Love it
How about guerilla aerodynamics...

If that is the VX model, it started out in the high 50's low 60's mpg when driving below 2000 rpm in top gear (highway speeds). Now the industry is toting their AMAZING 35 mpg compact cars. What happened? They should have just kept building what they were building 15 years ago.

For the millionth time, because cars like that won't meet today's crash standards and emissions controls.

Old civics, diesel rabbits, and other small cars of yore don't have big strong roomy frames, abs brakes, airbags, VSC, advance catalytic converters, power windows / locks, engines with at least 130 hp, and everything that adds weight and complexity in a more modern car.

All that stuff is either mandated by the gov or by market forces. Today's buyers expect all that stuff even an econo car and for it to somewhat survive a crash with an SUV.

Given the extra weight and emissions standards, car engines are actually more efficient, but people want more room, good acceleration, etc... and that's what manufactures will make.

Phrancis - there are other factors, too. I'm not saying that government regulations don't play a role, but don't make them out to be the sole bearer of responsibility.

Other factors include a steady gain in average horsepower (there are only a few cars out there that have less than 125 hp), a steady gain in average size of a car (if you pay attention, you'll notice that each time a car is updated it usually gets bigger in length and width and height), a steady gain in weight (although a lot of this could probably be attributed to regulations), and a steady gain in on-board (unnecessary) electronics.

Nevetheless... aerodynamics play such a huge role in mpg, yet are mostly ignored by all the automakers. All the wind tunnel testing espoused in glossy ads is more for noise than efficiency.

Virtually every car on the road could be given a drag co. of around 0.25 (or much less), without looking hideous, if the automakers cared to do it. Heck, some of the most beautiful cars of all time (eg: classic hard roof Ferrari's) had very good aerodynamics (from LeMans racing influence).

The 35 mpg standard is easily achievable right now, at a modest cost premium, despite what auto spokespeople try to remind us.

"Nevetheless... aerodynamics play such a huge role in mpg, yet are mostly ignored by all the automakers. All the wind tunnel testing espoused in glossy ads is more for noise than efficiency."

Well said, people question why the Honda Insight and Toyota Prius look different, and don't realize it's the same basic design as the old Honda CRX but more refined.

Aerodynamics costs very little, and barely effects usability of the vehicle. It's long over due that artists quit designing vehicles, and design them in a wind tunnel. OK, maybe a mix of the two, but you get the idea.

Mr. Turner has made a very good attempt at improved efficiency. He may find that he can eliminate part of the tail fairing and use a blunt surface at the end of his car, a savings in length or increased storage volume. In the thirties, Chrysler developed a car called the Streamliner. The goal was the same as Mr. Turner's, increased fuel economy. Chrysler discovered that a pure teardrop shape was not necessary because the airflow became turbulent and draggy the last third of the car length no matter how streamlined it was. Might as well increase the rear volume and have more usable space for the operator. The teardrop/raindrop shape works very well for small items like raindrops but not so well on a larger scale. Wings on aircraft retain this shape not for reduced drag but to deflect the airflow downward to provide lift. Click on this link http://www.airforce-technology.com/projects/f16/f169.html to see an external fuel-tank. An efficient low drag high volume design with a blunt rear surface. People building teardrop campers should take note!
Terry Lundby http://steelfeather.com/

@ Terry:
Very true. A teardrop shape with the tale cut off is referred to as a Kammback, named after Wunibald Kamm, the researcher that proved it was more efficient than a teardrop. http://en.wikipedia.org/wiki/Kammback

Some have done "Kamm" mods to their vehicles in order to taper the back with a 3-sided box shape to increase aerodynamic efficiency. I cannot remember with school did the research, but in the U.S.A it was found that a set of three clamp-on panels (Assembled to create a hollow taper) could be attached to the back of a large tractor-trailer in order to increase fuel efficiency up to 10%, a huge saving for large trucking companies.

Why can't we get a tax credit for buying cars that exceed 30 mpg's? Instead there are tax breaks still available for large SUV's???

why not just get a huge hamster ball and roll around in it? that would be more fuel efficient and aerodynamic!

can we please start including Mini Vans in the SUV bashing. I know my SUV is far more efficient than most Vans.

A properly shaped teardrop (boattail) rear end will maintain an attached airflow all of the way to its tip.

I question the claim that a Kammback is lower drag than a full boattail. If this were the case, then why don't you find Kammbacks in nature. You'd think, if a Kammback was lower drag, that some bird, fish,or squid would have evolved one. But all you can find in nature are boattails.

Also, if they are lower drag, then why don't you find Kammbacks in aviation. I can't think of a single Kammbacked aircraft. There's got to be a good reason (i.e lower drag) that NASA mounts a boattail on the back of its Space Shuttle when it piggybacks on top of the 747, considering the potential weight savings that could have been had if they had mounted a Kammback back there.

Also, the creaters of the Aptera chose to use a boattail rather than a Kammback when designing their ultra-low Cd car.

The auto industry prefers the Kammback since it if easier to package into a traditional automobile shape but for the absolute lowest drag the teardrop (boattail) is the way to go.

Kamm designs don't necessarily offer an aerodynamic improvement over long, pointy tails, Kamm merely observed that there was a point of diminishing returns and for reasons of packaging, mass, volumetric efficiency, polar moment of inertia and the drag of attached flow, (not to mention parking) a flat butt could work better than a near-infinite taper. That doesn't mean that a chunk of plywood Bondo'd onto the end of your Taurus is going to help.

Several coments : Free falling raindrops do not have a tear-drop shape, they are spherical. A "boat tail is more streamlined, but to maintain the attachment of the airflow, it would have to be VERY long. At anything approaching a reasonable length, the airflow separates just behind the passenger compartment.

Several years ago Road and Track Magazine designed and fabricated the most swtreamlined street legal car that they could, using all available data. They found that the Kamm shapt worked best.

To address the Kamm question: a very long, gradual tear drop shape (eg: Aptera, airplanes) is indeed the best, *however*, a sort-of-long rounded rear end (Audi TT) is the worst. The sharply cut off Kamm back(Corvette C6, Honda Insight, etc) is a neat compromise solution that comes close to the efficiency of the tear drop in a much more practical package.

As such, it's extremely frustrating to see cars on the road that don't employ it, or employ it half-arsed.

REPLY TO M_TURNER: "Kamm designs don't necessarily offer an aerodynamic improvement over long, pointy tails, Kamm merely observed that there was a point of diminishing returns and for reasons of packaging, mass, volumetric efficiency, polar moment of inertia and the drag of attached flow, (not to mention parking) a flat butt could work better than a near-infinite taper"

Thankyou for mentioning the matket side of things!! I am a Mechanical Engineering student at Fresno State and also persuing a minor in economics. I see first-hand how engineers must take the market into consideration when making designs. The only way improved technology can make a difference on a large scale is if it meets consumer demands while improving efficeny. The most advanced car/shape in the world won't do a bit of good overall if the consumers won't buy and use it.

my 2000 Saturn DOHC sedan achieved 37.4 mpg on a 129-mi run down the PA Turnpike at 70 mph on cruise control (any slower and I'd have been crushed!) as I watched boxy SUVs, pickups, and vans @85mph "ramming themselves through the wind", often with ONE passenger.

Sadly, the price of fuel reflects the AVERAGE behavior of all of us,. Comments on the web from "Green-haters" tell me that the American PSYCHE is far more important than aerodynamics to solving all this. As is the case with our foolish war in Iraq, we ALL pay for the stupidity/cupidity of our AVERAGE fellow-citizen. (Yes,yes, we also benefit from his/her GOOD points...)

There's a story in Herodotus of a Persian soldier who foresaw the catastrophic failure of their invasion of Greece. The conclusion is "much knowledge, NO control". It is up to those of us who understand this situation to resolve it...one person at a time. We can't expect either the automakers or the legislators to defy the "market forces" to which BOTH are subject...

Manufatures could make cars much more effecient with little changes that would not be visiable to the average consumer.
Auto manufaturers have been slow to embrace direct injections, varraible intake and exhaust valve timming, and dry sump oiling systems.

GM and others have way to slow in releasing 6 spead autos.

last and not least undercar airflow manangment would increase MPG and make autos safer at speed.

I always wondered why Honda said farewell to the CRX-HF......I had two.....An 88 and 89 and used to commute Tucson to Phoenix back in those years. When gas was 85 cents a gallon, I'd make the trek for $1.28........Plus, I could go Phoenix to San Diego for $5.50.....and Phoenix to Salt Lake for $10. Best I ever got out of it was 70.1mpg, which was some pretty good downhill from Jerome to Phoenix......But, i'd easily get 65 mpg out of it at 65-70 mph.....I do miss those cars.

While the Audi TT may not be the best design for aerodynamics......I can honestly say that it's really not that bad on gas......Once again, it's the driver vs. the car.......I've been able to squeeze as high as 47 MPG out of it using a stick......Coasting is a good thing........Whatever it takes.

Wow, the level of expertise and design knowledge here is amazing. If I were starting an advanced auto company I'd look you all up and hire you on as designers. Okay, so much for the kissing up, but thanks for the education. Your posts were very informative.