The Gen III's Lower Drag: Could be better?

[hill]

I'm wondering if Toyota could learn something from the humble Golf Ball:

Fastskinz Dimpled Golf Ball Fuel Economy - 430-mile 2009 Ford Flex vs Ford Flex Aero Test - Popular Mechanics

Or was this just too weird for a "normal" car design. The results say "NO" ... don't do it! At least not until the Gen IV Prius is shaped like a golf ball. Oh well, they get an 'A' for effort. I remember back in the 1970's & 80's we'd glue "disturbance strips" along the length of yacht masts for better drag. It looked like a zig zag shape, about 3/8" wide. Similar to the stealth fighter rear wing shape. I guess this too has limited auto applications.


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[usbseawolf2000]

Yea, it doesn't work. In fact it gives even less MPG. The problem is that cars don't rotate while moving.

Tire manufactures could use the same concept. The side walls ought to have dimples. The rims can use dimples too. Toyota, are you listening?

[FireEngineer]

No dimples but....



Wayne

[usbseawolf2000]

I see three tracks for the air to flow underneath. Wow, talk about attention to details...

[bwilson4web]

Originally Posted by FireEngineer

No dimples but....

Do you have any more photos from the underside?

I notice the heat shield material seems at the top of the photo to head to the rear but the exhaust pipe seems to jog to the right of the photo and somewhat where it might expose heat to the HV cables.

I'm especially interested in photos showing the vehicle tie-down anchors.

Thanks,
Bob Wilson

[TonyPSchaefer]

Originally Posted by usbseawolf2000

Yea, it doesn't work. In fact it gives even less MPG. The problem is that cars don't rotate while moving

Not intentionally.

I thought the same thing when I read about the golf ball dimples. A golf ball hit with absolutely no rotation would not only not travel as far but it would be hard pressed to stay in a straight line.

It's a good thought but you just can't apply the physics of one object to another.

[donee]

Hi USB...,

Rotation has little to do with golf ball dimple drag reduction. The only reason the dimples are evenly dispersed, is because its not practically possible to avoid the ball rotation in a plane or rotation with significant component parallel to the direction of flight. If it were (such as if launched from a riffled mortar barrel), less drag could be realised by putting the dimples just before the aerodynamic seperation point only. This has been demonstrated in with a trip ring attached to a sperical object, I read somewhere.

[donee]

Originally Posted by hill

I remember back in the 1970's & 80's we'd glue "disturbance strips" along the length of yacht masts for better drag. It looked like a zig zag shape, about 3/8" wide. Similar to the stealth fighter rear wing shape. I guess this too has limited auto applications.

Hi Hill,

These are called "turbulators". I have added some on my mirrors and the upper 1/3 of the A-pillar. You can make them with a "pinking" shear. They need to be the right thickness for the flow. In a high flow area they need to be very thin. One experimentor got significant results with only 1/32 inch thick Dymo label tape.

[usbseawolf2000]

I was thinking along this line of thought...

Picture Aptera wheels... they create less drag because they are covered. The same with the original Insight and EV1 rear wheel skirt.

My idea was to use dimples on the tires and rims to create a layer of air between the wheels and the air flowing around it. Basically, a layer of air would replace the cover or wheel skirt. This layer of air can cover more area than a wheel skirt can.

[SageBrush]

There is a Canadian company that has been working on windmill blades with fenestrated edges -- a bit of biomimicry from the hunchback whale if I remember right. I expect to see 'unusual' bumpers and grills on cars in hte future as aerodynamics becomes even more important. For now, smoothing out hte underside of the car seems like low hanging fruit