The Hopfner HA-11/33 was an amphibious flying boat built in Austria in 1933 to a specification by the
Dr. Oetker company. The result was a conventional, high-wing cantilever monoplane with a stepped flying boat hull and pontoons on struts under the wings at mid-span. The cabin was fully enclosed, and the twin engines were mounted tractor-fashion on struts above the wing.
Development
A HA-11/33 was purchased by the
Austrian Air Force, and was subsequently absorbed into the German
Luftwaffe following the
Anschluss. Deemed worthy of further development,
WNF (which had absorbed
Hirtenberg, which itself had taken over
Hopfner) was tasked with developing it into a military training aircraft for flying boat pilots. Designated WNF Wn 11 by the
RLM, testing was undertaken at
Travemünde in 1940, but the type was not ordered into production. Development of a highly streamlined derivative with
Hirth HM 508 engines, the WNF Wn 11C was also abandoned.
The Illustrated Encyclopedia of Aircraft. London: Aerospace Publishing. p. 2174.
Taylor, Michael J. H. (1989). Jane's Encyclopedia of Aviation. London: Studio Editions. p. 510.
Nowarra, Heinz J. (1993). Die Deutsche Luftruestung 1933-1945 Vol.4 – Flugzeugtypen MIAG-Zeppelin (in German). Koblenz: Bernard & Graefe Verlag. p. 43.
ISBN3-7637-5468-7.