Heinkel HD 28

The Heinkel HD 28 was a reconnaissance seaplane developed in Germany in the 1920s for export to Japan. It was a conventional single-bay biplane with equal-span, unstaggered wings and three cockpits in tandem, the rearmost fitted with a ring mount for a gunner. The fuselage was braced to both wings by a number of side struts in addition to the usual cabane struts, the rudder extended below the lower fuselage, and a large ventral fin was fitted. A single example was built by Heinkel and supplied to the Japanese company Aichi as a pattern aircraft under the name Experimental Three-seat Reconnaissance Seaplane, for possible production in Japan. It was rejected because of engine problems and because it failed to meet its performance and weight targets. It had a wingspan of 15 metres and a Lorraine Dietrich 18K engine of 485 kilowatts.