Hmmm. Ever more weird VW's. Never heard of a water cooled bus until the much later squared off vanagon.
And now for something completely different, yet aerodynamic. The 1921 Rumpler Tropfenwagen.
Rumpler Tropfenwagen - Wikipedia, the free encyclopedia VW wind tunnel tested it in 1979 and found it to have a drag coefficient of .28, a value VW wouldn't achieve until the 1988 Passat.