Model Variants (Including Prototypes)
Do 28 - Prototype Model Designation; Lycoming O-360-A1A engines of 180 horsepower.
Do 28A-1 - Main production model designation; fitted with Lycoming O-540-A1A engines of 250 horsepower each; increased wingspan from prototype.
Do 28A-1-S - Floatplane conversion model based on the Do 27A-1.
Do 28B-1 - Based on the Do 28A model fitted with Lycoming IO-540 engines; redesigned nose and tail; increased fuel capacity; 60 examples produced.
Do 28B-1-S - Proposed Floatplane based on the Do 28B-1.
Do 28B-2 - Single production model; fitted with Lycoming brand TIO-540 turbocharged engines.
Do 28C - Proposed eight-seat passenger model.
Do 28D - Seven production models featuring new fuselage, wing and tail; fitted with IGSO-540 series engines.
Do 28D-1 - 54 production models based on Do 28D models.
Do 28D-2 - 172 examples produced; based on Do 28D models with lengthened fuselage; increased overall MTOW.
Do 28D-2/OU - Environmental Patrol Platform based on Do 28D model.
Do 28D-2T - Single Do 28D-2 model fitted with Avco Lycoming TIGO-540 series engines with turbochargers.
Do 28D-5X Turbo Skyservant / "TurboSky" - Single prototype example fitted with Lycoming LTP-101-600 turboprop engines.
Do 28D-6X Turbo Skyservant - Single prototype example fitted with PT6A-110 turboprop engines.
Do 28E-TNT - Single trial example fitted with experimental wing; based on Do 28D model.
Do 28 G.92 - Conversion of Do 28D models by Zlovakia for skydiving purposes; fitted with 2 x Walter M 601-D2 series 450 horsepower turboprop engines; seven examples in existence.
Do 128-2 - "Improved" Do 28D model
Do 128-6 - Production Designation of Turbo Skyservant model of which 6 were produced.