Early production D.Is were powered by a single Austro-Daimler-built engine, capable of providing 185 hp; the majority of aircraft would be fitted with more powerful 200, 210, and 225 hp units instead. The adoption of the 225 hp engine proved to be too powerful for the airframe, requiring various changes to increase structural strength, particularly within the wing area. Regardless of the engine power, a standardised two-bladed Knoller-Jaray-built propeller was adopted, although an unusual four-bladed unit was used on a minority of aircraft (confirmed on serial number 138.106) in its place.