Arado SD II
|| Single seat fighter
||1 Siemens Jupiter with a 2-bladed propeller
|| Length 7.40 m, height 2.95 m, span 9.90 m, wingarea 22.90 m2
||Empty 1445 kg, flying weight 1770 kg, wing loading 77.29 kg/m2
||Max. speed 225 km/h, service ceiling 6400 m, climb to 1000 m 1.5 min.
||2 × fixed, forward-firing MG 08/15 7.92 mm machine guns
||Was tested at Staaken, Rechlin and Lipezk
Larger and substantially heavier than the preceding SD I, and utilising a more conventional unequal-span biplane wing cellule with N-type interplane struts and flying wires, the SD II was designed by Ing Walter Rethel and a sole prototype was completed in 1929 as a competitor for the HD 37, a second airframe becoming the SD III. Of mixed construction, with fabric-covered wooden wings and a welded steel-tube fuselage, the SD II was powered by a geared Siemens und Halske-built Jupiter VI nine-cylinder radial, which, with a maximum rating of 530hp, drove a large-diameter, slow-running three-bladed propeller requiring a high angle of attack on the ground. Armament remained two 7.9mm synchronised 08/15 machine guns. The SD II demonstrated rather difficult flying characteristics, but, together with the SD III, provided a basis for the series-production Ar 64.