[RolandF]

Certainly it´s genuine from 1938, but no official project.
But according to the stamps it is the final papers of student Helmut F.Weitzmann to get his diploma at the Technische Hochschule Hannover. The circular stamp is from "Diplomprüfungsausschuss" ("examining board for the diploma"). The student assures having made the design all by himself (Selbstständige und eigenhändige Anfertigung versichert an Eidesstatt...).
Professor Dr.Ing. A.Pröll, who has signed the design, was chairman of the AKAFLIEG Hannover, the "Akademische Fliegergruppe Hannover"
"Wn" might be an abbreviation of "Weitzmann".

Regards

Roland