Shaft Lag
- Thread starter hiroshiro
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Garth
New
Hiro... you just blew my mind. I asked to see it, not to be a smartass, but because i truly didn't believe it was possible. Learn something new every day i guess. I guess my question now is, even with an overly stiff shaft, isn't that an indication of some throwaway? If the idea is to sustain lag until after impact, then I would think that the shaft would look loaded at impact no matter how stiff the shaft. (although i could see why it would be more difficult with it too-stiff)
MizunoJoe:
Regarding the Whippy Tempomaster, it is designed to be used with a "pure" Swing. Most people "add" some "hit" which bends the shaft and causes the face to be open at impact. I have the Whippy 5-iron and the shaft really doesn't have any "kick", at least when kick is defined as a spring-like restoring force.
Thank you for your views. I am not a shaft expert either, and didn't intend this thread to be one on shaft dynamics. When I have some time I will attempt to find the threads to you which referred.
hiro
Tom Bartlett
Administrator
Used to be thought that flexible shaft hits hooks and stiff hits slices. But, Club fitters will tell you differently. Try Henry Griffiths or Swing Sync. Stiffer shaft hits pulls and hooks.
Take it to the extreme. If you swing a garden hose with a club head on it, is the club head going to be in front of or behind the hands? Barring you don't do anything "funny".
Take it to the extreme. If you swing a garden hose with a club head on it, is the club head going to be in front of or behind the hands? Barring you don't do anything "funny".
Garth:
Excellent question. TGM leads one to believe it is possible to bring a loaded, prestressed clubshaft into impact. To most, that would imply that the clubshaft is bent backwards, the clubhead lagging behind the shaft. I have never seen such a photo, so I question whether or not it is possible in a full swing, and hence the genesis of this thread.
In a full swing - Swinging or Hitting - I believe the fictitious centrifugal force acting on the COG of the clubhead is high enough to override the lag pressure that causes the shaft to bend back. This results in the shaft being bent forward at impact even if lag pressure is maintained by the hands (i.e., no throwaway). The question is, is the shaft still considered to be loaded and prestressed at impact when it is in a bent-forward condition?
hiro
bbftx
New
hiro,
This won't directly answer your question about loading, but you might find this PhD research paper interesting.
"Understanding the Role of Shaft Stiffness in the Golf Swing," by Sasho MacKenzie, Univ. of Saskatchewan, Dec 2005.
http://library.usask.ca/theses/available/etd-12212005-163850/unrestricted/Thesis.pdf
This work is commendable in that the author compares his mathematical model of the golfer, club and swing with live golfer testing, noting where the results agree or don't. This is a great way to conduct scientific inquiry on the golf swing. His conclusions therefore have more validity than those from simplified mathematical models alone.
He also mentions conclusions and limitations of some of the earlier research studies of shaft behavior, which is quite interesting.
He covers lots of ground here, including shaft lead/lag, and droop, as well as the influence of stiffness on clubhead velocity at impact.
But he does make an interesting summary of the lead/lag issue:
"Two additional points should be made regarding the results from the highspeed video data. First, with the exception of the left-handed golfer [swinging a right-handed club left-handed, so it's not representative of a real golf shot], every swing with every club resulted in a lead deflection at impact, as did the simulation results."
This won't directly answer your question about loading, but you might find this PhD research paper interesting.
"Understanding the Role of Shaft Stiffness in the Golf Swing," by Sasho MacKenzie, Univ. of Saskatchewan, Dec 2005.
http://library.usask.ca/theses/available/etd-12212005-163850/unrestricted/Thesis.pdf
This work is commendable in that the author compares his mathematical model of the golfer, club and swing with live golfer testing, noting where the results agree or don't. This is a great way to conduct scientific inquiry on the golf swing. His conclusions therefore have more validity than those from simplified mathematical models alone.
He also mentions conclusions and limitations of some of the earlier research studies of shaft behavior, which is quite interesting.
He covers lots of ground here, including shaft lead/lag, and droop, as well as the influence of stiffness on clubhead velocity at impact.
But he does make an interesting summary of the lead/lag issue:
"Two additional points should be made regarding the results from the highspeed video data. First, with the exception of the left-handed golfer [swinging a right-handed club left-handed, so it's not representative of a real golf shot], every swing with every club resulted in a lead deflection at impact, as did the simulation results."
Burner:
Thank you for your reply.
In your opinion, do you feel that in a full swing, by "dragging your wet mop right through to low point" that one can maintain the lag until the point of impact in a way that is manifested by the shaft bending backwards? And if you do believe this, can you direct me to any photos displaying this?
Thanks.
hiro
bbftx:
Thank you very much for the most interesting link. I was unaware of this paper, and will read it in depth if my 15-month old allows it (he is tugging on my arm as I type this).
The last line of your post was intriguing. If the left-hander's phenomenon is a valid one, perhaps we all need to buy the opposite-handed clubs and swing them upside down the way Mac O'Grady is purported to be proficient at
.hiro
So unless someone comes up with some new evidence, i think it's safe to say that essentially all golfers have a forward bending shaft at impact. In fact, varying the amount of forward bend is, besides feel and weight, the greatest way that shaft design can produce a change in ball flight.
Hiro that's a very interesting question. when the "line of pull" passes the hands, can you still feel the #3pp? Is there still a pull? Can you truly sustain the lag pressure with a forward deflecting shaft? How long does the shaft actually have a forward bend? Does is return to straight so quickly that any potential loss of the #3pp is overiden by impact? hmmm.
Someone on the Wishon forum built a "club" without the clubhead cog rearward of the shaft. would be interesting to have a swing of a club like that.
Hiro that's a very interesting question. when the "line of pull" passes the hands, can you still feel the #3pp? Is there still a pull? Can you truly sustain the lag pressure with a forward deflecting shaft? How long does the shaft actually have a forward bend? Does is return to straight so quickly that any potential loss of the #3pp is overiden by impact? hmmm.
Someone on the Wishon forum built a "club" without the clubhead cog rearward of the shaft. would be interesting to have a swing of a club like that.
Brian Manzella
Administrator
No matter what the clubhead is doing to the head, the grip end is still stressed by the golfer.
mandrin
New
hiroshiro, it might be useful to do the following very simple thought experiment, viewing a down swing somewhat prior and through impact.
Consider the angular velocity of the club handle of a completely rigid shaft to one with a small additional motion of the club head due to flexing of the shaft.
It is quite reasonable to assume that the angular velocity of the club handle in both cases will be the same, for equal conditions.
In other words one can consider the motion of the club handle to be virtually decoupled from the small motion, due to flexing, of the club head.
Hence, I do feel that one can maintain lag pressure prior to and through impact despite the fact that the shaft might bend forward.
The word ‘kick’ is misleading as it invokes a spring like action. The shaft in the hands of a golfer is really overdamped and can’t oscillate during a golf swing.
Too often one uses a shaft clamped in a vise as starting point which is leading one away from the reality of a golf swing.
mandrin
New
MizunoJoe,
Flexing of a particular shaft is mainly determined by :
(1) Torque/force time history as applied with the hands.
(2) Centrifugal force acting on COM of the clubhead.
First part of downswing ruled by (1), second part by both (1) and (2).
It is known that the force/torque time history varies considerably.
Flexing behaviour of shaft will hence accordingly be quite unique.
You could probably also throw in the effect air drag,
but forget the idea of a loaded shaft kicking. [8D]
mandrin,
A shaft kicks when the lagging clubhead starts overtaking the shaft. Do you think that all the photos of this phenomenon are illusions? Is all that launch monitor data a hoax? Do me a favor - go to the bombsquad forum and make that statement - now that would be fun to read! [
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