Dornier Do K

The first Dornier Do K was the K1 which first flew on 7 May 1929.[1] The K1 was a conventionally-braced high-wing monoplane, powered by a single nose-mounted 510 hp (380 kW) licence-built Bristol Jupiter VI radial engine, and had a conventional landing gear with a tailskid.[1] The square-section fuselage had an enclosed cockpit for two with a cabin behind for freight or eight passengers.[1] Test flights showed that performance was poor and the aircraft was redesigned.[1]

The Do K2 flew in December 1929 with similar wings and fuselage but had a changed landing gear and four 240 hp (179 kW) Gnome-Rhone Titan radial engines.[1] The four engines were strut mounted on each side of the fuselage in tandem pairs, one in tractor configuration and the other as a pusher.[1] Although the aircraft had an increase in available power, the performance was little improved on the K1.[1]

The K3 was a complete rethink of the design. The braced wing was replaced with a cantilever wing of larger span.[1] The fuselage was changed to oval and stretched for two extra passengers and the tailskid was replaced with a tailwheel and the main units were enclosed in fairings.[1] The four engines were in the same tandem arrangement as the K2, but located lower on the fuselage and changed to 305 hp (227 kW) Walter Castor radial engines.[1] The performance was greatly improved but still provoked little interest and no others were built.[1]