Which mass produced car is closest to a teardrop shape ?

[some_other_dave]

Originally Posted by basslover911

Whatever happened to the Mx3? ITS A GREAT PLATAFORM!

I know people take them down to around 2200 pounds, and they are VERY aerodynamic!

The CRX starts out with a great kammback type shape, and the 88-91 HF versions start at something like 1800 lbs before you start lightening them...

-soD

[aerohead]

Originally Posted by metroschultz

Hey Phil,
How about weighing in on one that perhaps us poor people could buy from a junkyard and play with.
I was thinking of the Ford Probe.
I have no numbers but, from what I remember they were designed with aero in mind from the factory.
Also their sister car the Mazda MX6.
Both are relatively inexpensive if you were to buy a rolling assembly from a bone yard and add your own drivetrain.

I'm thinking take my Metro/Swift engine /trans and put in a stripped out Probe rolling chassis.

I would play the devil getting the weight out (and for the suspension I would not be able to remove weight), but what about the possabilities for aero on something like that?
Schultz

Hey Schultz,just now catching up on posts.Yeah,the "poor people's",I'm definitely in that camp! You could probably do worse than the Probe,however it was never anything as slick as it's namesake.I think I have numbers for that car.Just shooting from the hip I'm thinking Cd 0.32 but I'll confirm that.--------------------

You'll want to check out engine swap vs state environmental regs if you live in a non-attainment area for air quality as I do.Texas will not allow mods as you are entertaining for any car under 24-yrs of age.If your cars have to be "smogged" or pass air quality tests during annual inspections you'll need to know this.--------------------

As far as powertrains,would a Ford Escort 4-banger and 5-spd overdrive slip in there? Those cars could hit in the 40-mpg range and with streamlined Probe coachwork could maybe really sing on the open road.----------------

I'll dig out those numbers for this Saturday.And I'll scratch my head in the meantime.--------------------------

As for those other cars like the MX-3 and say the Nissan 200-SX,and such,the bodies show promise but I've never understood why the powertrains were so inefficient.'suppose they were configured for "performance" not real economy.Too bad!

[aerohead]

Originally Posted by Cd

Aerohead : I believe you posted these pictures a while back. What car is this and what was it's Cd ?
While not a mass produced car, I still find it interesting. Also one more question for you : What was the Cd of the Oldsmobile Aerotech in both Longtail and shorttail versions ?

I think basjoos actually posted these.They are in Baron von Fachzenfeld's "Aerodynamiks des Kraftfarzeugs" published around 1952.I believe this car is a Maybach,but it seems that all German companies had purchased licenses from Paul Jaray's Streamline Car Company.Off the top of my head I don't have numbers for this car but I'll check.Perhaps basjoos has 'em.--------------- One thing to bear in mind is that a lot of these numbers are considered dubious by modern aerodynamicists.Hucho makes big mention of this in his book.For instance,Kamm's K-car which scored Cd 0.24 in model form and with coastdowns( I think on the BMW chassis) actually had Cd 0.37 when tested at Volkswagen's modern facility.-------------So these early numbers need to be viewed in this light.---------------- By the way,if your looking for a modern-day K-car,it would be the Toyota Highlander 2WD.

[aerohead]

Originally Posted by bryn

yes i know the difference between cd and cda

so the van is a whopping 5'6" tall, 5'7" wide at its widest (not including mirrors,still counting airspace under car) actual frontal area is pretty close to 30sq ft.

depending on your needs, it is a good shape. do you want to bring 6 friends in your metro, depends on your friends i guess.
i can fit full sheets of plywood inside the van, compaired to a pickup, or stacking them on the roof of a car. aero is going to be much better.

These vans began life as the Pontiac Trans Sport and was a real aero coup when it hit the marketplace.Cd0.30 is what I have for that form.There's very little lateral curvature to the windshield but other than that,the constant-rake front end is still kinda the aero benchmark for minivans.Critics really hammered these vehicles on interior space utilization,with the enormous dashboard expanse.----------------- Klemperer got his "brick" down to Cd0.16.If the last 30% of the roofline and sides were boattailed ala Mair and NASA,one could probably push the Cd into sub-0.2 territory.She wouldn't carry as much,but she'd be tough on the gas station.----------- I see a few around.I like 'em!

[Cd]

Originally Posted by some_other_dave

The CRX starts out with a great kammback type shape, and the 88-91 HF versions start at something like 1800 lbs before you start lightening them...

-soD

The CRX is nice, but I like the smooth lines of the MX-3.
Just my opinion, but the CRX looks boxy, and a full boat-tail would look more tacked on and out of place on it versus the MX-3.
Even the interior on an MX-3 looks more modern. ( And the MX-3 had an airbag )

I just wish the MX-3 had a decent engine like the CRX HF.

[Christ]

The MX-3's engine can easily be replaced with the Ford model 1.3 engine... or the considerably higher output 1.6 HSC engine.

IF weight were not a consideration for the MX-3 (with lots of work and money, its not) it would be a prime candidate for what we want here. Since the chassis itself is hardly ever sold cheaply (that I"ve seen) and it would require extensive modification versus other chassis' on the market today, it's not considered a prime candidate for said intentions.

I, however, am a firm believer in doing as one pleases... and that said, if you can get an MX-3, and wish to perform the work, by all means, I'm sure we'll all help out as much as humanly possible in each of our own cases.

[metroschultz]

That was my intent.
Not necessarily using the geo parts in the probe. (although...hmmm)
But to start out wiht something slipperry and then find the most efficient driveline to put in it.
If I had the body fab skills of Darin I would already have a teardropped Metro. (still working on that anyway)
But I can take a MX3 and put the 1.3 from an old Mazda Protege mated to a low gear MX6 (Probe?) tranny and make it work.
S.

[Christ]

You can, and it would work. But keep in mind, you're taking that small displacement engine from a low-weight vehicle, and putting it in a much heavier vehicle... it will be considerably less efficient... You might want to consider exactly what it takes to move 2200 lbs.

Weight reduction will be key in determining whether you can use the MX-3 effectively or not.

Keep in mind that reducing gearing is not always the answer either. I can personally vouch for this.

---

NOTE from Darin: discussion of the potential for taller gearing to reduce fuel efficiency moved to this new thread: http://ecomodder.com/forum/showthrea...nomy-6122.html

[Cd]

I'm trying to imagine how the back end of the car could be designed.
Since an MX-3 already has that teardrop shape from the start, you wouldn't have to extend the tail out so far.

[MetroMPG]

PS - Cd, your artistic & photoshopping skills are impressive! Nice work.