Golf Clubs

Golf Swing Physics
Here is a wonderful article, guest-authored by Rod White, a physicist with the New Zealand Measurements Standards Laboratory. It starts from basic Newtonian physics (like we learned in the tutorial) and shows how a good golf swing works. With animations, videos, graphs, and [completely optional] equations, the article covers both swing technique and club technology and how they combine for power drives.

Optimizing a Driver's Launch Parameters
Note: the computer output on which this program is based has been called into question. See the next article for more detail about the questions.

A lot of clubfitters use launch monitors now to fit the driver to the golfer. A common scenario is to get to a fast maximum, but one that doesn't match the spin and launch angle numbers that are supposed to be optimum. This is followed by tinkering to get to the optimum launch conditions -- usually with little or no additional distance to show for it.

Here is why that happens, and what to do about it.

Comparison of Trajectory Programs
This mini-study was provoked by response to my study of launch space surfaces, and my driver fitting recommendations based on that study. The accuracy of the Tom Wishon Trajectory Profiler was called into question. Here I compare the Wishon program to three others, and to measured, real-world data.

All About Gear Effect
Gear effect occurs when a driver strikes the ball, and the impact misses the sweet spot. The result is a rotation of the clubhead that imparts spin to the ball. It answers all kinds of questions, like: why woods are designed with curved faces... why weight screws may (or may not) give a hook bias... why a driver gives maximum distance when hit above center on the clubface. I was surprised by a few of the answers myself.

Early Experience with MOI Matching
In the first half of 1995, I was experimenting with MOI matched clubs. This was based on math and physics I did in 1994 suggesting this would be a better way to match clubs than swingweight. I posted my experiences to rec.sport.golf, the golfing interest newsgroup on the Internet. Here is an anthology of those postings.

More Recent MOI-Matching Experience
It took thirteen years and several tries, but I think I now know what sort of MOI-matched clubs I need. Here is the what and why of a set that fits me better than my earlier attempts at playing MOI-matched irons.

Golf Technology Forecast - 2008
In 2008, motivated by a forecast made by Tom Wishon at the fifth World Scientific Congress of Golf, I prepared a five-year technology forecast. I decided to use as a ground rule Tom's conclusion that much of the progress would be in the area of custom club fitting. Here is my cut at it.

Technology Forecasting
This article is a companion to a technology forecast I made in 2008. Technology forecasting itself is a "vocational skill", which involves being able to apply some well-understood principles. Here are some of the ways a professional forecaster looks at things.

The Nine Ball Flights
There is a common diagram in many golf books that purports to show the nine basic ball flights. Unfortunately, that diagram is somewhere between useless and incorrect. Here is a version (actually two versions) of the diagram that correspond to physical reality.

Flex-face Irons Can Be More Forgiving than Rigid-face Irons
Unlike drivers, irons are not about maximum distance, but rather reliable, predictable distance. I felt that high-COR irons worked against this principle because the COR falls off away from the center, adding to the losses from an off-center impact. Tom Wishon proved me wrong. Here's the real story.

The Great Square Groove Controversy
In the late 1980s and early '90s, it was widely -- and incorrectly -- believed that square grooves were illegal. Here's how that rumor came about, and what really happened.

Hardness and Distance, or A Myth is Not As Good As A Mile
This was inspired by a debate about whether a super-hard clubface material will give more distance. It was first written before spring-face drivers and coefficient of restitution was an issue, but it gives some hints that a hard face is not the way to get more distance; a face that flexes is.

Constant-Length Irons
Bill Wade asked my opinion of constant-length iron sets. I realized my study on this is more than ten years old now, and needs to be revisited. Here's my new take on the issue.

3-Dimensional Launch Conditions from Impact Conditions
Going from impact conditions to launch conditions is a challenge. It's even harder in 3D. Here's my cut at how to do it.
(Math warning! Most of this article consists of deriving equations for launch conditions, and is heavy with trigonometry.)

Phases for Physical Analysis
Applying scientific analysis to golf has as its ultimate purpose calculating how the inputs (things like club characteristics and the parameters of the golfer's swing) map to where the ball eventually ends up. This analysis can't be done in one big equation; that would be way too complicated. But, fortunately, the analysis can be decomposed into "phases" where the outputs of one phase become inputs for the next. Here are some musings on this decomposition.

Centripetal Matching
In July of 2005, a discussion started on the FGI forum about matching sets of golf clubs based on the centripetal force trying to pull the clubs out of the golfers' hands. They had the analysis and measurement all wrong, so I wrote this article on how it really works -- and found out that it really doesn't. I don't think this will ever be a classic, but it's a good study in how to see whether a proposal for improving golf club design has any merit.

Copyright Dave Tutelman 2010 -- All rights reserved