from the coupling point to somewhere in your upper torso where the rotatory shoulder center is found. The 'going normal' line is in the "air" and that defines the rotatory radius. If you want to align the arms and club into that radius, good luck ...

(My science explanations are subject to change by those who use the term 'going normal' in practice. )

 

[drewyallop]

Yes, there is a "reaction" to centripetal force generated by rotation and there is a stress reaction found in the arms and even the club shaft!. The "pulling out" feeling your body experiences is just the resistance to centripetal force, and the reaction force is found beneath the feet as ground reaction forces. If you use your non-inertial feeeelings, you will conclude with an erroneous force determination.

Feelings trump physics with the rationale: "I know what I feeel." ...and... "golf is a game of feeeel."


As for "going normal", that's sort of complicated to put in the context of what happens approaching impact. One of the GTE associates suggested that 'going normal' should be thought of as originating from the curvature of the hands coupling point path.

The perpendicular aspect of 'going normal' is the rotating radius from the tangent of the hands coupling path approaching impact. It's a line that goes from the coupling point to somewhere in your upper torso where the rotatory shoulder center is found. The 'going normal' line is in the "air" and that defines the rotatory radius. If you want to align the arms and club into that radius, good luck ...

(My science explanations are subject to change by those who use the term 'going normal' in practice. )

Steve,

I may be wrong but isn't the term "normal" common in the study of dynamics? I ask because I know that a mechanical engineer would have studied dynamics in depth. If you know, could you provide a definition that engineers would understand?

 

[SteveT]

Steve,

I may be wrong but isn't the term "normal" common in the study of dynamics? I ask because I know that a mechanical engineer would have studied dynamics in depth. If you know, could you provide a definition that engineers would understand?

It's not commonly used in this context because it's an adjective that describes the orientation of a force in a linear system. The full development of the radial centripetal force is assumed to be tangent to the a point in the circle where impact is supposed to happen... ergo it's perpendicular to the point in the circle where the tangential velocity is assumed to be at impact max.

The "normal' also can help define the radius of the rotation. The 'normal' radius is not necessarily drawn through the club shaft and lead arm. In fact it is drawn from the Center of Mass of the lead arm/club to the rotatory axis/point in the upper torso. The 'normal' radius is then drawn in the air going 'between' the arms to the rotatory center.

It's been mentioned that perhaps the 'normal' radius should be drawn from the hands coupling point arc to the rotatory center in the torso when at impact. That makes sense too because it ignores the orientation of the club at impact and whether it's supposed to be in-line with a flat lead wrist or a cupped wrist... both being valid depending on the club being swung.

The confusion may be interpreting it as NOT being "abnormal" which is a qualitative and feel error. To make full sense of "going normal" you should be familiar with the usual drawing of the mass on a weightless radius arm rotating around a fixed pivot point... and then try to superimpose the golfswing on it. Good luck ...

Hope that helps, because I think I know what I'm talking about ...

 

[BerntR]

I think the whole section could have been summed up by just showing figure 16.

Figure 16 is close, but the forces are pointing in the wrong direction. If an effort were made to apply such a force, point B would be snapped upwards until the force and the lever was aligned and then the force can be applied.This specific direction of force is only possible if there is mass or a real torque added to point B.

A similar hand path and result can however be created without mass or torque in point b. but the physics isn't as illustrated here. The force will always be aligned with the lever. You will get this sort of path as long as the force is bigger than the centrifugal force from the club. If the force is identical to CF it will be a pure CP force and there will be no motion of point B - and you will have a circular motion of the club. If the force is less than CF, the swing radius will simply increase, and point B will move on a curve that chases the club head instead of leading it.

I was going to post an illustration here, but I don't think I'm allowed to upload anything.

 

[Brian Manzella]

I was going to post an illustration here, but I don't think I'm allowed to upload anything.

:\

Sure you are.

Just post the pic to a server somewhere, and hit the "image" button, and there it is.

 

[mandrin]

Figure 16 is close, but the forces are pointing in the wrong direction. If an effort were made to apply such a force, point B would be snapped upwards until the force and the lever was aligned and then the force can be applied.This specific direction of force is only possible if there is mass or a real torque added to point B.

A similar hand path and result can however be created without mass or torque in point b. but the physics isn't as illustrated here. The force will always be aligned with the lever. You will get this sort of path as long as the force is bigger than the centrifugal force from the club. If the force is identical to CF it will be a pure CP force and there will be no motion of point B - and you will have a circular motion of the club. If the force is less than CF, the swing radius will simply increase, and point B will move on a curve that chases the club head instead of leading it.

I was going to post an illustration here, but I don't think I'm allowed to upload anything.

You are really desperately looking for anything you could possibly put your teeth in. It looks more and more like a vendetta than genuine critique. All details in Figs 14 to 16 are left out but most would have understood what is meant. Perhaps a surprise for you but a club is not swinging itself, it is driven by someone and that just happens to be a golfer, using arms having quite some mass and also having a fair rigidity creating a restraint for the point B in the illustration. For your guidance, just imagine a path, as indeed suggested in the text - "the force F, tracing the curvilinear path" - with both the point of application and the direction of the force to be appropriately constrained to this path. Curious what you will come up with next time.

With regard to your idea of applying a force aligned with the shaft. You are bit late. Have a look at my thread 'Miura - parametric acceleration'. Used this particular idea here to create a situation mathematically equivalent to pure shortening of the radius.

 

[leon]

Bernt, I'm sure fig 16 was intended a schematic, to show the idea, rather than to be technically correct. That's how I read it anyway. I still don't know why you insist on using the term centrifugal. Yes there is a force experienced by the hands, it's from the inertia of the club. If you want to call it centrifugal then go ahead, but it doesn't add anything to the discussion. And it doesn't add anything to the clubhead either! As far as I cam see, the only thing that is truly going round in a circle is this thread.

Steve, I'm sorry but I have no idea what you are talking about. Not because I don't understand the content (there is some in there) I just don't know what point you were trying to make.

Brian cleared up the 'normal' definition in two lines in another thread. Less is definitely more.

 

[SteveT]

Steve, I'm sorry but I have no idea what you are talking about. Not because I don't understand the content (there is some in there) I just don't know what point you were trying to make.

Brian cleared up the 'normal' definition in two lines in another thread. Less is definitely more.

No... I'm sorry for confusing you and all others with my bunch of words trying to describe a picture of a weight twirling on a string and then superimposing the human elements causing the rotation. mandrin and BerntR are arguing in circles ... mandrin is the pivot torque while BerntR is the string... and the mass is Isaac Newton rolling in his grand mausoleum in Britain.

I tried because I can see all the little parts of the equation and I know how they interact. You failed because you have little to no perspective of the science. Brian has the luxury of working with his scientific team and to vet his interpretations with them. "going normal" aims at "feel" and "image"... while "centripetal force radial orientation" is obscure to the golffing masses. Scientifically you can't just take one element and isolate it from the rest of the system... but practically you can.

So don't be sorry, just wait for Brian et al to bring the science to you in a palatable form that you can digest in your golfswing.