Sorry, no photos of the cura prints.
Sound was normal, printed the simplify gcode twice, the second time with 75% speed override.
Have this problem at even more stl's, and as I said always when there are more objects to print or with more complex parts. As an Example an picture of an segmented U-boat is attached, I used a bad filament with massive changes in diameter, so don´t look too close...
BTW, the wing rips print fine individualy.
Even made a singe stl-file for these rips in Autodesk Inventor but this doesn't help either.
Also checked the stl's in CAD but nothing strange here.