Source : "German guided missiles" by Heinz J. Nowarra" On January 14 1945, prof. Wagner proposed the S II (Schmetterling) project as a further developpement of the Hs 117 "Schmetterling". Two days later it was adopted at the anti-aircraft test facility.
However, the continuation of this project by the Oberkommando der Luftwafe...was not to be. "