12/15/2017. Remarks by Johan Visschedijk: "Eight copies of the twin-engined trainer WD 7 were built, of which the first had flown in December 1915. The biplane had two 120 hp Daimler D III engines mounted on the lower wing, the frontal coolers were fitted above the engine gondolas. The wood-clad hull had a rectangular cross-section, while the rear area had a steel-tube construction with fabric covering. The three-bay wings of wooden construction were fabric covered. The large trapezoidal tail plane was fitted on top of the fuselage, this as well as the double fins and rudders were of steel-tube construction, covered with fabric. Two two-step wooden floats were connected by steel pipes to the aircraft and gave the WD 7 a good seaworthiness. In the fuselage bow was a gunner position with a flexible machine gun. In May 1917, a 1.46 in (37 mm) cannon was experimentally installed in the spacious gunner position."