[proxlamus©]

Did anyone watch MythBusters on Discovery last night?!

They covered a car in clay and made dimples on the car like a golf ball.. and there was a 11% increase i believe in fuel economy...

They were joking saying Nascar will now have golf ball shaped cars...

then I started wondering...

Golf balls have been around for how many years?!

Aircraft and Formula One and Nascar teams have all played with vortex generators... but why not shaping the whole body like a golf ball?!

I mean the mythbusters test showed there was a dramatic increase in the reduction of drag?!

[cygnusx1]

The sphere shape of a golf ball does not make it aerodynamic. The sphere is a poor aero shape. The dimples decrease the drag by reducing the separation "wake" area behind the ball. Besides, people already have trouble driving. Imagine if they were hooking and slicing all over the road too!! Yikes.

[madlarkin]

I'm drawing a blank on the exact application but I believe the dimpled surface has already been used on underpans and aero parts in motorsports, it might be F1 I am thinking of. I think it was mentioned in an article in Racecar Engineering 3-4 years back.

[cygnusx1]

As I understand it:
The dimples cause the boundry air to stagnate "stick to the ball". The moving air slides better over the trapped "air skin" and it also "sticks" to the boundry layer, causing it to follow the contour, leading to a smaller wake zone.

[proxlamus©]

Correct..

now the dimples on the car allowed the air to stick to the boundary layer.. reducing the low pressure/wake behind the car.. increasing the slipstream.. increasing fuel economy.

Check out the video
http://dsc.discovery...y-vs-clean-car/

[big-phil]

yes I saw it also. pretty cool

[madlarkin]

Does this serve the same function as the desired slightly rough finish when porting cylinder heads or am I completely off base?

[MAG58]

madlarkin said:

Does this serve the same function as the desired slightly rough finish when porting cylinder heads or am I completely off base?

More or less. It's the same concept, you want to keep the boundary layer adhered to the port which it cannot do as well if the port is smooth as glass.

[Nismo280zEd]

Yeah I saw that last nght also. Infinity was playing with this idea on underpaneling about 2 years back. Not sure what happened.

[johnc]

Just park your Z out in a hailstorm.

[streeteg]

haha. nice

[Canadianz]

There is a company that actually makes a vinyl sticker type material that has this dimple effect. I saw it on discovery I think the other day, its a much more subtle effect. Kinda weird looking but same idea. It seems to have small but noticeable gains, most were using it on top speed vehicles.

http://fastskinz.blogspot.com/

[Valmont]

cygnusx1 said:

...Besides, people already have trouble driving. Imagine if they were hooking and slicing all over the road too!! Yikes.

lol - I saw this and was amazed - i understand the effect of the dimples, but am still having a hard time understanding the why - they said several time in the episode that they had explained that, but man i DVRd it and rewound several times... and no real explanation.

Val

[cygnusx1]

Sailplanes and airplanes can use "zig-zag tape" along the span of the wing. It has to be placed in the right spot on the airfoil to move the separation point further back on the wing.

[neotech84]

Give me 500$ and I can do it to your car with my ball peen hammer

[280zx 2by2]

I think they said they had a 11-12% increase in highway mpg?

well if your going to go this far why not add a few dimples

[olie05]

Zipp has been using dimples on their high end carbon fiber road bicycle wheels for a few years now.

[chunk]

olie05 said:

Zipp has been using dimples on their high end carbon fiber road bicycle wheels for a few years now.

Beat me to it!!

Are you a cyclist too? Im a mountain biker, but I follow all disciplines. Im a bicycle mechanic

[240zBoy]

I don't know if it was just me but I thought the car looked pretty cool:icon44:

[cygnusx1]

Why not? Textured cars instead of just painted. I think it could be a great innovation in style and function.