- #1
GENIERE
I haven’t seen a golf thread so …
About 20 years ago I began making my own golf clubs from purchased components, the club-head, shaft, and grip. I‘ve tried to understand the basic physics of golf to avoid a lot of trial and error, and expense. It takes about 15 minutes to assemble a club, which comprises trimming shaft to correct length, fastening the club-head to the shaft with epoxy, and after the epoxy cures installing the grip. I can make a quality set of clubs, 14 total, for about $550.00. About $120.00 of that is for the driver. An equivalent set of brand name, top-of –the-line clubs would run about $1300.00. Using the least expensive components, a set could be assembled for about $100.00
When a golf ball is struck properly, a horizontal spin (backspin) is imparted to the ball, with the top of the ball rotating toward the golfer. Off horizontal axis rotation or sidespin will cause the ball to arc to the left (draw or hook) or to the right (fade or slice).
In the late 19th century, it was noted that a scuffed up golf ball went further than a new smooth one. Ball makers experimented with a variety of ball surface indentations and finally came up with the familiar dimpled ball. Besides making the ball look cute, the dimples increase the air boundary layer. The boundary layer of air is coupled to the ball surface due to its viscosity. For a non-spinning ball in flight, the highest pressure point would be dead center in the front. As the air passes above and below the ball, its velocity must increase with the resulting lowering of pressure on top and bottom. At a relatively low speed laminar flow ceases resulting in a turbulent airflow at the rear of the ball. This turbulence (drag) absorbs the kinetic energy of the golf ball. With a non-dimpled golf ball, the area of the turbulent airflow begins near top and bottom dead center. With a dimpled golf ball the larger boundary layer results in the turbulence beginning later (rear of ball) and lessening drag. The horizontal spin of the golf ball generates lift. A properly struck ball has backspin with the lower part of the ball moving faster relative to the air than the top of the ball. This has the effect of lowering the point where turbulence begins and the air behind the ball moves down causing the ball to rise. The higher the rotational velocity, the greater is the lift. When drag exceeds lift, the ball begins to drop. To achieve the greatest distance one must choose equipment appropriate to his swing speed. Some considerations are, ball spin rate and compression, shaft stiffness, shaft torque, shaft length, the shafts flex point, and the multitude of factors of the club head.
Driver club head nomenclature:
- The face angle is the angle formed between the face and the bottom of the club head (sole) relative to the vertical. The face of the club strikes the ball.
- Lie angle is the angle formed between the shaft and the club head sole relative to the vertical.
- The center of gravity lies within the club head.
- Club head weight for the driver is about 200 +\- 10 grams.
- Club heads can be found made of titanium, stainless steel, aluminum, a variety of plastics, amorphous alloys and in the old days wood. Often the body of the club head is stainless steel with the face made of titanium or alloy such as maraging steel.
- Volume of a driver club head is 200-600cc. (Yes 600cc)
- Bulge is the horizontal curve of the club head face.
- Roll is the vertical curve of the club head face.
- The hosel of the club head accepts the shaft.
- The toe of the club is furthest from the golfer’s feet when addressing the ball.
- The heel of the club is closest to the golfer’s feet when addressing the ball.
I’ve read that about 2 horsepower must be generated to achieve a 200-yard ball flight. This generates club head speeds in excess of 100mph. Tiger Woods realizes speeds of 140mph. Long ball champions must develop speeds approaching 200mph. Apparently about 30 pounds of muscle tissue is needed to obtain 2 horsepower. That means that back and leg muscles must provide most of the muscle tissue required.
To be properly struck, the ball must contact the club head on its sweet spot, at the horizontal center of gravity and very slightly above the vertical center of gravity with the face of the club head perpendicular to the target line. As the club undergoes acceleration, the shaft flexes back and the toe of the club head twists clockwise, as the center of gravity is outward from the shaft. At speed, the golfer lacks a means correct a swing path error because of the inability to overcome the club head’s kinetic energy. Just before ball contact, the wrists must pronate (twist) to allow the club head to rotate square to the target line.
If the ball strike is at a point between the toe and the cg the club head will rotate cw as viewed from above (open face). The ball starts out to the right but immediately starts turning to the left. This occurs due to what is called the “gear effect”. As the club head rotates cw the ball is caused to rotate ccw. There is a naturally occurring correction to off center hits. To increase the correctional tendency, bulge and roll are designed into the club head. If the ball strike is on the sweet spot, but the club head is not square to the target line, the ball will be caused to slice or hook. To reduce the twisting of the club head for off center hits it is helpful to have the center of gravity towards the rear of the club. The sole of the club head should be parallel to the ground at the moment of impact. If not, the ball will roll diagonally up the club head face adding an unwanted vertical spin component.
Toward the end of the golf swing, as the rate of acceleration decreases, the bent back shaft will start to straighten due to its stored energy. Eventually just prior to impact the club head should be somewhat ahead of the hands and at its peak velocity. A more flexible shafted club will tend to strike the ball in an upward direction. A shaft with a low flex point will increase the effect. A lesser torsionally rigid shaft will tend to close the face angle of the club before impact. A longer shaft can provide greater club head speed, but will be more difficult to accelerate and control.
With the metal alloys available today, club heads can be made with much larger sweet spots, hi coefficient of restitution faces and maintain a low center of gravity
So, for example, if you drive the ball consistently with a too low trajectory consider:
Higher spin rate ball (you’ll also get bigger hooks and slices)
Higher loft angle club head
Club head with a low center of gravity
More flexible shaft with low flex point
Don’t make any equipment changes until you do what you do the same way each time every time. Like a machine!
My natural tendency is to hit a long, high ball with a 20 –30 yard fade. That’s ok but the ball’s angle of decent is so steep I get very short rolls. Carbon fiber shafts seem to make it worse, I think due to less torsional rigidity. What’s seems to work nicely for me is a stiff rated titanium shaft, which I’ve trimmed to get a 46 inch club length, attached to a maraging-steel-faced, stainless-steel-bodied, 250cc, 8.5 degree club head. I not seen a difference using 90-compression balls vs. 100-compression balls, nor in fact what brand it is. The longest drive I have hit that I could determine the distance with some accuracy was on a 320-yard hole where my ball rolled across the green into a trap behind the green. I am sure I have hit longer ones into the woods.
Tee 'em high, let 'em fly, or tee 'em low, win some dough
About 20 years ago I began making my own golf clubs from purchased components, the club-head, shaft, and grip. I‘ve tried to understand the basic physics of golf to avoid a lot of trial and error, and expense. It takes about 15 minutes to assemble a club, which comprises trimming shaft to correct length, fastening the club-head to the shaft with epoxy, and after the epoxy cures installing the grip. I can make a quality set of clubs, 14 total, for about $550.00. About $120.00 of that is for the driver. An equivalent set of brand name, top-of –the-line clubs would run about $1300.00. Using the least expensive components, a set could be assembled for about $100.00
When a golf ball is struck properly, a horizontal spin (backspin) is imparted to the ball, with the top of the ball rotating toward the golfer. Off horizontal axis rotation or sidespin will cause the ball to arc to the left (draw or hook) or to the right (fade or slice).
In the late 19th century, it was noted that a scuffed up golf ball went further than a new smooth one. Ball makers experimented with a variety of ball surface indentations and finally came up with the familiar dimpled ball. Besides making the ball look cute, the dimples increase the air boundary layer. The boundary layer of air is coupled to the ball surface due to its viscosity. For a non-spinning ball in flight, the highest pressure point would be dead center in the front. As the air passes above and below the ball, its velocity must increase with the resulting lowering of pressure on top and bottom. At a relatively low speed laminar flow ceases resulting in a turbulent airflow at the rear of the ball. This turbulence (drag) absorbs the kinetic energy of the golf ball. With a non-dimpled golf ball, the area of the turbulent airflow begins near top and bottom dead center. With a dimpled golf ball the larger boundary layer results in the turbulence beginning later (rear of ball) and lessening drag. The horizontal spin of the golf ball generates lift. A properly struck ball has backspin with the lower part of the ball moving faster relative to the air than the top of the ball. This has the effect of lowering the point where turbulence begins and the air behind the ball moves down causing the ball to rise. The higher the rotational velocity, the greater is the lift. When drag exceeds lift, the ball begins to drop. To achieve the greatest distance one must choose equipment appropriate to his swing speed. Some considerations are, ball spin rate and compression, shaft stiffness, shaft torque, shaft length, the shafts flex point, and the multitude of factors of the club head.
Driver club head nomenclature:
- The face angle is the angle formed between the face and the bottom of the club head (sole) relative to the vertical. The face of the club strikes the ball.
- Lie angle is the angle formed between the shaft and the club head sole relative to the vertical.
- The center of gravity lies within the club head.
- Club head weight for the driver is about 200 +\- 10 grams.
- Club heads can be found made of titanium, stainless steel, aluminum, a variety of plastics, amorphous alloys and in the old days wood. Often the body of the club head is stainless steel with the face made of titanium or alloy such as maraging steel.
- Volume of a driver club head is 200-600cc. (Yes 600cc)
- Bulge is the horizontal curve of the club head face.
- Roll is the vertical curve of the club head face.
- The hosel of the club head accepts the shaft.
- The toe of the club is furthest from the golfer’s feet when addressing the ball.
- The heel of the club is closest to the golfer’s feet when addressing the ball.
I’ve read that about 2 horsepower must be generated to achieve a 200-yard ball flight. This generates club head speeds in excess of 100mph. Tiger Woods realizes speeds of 140mph. Long ball champions must develop speeds approaching 200mph. Apparently about 30 pounds of muscle tissue is needed to obtain 2 horsepower. That means that back and leg muscles must provide most of the muscle tissue required.
To be properly struck, the ball must contact the club head on its sweet spot, at the horizontal center of gravity and very slightly above the vertical center of gravity with the face of the club head perpendicular to the target line. As the club undergoes acceleration, the shaft flexes back and the toe of the club head twists clockwise, as the center of gravity is outward from the shaft. At speed, the golfer lacks a means correct a swing path error because of the inability to overcome the club head’s kinetic energy. Just before ball contact, the wrists must pronate (twist) to allow the club head to rotate square to the target line.
If the ball strike is at a point between the toe and the cg the club head will rotate cw as viewed from above (open face). The ball starts out to the right but immediately starts turning to the left. This occurs due to what is called the “gear effect”. As the club head rotates cw the ball is caused to rotate ccw. There is a naturally occurring correction to off center hits. To increase the correctional tendency, bulge and roll are designed into the club head. If the ball strike is on the sweet spot, but the club head is not square to the target line, the ball will be caused to slice or hook. To reduce the twisting of the club head for off center hits it is helpful to have the center of gravity towards the rear of the club. The sole of the club head should be parallel to the ground at the moment of impact. If not, the ball will roll diagonally up the club head face adding an unwanted vertical spin component.
Toward the end of the golf swing, as the rate of acceleration decreases, the bent back shaft will start to straighten due to its stored energy. Eventually just prior to impact the club head should be somewhat ahead of the hands and at its peak velocity. A more flexible shafted club will tend to strike the ball in an upward direction. A shaft with a low flex point will increase the effect. A lesser torsionally rigid shaft will tend to close the face angle of the club before impact. A longer shaft can provide greater club head speed, but will be more difficult to accelerate and control.
With the metal alloys available today, club heads can be made with much larger sweet spots, hi coefficient of restitution faces and maintain a low center of gravity
So, for example, if you drive the ball consistently with a too low trajectory consider:
Higher spin rate ball (you’ll also get bigger hooks and slices)
Higher loft angle club head
Club head with a low center of gravity
More flexible shaft with low flex point
Don’t make any equipment changes until you do what you do the same way each time every time. Like a machine!
My natural tendency is to hit a long, high ball with a 20 –30 yard fade. That’s ok but the ball’s angle of decent is so steep I get very short rolls. Carbon fiber shafts seem to make it worse, I think due to less torsional rigidity. What’s seems to work nicely for me is a stiff rated titanium shaft, which I’ve trimmed to get a 46 inch club length, attached to a maraging-steel-faced, stainless-steel-bodied, 250cc, 8.5 degree club head. I not seen a difference using 90-compression balls vs. 100-compression balls, nor in fact what brand it is. The longest drive I have hit that I could determine the distance with some accuracy was on a 320-yard hole where my ball rolled across the green into a trap behind the green. I am sure I have hit longer ones into the woods.
Tee 'em high, let 'em fly, or tee 'em low, win some dough