Number of dimples

There must be an optimum number. I think the number of dimples in use now (between 330-440) is about right. Any more dimples would make the ball shorter as it would make the ball smoother and therefore lose it's aerodynamic properties. Not enough dimples would render the ball short too.

Well bridgestone only uses 330 and their balls are great. So really their obviously is not perfect number.

I think for a lot of companies, its a matter of getting their dimples not too large, not too small, but more importantly evenly spaced on the ball so there are less flat areas, and less of a seem.

I wondered about this because the Pro V1 has 392 dimples. The 1x has 332.

according to the Titlesit site the 1x:

"New, higher coverage 332 dimple design - penetrating trajectory for longer, consistent distance"

while the V1:

"Higher coverage 392 dimple design - penetrating trajectory for long, consistent distance"

confusing. obviously they both claim to be long but the 1x claims to be long-er with the fewer dimples.

so it seems, if any generalization can be made, that the fewer dimples equals longer drives?

Before asking about the # of dimples, perhaps we should first examine why a golf ball has dimples. The answer to this question can be found by looking at the aerodynamic drag on a sphere. There are two types of drag experienced by a sphere. The first is the obvious drag due to friction. This only accounts for a small part of the drag experienced by a ball. The majority of the drag comes from the separation of the flow behind the ball and is known as pressure drag due to separation. For laminar flow past a sphere, the flow separates very early. However, for a turbulent flow, separation is delayed. The separation region in the turbulent case is much smaller than in the laminar case. The larger separation region of the laminar case implies a larger pressure drag on the sphere. This is why the professor experienced a longer drive with the marked ball. The surface roughness caused the flow to transition from laminar to turbulent. The turbulent flow has more energy than the laminar flow and thus, the flow stays attached longer.

1 ­ ­ ­ ­ 2

1 Laminar Flow Over a Sphere. 2 Turbulent Flow Over a Sphere

So, why dimples? Why not use another method to achieve the same affect? The critical Reynolds number, Recr, holds the answer to this question. Recr is the Reynolds number at which the flow transitions from a laminar to a turbulent state. For a smooth sphere, Recr is much larger than the average Reynolds number experienced by a golf ball. For a sand roughened golf ball, the reduction in drag at Recr is greater than that of the dimpled golf ball. However, as the Reyn olds number continues to increase, the drag increases. The dimpled ball, on the other hand, has a lower Recr, and the drag is fairly constant for Reynolds numbers greater than Recr.

Therefore, the dimples cause Recr to decrease which implies that the flow becomes turbulent at a lower velocity than on a smooth sphere. This in turn causes the flow to remain attached longer on a dimpled golf ball which implies a reduction in drag. As the speed of the dimpled golf ball is increased, the drag doesn't change much. This is a good property in a sport like golf.

Although round dimples were accepted as the standard, a variety of other shapes were experimented with as well. Among these were squares, rectangles, and... hexagons. Hexagons actually result in a lower drag than the round dimples.

Lift is another aerodynamic force which affects the flight of a golf ball. This idea might sound a little odd, but given the proper spin a golf ball can produce lift. Originally, golfers thought that all spin was detrimental. However, in 1877, British scientist P.G. Tait learned that a ball, driven with a spin about a horizontal axis with the top of the ball coming toward the golfer produces a lifting force. This type of spin is know as a backspin.

The backspin increases the speed on the upper surface of the ball while decreasing the speed on the lower surface. From the Bernoulli principle, when the velocity increases the pressure decreases. Therefore, the pressure on the upper surface is less than the pressure on the lower surface of the ball. This pressure differential results in a finite lift being applied to the ball. The dimples also help in the generation of lift. By keeping the flow attached, the dimples help promote an asymmetry of the flow in the wake.

So long copypasta short there are many factors to consider when making a golf ball. The depth, size and angle of a dimple will also determine the appropriate number of dimples.

In short, the more dimples on the ball the higher it flies, the fewer the dimples the lower it flies.

Boba -

That's exactly how I would put it. Seriously though, do you get out much? :)

I went outside once, but I got a sunburn. I won't try that again.

Boba,

Great post - and a better put lesson in aerodynamics than any of the instructors I had in my RN days ever managed... :)

Truth be told, when it comes to the question of how the number of dimples relates to performance, I'd be fascinated to hear a definitive answer (or probably several definitive answers) from the golf ball manufacturers.

...

So long copypasta short there are many factors to consider when making a golf ball. ...

but what I don't know if there is a general rule as to the effect of the number of dimples has on ball characteristics. it is obvious, assuming the same surface area - that is, same ball diameter, that the fewer dimples would require the individual dimples to be larger, and because manufacturers promote number of dimples, I'm not sure how important that is.

nor am I sure how significant of an effect is created by the shape or size of the dimples. however, almost all balls have several sizes of dimples. I a**umed this is to facilitate better coverage on a spherical surface but I really don't know that to be true or not. I am only going by a vague recollection of an old advertisement when Maxfli came out with this and stated they got more full and uniform coverage.

short answer is, I don't know. I just wanted to know if there was a generalization that could be made regarding number of dimples as that seems to be a significant spec that manufacturers quote in their advertising.

I think a lot of the reasoning behind manufacturers quoting the dimple numbers is simply to give the product some sort of 'identity'.

Titleist hammered the '384' thing to death for a long time - as did Maxfli with the old DDH 500 pattern. Wilsons had 432 dimples.

It must work because we can all still remember them.

In short, the more dimples on the ball the higher it flies, the fewer the dimples the lower it flies.

OK, that seems general enough. It would seem, anecdotally, that the balls that advertise the higher number of dimples, generally are the "distance" balls. whether this is due to their being "harder" and needing more lift due to less spin, or whatever else, I suspect a correlation.

am I right?

I'm not sure, but going back a few years I always hit a Titleist Tour Balata (384 dimples) higher than a Maxfli HT balata - that had more dimples. :)

I think a lot of the reasoning behind manufacturers quoting the dimple numbers is simply to give the product some sort of 'identity'.

 

Titleist hammered the '384' thing to death for a long time - as did Maxfli with the old DDH 500 pattern. Wilsons had 432 dimples.

 

It must work because we can all still remember them.

ah, a very logical answer. it is true that marketing does indeed focus on "branding" but in my experience, there has to be something behind the brand, ie. form follows function.

so I suspect that the difference in number of dimple is grounded in very simple physics but I have yet to see an explanation from manufacturers as to the principle. it would be helpful to know. I think...

I'm not sure, but going back a few years I always hit a Titleist Tour Balata (384 dimples) higher than a Maxfli HT balata - that had more dimples. :)

mm-hm. I seem to remember Slazenger had 492 dimples on their "pro" ball and advertised is as long.

the thing with the Pro V1 and 1x having a different number of dimples got me thinking. I always assumed the difference between the two balls had more to do with their cores than the cover...

In short, the more dimples on the ball the higher it flies, the fewer the dimples the lower it flies.

The Titlesist DT Carry only has 252 'high lift' dimples and really flies high. Those dimples look like craters but it's a great ball if, like me, you hit it low.

Jim

more on ball aerodynamics http://www.aerospaceweb.org/question/aerod...ics/q0215.shtml

more on ball aerodynamics http://www.aerospaceweb.org/question/aerod...ics/q0215.shtml

very interesting. I notice that the discussion only references a stable body in airflow, though, and does not indicate the effect of the golf ball spinning.

it was my (very crude) understanding that the backspin on the ball causes the bottom of the ball to move forward against air faster than the top of the ball as it flies through the air, creating lift and that without backspin, a ball would not stay airborne for very long.

good find on that article but again, what I'm looking for, and these explanations still don't address this, is what does the number of dimples does to this system...

I little bit or trivia I heard recently. All (with the exception of one which I can't remember) balls have an even number of dimples. Dont' knwo how true the is but all the dimple numbers I've read lead me to believe it. I just don't remember the odd ball out. Seems to me it was a recent ball within the last five years or so.

very interesting. I notice that the discussion only references a stable body in airflow, though, and does not indicate the effect of the golf ball spinning.

 

it was my (very crude) understanding that the backspin on the ball causes the bottom of the ball to move forward against air faster than the top of the ball as it flies through the air, creating lift and that without backspin, a ball would not stay airborne for very long.

 

good find on that article but again, what I'm looking for, and these explanations still don't address this, is what does the number of dimples does to this system...

If I'm not mistaken, what you're looking for (x dimples does this, y dimples does that) is an over simplification of golf ball aerodynamics. The depth, volume, draft angle... has more to do with the quantity of dimples on a ball, than a manufacturer going out and giving a ball 392 dimples just for the he­ll of it. That being said, you may have noticed that lower spinning tour level balls tend to have larger dimples and higher spinning balls have smaller dimples. The larger a balls dimples, the fewer will fit on the cover and vice versa.

has anybody ever counted the dimples on the ball to make sure it has the exact amount? :)

very interesting. I notice that the discussion only references a stable body in airflow, though, and does not indicate the effect of the golf ball spinning.

 

it was my (very crude) understanding that the backspin on the ball causes the bottom of the ball to move forward against air faster than the top of the ball as it flies through the air, creating lift and that without backspin, a ball would not stay airborne for very long.

 

good find on that article but again, what I'm looking for, and these explanations still don't address this, is what does the number of dimples does to this system...

 

If I'm not mistaken, what you're looking for (x dimples does this, y dimples does that) is an over simplification of golf ball aerodynamics. The depth, volume, draft angle... has more to do with the quantity of dimples on a ball, than a manufacturer going out and giving a ball 392 dimples just for the he­ll of it. That being said, you may have noticed that lower spinning tour level balls tend to have larger dimples and higher spinning balls have smaller dimples. The larger a balls dimples, the fewer will fit on the cover and vice versa.

you may be right. but I started this thread asking if anyone knew, generally, what the effect the number of dimples has on a ball's flight.

it may be that the number is meaningless in light of he other technology. However, it is a number that every manufacturer includes in their description so I suppose it is a legitimate question, right? if it were not, why advertise it?

and obviously, all those other factors have some effect, I'm sure, but if so, why not advertise them as well? it seems to me that there is something special about the number, no?

I ask simply because I noticed the the Pro V1 and 1x have 392 and 322 dimples, respectively. these balls are scientifically designed to have different flight characteristics so there has to be a reason other than they sent a query to their marketing dept, ie. " hey, what number of dimples should we put on our ball so you can advertise it and sell more of 'em?"

and they also have up to seven different SIZES of dimples (Pro V1) so it doesn't seem that the number of the dimples is necessarily reflective of the size, nor vice versa...

so therefore, I simply wondered what was special about the number. do you know?

has anybody ever counted the dimples on the ball to make sure it has the exact amount? :)

LOL!

geez, you're right! they could be cheating us out of a dimple or two and we'd never know!

I suppose you could start counting by putting a dot in each of the counted dimples but that might be a better topic for the thread, "How do you mark your Ball?"

anyway, would you mind giving it a go and let me know what you come up with? ;)

I've read that it's the depth of the dimples that affects ball flight [high vs. low], not how many. A ball with shallower dimples will generally have a higher ball flight. Granted, on a ball with more dimples the dimples will tend to be shallower.

And the only ball with an odd number of dimples is the Srixon AD-333.

I believe that it's the depth of the dimples that affects ball flight [high vs. low], not how many. A ball with shallower dimples will generally have a higher ball flight.

 

And the only ball with an odd number of dimples is the Srixon AD-333.

Boba? Care to field this one?

I've read that it's the depth of the dimples that affects ball flight [high vs. low], not how many. A ball with shallower dimples will generally have a higher ball flight. Granted, on a ball with more dimples the dimples will tend to be shallower.

 

And the only ball with an odd number of dimples is the Srixon AD-333.

interesting. then why would the manufacturers make it a point to advertise the number?

I believe that it's the depth of the dimples that affects ball flight [high vs. low], not how many. A ball with shallower dimples will generally have a higher ball flight.

 

And the only ball with an odd number of dimples is the Srixon AD-333.

 

 

Boba? Care to field this one?

Sure, Srixon also makes the trispeed with 333 as well as the hr-x 333 a few years ago.

Ball manufactures all try to cover the surface area with dimples as much as possible. The greater the coverage, the more aerodynamic the ball will be. However as I stated earlier, the depth, volume and draft angle will have more of an influence on the flight of the ball than a specific number. Larger dimples will result in additional lift whereas smaller dimples will result in a lower trajectory. I'll highlight the next part as some of us don't get it yet: The larger the dimples, the fewer will fit on the cover of the ball and vice versa. Take the Titleist DT line for example, two nearly identical balls with very different dimple patterns and sizes. The DT carry has larger dimples than the DT roll and as a result... 140 fewer dimples.

Most golf balls have between 300 and 500 dimples, which have an average depth of about 0.010 inch. The lift and drag forces on a golf ball are very sensitive to dimple depth, a depth change of 0.001 inch can produce a radical change to the ball's trajectory and the overall distance it can fly.

... Larger dimples will result in additional lift whereas smaller dimples will result in a lower trajectory. I'll highlight the next part as some of us don't get it yet: The larger the dimples, the fewer will fit on the cover of the ball and vice versa. Take the Titleist DT line for example, two nearly identical balls with very different dimple patterns and sizes. The DT carry has larger dimples than the DT roll and as a result... 140 fewer dimples.

Most golf balls have between 300 and 500 dimples, which have an average depth of about 0.010 inch. The lift and drag forces on a golf ball are very sensitive to dimple depth, a depth change of 0.001 inch can produce a radical change to the ball's trajectory and the overall distance it can fly.

I'm not doubting anything you say, but the Prov1x has seven SIZES of dimples on the ball (per the Titleist website) and the ProV1 has five. obviously, this is done to provide as complete coverage of the surface as possible but given the same surface area and with a difference of sixty dimples between these two somewhat similar balls, it doesn't seem that size has that much to do with number.

so again, if the number is the least affecting factor in the ball's flight characteristics, why is it the most common (only) spec quoted in advertising?

sorry if this seems to belabor the point but I'm just a curious person by nature. I'm sinceerely not trying to be contentious. It would be great of a golf ball designer/engineer came on and said, "the number of dimples has X effect on the ball, but I would be just as happy if they said, "it's all hype".

thanks for taking the time to reply.

my best to you,

ra2bach