A sidebar comment in passing.
Ronald Miller+ David Sawers: The Technical Development of Modern Aviation is the best and most readable title I have found on the technical developments underpinning aviation. Yet even these very well informed authors were fooled into classing the Fw 200 as an all-metal, stressed-skin design.
This excerpt from pages 129/31:
"The most important of the American airliner designs were the Douglas DC-4E and its production derivative, the DC-4; the civil development of the B-17, the Boeing 307; and the Lockheed Constellation. British competitors, none of which proved commercially successful, were the de Havilland Albatross, Armstrong-Whitworth Ensign and two which were unfinished at the outbreak of war, the Fairey FC-1 and the Short S-32. In Germany the Junkers Ju 90, and the Focke-Wulf Fw 200 were equally unsuccessful.
All these aircraft owed a great deal to the DC-2 and Boeing 247. They shared with them all-metal stressed-skin structures, generally modified to take account of Wagner's theory of the diagonal tension-field beam, and later elaborations of the theory, so that they were rather lighter in relation to their strength than earlier designs."
However, there can be no doubt about the substantial areas of the Fw 200 outer wing, seen first bare and then covered in blindingly white linen, and plainly visible at
https://fw200-restaurierung-bremen.de/2017/08/04/824/
on the Außenenflügel during the recent Fw 200 restoration in Bremen.
[Success in the above extract is defined at the end point and in purely US commercial terms. In fact, by the summer of 1945, although the DC-4/C-54/R5D lead the field by a good margin, a great many more of both the Fw 200 C and the Ju 90/290 had been built than all wartime construction of Constellations.]