Will flex affect Impact/Smash Factor even if ball goes straight?

If a golfer uses a R flex driver has a swing speed of 110mph, ball speed of only 140 (Smash Factor: 1.27) but ball flies straight with a nice trajectory with 210m+ carry (and feels like a good hit on the sweet spot), will changing the shaft to a "S" or "X" improve the smash factor?

I was recently presented with this question and I can't really answer it as even though a "R" flex shaft may seem a bit soft for a 110mph swing speed, the fact that the ball is going straight should mean the club head returned squared to the ball. Furthermore, 140mph ball speed for 210m carry would indicate near ideal launch angles (so not really a problem with the kick point). Thus, I would guess that a "S" or "X" flex would not make much difference.

Anyone (esp club fitters) has any comments if the flex has to play a part in this low smash/impact factor?

In the meantime, I just tell him "you are using range balls lah... not meant to fly far one".

for me the only thing different is the timing of the release. If the club speed is fast and the flex is whippy, it's quite hard to get a consistent impact and small dispersion.
I will normally ended up with lots of slice if the shaft is too whippy. But hey that's just me.

But if you are using too stiff, you might also end up with the same problem, so all in all they do need to match (swing speed and shaft).

good luck.

Read this. http://www.andrewricegolf.com/tag/smash-factor/

The weird thing about this particular golfer and scenario is that from the ball flight, it seems that the strike was good, sounded good and felt good (so he says).. however, the smash factor was just low. I can imagine if the smash factor improves to 1.4, then ball speed would be 154 which should result in a 225+ carry... then he would drive further than Rocco Mediate.

@eiji... thanks for the link. I read though it but still puzzled as to whether a change in shaft flex will help the impact factor in this case... maybe it is time for him to visit the den.

its more important to determine why ur smash factor is so low, it could be you are hitting it all over the club face, your swing path, etc etc.

swingspeed = 110mph

smash factor = 127

shaft flex = only regular

carry distance = only 210m





i can see the potential....

cant imagine if his smash factor improves to 1.5...

I guess impact/smash factor is the energy power transfer from the swing speed to the ball speed. Example if you have a swing speed of 100mph and generate a ball speed of 150mph, your smash factor is 1.5
Smash Factor = Ball Speed divided by Swing Speed
One thing I don't understand is that max smash factor can arrive to 1.5 but there is a CoR control of 0.83 which will limit the driver's smash factor to 1.205 (1/0.83), where does another 0.3 come from? I can only guess is the factor from the ball itself.
Let's say that my above assumption is true, it still does not answer to the TS question. Personally I think flex does contribute to swing speed but not Smash Factor (Maybe indirectly)
We can discuss about whether flex will affect swing speed in another thread




Disclaimer: Stated above are from hear-say and majority from what I guess. All the figures do not based on any proven facts or data.

Just wondering, what equipment was used to measure the swing speed and ball speed?

Derek wrote:

Just wondering, what equipment was used to measure the swing speed and ball speed?

Radar? Ruler? Speed trap camera?

Do we know the driver's loft, spin rate, launch angle and land angle?

jimmychoo wrote:

I guess impact/smash factor is the energy power transfer from the swing speed to the ball speed. Example if you have a swing speed of 100mph and generate a ball speed of 150mph, your smash factor is 1.5
Smash Factor = Ball Speed divided by Swing Speed
One thing I don't understand is that max smash factor can arrive to 1.5 but there is a CoR control of 0.83 which will limit the driver's smash factor to 1.205 (1/0.83), where does another 0.3 come from? I can only guess is the factor from the ball itself.
Let's say that my above assumption is true, it still does not answer to the TS question. Personally I think flex does contribute to swing speed but not Smash Factor (Maybe indirectly)
We can discuss about whether flex will affect swing speed in another thread




Disclaimer: Stated above are from hear-say and majority from what I guess. All the figures do not based on any proven facts or data.

Am obviously not an expert in this area by any means, but allow me to chip in my 2 cents in the hope that I too will learn something from it.

COR is a measurement of the energy loss or retention when two objects collide. When there is perfect energy transfer, COR is expressed as 1. When there is zero energy transfer, all energy is lost in the collision, COR is expressed as 0. In golf, the limit is a COR of 0.83 as stated by bro Jimmychoo.

So, the COR ratios deals with energy. Not pure speed. So lets see what formula we can find that relates COR ratio to ball and club speed, ie. smash factor.

The more efficiently the energy is transferred from club head to ball, the faster the ball will fly, right?. Seems logical, so lets start from there.

What else would affect the transfer of this energy?

How about the angle of the club face compared to the angle or direction of the club path?

When cars collide, a head-on collision is obviously more powerful than a side glancing collision. That's because all the energy is directed at the object. A glancing collision would need to factor in the angle at which the collision occurred compared to the point of contact.

So it makes sense that a club face that is totally perpendicular to the club head direction would make the most powerful collision, ie. the most efficient transfer of energy. The term is spin loft, which is the angle between club face orientation and club head direction.

How about mass? An infinitely heavy club head contacting an infinitely light golf ball would make the most efficient energy transfer. Obviously, the clubhead is not infinitely heavy and neither is the ball infinitely light. But we can deduce that the weight of the clubhead would increase the efficiency of the transfer and the weight of the ball would detract from it. So we need to deal with ball mass and clubhead mass.

Turns out, the equation we are after looks something like this.

Smash factor ~= (1+COR) x cosine(spin loft) / (1+(ball mass/clubhead mass))

Wow, that's quite a mouthful. Lets put in some numbers and see what we are dealing with here.

COR = 0.83

Spin loft, my driver loft is 10.5 degree, so lets try that.

Ball mass, I weighed my ProV1 using my kitchen scale, and it's around 42g.

Clubhead mass, from what I could tell, around 200g.

Putting all those numbers in to the equation,

Smash Factors ~= (1 + 0.83) x cosine (10.5) / (1 + (42g/200g) = 1.487

Ah, that's pretty close to 1.5.

What if I used a lower lofted driver that the long drivers seem to use?

Say I change the spin loft from 10.5 degree to 8 degree.

We get, Smash Factor = 1.497678

Hmm., interesting.

Assuming clubhead speed of 100 mph, I can either get 148.7 mph ball speed with my 10.5 degree lofted driver, or 149.77 mph ball speed with an 8 degree loft. That's an increase of 0.7% in ball speed.

Of course, to get further distance, we must also factor in spin and launch angle, and that's another set of equation to consider. So I can't just lower the loft of my driver, I must also be able to get the launch angle and spin to make the most of it.

But I am beginning to understand quantitatively why long hitters favour lower lofted drivers.

What if my driver head was made lighter?

If I reduce my clubhead weight from 200g to 195g, I lose 0.4% in smash factor.

At 200g, each additional 1g of club head weight increases the smash factor by about 0.1%. And therefore, increases ball speed by the same percentage.

No wonder when I added weight to my driver, I can feel the impact is more solid. But adding weight obviously slows down my swing. So, it's a question of finding the right set of variables.

This gives me a picture of the factors at work affecting my ball speed in terms of smash factor within the limit of 0.83 COR.

Conclusion

The elements affecting smash factor are spin loft, ball mass and clubhead mass. And ball mass is fixed, so that leaves spin loft and clubhead mass.

I need to go to the gym to build up strength to hit a heavier club to get a higher smash factor.

I need to learn to hit up on the ball in order to use a lower lofted club to get a higher smash factor AND achieve optimum launch spin and launch angle for maximum distance.



Thank you for reading, and if you finished reading the entire post, well done!

Peace.

The club speed, ball speed and impact vector is measured using the Zelocity pureflight in Mode 2. More details of the unit can be seen at: http://www.zelocity.com/golf/pureflight.shtml

It is pretty accurate and shows similar readings to the Zelocity PureLaunch.

...

@jimmychoo:

Bro, the CoR is the ratio of engery (in joules) transfer from club head to ball so E=M(C^2) where E is energy, M is mass and C is Speed.

Thus, the therotical maximum smash factor with a CoR of 0.83 is not (1/0.83) but in the simplified form (not taking into account SPIN LOFT, the energy source, inertia of ball, ball hardness, ball compression, etc) will be:
(Mass of golf ball * Ball Speed^2)/(Mass of club head * Clubhead Speed^2 * 0.83)

Since regulations limit the weight of the golf ball and the volume of the club head, the maximum smash factor can be calculated.

...

@Yarra: The driver is a 9.5deg D910 stock shaft. Not sure about the spin rate, launch angle and land angle but assume that these will affect the carry distance but not the smash factor. Also, looking at the ball speed of 140mph, the maximum carry should be around 210m under ideal spin (<3000rpm) and launch angles so I guess this two factors should not be the problem.

....

Even though I highly suspect that the low smash factor is due to the range balls, maybe I should still advice the friend of mine to buy a $1000 stiff flex shaft to try it out. If it doesn't help him, I can always get him to sell it to me at $100.

@Lee36328..

Bro, don't forget that E=MC^2. So rather than going to the gym to increase the weight of your club head, it might be better to go to the gym to improve the swing speed. Different gym training prgrammes are needed for speed training vs. weight training.

LousyGolfer wrote:

Bro, the CoR is the ratio of engery (in joules) transfer from club head to ball so E=M(C^2) where E is energy, M is mass and C is Speed.

Thus, the therotical maximum smash factor with a CoR of 0.83 is not (1/0.83) but in the simplified form (not taking into account SPIN LOFT, the energy source, inertia of ball, ball hardness, ball compression, etc) will be:
(Mass of golf ball * Ball Speed^2)/(Mass of club head * Clubhead Speed^2 * 0.83)

Since regulations limit the weight of the golf ball and the volume of the club head, the maximum smash factor can be calculated.

Bro LousyGolfer,

e = mc^2, where c is a constant, which is the speed of light. That as we know, is Einstein's equation.

Perhaps not so applicable when we are trying to measure speed of golf ball and clubhead.

A more applicable formula might be the formula for kinetic energy:

e(kinetic) = 1/2 mv^2

Assuming ball weight of 42g and clubhead weight of 200g, and a COR ratio of 0.83, and if and only if we assume no energy loss during impact, we can say,

e(ball) = 0.83 e(club)

Solving that gives us a theoretical maximum smash factor of 1.98806

This is of course not possible because of energy loss in sound and heat which causes the smash factor to be around 1.5 in practice

LousyGolfer wrote:

@Lee36328..

Bro, don't forget that E=MC^2. So rather than going to the gym to increase the weight of your club head, it might be better to go to the gym to improve the swing speed. Different gym training prgrammes are needed for speed training vs. weight training.

Well, e = 1/2 m x v*2,

but I see what you mean.

I will bear that in mind, thanks.

Wah lots to read on the science to golf swing... thanks for the info...

There are two things i learned and thought are always overlooked - consistency in our golf swing and your mental game...

Lee36328 wrote:

e = mc^2, where c is a constant, which is the speed of light. That as we know, is Einstein's equation.

Perhaps not so applicable when we are trying to measure speed of golf ball and clubhead.

A more applicable formula might be the formula for kinetic energy:

e(kinetic) = 1/2 mv^2

Assuming ball weight of 42g and clubhead weight of 200g, and a COR ratio of 0.83, and if and only if we assume no energy loss during impact, we can say,

e(ball) = 0.83 e(club)

Solving that gives us a theoretical maximum smash factor of 1.98806

This is of course not possible because of energy loss in sound and heat which causes the smash factor to be around 1.5 in practice

rocket science

It's so interesting to see all the physic theory surfaced, thanks for the physic lesson
So now, will flex affect the smash factor? Did I luckily guess the correct answer?

No one told me I needed an education to play golf...

botak wrote:

No one told me I needed an education to play golf...

Bro... you think we need to go back to tuition for this?

Technospaz wrote:

botak wrote:

No one told me I needed an education to play golf...

Bro... you think we need to go back to tuition for this?

Tuition can only help in tallying up the scorecard, but won't help with keeping track of Vegas scoring... this is a whole upper level!

Just curious, is there any PGA members out there who happen to be a Physic lecturer or scientist as well

more likely we have Master of Science degree holders from Caltech or MIT who are golf fanatics as well

BigblackGoof wrote:

Wah lots to read on the science to golf swing... thanks for the info...

There are two things i learned and thought are always overlooked - consistency in our golf swing and your mental game...

And.... believe it or not, science can shed some light there as well. There is some research being done.

LousyGolfer wrote:

If a golfer uses a R flex driver has a swing speed of 110mph, ball speed of only 140 (Smash Factor: 1.27) but ball flies straight with a nice trajectory with 210m+ carry (and feels like a good hit on the sweet spot), will changing the shaft to a "S" or "X" improve the smash factor?

I was recently presented with this question and I can't really answer it as even though a "R" flex shaft may seem a bit soft for a 110mph swing speed, the fact that the ball is going straight should mean the club head returned squared to the ball. Furthermore, 140mph ball speed for 210m carry would indicate near ideal launch angles (so not really a problem with the kick point). Thus, I would guess that a "S" or "X" flex would not make much difference.

Anyone (esp club fitters) has any comments if the flex has to play a part in this low smash/impact factor?

In the meantime, I just tell him "you are using range balls lah... not meant to fly far one".

I have played with an ang mo who used a stock Nike SQ 5900 R flex ( I should know because I bought it for him), who hit the trees, carry mind you, with his swing at Green Fairway Range. Those who played at GFairway, whats the range dropping at the trees and with range balls at that.