I have some vague information of a German Kassel 25 mail plane that was changed into the Heinkel HE 70 for the German airforce.
A wild guess but fits some of the clues.
Edit: My mistake, reference to the Kessel 25 was in error as the text was referring to another picture on the same page. Kessel 25 was a glider
Last edited by Akubra; 14th Dec 2007 at 11:41.