quote:Originally posted by EdZ
Mandrin - do you think it is potentially the case that what you are seeing as a forward 'kick' through impact is really simply a timing/acceleration issue? That the RATIO of loaded to unloaded force vs TIME is an important factor?
I fully agree that a shaft 'can be' kicking forward through impact, but doesn't that really indicate that there is a another variable at hand?
If I take a piece of paper and hold it on its side and swing it back and forth, a 'lag' is created such that the bottom edge clearly lags behind the top. If however I change directions too slowly and/or don't 'keep up the forward motion fast enough' the bottom edge will 'kick past' the top.
Isn't this basically the same issue we are seeing when a shaft has 'kicked' forward through impact? A timing and/or acceleration problem. A problem with the ratio of load/unload force vs. time?
EdZ, your questions, and comments from other posters so far, don’t seem to address the issue raised in my linked post.
But, let me first deal with your concerns. I thought being alone having developed a mathematical model for the golf swing which includes bending of the shaft. Rather complicated stuff. Recently someone pointed out to me that Wishon et all are also working on the same issue. However, shaft bending issues in a golf swing is not part of my present linked post, which deals exclusively with the collision of clubhead with ball.
However I will for now just say that the popular notions of ‘loading’ the shaft at the top, ‘forward kicking’ at impact are myths stubbornly surviving in golf. Opinions are often extrapolated from considering a golf shaft clamped in a vice which is completely different from a shaft in the hands of a golfer in a down swing, due to different respective mechanical impedance of vice vs hands.
Any ‘loading’ (potential energy of shaft due to bending) at the top is immediately thereafter largely dissipated and not available at impact. The illusion of energy being released is created with the shaft seen bending forward at impact. This however is not due to forward kicking but primarily due to the centrifugal force operating through the offset center-of-mass of the clubhead.
Back to my linked post. I would appreciate it to have your opinion on it. Let me reformulate the issue from a different angle - perhaps the basic idea will be easier understood as to what I am trying to say.
There is the intuitive conviction, taking on different formulations, that a slow, heavy, deliberate swing will produce equal or more ball speed than a quick, light, speedy swing.
There is the intuitive notion that sustaining the effort, keeping pressure on the ball through the shaft results in a clubhead better resisting impact, to decelerate less and therefore resulting in more ball speed.
With
Ike S. Handy these ideas are put forward as:
- “Speed in the clubhead is NOT the power which drives the ball.”
- “No degree of speed in the clubhead will supplant the power of swinging the weight of the body into the ball into the stroke.”
- “You will find that the slower you make the downswing, the harder and farther you hit the ball.”
Mindy Blake, notwithstanding a solid scientific background, gave in to the same illusion:
- “It is widely accepted that the critical factor in determining the distance a golf ball travels is club head speed at impact. This is not true. Supporters of that view do their mathematics on the assumptions that the clubhead is a freely-moving object colliding with a golf ball. In fact, a golf club is not a freely-moving object. It is an extension of the body, gripped by the hands, and the critical factor in determining the distance the golf ball travels is
pressure applied to it or, to put this in a more scientific way, the application of
force through distance.”
Blake feels that by swinging slowly and applying pressure onto the ball with the shaft that the clubface stays on the ball longer and that more ball speed is being generated. He differentiates between a
high-speed-swing and his type golf swing, the
high-pressure-swing, being superior.
Homer Kelley is toying with similar ideas in The Golfing Machine.
(12) “The secret of Golf is
sustaining the ”Line of Compression.”
(15) “... compress the ball through a particular point along a particular line, and
maintain this compression ...”
(25) “Speed and Prestress stiffen the Clubshaft for consistent
resistance to impact Deceleration.”
(36) “... and the
sustaining or
driving actions of the above mentioned Thrusts - all of which contribute
resistance to Impact Deceleration.”
(51) ”The ideal - even with an Automatic Release- is to be
very deliberate, positive and heavy.”
(51) “... until a positive Clubhead Lag can give the Hands a
heavy Clubhead to drive (or swing) against the ball - at al speeds.”
(80) “
The prestressed Cubshaft will resist the added weight of the ball during Impact, .... “
It is evident form above that Homer is clearly convinced that clubhead deceleration can be reduced, and hence more ball speed obtained, if the various thrusts and a bent (stressed) clubshaft condition is maintained during impact.
I have shown conclusively that it is of no use to try exerting any force through the impact interval. Therefore either I am wrong or Homer has stretched his intuitive powers a bit too much and has made an error. EdZ, you have an inquisitive mind, what do you think?
