Siemens-Schuckert D.IV

Siemens-Schuckert D.IV
Siemens-Schuckert D.III on display at the Lutwaffe Museum at Gatow
Role	Fighter aircraft
National origin	Germany
Manufacturer	Siemens-Schuckert
First flight	1918
Introduction	1918
Primary user	Germany
Number built	123 (by the end of the war)

The Siemens-Schuckert D.IV was a late-World War I fighter aircraft from Siemens-Schuckert (SSW). Considered by many to be the best fighter to see action during the war, it reached service too late and was produced in too few numbers to have any effect on the war effort.

Siemens-Schuckert's first production fighter aircraft was the Siemens-Schuckert D.I, which was based closely on the French Nieuport 17. Apart from the use of the Siemens-Halske Sh.I, a geared rotary engine in which the cylinders and the propeller rotated in opposite directions, the D.I was in fact a fairly literal copy of the Nieuport. By the time production D.Is appeared in 1917, the design was no longer competitive and after 95 had been built, production was cancelled, the type serving mainly as advanced trainers.

Development work on the Siemens-Halske Sh.I culminated in the Siemens-Halske Sh.III, which developed 160 PS (120 kW). The new engine was fitted to a series of original prototype designs from the SSW works, the D.II, D.IIa and D.IIb. These featured a much rounder and wider front fuselage to hold the larger engine, leading to a rather stubby-looking aircraft which pilots later referred to as the flying beer barrel. Flight tests started in June 1917, and while the aircraft did not have a very high top speed, they showed outstanding rates of climb. The only serious concern was the extremely long landing gear needed to keep the huge 2-bladed prop clear of the ground.

Three more prototypes were ordered, two D.IIc's with shorter and longer span wings, and the D.IIe with the original sized wings. After completion in October 1917 the design proved to be worth producing, and in December an order for twenty long-span D.IIc's was placed with a smaller 4-bladed propeller that allowed for shorter landing gear legs. These aircraft, now known as D.III, started delivery in January and were followed by an order for thirty more in February.

All fifty were delivered to front-line units in May, where they proved popular. However, after only 10 hours of service the engines started showing serious problems, overheating and eventually seizing. Although Siemens blamed the problem on the Voltol-based oil that was used to replace scarce castor oil used to lubricate the engine, the planes were withdrawn from service and replaced by Fokker D.VII's. When they were removed Rudolf Berthold, commander of JG.II, noted that he felt the Siemens fighter be made available again for front-line use as quickly as possible for, after elimination of the present faults, it is likely to be become one of our most useful fighter aircraft.

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Wikipedia