50-year old concept car had lower drag coefficient than Prius

the font is cool, the back is cool, but the profile is a$$-ugly!!!

 

Nice. Although the price is steep. I wonder if it runs?

btw: I think the ev1 had the lowest cd of a production car at 0.19.

 

I don't want to hijack this thread, but I've often wondered about the drag coefficient.

I know it makes the Prius more efficient. But when Toyota boasts about an improvement between Gen 2-Gen 3 of what? 0.01%, or having the highest drag coefficient of any commercially available car..I just wonder how much of a difference it really makes.

Insight, Prius, Honda Fit..they are all so close does the drag coefficient make any difference at all?

Seems like The Cube and The Scion Xb are able to get decent gas mileage and that is in the face of flaunting any nod to coefficient body design.

Wouldn't something like mudflaps or the simple addition of side mouldings instantly negate the .oo1% improvement of The Prius drag coefficient?

I know does make a difference, I just wonder if anyone can simply and comprehensibly tell me how much of a difference.

 

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Um, what's with the 57 BellAir fins ... axing those would reduce drag
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Drag coefficient is the comparison of the car under test to a "bluff box" of the same frontal area and length. The frontal area is the distance from the ground to the highest point of the car and the distance from the furthest side point to the furthest other side point. It makes a rectangle. Now make that a box by lengthening it to the length of the car under test. Test that object for drag. Then test the car and compare. The car will almost always have less drag, so it's a number like 0.3, or about 70% less drag. It's wind speed dependent, so that the wind speed under test must be considered. I don't know what the standard wind speed for measurement is.

Note that the lowest drag coefficient so far is a concept car being considered by a French company for production. They copied the box fish. It's ugly, in a cute sort of way, like the Soul or Cube, but anything for efficiency!

Further, note that the Prius beats the third gen RX-7, which had a drag coefficient of 0.31. But it had a lower frontal area, so probably had less drag than a Prius.

Just some things to keep in mind re drag coefficient.

 

Drag is proportional to Cd, Frontal Area, and the square of the speed of the car. As you go faster drag is more important, at low speeds other forces dominate. A reduction in Cd from 0.25 to 0.24 will result in a 4% (0.01/0.25) reduction in fuel needed to overcome drag.

But when the car was built those fins made it go fast, just like fins on a rocket.

 

3 wheels and rear wheel skirts. No thanks.

 

I think it has 4 wheels, in a diamond, not a rectangle.

The operative word is 'concept', that means it did not have to meet even the lax safety or pollution requirements of it's day, let alone what a production car has to meet today. Building an aerodynamic car no one has to live with day in and day out is easy. It is tricky to build one that folks can live with. Car seats, groceries, 5 adults or a soccer team mean it has to be practical.

Besides if they made it today, window tint, headlights brighter than the sun, 22 inch wheels and a lowering kit would be needed.

The Lotus Europa managed a .29 Cd in 1966 in a production car that was (mostly) D.O.T. legal.
[ame]http://en.wikipedia.org/wiki/Lotus_Europa[/ame]

 

It probably does or at least did back then. The interior is majorly chewed up... look at the driver's seat.

And good luck changing the front tire if you get a flat Best get AAA with the purchase of this unique ride.

 

Interesting to see this design. I'm not sure about that back wheel, if it really helps. Hopefully the engine (and the weight) is in the back or this looks unstable. But it goes to show that the Prius shape is not the only way to get a low Cd.

When the Insight II came out, people said it looked like the Prius because that's how you get a lower Cd value, but this shows there are other options. Including the EV-1 with a Cd of .195 and apparently the Czech Tatra T77 with a Cd of .21, sold in limited quantities in 1934 and 1935. Then there's the 1921 [ame=http://en.wikipedia.org/wiki/Rumpler_Tropfenwagen]Rumpler Tropfenwagen[/ame], which had a Cd of .28, beating anything VW had until 1988.

According to the authors at [ame=http://en.wikipedia.org/wiki/Automobile_drag_coefficient]Wikipedia's auto drag coefficient page[/ame], the original Insight had a Cd of .25, and the 2004-2009 Prius was .26, dropping to .25 for the 2010 model. I'm unclear what the new Insight is at, either .25 or .26.

 

Hi All,

Add flush wheel covers, and the Prius probably matches that Pininfarina Cd.

BTW, Cd is the ratio between body drag and a flat plate of the same cross section area, not a bluff box.

Bluff boxes are not that terrible, with Cd's of around .5. Add radiused edges and corners to a bluff box, and they improve dramatically, .35 if memory servers. This is as good as some sports cars from the 70's. The long low hood is a really bad for Cd. Which explains the design of the Volkwagon Vanagon, Nissan Cube et al.

Some people say why is this important when one's driving maybe in the 30 to 40 mph range. Like mine. But yesterday's drive home was into a quartering steady 20 mph wind, with gusts to 30. So, that means at times I had a 70 mph air speed when only doing 40 mph. At that airspeed aerodymanics are very important to MPG.

 

Looks like a takeoff of Bucky Fuller's Dymaxion car of '33.

The Citroen DS series, launched in '55, had a DC of .31. It was also front wheel drive, had an adjustable hydraulic suspension, power assisted steering and brakes(front disc), and in '67 steerable headlights. Employing unit body type construction as well, it could be considered the the advent of the modern automobile. Varients were in continuous production well into the 70s.

The Tucker was also heading in the same direction, but unfortunately the Big Three decided to squash it.

 

Now THAT's an understatement ... "lax" pollution requirements?
In 1960, there were NO pollution requirements for autos in the U.S. ... even oily BLOW by was shot directly out onto the street. The 1st smog req's came a few years later. Even when the 1st smog restrictions evolved, the only requirement was that blow-by was recirculated back up through the carburetor's vacuum.

As a kid during the early 1960's in the L.A. basin, I recall leaded gas, brown air, watery eyes, and difficulty breathing. Ah, yes ... those were simpler times ... the good ol' days ... cough cough ... hack hack!
Oh! and let's not forget OTHER wonders of 1960 autos ... like SOLID shaft steering columns that would spear / puncture lungs during front end collisions ... and then there's the dash. Few models actually even had a padded dash. If you had one, it was often a thin film of (my favorite word) naugahyde (often made of off-gassing polyvynal chloride carcinogens) . Yep, there were a lot of nauga's running around without their hyde.



.

 

I moved to SoCal to go to school in '69. My dad lived in the San Gabriel valley and the LA mountains were less than 10 miles away. Most days you wouldn't even know the mountains were there, just a wall of grey/brown. And if you went up on Angeles Crest, most days you wouldn't know LA was there. Heck, visibility was usually measured in blocks. The original inhabitants called it 'Valley of the Smokes'.

And don't forget the thrill of spearing pedestrians with your hood ornament.

Ah...blowby, brings a tear to the eye just thinking about it. Quite a few folks did oil changes by the constant loss method back then. They both made for some fun driving durring the infrequent rains.

 

Yes my 1962 Ford Falcon wagon had a tube aimed at the ground for crankcase blow-by, later cars would get PCV valves to stop that.
Clean Air Act (United States) - Wikipedia, the free encyclopedia
Ford Falcon (Americas) - Wikipedia, the free encyclopedia
http://en.wikipedia.org/wiki/Ford_Straight-6_engine#144
[ame]http://en.wikipedia.org/wiki/PCV_valve[/ame]

" it was discovered in 1958 that the road draft tube was a major source, about half, of the hydrocarbons coming from the automobile."

 

I can't figure out the reason (or the placement from the pictures) for the single rear wheel. What could it possibly help?

Yup. four wheels in standard configuration, except distance between the rears was 12" narrower than the distance between the fronts. Definitley using the teardrop shape to max advantage.

Odd to compare the Cd to a Prius. There are several more aero production cars than the Prius. But none more aero than the EV1 as far as I'm aware. And the EV1 actually existed! In fact I was just lamenting mine as a friend's Mini-e is about to be reposessed... er... returned at the end of the closed-lease.

RIP EV1. Crushed for my own good.

 

I would love to see the AAA guy's face when they pull up to that thing!

 

Cool!
I want one!

 

Especially for the volume, and especially at lower speeds. Look at the design of most cargo ships. What you have is a very long bluff box with rounded corners. You get an easy to build shape with a huge volume and acceptable drag. On the other hand, they are pretty ugly, but ugly doesn't pay bills.

Tom