Hello, The girl might as well drink the whole case. With all of the weight on top of the vw bus, it is not going anywhere fast. Or at all. Especially, with the rear opening window to suck in all of the exhaust fumes finding their way inside. Even with the side pipes muffler systems that were so popular, it only goes out to the side, but eventually the swirling winds due to the boxy design is the culprit of sucking in the deadly fumes. Jnaki Despite the coolness of the lowered rake van with custom wheels, it is a rolling death trap coming down the street. Yes, we grew up on our adventures using a custom interior van with different exhaust pipes going every which way. But the rear lifting door and latch was always securely shut to keep out those deadly fumes. On some of our window vans, we even kept the last window on each side panel closed. After all, it created a nice way to spend a week or longer in deserted Baja Mexico surf spots, despite the low power, “box on wheels” trying to fight the oncoming wind while maintaining a straight line to those pristine beaches… YRMV
I don`t speak German,,,but it looks like it is a DC-4E. https://simpleflying.com/douglas-dc-4e-experimental-aircraft/
With respect,I think your reasoning is a bit out of date. Bigger motors,better exhaust headers etc.etc. And if they have a "safari" on the rear window,I'd bet they have them at the front;flow through..