"... it could only fly at 500 feet ..." In other words, it was the world's first successful Ekranoplan, decades before the Soviets developed theirs, sometimes called the "Caspian Sea Monster".
I literally came here from researching to see if that's where the Ekranoplan idea came from lol I do see the dornier didn't have the idea of ekranoplan where it would use the wind draft to keep it in flight.
Problems of power-weight ratio beset this plane, then the Spruce Goose and finally UK' Princess. Their makers pretended they were viable but they never successfully flew.
I believe there was an engine for each propeller and the idea being front-engine pulled while the back engine pushed... despite terrible aerodynamics it made for a very efficient design but also the operative idea was that a technician could work on one of the engines in Flight if it had to be shut down while the rest of them were kept running
That was a test flight across Lake Constance in order to check out its performance. Almost all factory members and their families were invited to have a ride. They had. Must have been an amazing impression!