Lotus 7/Locost Aero Rebody

[lunarhighway]

the eco speedster might be worth looking at, it's esentially the same sort of car you want to build, an economy two seater... it's supposed to have an 0.20 Cd

[MetroMPG]

Originally Posted by JackMcCornack

Models and tufts, that's what I need.

Another advantage to this KISS/minimum compound curves design is models are relatively easy to make.

As a roadster it'll have a tonneau and a fairing behind the driver's head (with a roll bar inside). It's a pity the road rules prohibit Lexan canopies...I'll have to look at how that single seat Metro was done (second post on this thread--MetroMPG, do you have a link to that?).

Photo album: 1989 Geo Metro Gets 75 mpg

Also FYI, the initial angle of my boat tail was 4 degrees, but it transitioned to 7 at about the 25% point down its length and retained attached flow to the end.

[JackMcCornack]

The Morgan Lifecar, the Atlantic, the Opel EcoSpeedster = three cars I love--I love the Opel so much it makes me want to touch myself--BUT to quote from the first post on this topic,

Originally Posted by JackMcCornack

What makes this project interesting is I have about a $2000 body budget. ]

The Opel is my dream car. I would rather own and drive that Opel than a Veyron or Enzo or any other car on this planet. If I were Bill Gates I'd be driving one already (they say they're not for sale, but if you said, "I want one, here's a million dollars," they might let go of a demo model). They claim 112 mpg at 140 mph and as far as I've heard (and I've been looking into this car for 7 years) the only fudge is the traditional one of using imperial gallons. Okay, so it only gets 90 mpg at 140, I hardly ever go 140 anyway, I'm sure it's well over 100 mpg at half that speed.

So I'm trying to make something cheap and easy to build, in hopes other folks will build others like it. It's not going to be carbon fiber in structure nor body (the Opel is both) and it's going to be a two seater (the Opel is no more of a two seater than the FIA rules require for records in that class--Daytona Prototypes and Le Mans prototypes are the same way) and it's not going to be anywhere near as pretty. I get great pleasure from looking at aeroporn but I know my limitations.

From MetroMPG:

> Another advantage to this KISS/minimum compound curves design is
> models are relatively easy to make.

For me, models are ridiculously easy to make. The Foam Ranger (my car sized 3 axis CNC low density foam router) was ridiculously hard to make--took me a few years--but now that I've got it I can make an accurate scale model in styrofoam the day after I'm done concocting the Rhino files.

Which brings me to my next technical question: How large a scale model do I need for reasonable prediction of airflow on the full size version, using tuft testing on a moving platform (affixed to a boom on the front of a car)?

[Christ]

I might be pissing in the wind here, but I thought you could get away with almost any size model as long as it was scaled properly and proportionate to the full-size chassis? (To get an idea, anyway... certain things will change anyway, because the boundary layer will stay the same depth, while small protrusions will get even smaller on the scaled-down version.)

Then you take the Cd number you got, and * it by the A of the full-size version to get the CdA, which is your best representation of aerodynamic efficiency.

If I'm right, I'm right. If I'm wrong, you'll get some crooked number that's probably unrealistically low, and you can kick me in the shins.

[Frank Lee]

Originally Posted by JackMcCornack

The Opel is my dream car... (and I've been looking into this car for 7 years)

You've come across the height spec then...

or a pic with someone standing nearby...

appears a driver would have to be petite and/or a contortionist to get in...

[Christ]

Frank, I'm going to say those wheels are 20's, at least.

That makes the roof of the car approx 38" tall, or just over three feet... You don't fit. Then again, the seating arrangement probably has the driver about as close to laying down as you can comfortably get and still see over the wheel, because that's the "sport" arrangement, it seems. (I prefer to sit just slightly lower than straight up and down... about two "clicks" of most seats.)

Of course, the car was probably designed around a 5'8" frame.

[Frank Lee]

37.4"!

I'd need a Gurney bump if not more.

[Christ]

Where'd the 37.4" figure come from?

[Frank Lee]

The Opel Eco-Speedster: Sports car prototype as a bold stroke to launch Opel's diesel campaign

but you missed it on the wheels which are 17z

[Christ]

Damn, I must be have halfway decent perception, then.