Honestly, I was in the process of formulating a German search before seeing your clue. But this one is pretty difficult to crack, me lacking proper terminology in German. Probably Druckpropeller is commonly used, but usually see them called pusher, even in German context.
Excellent Challenge - a bit pity that it aborted. But my PPRuNe got completely unstable, too.
Here is the direct link for those interested.
Pützer Bussard