The Siemens-Schuckert Werke S.S.W. D I was a single engined scout based very closely on the successful French Nieuport scouts, but that reached the front too late to have any significant impact.
In the summer of 1916 the French Nieuport scouts were achieving a great deal of success over the Western Front. The German Inspectorate of Aviation Troops (Idflieg) asked Albatros, Euler and S.S.W. to produce a copy of the Nieuport fighter. A number of captured Nieuports were given to the companies, and both Albatros and Siemens produced designs.
The Siemens design was an almost identical copy of the Nieuport 11 and Nieuport 17. It was thus a sesquiplane, with a significantly smaller lower wing, and with swept back wings. The upper wing had two box spars, the lower wing only one. The ailerons used a steel tube frame. The fuselage was built around four longerons and was slab-sided, with slightly tapered sides. The fuselage had metal panels at the front but was fabric covered elsewhere.
The S.S.W. D I did have one unusual feature, in its Siemens-Halske Sh I geared rotary engine. In most rotary engines the crankshaft was fixed and the crankcase and cylinders rotated around it. The resulting engines were very powerful, but generated a lot of spin - aircraft powered by them wanted to spin in the same direction as the engine. On the Sh I the crankshaft rotated in the opposite direction to the crankcase and cylinders. This reduced the amount of spin that was generated, and gave the overall engine a speed of 1,800rpm. The engine was given an open fronted cowling with a cut-away bottom half, and doesn't appear to have suffered from the same cooling problems as the Sh III engine used in the S.S.W. D III and S.S.W. D IV.
The D I was approved by Idflieg in October 1916, and on 25 November an order was placed for 150 aircraft. This was followed on 21 March 1917 by an order for another 100 aircraft. Of these aircraft 95 were completed, 73 at Nurnberg and 22 at Berlin. The remaining 55 from the first order were delivered as uncovered airframes.
By the time these aircraft were delivered their performance was no longer adequate, and the second order was cancelled. Of the 95 aircraft that were completed only around 65 were delivered before the contract was cancelled. Some did reach the front, where they served with Jastas 1 to 5, 7, 9, 11 and 14, but most went to training schools.
The last aircraft from the first order, D3768/16, became the sole D Ia, and was given a larger wing (15.7sq.m compared to 14.4 sq.m on the normal aircraft). It was also somewhat slower. The first two aircraft in the second batch were also used as development aircraft - D1230/17 was given larger wings, with an area of 16.2sq.m, while D1231/17 had a high-compression Sh I engine, which produced 140hp, along with a much larger 19.2sq.m wing. Both of these aircraft were given the designation D Ib.
Engine: Siemens-Halske Sh I 9 cylinder geared rotary engine
Span: 25ft 7 3/8in
Length: 19ft 8 1/4in
Empty weight: 946lb
Loaded weight: 1,485lb
Maximum take-off weight:
Max speed: 97mph
Climb Rate: 3.5 min to 3,280ft; 14.5 min to 9,840ft
Endurance: 2hr 20min
Armament: One fixed forward firing Spandau machine gun as built, second added later