Thanks for the "shazam" moment, Geoff ... and as lawyers say: "Don't ask a question for which you do not know the answer!"
As the scientist says: "Always ask what you don't know, so you know where to start with science."
1. Re Medicus Revolver ... now that heel-toe rotating weight rod design should provide even the most insecure golf-ing buckaroo with the ultimate in putter one-upmanship ... but is the design in keeping with the tradition of golf as protected by the manufacturer-infiltrated USGA? We await your review with bated breath ... go for it .. please.
All putters that have "adjustable" features like changeable weights, lofts, lies, aim lines, etc., are required to be "fixed" so as not to present much chance of altering during play. The USGA allows equipment that can be changed between rounds, so long as the changes get locked down adequately. In approving these designs, the USGA tests the locking down to make sure it is adequate. Then the approval by the USGA constitutes the "de facto" tradition of the game. The USGA and R&A define the traditions.
2. Yes Geoff ... as you say: "The better you are, the less MOI matters." If you do strike the ball say 0.5" off the sweet spot, you can compensate with a firmer grip pressure in a torqued putting stroke ... whereas in a soft-handed gravity-assisted stroke you will be at the mercy of the eccentric impact causing putter head and shaft torque going into your hands. Most novice putters are taught to hold the putter handle very lightly and that destroys their feel and feelings as they lose control when they hit off center ... which induces the manufacturers to go to extreme MOI designs to compensate for klutziness. If the stroking techinque was improved, this MOI issue would vanish and relieve putting angst.
The "insurance policy" of high MOI is a little like wearing a scuba tank in the swimming pool -- potentially useful if you get your toe stuck in the drain grate, but sooner or later you have to learn not to stick your toe in the grate. you SHOULD want high MOI so long as it doesn't take a weirdly shaped and looking and weighted putter head to get there.
3. Ball 'launch' must be a function of initial ball velocity. A high initial ball velocity may launch upwards or skid level depending on the putter loft position at impact. The putter head becomes a virtual moving target attempting to meet the stationary ball at some loft amount. If impact is ascending, the ball will launch ... if level it will skid horizontally ... if descending it may even get driven into the ground . For very short putts, there is no launch, only short skid and immediate rolling. The position of the CofG of the putter head obviously is a factor in these examples.
Again, I suggest that novice and even decent golfers may not be able to hold the dynamic loft conditions constant, making initial impact putting conditions problematic. The solution requires knowledge how to properly present the putter to the ball, and actually doing it consistently.
I think the physics of launch is a bit more complicated. First, a straight line of force thru the center of gravity of the ball will "punch" the ball in the same direction, and with a "slab" planar putter face that can only touch the back of a sphere on the sphere's tangent plane that matches the slab's presentation plane ("dynamic loft at impact"), hitting level;, up, or down thru the ball all will equally "punch" the ball off the face in that one direction (normal to or perpendicular to the tangent plane of contact, whatever that might be). This isn't quite what actually happens, because the presentation loft of the putter actually (99%+ of the time for all golfers, except perhaps Dave Stockton Jr. and a couple of others with techniques that are learned and honed over 3+ decades) changes DURING impact / contact between ball and putter fro straight thru the COG of the ball to some other line of force that misses the ball COG to the high side of the ball's COG. The "resultant" line of force from the "impulse" over the contact time does not normally "punch" the ball but affords a bit of "knocking a top half of the ball over a bottom half". I say "a" bottom to avoid the mistaken notion that there is only one top and one bottom of a golf ball defined by the equator. The "equator" divides above and below in reference to "level in gravity". That's one definition of top and bottom, but in physics the reference is not gravity but the COG of the ball that combines with ANY line of force thru the COG to define a top and a below. Balls can be 'rolled" to some degree regardless of whether the initial contact tangent plane directs the line of force level, up or down thru the ball. These differences make a difference in launch and skid, but starting contact straight thru the center is ALWAYS the case. You cannot possibly in geometry use a slab to touch or hit a sphere EXCEPT by matching slab to tangent plane, and this by definition means ALL initial contact with ANY ball by any PLANAR putter face directs the initial line of force ONLY thru the center of the sphere, where the ball's COG is (supposed to be) located.
Second, "skid" is pretty much misunderstood. Most people have the false notion that skid means "no rolling at all." What "skid" really means is "bottom of ball is engaged with the sliding friction of the surface and this friction torques the mass of the ball and imparts a forward rolling force". The torquing force on the ball decreases as the ball rolling velocity speeds up, but the "skid friction" or "slide friction" does not really change. Calling something "skid" is just referring to the rolling state of the ball being less than 100% rolling. Skid disappears altogether when the ball's rolling matches its "translational" lateral motion across the surface, so that in the course of 5.28" of distance the sphere rolls so that each point on the perimeter of the ball comers in contact with the surface without sliding laterally. For a sphere, this point always occurs whenever the surface friction slows the ball translational velocity to 5/7th its initial velocity when first engaging the surface. That's because this is the magic point when translational velocity matches rotational velocity of a sphere, from the geometry of the relationship of rolling sphere and lateral motion of the bottom-most point of the sphere across a plane. So "skid" is what happens when the ball translational velocity is faster than 5/7th the initial velocity -- period. The green surface does not present DIFFERENT sliding friction except by irregularities in the grass and surface shape. For purposes of science and clear thinking about "skid", this variability is ignored. Hence, ALL skid on one green or common-speed greens is the SAME skid at all times until the ball velocity reaches the 5/7th point in the putt, when skidding stops. The "relative" combination of skid and roll at different points in this skid phase is actually the state of forward rotation as it approaches the angular rotation velocity of the magic 5/7th velocity. The notion that there is 100% skid and 0% roll at the start of skidding and then gradually the friction of the surface "adds" more rolling so that there is a 50-50 point and then there is a 0% skid -- 100% roll point at the 5/7th velocity is not exactly correct. The "skid" does not really change. What changes is the angular velocity of the ball due to the rate of acceleration imparted by the skid's torquing the bottom of the ball. The more the ball accepts this accelerating force, the faster the angular rolling velocity of the ball, and that means in turn the less torquing force. The torquing force depends upon the DIFFERENCE between rolling speed and sliding speed.
On the green, the golfer does not want to know when the ball reaches 100% rolling, and instead needs to know how long engagement with the surface takes to get a ball's rotational state to match or equal something reasonably attainable with a different stroke technique that does not sacrifice something valuable. What does that mean? Forget "true roll" as an ideal and focus on what's real and what matters. What's real is what you can get done without going nuts and making a mess of something else in the putting consistency and accuracy. It's a trade off. Don't give up something for nothing, and don't make a bad deal. If you MUST own the Brooklyn Bridge of putting, then give me $100 and a) I'll show you how and hand you the title today, and then b) I'll beat you on the greens and take another $100 every day of the week until you're older than Dave Stockton Jr., at which point you'll receive a diploma as a graduate of the School of True Roll that you can put in a lock-box along with the bridge title. So what is normal for 99% of golfers? A putting stroke combined with a putter that imparts some backspin (about 30-50 degrees backspin at launch and landing). What's realistically attainable with all the special putter design features plus special stroke techniques? A launch of 2-3 inches in the air and initial landing rotational state of positive spin of 30-50 degrees forward rolling. Only about 10% of all golfers will ever get this latter combination of skill and putter, and perhaps you're one of these. If not, it is a total waste of effort to pretend otherwise. But if you are and spend the time and money chasing this level of realistic "true roll", what difference does it actually make? Comparing putt A with "true roll" putt B, Putt A hits the ground with backspin and then the friction accelerates the ball into forward spin. Okay, how long before putt A's initial backspin rotation / rolling state gets changed by friction and "catches up" with the initial rolling state of putt B (30-50 degrees forward roll on landing)? About 2/100th of a second and 2" of grass. You would really have to do something weird to get much more "bad" backspin into a putt than this, and you would also have to do something really weird to get much more "good" forward spin into a putt than this also. So you can either: a) not worry about 2" of the putt and just try to make solid impact with accuracy and consistency, or b) shift your practice and attention to less backspin / more forward roll because you're afraid something horrible will (eventually) happen in that dreaded 2" of extra "skid" in the usual stroke. Knock yourself out. But for my money, I'd rather see you work on a "plain jane" technique and get the consistency and accuracy down.
8. Amen ... and I notice several of your preferred putters have the hosel and shaft aligned directly into the putter head, or at least reasonably so. A slight deviation is not that significant, but when the hosel or shaft have many bends and twists and turns, I find it near impossible to adapt to that orientation, regardless of my putting skills.
9. Re: Face-balanced. Yes, I was thinking of a simple bilateral blade putter with the shaft and gravitational hanging axes coincidental so it can be rotated and hold that rotation in any axial position. Face-balanced for the masses is with the putter face flat and pointing upwards because of backweighting ... and since the word "balanced" is uses to improperly describe an axial condition, everybody believes such a design is desireable. Obviously a backweighted face-balanced putter is not balanced in all axes.
10. If I understand you, the putter "footprint" is actually the shape of the putter sole and how it's designed to compensate for "scuffing" in the downstroke should contact be made with the grass. This kind of goof is lack of control of the putter's elevation off the green, and is a sign of inadequate stroke control. I must admit this occasionally happens to me, but only when I fall into a lackadaisical moment and botch the stroke. Forward stroking bravely with increasing velocity or even constant velocity together with concentration on the task, eliminates scuffing. Of course a longish front-to-back putter head with inadequate clearance can be dragged in it's derriere if the stroke is too ascending.
No, I mean the brain-body relationship to the plane of the green surface via the tool of the putter and its sole. This "footprint" is the unseen area of putter contact with the surface felt in the body. Scuffing has to do with a) stability of the stroke shape and setup during the stroke, and b) bad putters with the front-back dimension too long. If you have a reasonable putter head shape, scuffing is ALL down to maintaining the height of the putting pivot point in the base of the neck and not allowing any "play" in the arms at setup to change the putting shape during the stroke. So if you hang the arms to eliminate "play", set muscle tone to a steady tonic level in light of the violence level of your forthcoming stroke so the arms don't grow longer in the stroke, set the height of the pivot point and don't let it "bob" during the stroke, you eliminate scuffing entirely.
The safest designs are the Bullseye "thin sole" models. And as for highly rockered putter soles to accommodate a range of shaft lies, that brings in the question of the 'problematic' effective face lofts at impact ... because rotating a 3º lofted putter face through say a range of 60º flat lie to 80º vertical lie will skew the static face loft on it's stroke path to the ball. However it seems irrelevant if the golfer knows how to compensate for his/her biases .. whether they consistently pull or push the putt.
No, I disagree. The area of contact helps the stability of the setup, helps the stability of the body during the stroke, helps the brain's planning the stroke motion thru the bottom, and helps the making of the stroke for timing and for form. The implicit or explicit awareness of the putter sole's contact foortprint during the setup and stroke motion definitely helps consistency and accuracy. Putter soles that are too thin compared to larger-but-not-too-large areas of contact simply do not perform as well for almost all golfers, and golfers using these too-thin soles can certainly do better with a larger-area sole, but they will have to kiss their devotion goodbye before finding this out.
The radiusing you're talking about above is in the heel-toe direction. For this, the trouble does not arise if the putter face has ZERO loft at impact. But for all other situations, a toe-up positive loft at impact biases the direction of the force up and to the inside, and a heel-up positive loft at impact biases the direction of the force up and to the outside. Okay, but how much and does it matter? Not much, but yes, a little, since a 10-foot putt can afford no more line error than about 1 degree off center left or right. Here is the deal:
I don't have time right now to calculate the line error introduced with impacting a ball with 4 degrees of positive loft and the toe up 1/4th an inch off the surface, but I believe it's on the order of "don't go there" for most putts 10-feet and longer. I do this later and post it below.
Re: golf-ing suckers ... being exploited psychologically by avaricious manufacturers. I refer you to the 1994 paper by Frank W. Thomas (when he was in his last days as USGA Technical Director) contained in the Science and Golf II published proceedings on pages 237-246.
Some snippets ....
Manufacturers are supplying a demand driven mostly by our insatiable urge to gat a little more our of equipment than we are prepared to work for. Our wishes seem to be granted by each new piece of equipment we decide to purchase, as this seems to carry with it a presently unexplained phenomenon, which temporarily separates our minds from interfering with our natural swing movements, exposing our real potential for a brief period of time. .......
It is understood by the administrators of the game, as it is by the participants, that a golfer's need and wants differ fairly dramatically at times.
It is very common that extraordinary performances are credited to new equipment by the golfer, his golfing companions, and the manufacturer "Placebo Effect". The manufacturer would like to believe that the new design actually works and the golfer would like to believe the manufacturer's claims. This synergistic form of wishful thinking results in a temporary dislocation for the golfer's mind from interfering with his body. He is on fringes of the world of "make believe," and the results are extraordinary. The golfer swings better and the manufacturer takes heard ( considerably more than he should) from this extraordinary performance. This then snowballs, wending the manufacturer's marketing division into a "hype frenzy". The elders of the game understandably express concern and call for something to be done to curb this new innovation. At the same time, they seem anxious to get their hands on the particular piece of equipment in question. This cyclical phenomenon is as predictable as winter following summer, and almost as common.
Science has at last entered every aspect of the game of golf. This is, in the most part, due to competition in the marketplace, and thus, the need to produce something that really is better. Also, men of science are among those who have taken to the game. From the rules making point of view, it has become evident that a rule which permits only clubs of the "traditional and customary form and make", is extremely important to retain, but may not be sufficient any more, and that as science enters the game, so must science be used to protect it.
Science is entering golf, and the game can only benefit from this.
..............................................
The references are to the golfswing, but it can also be applied to the putting stroke and putters.
Personally I agree that chasing the performance of Tour players harms the game by changing courses, equipment, instruction, and all of the game in a bad way for 99% of the people who should want to play it. Magazines and television shows feed this nuttiness. Perhaps one day a person can simply find a well-groomed golf course and have a nice round and try to bring real skills to bear with reasonable equipment to play very well and do the best they have ever done in golf, with the hope of going lower the next day, whatever the "par" might be according to the folks manically watching Tour players when they determine what passes for "par." No thanks. That's as a person who enjoys golf and wants children to take to the game without visions of "Superman" Tour stars clouding their eyes when they stare down a 175-yard pitch shot with their suped-up clubs. No one wants the child not to emulate "sports heroes" in terms of their skills, but that doesn't mean teaching the child that anything less than 300-yard drives and near-perfect wedge play constitutes no more than "Goofy Golf" or that 6,500-yard aged-in golf courses are somehow not "really" golf.
As a coach, I accept the challenge of helping ANYONE gain better skills than they currently have, including Tour players. If a Tour players wants to get better and doesn't believe he is at full capacity for performance on the greens, who should he turn to -- his caddie or someone like me who has spent twenty or thirty years focused solely on being able to offer real solutions to real issues? It's not vanity on my part to suggest a common-sense answer to this question: try both and see which one knows more that actually helps performance.
