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Old 03-21-2010, 10:14 PM   #1 (permalink)
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"Golfball effect" thinktank...

Yes, I've seen the other two threads. This is less related to that, and more related to the "whys" of the functionality. For this thread, lets make the following assumptions: Adam and Jamie of Mythbusters didn't screw anything major up in the science and testing and that some of their testing might hold merit. Dimpling has some affect on the aerodynamics. Adam and Jamie scaled a golf ball up to car size. (Use this third item to establish a baseline dimple size)

I am proposing that dimpling the whole vehicle might not work to our advantage. That dimpling starting at the furthest ranges of the Z and Y axis then working back to the rear of the vehicle is all that's actually required, and that any more than that might work against us. I am also proposing that there is an optimal dimple size for said construction, and that simply scaling up a golf ball might not be the optimum solution. However, investigating this phenomenon has many benefits to this community and should be explored. Currently "boat tails" cause a large extension to the rear of the vehicle. With the golf ball dimpling, it might be possible to lessen the distance and cost of the current home brew iterations. Unfortunately, creating something new like this, takes time and resources.

Now, with all that under advisement, how would we test this? Is this something that can even be done small/medium scale first? How does one figure out the "optimal" dimple size? Is there a mathematical representation for this somewhere? Any other stray thoughts?

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Old 03-22-2010, 02:10 PM   #2 (permalink)
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Schlicting

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Originally Posted by thedarave View Post
Yes, I've seen the other two threads. This is less related to that, and more related to the "whys" of the functionality. For this thread, lets make the following assumptions: Adam and Jamie of Mythbusters didn't screw anything major up in the science and testing and that some of their testing might hold merit. Dimpling has some affect on the aerodynamics. Adam and Jamie scaled a golf ball up to car size. (Use this third item to establish a baseline dimple size)

I am proposing that dimpling the whole vehicle might not work to our advantage. That dimpling starting at the furthest ranges of the Z and Y axis then working back to the rear of the vehicle is all that's actually required, and that any more than that might work against us. I am also proposing that there is an optimal dimple size for said construction, and that simply scaling up a golf ball might not be the optimum solution. However, investigating this phenomenon has many benefits to this community and should be explored. Currently "boat tails" cause a large extension to the rear of the vehicle. With the golf ball dimpling, it might be possible to lessen the distance and cost of the current home brew iterations. Unfortunately, creating something new like this, takes time and resources.

Now, with all that under advisement, how would we test this? Is this something that can even be done small/medium scale first? How does one figure out the "optimal" dimple size? Is there a mathematical representation for this somewhere? Any other stray thoughts?

Thanks for reading and not throwing bottles at the fence!
I would respectfully recommend that you take a look at 'Boundary Layer Theory' by Schlichting.There is extremely solid science which disputes the physical possibility of dimples ever improving the airflow over an automobile.

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Old 03-22-2010, 02:26 PM   #3 (permalink)
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Old 03-22-2010, 02:28 PM   #4 (permalink)
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The folks at Myers Motors, maker of the NmG, (an updated/upgraded Corbin Sparrow) might disagree that the dimples have no positive effect on airflow. If you take a close look at the trailing sides of the front fenders and the lower aft sections of the vehicle, you will find them dimpled. When I toured their (MM) factory a couple years ago, I asked what the dimples were for. They told me that they increased the range because they reduced the drag on the body.
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Old 03-22-2010, 02:44 PM   #5 (permalink)
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The folks at Myers Motors, maker of the NmG, (an updated/upgraded Corbin Sparrow) might disagree that the dimples have no positive effect on airflow. If you take a close look at the trailing sides of the front fenders and the lower aft sections of the vehicle, you will find them dimpled. When I toured their (MM) factory a couple years ago, I asked what the dimples were for. They told me that they increased the range because they reduced the drag on the body.
I would respectfully take them to task to demonstrate,scientifically,how they accomplished something no one else on Earth was able to accomplish,when they had the resources,technology,and motivation to do so.
It's like the old adage,that extraordinary claims require extraordinary evidence.
The dimples may have an effect,but it may reside in an effect which has nothing to do with golf ball dimples.
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Old 03-28-2010, 06:58 PM   #6 (permalink)
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Hi All,

To fill in some of Aeroheads remarks. The dimples on the new version of the Corbon Sparrow might (probably) be there for sheet-metal vibration reduction / sheet metal stiffening purposes. Dimple sheet metal like that and it gets quite stiff from work hardening, as well as the 3-d nature of the dimple feature.

That said, I think dimples will work on cars that look like golf balls. Right now, the only one is the New VW Beetle.
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Old 03-28-2010, 11:59 PM   #7 (permalink)
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Dimples work on golf balls because the shape is so abrupt. If you can keep a ball from rotating, all it needs is a thin ring or groove as the air approaches the widest part.

I believe the Corbin Sparrow is fiberglass, and the dimples are placed as boundary layer turbulators where they might do a bit of good to fix the shape. It would be easier than more extensive mold mods.
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Old 03-29-2010, 12:45 AM   #8 (permalink)
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I believe the Corbin Sparrow is fiberglass, and the dimples are placed as boundary layer turbulators where they might do a bit of good to fix the shape. It would be easier than more extensive mold mods.
I can't tell from your post, do you think they are cosmetic or, they help lower the overall drag and they are just easier to add than say, vortex generators?
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Old 03-29-2010, 06:05 AM   #9 (permalink)
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A Vortex Generator is harder to add to a mold, and is just a better Boundary Layer Turbulator. IMHO, either type is barely functional in those locations, except to show model changes at a glance and give the sales force something to chatter about.
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Old 03-29-2010, 01:53 PM   #10 (permalink)
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Dimples on a car could work if you kept your car in a constant 180 degree spin like a golf ball something which I, for one, make every effort to avoid!

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