[DMoriarty]

Paul,

I understood what Frank Thomas wrote on the issue but what you wrote indicates that you do not.  For example . . .

Garland

Is that 0.79 COR for wooden club with a modern ball?

COR is a constant that applies to the entire collision.  When clubs were solid and wooden the COR was determined by the ball.  It's only when Callaway started achieving the spring like effect (trampoline) that the driver design influenced (increased) the COR.

The COR of a wooden club is NOT dependant on the golf ball used, nor is the COR of the golf ball dependant upon the the club.   In an impact between a solid wooden club and any golf ball both the COR of the ball and club influence the resultant impact.  In such an impact the what you call the COR of that impact was NOT determined solely by the ball but by the inpact between two objects with seperately measurable CORs.

As for the actual USGA study it does NOT support the conclusions you (and they) claim it does.   I addressed the problems in  one part of their study in the other thread and would be glad to address the appendix with the tour stats but we should do so on the other thread so as not to distract from the point of this one.

A good place to start might be with you review of your own past statements on this issue over the years where you have been consistent but wrong throughout.  Nothing necessarily wrong with being wrong, unless one refuses or fails to learn from it , and that unfortunately appears to be the case here.

—-------------------------------

Craig, your skiing analogy falls flat as, unlike golf, the improvement in equipment there  has had the greatest impact on novices.  Plus the greatest positive impact has been on safety.  What does you driver have to do with whether you might blow out your knee or even die?    

[Rich Goodale]

Richard The Magnificent:


That post #41 (particularly the pros and cons) is just so Goodalish and magnificent (and hilarious!). Only you can come up with stuff like that!

YOU are indeed a 266 yard REDAN type of guy!

I can just see you bringing a myopic standardized thinking American to a tee to the left of NB's redan from 266 yards and listening to him scream: "What the hell is this thing, a par 3 or a par 4 and how am I supposed to play it without knowing?" and you responding, "AHA, EUREKA you mush-brained architectural troglodyte!"

Tommy the Swami

Now I know why you didn't invite me to play NB when you and that Ammerman guy came over to the auld sod.  You would both still be stymied by that stone dyke after hitting your mashie off the back tee of the 266 yard Redan just a little bit too far.....

PS--don't get too excited about the Fillies unless they get 3-0 up and 13-0 in the 9th inning of the 4th game (I'm assuming that the Yankees will be the home team, as is always their right....).

Rich

[TEPaul]

Interesting questions (and discussion) about whether COR (in the context of these threads) is about the COR of a golf ball only, the COR of the face of a golf club (driver) only or some combination of both when one impacts the other.

I've said I'm certainly no scientist, and I'm not, but it does seem ironic to me that I had this very discussion with Frank Thomas (and others) while spending most of a day at Pocantico Hills a few years ago.

These questions were asked of Thomas and I recall he was asked to try to explain them in the context laymen might understand. I think he did that and I also recall he tried to explain his position that he felt (while he was the Tech Director of the USGA Test Center) that  the COR of a persimmon wooden club was around (.078-.079) and that the I&B Rules and Regs of the COR of a conforming driver should be set and limited to that driver COR and not go higher). Of course, at that point the market had been flooded with metal drivers that had CORs higher than that.

I also recall Thomas saying when COR of a driver increased (from say .079 to .086, the latter being the former COR limitation of a driver face before being taken back to .083) that the minuscule increased time a golf ball stayed on the face of a driver (.086 or .083 compared to .079) simply served to impart additional energy transfer (springlike or trampoline effect of a driver) and additional distance because of that additional energy transfer.

In the symbiotic effects of physics this might be explained in some various ways but I think Thomas' only real concern was with WHERE to set maximum limitations on the various factors of implements and golf balls to produce some maximum point that would simply serve as an over-all "pass/fail" test or line (ODS).

In perhaps somewhat the same vein, Thomas was asked why he set the swing speed MPH test protocol at 109MPH rather than some MPH that was higher (today it's at 120-122MPH)? I recall he said it really didn't matter since the swing speed MPH was only chosen as a factor in the over-all ODS test which was nothing more than a "pass/fail" conformance test on overall distance. He also said when that swing-speed MPH was set it seemed that was about the swing speed of the longest players of the time (I think that original ODS test and its protocol factors might have been established as far back as 1976).

[TEPaul]

Richard:

I want you to know that still today Ammerman considers NB to be the neatest course he has ever seen. I think he might even say it is the best golf course architecture he has ever known. So much for him being some standardized mush-brained American architectural troglodyte.

Of that I am completely convinced. Now, why he hit Mrs. Majors in the ass with his golf ball two and perhaps three times in that one round is a world straddling complexity the answer to which I may never completely know.

[Garland Bayley]

Garland

The COR measured in "Search for the Perfect Swing" published in 1968 was 0.70.

Tom

I didn't know about the composite wood and COR influence.  I guess it must have been pretty small, cos I just can't see much compressive elasticity in wood.

"The COR of persimmon is .78 against a current USGA ceiling of .83. When the club face hits the golf ball, the ball isflattened and there is a loss of energy." from a search result that yielded a website not currently accessible.

EDIT: Found it on a different website.
http://www.persimmongolfeurope.com/acatalog/FAQ.html

[Garland Bayley]

Threads like this make me laugh...if you want to drive (no pun intended) more people form the game go ahead and roll back to difficult to hit irons and woods...and a ball that goes 250 yards when the BEST players hit it square...

That's because you subscribe to the myth that real improvements in clubs have been made for the average golfer. It's all marketing nonsense Craig. The ball is a different story, but this thread is about clubs.

[Rich Goodale]

Swami

It seems obvious that either:

1.  Ammerman forgot to factor in the fact that COR's of metal clubs increase counterinversely to the depth of the sand below them.  With the impressive depth of sand on most of the NB tees, when Mrs. Majors arse seemed to be out of range for Ammerman, in fact it was not.

2.  If Ammerman was using a ProV1/ProV1x off the tee, he should have also known that there is a weak atrractive force between the polymers used by Titleist and the lycra in certain ladies knickers.  It could have been an honest mistake, or did he pull her later in the bar?

Cheers

Rich

[Paul_Turner]

David

I'll stand by my statement.  With a solid club and no trampoline effect the driver design had very little, to no, influence on the COR of the collision.   Any solid surface that doesn't flex, traveling at the same speed and with same mass would produce the same (or very close) COR in the collision.
In the 2000-2005 time frame that we discussed this, you consistently claimed that the longest players on tour gained disproportionally over the shortest and the USGA report disproves that.  Feel free to start another thread to discuss.

[TEPaul]

Swami

It seems obvious that either:

1.  Ammerman forgot to factor in the fact that COR's of metal clubs increase counterinversely to the depth of the sand below them.  With the impressive depth of sand on most of the NB tees, when Mrs. Majors arse seemed to be out of range for Ammerman, in fact it was not.

2.  If Ammerman was using a ProV1/ProV1x off the tee, he should have also known that there is a weak atrractive force between the polymers used by Titleist and the lycra in certain ladies knickers.  It could have been an honest mistake, or did he pull her later in the bar?

Cheers



Rich:

You are, as usual, a theoretical genius with your #1 and #2 above. Indeed, it could've been those two things or it could've been the fact that at that time Ammerman only had sight in one eye and obviously that does significantly influence one's ability to suss out spatiality and distance!  

However, even without good spatial ability I have no doubt he is able to pick out targets and lock onto them visually regardless of how far away he thinks they are and on the subject of his target and what his eye picked up for his target on that particular day on NB Mrs Majors' derriere may've had something to do with it.

I haven't spoken with him in some time about all this (I'm not so sure he likes to talk about it) but I think at the very least I should call him soon to try to determine if the COR of Mrs Majors' derriere might have also been somewhere on his mind on that fateful day at NB.

And I'm sorry you could not have been with us on that grand day at NB. Apparently you did not hear me calling you across that body of water between us. What is it called?  ;

[Paul_Turner]

Interesting questions (and discussion) about whether COR (in the context of these threads) is about the COR of a golf ball only, the COR of the face of a golf club (driver) only or some combination of both when one impacts the other.

I've said I'm certainly no scientist, and I'm not, but it does seem ironic to me that I had this very discussion with Frank Thomas (and others) while spending most of a day at Pocantico Hills a few years ago.

These questions were asked of Thomas and I recall he was asked to try to explain them in the context laymen might understand. I think he did that and I also recall he tried to explain his position that he felt (while he was the Tech Director of the USGA Test Center) that  the COR of a persimmon wooden club was around (.078-.079) and that the I&B Rules and Regs of the COR of a conforming driver should be set and limited to that driver COR and not go higher). Of course, at that point the market had been flooded with metal drivers that had CORs higher than that.

I also recall Thomas saying when COR of a driver increased (from say .079 to .086, the latter being the former COR limitation of a driver face before being taken back to .083) that the minuscule increased time a golf ball stayed on the face of a driver (.086 or .083 compared to .079) simply served to impart additional energy transfer (springlike or trampoline effect of a driver) and additional distance because of that additional energy transfer.

In the symbiotic effects of physics this might be explained in some various ways but I think Thomas' only real concern was with WHERE to set maximum limitations on the various factors of implements and golf balls to produce some maximum point that would simply serve as an over-all "pass/fail" test or line (ODS).

In perhaps somewhat the same vein, Thomas was asked why he set the swing speed MPH test protocol at 109MPH rather than some MPH that was higher (today it's at 120-122MPH)? I recall he said it really didn't matter since the swing speed MPH was only chosen as a factor in the over-all ODS test which was nothing more than a "pass/fail" conformance test on overall distance. He also said when that swing-speed MPH was set it seemed that was about the swing speed of the longest players of the time (I think that original ODS test and its protocol factors might have been established as far back as 1976).

Tom

Here's excerpts from "Search for the Perfect Swing" published in 1968 so all the data is for wound balls with solid wooden head.  

"it will be clear to the reader at once how important for the length of the drive is the degree of the elasticity of the collision between the clubface and ball; and this very largely depends, of course, upon the elasticity of the ball's behaviour,rather than the club's.  The face of a club is so hard compared with the ball, that there is virtually no deformation of the clubhead, and consequently little energy loss in it"

So with the solid and hard wooden heads the COR of the collision was essentially determined by the ball at any given swing speed (I'm assuming all drivers had v similar masses).

Once the driver faces started to flex, deform and exhibit elasticity at impact then the driver design started to affect the COR of the collision.  Because the driver face became elastic, the ball deformed less.  So at impact less elastic energy is stored in the ball but now elastic energy is stored in driver as well.  The thin metal face is more efficient than the ball at storing and transferring elastic energy into kinetic energy (motion).   Which results in less energy losses and a subsequent increase in the COR for the ball/club collision.
 



Ball Compression and how it equates to a higher COR.




And finally some discussion on how to make a lighter 1.3oz and therefore shorter ball that would affect the pros more than the rest of us.  Some prescience re the ball and developments too...solid balls.

[Craig Sweet]

Craig, your skiing analogy falls flat as, unlike golf, the improvement in equipment there  has had the greatest impact on novices.  Plus the greatest positive impact has been on safety.  What does you driver have to do with whether you might blow out your knee or even die?   

David...I totally disagree...the changes in the ski industry have benefited skiers across the board...have you ever seen the skis Bodie Miller runs slalom with? They are way shorter than him, have a serious side cut and shape for quick, effortless turning....an intermediate uses the same skis only tuned down...how about guys that ski in a half pipe or terrain park? Could they do that 25 years ago? NO!   The greatest impact from shaped skis and better boots has been ease of turning and comfort...something that skiers of all abilities want.  Safety had to improve..no question....but the ability to turn with little effort, and the comfort of the new boots is the greatest impact.

I use the same driver as Sergio and many others...same technology, only tuned down...what makes the equipment good for Sergio makes it good for you and me...

And therein lies one of my problems with this whole idea that "better" golfers should use different equipment than you or me...I think you do that and you lose the cash incentive  to do the research necessary to continue to improve equipment.

[Ulrich Mayring]

Competition clubs won't work, because of economics. The equipment manufacturers wouldn't make special clubs for just a fraction of the golfing population and, frankly, a fraction that is not used to paying for their clubs either.

A competition ball could be a different story, as it is vastly cheaper to make one special ball compared to 14 special clubs. But even then I wonder what the incentive of the equipment manufacturers would be? Why should they invest in creating any special piece of equipment, if they can't sell it afterwards?

If I were Titleist and the USGA/R&A decided to mandate a competition ball, I wouldn't make one and just continue to sell my Pro V1s to amateurs. Sure, I would lose all the Tour player endorsements for my ball, but they would be worthless anyway if people knew that these guys were playing an inferior ball. To put it bluntly, why would any company choose to market a ball that is so inferior that Tiger Woods hits it only 250 yards?

If a rollback in equipment is to occur, it needs to be done in a way that pros and amateurs play with the same equipment, but that the "roll-back factor" affects only very good players. It appears that is the route the USGA/R&A are taking with the new grooves.

Ulrich

[Paul_Turner]

The COR of a wooden club is NOT dependant on the golf ball used, nor is the COR of the golf ball dependant upon the the club.   In an impact between a solid wooden club and any golf ball both the COR of the ball and club influence the resultant impact.  In such an impact the what you call the COR of that impact was NOT determined solely by the ball but by the inpact between two objects with seperately measurable CORs..
  


David

What do you mean by separately measurable CORs and how is this done?

[Garland Bayley]

Paul,

Perhaps you could look it up, but I believe the USGA test for measuring the COR of the driver uses a little metal ball so as to measure the COR of the driver and not the COR of the ball.

[Paul_Turner]

Paul,

Perhaps you could look it up, but I believe the USGA test for measuring the COR of the driver uses a little metal ball so as to measure the COR of the driver and not the COR of the ball.

Garland

Thanks.  I didn't find it but will check.  I'd like to know what COR value they measure for the steel ball/ club face impact and what speed they use.  A steel ball would make sense because there would virtually no energy loss in the ball.  They must then compute back somehow to make sure the COR is 0.83 or less with a standard real ball at the standard speed.

In the USGA report they measure the COR of the impact by:

Independently, the coefficient of restitution was tested for, using an unshafted USGA
conformance clubhead (“Aeson”, 9° driver) as an impact target. The test setup was
identical to that for the expired USGA coefficient of restitution test protocol for clubs,
with the exception that multiple speeds and ball types were used with the single clubhead.
The impact speeds were the same as the swing speeds described in table 1.

i.e. firing balls at a standard driver. 

[TEPaul]

"that there is virtually no deformation of the clubhead, and consequently little energy loss in it"


Paul:

When that statement says there is consequently little energy lose in it (the wooden clubface) does that mean to you that the club face is imparting little "energy transfer" to the golf ball?

[TEPaul]

"Perhaps you could look it up, but I believe the USGA test for measuring the COR of the driver uses a little metal ball so as to measure the COR of the driver and not the COR of the ball."


Garland:

That was a test developed by the USGA Test Center to test the COR of drivers but I don't believe that test was developed any earlier than maybe the mid to late 1990s, if even that early. We have to remember that it took quite a bit of time after those metal drivers got out there for concern about the distance enhancing effects of increased COR of driver faces to even develop. Put another way, driver face COR was not exactly something that they saw coming until after it got past them and out on the market. Once it got tested sufficiently Thomas' position and recommendation was to just ratchet it back (limit it) to the COR of a wooden faced driver (about .078-.079) but at that point the board got nervous about lawsuits and essentially did not take Thomas' recommendation to limit driver face COR to .078-.079!


I think the thing that some don't appreciate enough is when some problem appears to arise with golf ball and club physics or dynamics which seems to be skewing ODS testing and results that the USGA people have to actually first design and manufacture an appropriate test to measure the problem. Obviously the manufacturers are going to have something to say about that as well (the USGA test machines and tests).

Thomas' "Optimization Test" was apparently a way to get the USGA and manufacturer testing on the same page. As far as I can tell that "Optimization Test" was not accepted by the manufacturers.

[JMEvensky]

If anyone knows,would there be a significant difference in distance if the COR had been set at .079 instead of .083?

[TEPaul]

Jeff:

I don't know that a guy like Thomas would've wanted to precisely quantify the distance increase specifically from the allowed increase of the COR of a driver face from .079 to .083. I tried one time to get him to quantify the various aspects of the distance increase of that time span and he didn't like to do it because he said all of this science taken together is pretty complex but my recollection is he did sort of ballpark it at 1/3 equipment, 1/3 ball and 1/3 athleticism.

One thing we should take note of is that the so-called USGA/R&A Joint Statement of Principles that was written in 2002 did for the first time, I believe, mention athleticism as an aspect of distance increase that they would also consider if they felt it was significantly increasing ODS distance.

[JMEvensky]

TEP,I was just curious if the extra .004 would have really made any difference.

I have a theory that probably deserves its own thread.It would be my opinion that golf's "decline" can be traced to when it became a game,as opposed to a sport.Might dovetail with the popularity of Palmer and its growth.I'm still working on the details of my thesis.

People are kind of comfortable being relatively bad at a sport.But when something is just a game,any means of improvement is fair --including rules and/or equipment.

Seems like when something is universally considered a sport,it's attachment to the past is more sacred.

[Garland Bayley]

Naively assuming a uniform ball flight without friction, drag, etc. with a 300 yard carry the wood would send it 14.5 yards shorter if my math formulation is correct. So the upper limit would be 14.5 yards.
.83x = 300
.79x = 300 - y
y = 14.5

My recollection of reading articles at the time it was put in place was that the tour pros were going to get perhaps 5 yards. Also, my recollection is the reg allows .01 variation, so the pros will trial drivers until they find the .84 driver and use it.

[Garland Bayley]

Jeff,

Notice that TEP gave the wrong figure. It is .79 and .83. That means a ball traveling at 100 mpg will rebound off the driver 79 mph and 83 mph respectively.

[Paul_Turner]

"that there is virtually no deformation of the clubhead, and consequently little energy loss in it"


Paul:

When that statement says there is consequently little energy lose in it (the wooden clubface) does that mean to you that the club face is imparting little "energy transfer" to the golf ball?

The club face is obviously transferring energy to the golf ball otherwise the ball wouldn't move.  It's just that there's very little elastic energy involved within the club face if the club is solid (the club face doesn't deform).  All the elastic energy is in the ball as it compresses and consequently all the energy losses are in the ball.

[JMEvensky]

Jeff,

Notice that TEP gave the wrong figure. It is .79 and .83. That means a ball traveling at 100 mpg will rebound off the driver 79 mph and 83 mph respectively.

Thanks.Of course,now I have to deal with the possible fallibility of Tom Paul.My whole world might implode.

[TEPaul]

"It would be my opinion that golf's "decline" can be traced to when it became a game,as opposed to a sport."


Jeff:

First of all the distinction that was made between golf as a game compared to golf as sport was a distinction that appears to have never been very well understood. Even Macdonald said he did not understand the distinction at all. It appears the one who developed the distinction the best and wrote about it the best was Max Behr.

If one reads carefully what-all he said about it and considers it very carefully it is actually truly fascinating in that it has many parts and many factors associated to it, perhaps the best of them being his push for greater naturalism in golf course architecture and in the playing of golf itself!

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