Why do you think there are not any cars out there with a sharkskin or golfball surface texture?

My guess would be that it isn’t cost efficient.

Might also be hard to clean, and people are used to shiny cars.

Isn’t the whole point of the dimples in golf balls to maintain a true path of flight?

@andrew Not according to Mythbusters.

@Sampson Links please. I believe you, but I think @andrew is at least partially right.

Link to the Mythbusters golf ball dimpled car info

@rangerr thanks!

[citation needed]
Why do you think it would “reduce drag and improve fuel efficiency”?

@jaytkay
http://www.bio.davidson.edu/Courses/anphys/2000/Tuscano/Drag%20Reduction.htm

http://en.wikipedia.org/wiki/Golf_ball#Aerodynamics

“the dimples delay separation of the boundary layer from the ball. Early separation, as seen on a smooth sphere, causes significant wake turbulence, the principal cause of drag. The separation delay caused by the dimples therefore reduces this wake turbulence, and hence the drag.”
and mythbusters have shown that it does.

HAHAHAHAHAHAHA!!!!!!!!!!!!!!!!!!!!!!! i want a sharkskin car. i would also assume it is due to cost…what would it be made out of? something pretty funky probably. who knows. not me. but i want one.

@deni – Probably fiberglass.

@Darwin
nah. carbon fibre is much more common.

@ragingloli – Only in very high end vehicles. It is less common in cheaper cars.

“Until recently, the material has had limited use in mass-produced cars because of the expense involved in terms of materials, equipment, and the relatively limited pool of individuals with expertise in working with it. Recently, several mainstream vehicle manufacturers have started to use CFRP in everyday road cars.

Use of the material has been more readily adopted by low-volume manufacturers who used it primarily for creating body-panels for some of their high-end cars due to its increased strength and decreased weight compared with the glass-reinforced polymer they used for the majority of their products.

Often street racers or hobbyist tuners will purchase a carbon fiber-reinforced polymer hood, spoiler or body panel as an aftermarket part for their vehicle. However, these parts are rarely made of full carbon fiber. They are often just a single layer of carbon fiber laminated onto fiberglass for the “look” of carbon fiber.”

Source

I watched the full Mythbusters on this (thanks for the link).

According to a conversation with TIm, who is an expert on car aerodynamics (and too busy * cough * lazy *cough * to write a response):

The perfect airshape for aerodynamics is a teardrop. Until very recently, car manufacturers have been very slow to deal with aerodynamics in design.

Ultimately, while you would get a small benefit from dimpling the car, which has a fairly poor shape to begin with, you get much more benefit by designing a more aerodynamic shape. This is why you don’t see any dimpled aircraft or spaceships.

The reason golf balls are dimpled is because they have a requirement for being round—and so you can’t make aerodynamic changes to them without compromising the fact that they need to roll. And be struck by a golf club. Hence, dimpling.

Alright, fine. I’ll answer this one. Hmph. I’m by no means an expert, but I have an amateur interest in aerodynamics and have spent a fair amount of time talking to aerodynamicists about cars, aircraft and spacecraft.

There are five main reasons why there are no cars like that:

1. Costs. Certainly not astronomical, but enough that to make it impractical.

2. Safety. Introducing dimples would reduce the structural integrity, which would require more computer simulated crash testing and use more material, increasing the weight. Sharkskin would probably be the same, requiring more material for the same survivability results.

3. Weight. Increased weight would reduce braking performance (making safety worse again) and would offset some of the gains from aerodynamic improvements.

4. Looks. Seriously. How well would that dimpled car sell? Better than ice cream in Antarctica? I think not.

5. It would be easier and better to just build a more aerodynamic shape to begin with quite honestly. This hasn’t been a focus for car makers until recent interest in MPG. I used to race solar car in college and we used this equation to calculate the performance of the vehicle. Basically what you should note is the aerodynamics quickly dominates the energy required to move a vehicle as it has the velocity cubed in its equation. So aerodynamics is more costly than rolling resistance (total area of the tires touching the road, tire pressure (lower pressure absorbs more energy, so keep your tires inflated!)), vehicle weight, etc. It’s important for a vehicle to have the air come cleanly off the rear of the vehicle (I’m avoiding jargon). Golf balls have to be round and there’s always going to be a turbulent wake behind them so the dimples can help that but it’s better to design the aerodynamics so the air leaves the trailing edge of the vehicle with little or no turbulent wake. If you want to see a car that’s take all of these things to the extreme I can provide an example. The tires are inflated to three times the normal pressure, the suspension is very firm (again not absorbing much energy), there’s only three tires and they have no tread. The car weighs ~400 lbs. It has fairings which are wheel covers to prevent the creation of turbulent air over the non-aerodynamic shape of a wheel. Everything on the car is moved back as far as possible to delay the disruption of air as long as possible. The trailing edge lets the air coming off the back without a giant turbulent wake compared to a normal flat car rear. Here it is, Ra 7. The Aptera 2e is another good but less extreme example.

This is why aircraft and spacecraft don’t have dimples. They are simply designed in a more aerodynamic way to begin with.

Does that cover everything you were wondering about?

@timtrueman you sound like an expert to me. (;

Also another good example of reducing turbulent wake to increase aerodynamics is the wing tips of birds. They flare up at the very tip. I’m sure you’ve noticed in the last 5–10 years all the jet aircraft have added winglets in order to avoid the vortex created by a flat wingtip as seen here.

Well, if you live in an area where hail storms are common, you may end up with a dimpled car anyway, like it or not.

Oh! But there ARE such cars! Whilst shopping for a car a few years ago, I happened to look closely at the surface texture of a Ford Torus. The paint definitely had a dimpled texture much like a golf ball, but you could only see it with dark colors under certain lighting conditions. I thought it was a fluke, so I looked closely at all the other Toruses in the showroom, and they all had the dimpled texture. For some reason, all the Toruses in the showroom were black (something to do with a Ford anniversary or something if I recall correctly), so it was easy to check. In normal sunlight, the paint looked smooth and shiny, and you couldn’t see or feel the dimples. Oddly enough, the brochure didn’t mention it as a feature, and the salesmen didn’t even know anything about it until I pointed it out to them!

Would clearly remind people of epicot too much, and we certainly don’t want that.