Our “Bastard” relative, “Frisbee” (or disc) Golf

Most of you probably never heard of the PDGA which is short for Professional Disc (?!) Golf Association.

The “game” is played by throwing a disc into a trashcan looking basket or at (?) it.

According to the PDGA the object of the game is to traverse
a course from beginning to end in the fewest number of
throws of the disc. The game is very inexpensive and requires
no athletic ability whatsoever! Apparently there are over
3000(!) established disc courses as of 2010 and most of them
supposed to be free!

No one really knows for sure who invented it or when. If i had
to guess it had to be on or near some military base where
people decided to throw their paper plates into the trash
instead of taking it there. (Hey, my theory is as good as the
ones that are out there!)

Anyhow, if you have absolutely nothing better to do and just
have to know more about “Disc Golf” click HERE.  And if you happened to be in the Netherlands in 2010 and just aching to play some Disc Golf check out this awesome indoor facility below…

for more info click HERE

Why are Golf Balls Dimpled?

So Why are Golf Balls Dimpled? Who knows, i guess someone somewhere down the line started
making them like that and everyone just started using them! Not quite, but close enough!
In a way, the reason why golf balls have dimples is a story of natural selection. Originally, golf
balls were smooth; but golfers noticed that older balls that were beat up with nicks, bumps and
slices in the cover seemed to fly farther. Golfers, being golfers, naturally gravitate toward anything
that gives them an advantage on the golf course, so old, beat-up balls became standard issue.

At some point, an aerodynamicist must have looked at this problem and realized that the nicks and
cuts were acting as “turbulators” — they induce turbulence in the layer of air next to the ball
(the “boundary layer”). In some situations, a turbulent boundary layer reduces drag.

The dimples, paradoxically, do increase drag slightly. But they also increase what is called the
“Magnus lift”, that peculiar lifting force experienced by rotating bodies travelling through a medium.
Magnus lift is present because a driven golf ball has backspin. The same Magnus effect can cause a
ball to hook or slice if it has sideways spin.

impetus trajectory

Contrary to simple ideas of trajectories in a vacuum, golf balls do not travel in inverted parabolas. They follow what is called an “impetus trajectory”. This is because of the combination of drag (which reduces horizontal speed late in the trajectory) and Magnus lift (which supports the ball
during the initial part of the trajectory, making it relatively straight). The trajectory can even curve upwards at first, depending on conditions!

A golf ball leaves the tee with a speed of about 70 m/s and a backspin of at least 50 rev/s. The
Magnus force can be thought of as due to the relative drag on the air on the top and bottom
portions of the golf ball: the top portion is moving slower relative to the air around it, so there is
less drag on the air that goes over the ball. The boundary layer is relatively thin, and air in the
not-too-near region moves rapidly relative to the ball. The bottom portion moves fast relative to
the air around it; there is more drag on the air passing by the bottom, and the boundary (turbulent)
layer is relatively thick; air in the not-too-near region moves more slowly relative to the ball. The
Bernoulli force produces lift. (Alternatively, one could say that “the flow lines past the ball are
displaced down, so the ball is pushed up.”)

A difficulty comes near the transition region between laminar flow and turbulent flow. At low
speeds,the flow around the ball is laminar. As speed is increased, the bottom part tends to go
turbulent first. But turbulent flow can follow a surface much more easily than laminar flow.
As a result, the laminar flow lines around the top break away from the surface sooner than
otherwise, and there is a net upward displacement of the flow lines. The Magnus lift becomes
negative.

dimples vs. smooth

The dimples aid the rapid formation of a turbulent boundary layer around the golf ball in flight, giving more lift. Without them the ball would travel in more of a parabolic trajectory, hitting the ground sooner (and not coming straight down). This was discovered by accident in the early days of golf when golfers noticed that old roughened golf balls went farther.

Despite the drag, a dimpled golf ball can even go farther in air than it would in vacuum given the same initial velocity and low angle. However, a golf ball shot at 45° and 70 m/s in vacuum would go 500 metres to the first bounce, which exceeds all records!

References:

Lord Rayleigh, “On the Irregular Flight of a Tennis Ball”, Scientific Papers I, pg 344.
R. Watts and R. Ferver, “The Lateral Force on a Spinning Sphere Aerodynamics of a Curveball”, Am. J. Phys. 55, 40 (1986).
Steve Haake, “Physics and Golf? You must be joking!” Physics World 10, 76 (1997).
Journal of Applied Physics 20, 821 (1949) by Davies.
American Journal of Physics 56, 933 (1988) by McPhee and Andrews.
“The Physics of Golf” by Theodore P. Jorgensen

Egg Suit

Inexperienced Golf Instructors

Time and time again I see this on the range, golf instructors try to teach students to many things in one lesson.  They obviously don’t know that I’m a pro eavesdropping on their lesson but 7/10 times a pro would tell a student more than three things.  Trying to accomplish too much during a single golf lesson is one of the most frequent teaching mistakes made by inexperienced golf instructors.  If you’re a victim of this you have probably experienced nothing but failure.  The human mind can only absorb so much in such a little amount of time.   Lets face it you don’t know anything about golf, hence why your paying some idiot in a pair of golf shoes $50 to make you a worse golfer.  Try to stick with just one thing at a time.  Focus on that one thing and practice, practice, practice.  Learning a new golf technique requires repetition so if you are not practicing you are not moving forward.  Slow progress is still progress.

Make Sure You Warm Up

When we all get out there to play the occasional round of golf, its extremely important that we all warm up.  Last time I checked I too was getting older.  Warm-up is important for speeding the flow of blood to the musculoskeletal system to enhance our bodies movements and prevent the injury of our muscles, ligaments, and tendons.  Its the same principal as getting into a sports car, if you had half a brain you wouldn’t get right in there start her up, pull out the garage put it in drive and floor it would you?  We also have protective reflex signals in our muscles and when we aren’t properly warmed up these signals don’t fire as quickly as they should and we then become more susceptible to injury. Take a club or two and hold them with both hands.  Get a good hamstring stretch by touching your toes with the clubs, twist your torso back and forth, and take 30 seconds of fluid practice swings without hitting balls.  I find these three stretches to be a great way to get in a quick warm-up.

Body Limitations Could Be Causing Bad Ball Striking

The golf swing is the proper sequence of different movements in our body.   In order to obtain a proper golf swing one must be physically able to make those precise movements. When studying a persons physical limitations we must first be certain that this person can even put their body into the desired position without feeling any pain or discomfort.  Golf is supposed to be fun remember?  Kinesiology is is the study of human motion, it comes from the Greek word kinesis which means motion and logy means “the science of.”  When we look at our swings on video we are studying our body’s movements and the rhythm and timing of our motions. If we are physically unable to turn our hip through the ball at break neck speed we must adapt to our bodies limitations and find the right swing for each individual golfer.  One swing is not the best for everybody, and remember to stretch every time you play golf.

Consistent Tempo Consistent Ball Flight

I know you’ve heard this before.  Maybe a few pros have tried to tell you to take an extra club and swing easier? If no one has let me be the first to tell you that its true.  Swing easier, you don’t need to kill the ball.  Trust me if you could meet me in person you would think that I would destroy the ball, but I in fact swing slow and easy like Ernie Els.  I already know you’re thinking then well what about Tiger.  Well what about him, there’s maybe one or two golfers on the planet that have his talent and let’s face it your or I are not and together don’t make a Tiger Woods.  So let’s all save us the hassle of needing to bring him up in future discussions.  A more consistent tempo and rhythm creates better timing resulting in more consistent centeredness of contact.  You would be surprised to notice that must amateur golfers see longer yardages with their clubs by swinging easier.  It does take a lot of discipline and I myself in the 25 years I have been playing golf have only come to realize this recently.  Thanks Mike!

Around The Green With 7, 6, 5 irons

Ask yourself what club or clubs you use when you’re chipping about 5-10 yards off the green.  If you have just one or two clubs that you use then I already know that your an amateur golfer.  Any pro will tell you that they utilize all the clubs in their bag around the greens, especially when there is a lot of green to work with.  Remember the ultimate goal of chipping is minimum air time and maximum ground time.  When you’re chipping with a 7 iron you obviously have a lot of green between the ball and the cup and your trying to put to ball on the necessary line as quickly as possible in order to set yourself up for a make-able putt.  It takes time to develop the necessary feel  in order to control your chips with these clubs but you will notice that your chances of  getting up and down will increase. 

The “D” Line

Growing up I had more golf instructors than I can remember.  They all had their own versions of what a pre-shot routine should consist of, but only one technique sticks out into my head to this day.  The”D” line as he called it is an imaginary line that is drawn about 5-10 feet behind the ball.  The purpose of the line is to stand behind it and evaluate your lie, make your shot selection and then choose your club.  Once all the variable decisions have been made you are now ready to make a stroke.  Before you cross the “D” line to take your stance the last thing that passes through your mind is the visualization of the flight of the ball.  Once you cross the “D” line you are focused on making that shot and only that shot.  The crowd, the people you play golf with, the elements all seems to disappear.  You have nothing but focus and the only task at hand is hitting the shot that you visualized.  This is a technique that most be learned in order to to deal with high pressure situations out on the golf course. 

Rule 2 Match Play

Rule 2. Match Play

2-1 GENERAL

A match consists of one side playing against another over a stipulated round unless otherwise decreed by the Committee. In match play the game is played by holes. Except as otherwise provided in the Rules, a hole is won by the side that holes its ball in the fewer strokes. In a handicap match the lower net score wins the hole. The state of the match is expressed by the terms: so many “holes up’’ or “all square,’’ and so many “to play.’’  A side is “dormie” when it is as many holes up as there are holes remaining to be played.

Next Page »