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The Schlörwagen (aka Göttinger Ei) has obvious flaws around the lower/rear as shown in the wind tunnel picture I found on the German aeronautics site a while back: the air lifts up starting just ahead of the rear wheels and it lifts up a lot behind the rear wheels. The trailing edge needs to be widened and flattened (into a "beaver tail), not unlike the Morelli/Aptera does. Also wheel strakes would help a lot.
Don't forget it has the Mercedes 170H chassis with it's rear 4-cylinder engine -- this makes cooling it quite difficult -- and it needs a lot of cooling like all ICE's. Make the Schlörwagen an EV and you probably can claim back much of the .061 drag, and with the outside aero tweaks, it might even go below the 0.13 of the early model.
The early Mercedes B/B model beats the Schlörwagen model by about 0.035 (in an already stellar realm) and you don't think that is amazing? This is about a 27% reduction -- from amazing down to stellar, in my opinion.
Can you point to *any* four wheeled street car with a Cd within even 50% of this?
The Edison2 VLC has an "old" method Cd of 0.145, which is ~52% higher drag than the 0.095 that this Mercedes B/B model achieved!
Obviously, the Cd gets worse as you make it "real", but if we can see even some of the benefits of such a stellar starting point (as opposed to even the 0.13 of the Schlörwagen!), then it is worth trying.
We can't forget the most real example of ultra-low drag: the early Aptera "Zen" -- with a CFD drag of 0.11, it falls between the Schlörwagen and the Mercedes B/B model. And it seats 2 people. The Mercedes B/B is 4 (5 if you make it an EV and set it up like the CarBŒN) -- and the Schlörwagen seated up to 7 people!
Which brings us to the next challenge: keeping the covered front wheels without the huge increase of frontal area that that hampers the Schlörwagen design. I think I have the best answer in the articulated hinged panels on the CarBŒN. With the Morelli based solutions, you are forced to add the outboard wheels and the required structural supports and the *interaction* that these will necessarily have with the main chassis.
The Aptera "Zen" is the best example of how this can work -- it more than doubled the 0.05 Morelli shape up to 0.11. The Mercedes B/B model takes the 0.04 fish and the 0.06 computer version, up to 0.095. So, unless there is something I am missing, I stand by my assertion that the Mercedes B/B model is the best starting point for the lowest possible drag car. The fact that it does this while seating 2X as many people puts it into the stratosphere...
And if you require 4-5 seats, it is even better, since it beats the (unimproved) Schlörwagen, as well.
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