Gotha WD.10 Ursinus Seaplane Fighter
The Gotha WD.10 Ursinus was designed to improve the performance and maneuverability of seaplane fighters. To achieve this, it was designed with centre floats that retractable onto the underside of the aircraft to reduce drag. The engine was placed at the centre of gravity and drove the propellor through and extended drive shaft.
Unfortunately, while taxiing for its maiden flight, the aircraft nosed over and was damaged and the project abandoned shortly after.