Anyone have 800 Lbs of clay handy? New mythbusters episode

[Jabber]

VIDEO: Mythbusters test golf ball-like dimpling effect on fuel economy (*Spoiler Alert!*) — Autoblog Green

They actually got a 15% increase in fuel economy by "dimpling" the car.

[smartalec89]

Originally Posted by Jabber

VIDEO: Mythbusters test golf ball-like dimpling effect on fuel economy (*Spoiler Alert!*) — Autoblog Green

They actually got a 15% increase in fuel economy by "dimpling" the car.

Maybe 1600lbs. I will take some too. I saw that episode too. It was awesome.

[yardman 49]

Yes, I saw this episode also, and I thought that it was one of their better ones.

I couldn't see anything wrong with their methology for this test. They must have had some real scientists/engineers/statisticians help them design their testing protocols this time.

[hyo silver]

Sounds plausible, but why does it work? I remember posing this question to my high school physics teacher, and he said it works for golf balls, but not cars. The dimples, he said, actually increase drag, but because of the spin of the ball, more lift is generated, and it flies farther. On things that are only somewhat streamlined, the dimples would help by bringing the airflow closer to the surface. On really smooth surfaces where the boundary layer flow is already laminar, dimples would only cause turbulence. When I asked about pressurising the inside of the body, and letting air out through tiny holes in the base of the dimples, to make little 'ball bearings of air', he said I was making his head hurt.

Maybe I should watch the show, eh?

[dogfriend]

Does this mean I should get out a ball pein hammer and go to town on my car?

[hyo silver]

Shouldn't you wait to find out the optimum dimple size? Or would you rather make a bunch of different sized dents to see what works best?

[carz89]

Can you Clay-bar a clay car?

[carz89]

With the latest in computer technology (hardware & software) being used by automotive and aerospace engineers, I would think that this "golf ball dimpled car" experiment could have been perfectly simulated on a computer, with fantastically accurate results. I wouldn't be surprised if many automotive companies have already done this experiment and either yielded unconvincing results, or are keeping their discoveries secret.

Or perhaps the car companies already discovered the slight improvement in MPG, but the increased manufacturing cost of a dimpled body was prohibitive. Or perhaps they did a marketing analysis and discovered that most buyers (except golfers) were turned off by the dimpled appearance.

[dogfriend]

Originally Posted by hyo silver

Shouldn't you wait to find out the optimum dimple size? Or would you rather make a bunch of different sized dents to see what works best?

Start with small dents, then make them bigger to see if it improves mileage.

[Matt Herring]

Complete absurdity...and unfortunate that many of the uniformed take Mythbusters results as fact or anything "scientific" just because they do "tests" of urban myths. This leads to snake oil salesman selling "dimple kits" to add to your car and other illegitimate products along the same line...unfortunately they make their money...and the uniformed lose theirs with nothing to show for it other than an empty wallet.

Why are golf balls and cars different? Because a golf ball is in a constant state of rotation...cars are not. Cars are basically rolling blocks of drag compared to a rotating golf ball that gains its aero advantage due to "turbulant" air flow. Turbulant air flow works for golf balls...not cars. It makes no sense to dimple a car because they already have laminar air flow...in fact car manufacturers spend millions and millions of dollars to reduce turbulent air flow and air separation to make their cars with the lowest coefficient of drag as possible.

If dimples decreased drag on a car do you think you would not have already seen a dimpled car on the salt flats breaking world speed records?