German experimentation with low Cd automobiles in the 1930's

[botsapper]

Always prefer to see Deutsch aero in action.

http://www.youtube.com/watch?v=664C-p8NbT4

http://www.youtube.com/watch?v=14dCNL1pzCA

[NeilBlanchard]

Here is a new article with a brief video showing the Schlörwagen model in a wind tunnel, and some stills - including several I have not seen before:

Meet Germany's ultra-aerodynamic car from 1939 [w/video] - Autoblog

http://www.wired.com/2014/09/german-aerodynamic/

http://www.youtube.com/watch?v=JRfb2...3Xbj3wPBot1-ZQ

[Eighty-Nine Si]

As a former pilot (!) of hopped-up VW Type 1s, the multiplicity of compound curves creates significant lift (i.e., drag) in motion. An old Beetle at speeds over 80mph offers about as much excitement as one can tolerate. I have always wondered how much of the lift on these interwar streamliners could be tamed with a modern aerodynamic undertray. I have noted the Rosemeyer record car appears to have a rear diffuser (for all the good it did him).

[NeilBlanchard]

The Schlörwagen is very low drag. It was unstable in side winds (apparently), though that may have been partly because of the rear engine; but certainly it would probably need a fin on the back to reduce that effect.

[freebeard]

Originally Posted by Eighty-Nine Si

As a former pilot (!) of hopped-up VW Type 1s, the multiplicity of compound curves creates significant lift (i.e., drag) in motion.

I just put 1800 miles on mine this weekend, and I never left the ground once. Of course it's stock except for the electronic ignition, maybe that's it.

You are correct: It's the multiplicity or complexity of the shape, not the compound-curvedness that is the problem. Basically the roof falls off far too rapidly, creating involving vortexes; and the nose high stock stance creates a positive angle of attack.

That's why the classic California look features a radical rake. Negative angle of attack, the tires are shrouded to lower the frontal area and, I believe, the rake pulls air off the lower sides into the underbody—counteracting the tendency for the air on the sides to be pulled upward by the too-fast roofline.

NeilBlanchard -- Thanks for the 3-view. That floorpan's a beauty. I take it those are lightening holes. Very dieselpunk.

[kafer65]

Once I got my Resto Custom Beetle's nose down it was very stable compared to the old nose high stance. Unfortunately I'm suffering from blown lifter bore-itis and haven't driven mine in almost 2 years. I'm jealous freebeard!

[NeilBlanchard]

New higher quality version of this picture:



A different print of this iconic shot:



Here's the actual pictures (as opposed to the screen captures I posted earlier):

[freebeard]

The [electric] flow-through ventilation in my Superbeetle is completely drowned by the operable vent windows. I wonder how the Schlörwagen is.

[NeilBlanchard]

The two windows either side of the windshield are operable, so if there was exhaust vents, the air flow would be vigorous.

[elhigh]

"Vigorous."

That's an understatement.