09/30/2013. Remarks by Johan Visschedijk: "In late 1916, while working for the aircraft manufacturer Gotha, aviation pioneer Carl Oskar Ursinus designed a single-seat seaplane fighter to embrace several features intended to obtain the very best performance from the 150 hp Benz Bz III six-cylinder engine, which was located in the center of gravity and drove a two-bladed propeller through a short extension shaft. The aircraft, designated WD 10, was constructed by the aircraft company Rex, and the general cleanliness of the single-bay aeroplane was remarkable for that period.

The most revolutionary feature of the design, was its retractable float landing gear, in an attempt to overcome the inherent disadvantages of drag and maneuverability which attended floatplanes generally and fighters in particular. The pilot manually operated a small differential winch which reduced the lengths of the bracing cables on one diagonal of the landing gear struts and lengthened corresponding cables on the other diagonal, allowing the floats to be cranked to the 'up' position (site files). They were retracted forward against the airflow; this kept the center of gravity forward and also assisted with float extension.

In the event, the estimated top speed of 124 mph (200 kmh) was never achieved, since during initial taxiing trials at 900 rpm in late April 1917 the machine nosed over. After further investigation the design was abandoned."

Span: 29 ft 6.375 in (9.00 m)
Length: 25 ft 6.5 in (7.77 m)
Height, floats down: 9 ft 6.25 in (2.90 m)
Height, floats up: 6 ft 6.75 in (2.00 m)
Empty weight: 1,649 lb (749.5 kg)
Loaded weight: 2,205 lb (1,002 kg)