W.Green, G.Swanborough The Complete Book of Fighters

SIEMENS-SCHUCKERT (SSW) DD 5 Germany

   The first single-seat fighter biplane to be designed by Franz Steffen (who was subsequently to lose his life while demonstrating the E II monoplane), the DD 5 featured sharply tapered wings built up around steel tube spars, steel I-type interplane struts and a similar fuselage and tail to those of the E I monoplane. Powered by a 100 hp Siemens-Halske Sh I nine-cylinder rotary engine, the DD 5 was tested by the Idflieg in August 1916, but was rejected owing to its poor aerodynamic qualities and the restricted field of view provided by the cockpit. Armament comprised a single 7,9-mm LMG 08/15 machine gun. Only one prototype of the DD 5 was built and tested, development being discontinued in favour of an almost identical copy of the Nieuport 11 that was being developed (as the D I) in parallel. No specification for the DD 5 is available.

J.Herris Siemens-Schuckert Aircraft of WWI (A Centennial Perspective on Great War Airplanes 12)

SSW DD 5

   Designed by Franz Steffen, the SSW DD 5 was basically an E.I airframe with a biplane wing cellule, and was SSW's first biplane fighter. Power remained a 110 hp Siemens-Halske Sh.I counter-rotary engine, and a single synchronized machine gun was fitted. Tubular steel was used for the wing spars and I-struts. Tested in August 1916, it was rejected because of poor field of view for the pilot and poor handling qualities. Development then focused on the SSW D.I.
   Unusually for a WWI aircraft, the DD 5's wing planform tapered from the fuselage to the wing tips,- most WWI featured wings of rectangular planform as seen in the SSW E-types. Tapered wings are more efficient because they generate less induced drag (drag induced by creating lift, which generates vortices at the wing tips) and also reduce weight, which is likely why the designer used taper.
   However, tapered wings aggravate the tendency of the wing to stall first at the tips. Since the ailerons are normally fitted at the tips of the wings for greatest effectiveness, the tendency of the wing to stall first at the tips is very dangerous because it robs the pilot of roll control in a critical situation, increasing the likelihood of the aircraft entering an unintended spin. Most designers of the time 'washed out' the angle of incidence at the wing tips to prevent the wing from stalling at the tip first, and more sophisticated means were developed later to prevent tip stall. However, a look at the DD 5 shows no evidence of any aerodynamic measures designed into the wing to alleviate the tip stall problem, undoubtedly resulting in poor handling near stalling speed.

M.Dusing German Aviation Industry in WWI. Volume 2 (A Centennial Perspective on Great War Airplanes 85)

Siemens-Schuckert-Werke, Abt. Flugzeugbau, Siemensstadt b. Berlin (SSW)

Aircraft Development:

Transformatorenwerk Nuremberg

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  Due to the fact that these monoplanes were replaced by biplanes at the front and a repeat order was not planned, the construction of a new biplane "D.5” was started in June 1916 as a type aircraft for a new series. However, no delivery contract was signed.
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