Mythbusters Golf Ball Car
 

Mythbusters just did a new episode where they tested to see if a car that is clean, dirty, or covered in golf ball dimples is more fuel efficient.

Clean car: 26.4 mpg.

Dirty car covered in chunky mud: 24 mpg

Car covered in 850 pounds of clay, with thousands of golf ball dimples: 29.6 mpg.

The test was done on a Ford Taurus V6, over a distance of one mile at 65 mph on a closed road 6 times per test.

cool
i saw most of it lol

but like they said it would be awfully hard to make a buncha small dimples in sheetmetal

Hail damage doesn't count?

Maybe that's why my Cad does better than EPA...all the dimples from hail damage!

A 11% Fuel Economy Increase
 

Hello All
Yes I watched this show at mythbusters that was on 10-21-09 pm. According to their report the test was run at 65 mph in a repeatable manner. They used whatever Car that was available. The golf ball indentations were to scale unlike the stick on stuff sold. This makes the car ugly and hard to wax. But the important thing is gas miliage increased 11%.

Why clay? They could've use something a little lighter. Who sez that the extra weight plus the aero effect didn't affect the results? Did they do 850lbs of clay spread over the entire car without the dimples and check that? ;)

11% Increase in Fuel Economy
 

Hello All
Clay was used so the car was not destroyed to do this TEST.

Ok , so the test showed an 11% improvement in FE at 65 mph, with an extra 850 lbs in the car. This then in theory should show a larger FE gain using something that weighed considerably less. Whos going to do it first?

Though weight has less of an effect if you're maintaining speed so I don't think it'd help all that much unless they encountered a lot of up hill driving.



Here is the video:https://www.megavideo.com/?v=17PNUJM8

After watching the video, I guess the only thing I would have hoped for were for the mythbusters to have used smaller but more numerous dviots but that would have taken considerably more time and they had the worry over the clay falling off so I understand why they choose that divot size.

Something like this plastic on the underside of my VW?

https://lh4.ggpht.com/_oNsRR_T1Qx0/SB...0/IMG_0658.jpg

Much of the bottom is covered in large panels of it.

There must be a textured vinyl material out there like wall paper or something. Check out this lexus: https://www.blogcdn.com/www.autoblog....xus000_opt.jpg
I wonder where they got that stuff?
https://green.autoblog.com/2009/02/16...nt-than-paint/
https://www.fastskinz.com/

I look into the future, an industry making fibergalss or vinyl dimple panels to retrofit cars. The Pontiac Fiero with its plastic body panels could do a dimple car. The electric Sparrow had dimples behind the fenders to have air release from the fenders and thus getting rid of the stickieness of drag. Like the Holy Cow said about his Golf having dimple panels underneath, breaking up drag.

Update that to the future and we could have manufacturers making purpose built dimple cars, headlights and turn signals inside the dimples, can't dimple the glass though. lol

I guess how the mathematics of it works is by causing a ruffled air area above the surface and the air lubricates itself, making the air slipprier. Hard edges that create drag are now rounded by the layer of disturbed air around it. Somebody check my math.

Like the Mythbusters golf ball car, it is a thing of beauty, kind of like some retro 60's or 70's art, if IKEA were to design a car, it would probably look like the golf ball car. Now sell it to the American people, the dimple Hummer, dimple Escalade, dimple Jeep, or a dimple 18 wheeler with a 53 foot box trailer covered in dimples. Better yet, dimple the Prius, I am going to have to stop now, I'm going to dimple everything.

Runners will be wishing for cellulite and acne pocks...

But seriously, I wonder if a thermal roller set up could dimple everyone's favorite prototyping and belly skin material - coroplast? 4x8 sheets could easily be run through a roller press, and the material is thick enough to accept a dimple.

Why aren't auto manufactures looking at this?

So if my G/Fs *** is dimpled, is she more aerodynamic???
:D

Yes, the dimples removed clay, so they threw it back inside the car, so weight was the same. It was smooth clay vs dimpled clay.:thumbup:

I'm always a little disappointed in the myth busters approach to science. I get exited about what they are testing (not so much the getting drunk part), but usable can think of a better way to test it. For example, cruse control??? and something better than a toggle switch on the dash. 1 mile at 65mph takes ~55.38 sec. so if you can flip the switch with an accuracy of +or- 1 s, then the total for each run would be +or- 2s which would be about 3.6% then compare to the control run with the same accuracy which puts total accuracy for the test at +or- 7.2%. Then take into account the potential for driver inconsistencies, I'd put it at +or- 2%-5%, (lets just say 2%) so to compare two runs with give +or- 4%. Add that to the switch accuracy and you get +or- 11.2% high enough to show the results are meaningless. They did average the results of multiple testes to "smooth out" any numbers that were way off. I do think they got real results, but i could have gotten more accurate ones with a smaller budget.

I had a parking lot hit and run, leaving a big dent in my door on Tue. It would be a good day to take the old ball-peen hammer out to do some dimpling.

The dimple effect makes turbulence which adds resistance across the surface, as energy is being put into air swirling motion. But now that the air is moving in this way the back of the ball/car has less turbulence.
It's a strange approach, reduce turbulent effects be causing some more. It seems more sensible for golf balls than cars, as golf balls have to be round, you can make a tear-drop shaped car. But my car isn't tear-drop shaped, and I want it to have less air drag.

The thing to think about here is what made this work.
-the car had bad aerodynamic quality in one region
-the surface texture created turbulence in the fluid before it entered this region

there are many ways to approach this. I don't see the full skin as a the best approch. It seems like it would be better to have the texture/dimples/fin things/ 50 2"X3" flags, just before the region that needs the help.

It would be really nice to have a bunch of 1:4 scale models of my car and a wind tunnel to do some testing.... I do have a big blower fan, and a smoke machine is easy enough to put together... Maybe some company made some cheap model cars like my subaru, time for some research. or sleep

Mythbusters did find a great alternative to a windtunnel when testing "Tailgate up / Tailgate down" They used a toy truck in a tank of water, and used a pump to create a current. They then dumped oatmeal in the tank, and it easily showed the flow around the vehicle.

I just thought about another thing...ride height. I'm sure that extra 850lbs of clay did some "lowering" effects to the vehicle. I'd be curious if the dimples didn't drop the height of the car some more while driving. I'm pretty sure they didn't measure the height... :(

That's a good point! I guess what they could have done is have an air dam on the car for the control test, then do the test with the clay. The goal would be to try to have the control vehicle's front end be at the same height as when the vehicle is loaded down.

A few posts ago, slurp812 said that they controlled for that issue by still having the clay in/on the car before the dimples.

ROFL!

Yes, they applied clay smooth. Then ran course. Then using a tool they created, added dimples. This removed some clay of course, which was put back inside the car, so the weight was equal. And ran 2nd run.

Who says it has to be done with dimples? Why not bumps (anti-dimples) or ribs, perpendicular to direction of travel. Just get some Styrofoam chunks, get a hot wire cutter (similar to the tool they used to cut out dimples) and glue them on.

Am I the only one who fully expects to see production cars like this in the (sorta) near future? Man, the industry is gonna throw a fit.

To quote Astronaut Farmer, "Sir, they launched the rocket!"
"No they didn't"

That sounds like something worth looking into!

Well an fyi, there aren't any golf balls with "anti-dimples" but feel free to try it out! My guess is the reason why is because it increases the overall surface area that is exposed to the air. The point of the dimples I believe is to create a vortex that spins around in the depression, causing the air flowing over to get agitated. Watch the mythbuster's episode with the tailgate up or down, it's the same idea. But again, feel free to experiment and post back with your results.

I might actually be willing to try ribs going up and down (and side to side on the top) if I had the right material. Maybe foam rubber? I could just try it out with cardboard or PVC pipes, but I would need a good road trip to try ABA testing.

ANYONE wonder if the repeated driving may have improved the car mileage and it has little to do with the dimples but actually the car running more at 65mph and getting warmed up or maybe loosened up from driving. Maybe they should have done the old ABA test to verify that without dimples then with dimples and then again without dimples yields consistant results. I know that on occasion my xB when run and then stopped for several minutes then started and run again gets way better gas mileage for some unknown reason.

Everyone is a critic. Watch the video. The evidence speaks for itself.
https://www.megavideo.com/?v=PMB935S8

hey what was that??? 3 popup ads no video?

Would weight distribution have any effect on MPG then? I think they just tossed the box of dimples in the back seat... ;)

I'd also be curious on what the air pressure was in the tires... ;)

Unless the box of dimples weighed 1000 pounds, it could not have made a measurable difference.

If it was heavy and weighed down the rear of the car, I suspect that would have reduced fuel economy through bad aerodynamic effect.

You can see how much further the rear of the dimpled car squats down compared to clay car. I think they could've improved their numbers if they tossed the clay in the engine bay instead... ;)

https://www.fuelly.com/attachments/fo...7bb02d081d.jpg

https://www.fuelly.com/attachments/fo...23121f413c.jpg

Weird. The first picture looks more level than the other three. I wonder what's up with that?

lol cars on the other side of the arched road :D

even then, if it were more level it prolly woulda gotten better mpg

The car is bouncing over bumps in the road.

Hmmm...that car should have ODBII on it, right? I'm surprised they didn't hook up a data logger to log all the parameters of the car while making those runs. I'm sure that would give us more confidence if that data would've been captured and posted along with the results. :D