Optimal Mass of a Club Head



Our objective in driving a golf ball down the fairway is to keep it as straight as possible and to drive it as far as possible. It is therefore logical to ask "what mass of a club head would give the longest drive?"

From equation 5 we found that the velocity of the ball after impact is given by:

5) vf = [MVi(1 + e)] / (M + m)

From this equation, we can see that the velocity of the ball should increase if we increase the velocity of our swing, the elasticity of the ball, or the mass of the club head.

We should also recognize that increasing the mass will decrease the velocity, but let's suppose that it does not. Therefore Vi(1 + e) would be constant and the velocity of the ball would be proportional to M / (M + m). A typical driver has a mass of 200g, whereas a golf ball has a mass of 46g. Thus the ratio would be 200/246 or ~ 4/5. Now if we increase the mass of the club head infinitely large the ratio would approach M/M or 1 a net gain of 1/5. In a typical drive of 250 yd's, increasing the mass significantly would result in a 50 yard increase. Hardly worth the effort, to swing a huge club with the same velocity as our 200g club.

Let's look at the physics of the situation. We know that an individual can only supply a finite amount of force to accelerate the club head. Using the well known equation:

(sum of the torques) = (moment of inertia)•(angular momentum)
where moment of inertia = kmr2, angular momentum = a/r and the sum of the torques = Fr we yield the equation:

Fr = kmr2a/r or F = kma

Since F is finite and k is a constant, increasing the mass will decrease the acceleration, and thus decrease the club head's velocity at point of impact.

Daish2 found that varying the mass of a club from 150g to 200g results in a longer drive. From 200g to 300g, the drive remains relatively unchanged, and for values greater than 300g, the drive decreases.

Therefore look for clubs whose mass is approximately 200g. You can increase the velocity of the club head by finding more aerodynamic club heads, club shafts made out of lighter material such as graphite, or clubs with longer shafts. A warning that longer shafts usually result in less control.