15 April 2013

Gravity Depth

It is said direction of a golf ball is good when the gravity depth is deep.
Let's think about functions of gravity depth .
In these case of hitting position is d away from the sweet spot.

Graph shown above are both cases of gravity depth

shallow gravity depth : G1
deep gravity depth : G2
The force that ball push the head : f

Deepness of both gravity depth : x1,x2

θ1,θ2 are expressed in formula ①,② by using trigonometric .

f (red) is divided by f1(green) and green dash line force.

The angle between f and f1 is θ1.

f1 --> formula③　 and f2 --> formula④

It is easier for you to calculate this method by using YUJI GOLF TECH BASE.

Try to calculate this case x1= 5mm , x2 = 35mm , d = 10mm

→　f1= f x 0.894 f2 = f x 0.275

f2 is much smaller than f1

It means = "deeper gravity depth"

⇔ "the force to turn the head is small"

⇔ "better direction"

This calculation only apply to miss shot ball , if d=0 , makes no difference for G1 and G2.

How do you think about many people opinions: :
It is easier to launch up a ball when the center of gravity depth is deeper?
My opinion & answer is: A ball is easier to launch up as the shaft bends in direction to increase the impact loft.
When the gravity depth is deep, the center of gravity becomes far from the shaft axis then the centrifugal force push downwards the center of gravity.
How do you think with many people opinions: That the ball backspin increases when the gravity depth is deep? When the gravity depth is deep , you will have more chances to hit below sweet spot. ??
I could not agree with this.
My conclusion is: It's depends on the club head design itself . 