If you didn’t catch the first article then check it out here. They work as part of a series so be sure to have read Part I before starting on Part II.
As a general summing up, however, the first part concentrated on what smash factor is and what parts are the important factor for calculations.
Now that we know what the important factors are - how do we actually calculate the smash factor?
Well, brace yourselves…
Say what?
Okay, from the important factors we discussed in Part I, let’s figure out what everything means.
m = mass of the golf ball
M = mass of a driver
e = COR
Part 1
Taking the first part of the equation…
We know that the speed of the golf club at impact imparts speed to the ball. This depends on two main things:
- The efficiency which the ball bounces of the club face. This is given by the formula 1+ the coefficient of restitution. In a “perfect” collision this value would be 2. However, the rules of golf state that the maximum COR is 0.83. So 1 + 0.83 = 1.83.
- The relative mass of the golf ball and the club head. This is given by the formula 1 + the mass of the ball divided by the mass of the club head. The mass of the ball is fixed at 46g by regulation while the “normal” mass of a driver is 200g. So 1 + 46/200 = 1.23.
So we have 1.83 divided by 1.23 = 1.487.
Part 2
Second part...
We know that a perfect hit will have a club face loft of 0º. So a loft of, say 10º, will cause a less than perfect collision. The effect of this is minimal and is given by the approximation of the value of the cosine of the loft. The cosine of a 10º loft is 0.98.
Part 3
Last but not least...
This part attempts to give a value to the effect of a slight miss-hit. The formula is 1 - ( 0.12 x miss).
A miss by 1/4 inch (6 mm) would have an effect of reducing the effectiveness of the hit by approximately 3%. We find this by multiplying 0.25 (1/4 inch) by 0.12 which equals 0.03 or 3%.
The figure of 0.12 is an historic measure of the effect of missing the sweet spot. If you miss the sweet spot then your golf club will loose its effectiveness. With modern golf clubs the effect of missing the sweet spot is less than with old persimmon heads.
So, 1 - 0.03 means we have a value of 0.97 for part 3.
So for this particular example:
Okay - that’s that bit sorted.
But what does smash factor actually tell us?
The generally accepted maximum smash factor is approximately 1.50.
If you had achieved a smash factor of 1.50 this would mean that for a given club head speed the resulting ball speed will be 1.5 times faster.
So, for example, your swing speed is 90mph. With a smash factor of 1.50 your ball speed would be 135mph.
So, we’ve used smash factor to calculate the speed of our ball! Result!
But that was using the maximum accepted smash factor. What about when we use our example above?
We missed the sweet spot by 1/4” which reduced our smash factor to 1.41
So our calculation would be velocity of club x smash factor to get our ball speed.
We’re still swinging the club at 90mph and our smash factor is 1.41. That means the velocity of our ball is approximately 127mph.
Let’s say our playing partner had the smash factor of 1.50. We have 1.41. We both swing our clubs at 90mph yet our playing partner gets 135mph and we only got 127mph. All because we missed the sweet spot by a quarter inch. That sucks.
So what to do?
Let’s say I then decided to slow my swing down so I could hit more accurately. I could effectively improve my smash factor by hitting the sweet spot (or missing it by less). If I got my smash factor up to 1.5 then I could reduce my speed of club to 85mph and still get the same ball speed as I did before - 127mph.
Of course, it’s not just not hitting the sweet spot that can make a difference to the smash factor. Other things that affect the smash factor include the weight of the driver and the face angle. A smaller driver with a loft of 12º will result in a reduced smash factor thus reduced potential ball speed. Also if the face angle is open or closed in respect of the swing path of the club there will be a small reduction in the smash factor.
So what does this tell us? How can we use this to be better golfers?
Well, to be honest, for all those complex equations and mind numbing flash backs to high school math class, the point of smash factor can really be summed up quite simply.
What a measurement of the smash factor tells us is the effectiveness of the swing: The more accurate your shot, the better results you will have.
When you are practising, learn to swing in such a way that you hit the ball from the sweet spot as consistently as possible. Kind of obvious really! You may have to swing more slowly to achieve this but you will hit the drive consistently further.
Basically a slower but more consistent swing will benefit the golfer.
When a reduction of the smash factor is translated into ball speed, and by extension the length of a drive, you can see that a slower but more accurate swing can produce a longer drive.
Smash factor is important but you have to consider it in the context of other aspects of swing performance such as launch angle; spin rate; club choice; fitness and course conditions. The list goes on…
So, there is no need to sit there with a scientific calculator either on the golf course or when you get home. When smash factor is translated into ball speed, and by extension the length of a drive, you can see that a slower but more accurate swing can produce a longer drive. The point of calculating the smash factor is then really just a tool by which we can validate that the better your swing, the better your game.
And that, ladies and gentlemen, is Smash Factor. I think I need a lie down!
Last but not least...
This part attempts to give a value to the effect of a slight miss-hit. The formula is 1 - ( 0.12 x miss).
A miss by 1/4 inch (6 mm) would have an effect of reducing the effectiveness of the hit by approximately 3%. We find this by multiplying 0.25 (1/4 inch) by 0.12 which equals 0.03 or 3%.
The figure of 0.12 is an historic measure of the effect of missing the sweet spot. If you miss the sweet spot then your golf club will loose its effectiveness. With modern golf clubs the effect of missing the sweet spot is less than with old persimmon heads.
So, 1 - 0.03 means we have a value of 0.97 for part 3.
So for this particular example:
But what does smash factor actually tell us?
The generally accepted maximum smash factor is approximately 1.50.
If you had achieved a smash factor of 1.50 this would mean that for a given club head speed the resulting ball speed will be 1.5 times faster.
So, for example, your swing speed is 90mph. With a smash factor of 1.50 your ball speed would be 135mph.
So, we’ve used smash factor to calculate the speed of our ball! Result!
But that was using the maximum accepted smash factor. What about when we use our example above?
We missed the sweet spot by 1/4” which reduced our smash factor to 1.41
So our calculation would be velocity of club x smash factor to get our ball speed.
We’re still swinging the club at 90mph and our smash factor is 1.41. That means the velocity of our ball is approximately 127mph.
Let’s say our playing partner had the smash factor of 1.50. We have 1.41. We both swing our clubs at 90mph yet our playing partner gets 135mph and we only got 127mph. All because we missed the sweet spot by a quarter inch. That sucks.
So what to do?
Let’s say I then decided to slow my swing down so I could hit more accurately. I could effectively improve my smash factor by hitting the sweet spot (or missing it by less). If I got my smash factor up to 1.5 then I could reduce my speed of club to 85mph and still get the same ball speed as I did before - 127mph.
Of course, it’s not just not hitting the sweet spot that can make a difference to the smash factor. Other things that affect the smash factor include the weight of the driver and the face angle. A smaller driver with a loft of 12º will result in a reduced smash factor thus reduced potential ball speed. Also if the face angle is open or closed in respect of the swing path of the club there will be a small reduction in the smash factor.
So what does this tell us? How can we use this to be better golfers?
Well, to be honest, for all those complex equations and mind numbing flash backs to high school math class, the point of smash factor can really be summed up quite simply.
What a measurement of the smash factor tells us is the effectiveness of the swing: The more accurate your shot, the better results you will have.
When you are practising, learn to swing in such a way that you hit the ball from the sweet spot as consistently as possible. Kind of obvious really! You may have to swing more slowly to achieve this but you will hit the drive consistently further.
Basically a slower but more consistent swing will benefit the golfer.
When a reduction of the smash factor is translated into ball speed, and by extension the length of a drive, you can see that a slower but more accurate swing can produce a longer drive.
Smash factor is important but you have to consider it in the context of other aspects of swing performance such as launch angle; spin rate; club choice; fitness and course conditions. The list goes on…
So, there is no need to sit there with a scientific calculator either on the golf course or when you get home. When smash factor is translated into ball speed, and by extension the length of a drive, you can see that a slower but more accurate swing can produce a longer drive. The point of calculating the smash factor is then really just a tool by which we can validate that the better your swing, the better your game.
And that, ladies and gentlemen, is Smash Factor. I think I need a lie down!
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