[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] 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] 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.