The Dornier 17 Z had a wingspan of 59ft (18m), and a length of 52ft (15.8m). Its empty weight was approximately 5 tonnes. The aircraft was of all metal construction with a flush-riveted aluminium alloy skin over aluminium alloy ribs, stringers and semi-circular frames.

The wings were built up on two open-section girder spars that ran through the fuselage. The spars and wing root fittings were of chromium-molybdenum steel while the flanges were made of light-alloy extrusions.

Fuel and oil tanks were placed within the wings between the two spars. The fuselage was constructed in 3 sections: the cockpit; centre-section; and rear portion. Each part of the fuselage was joined to the next by about 25 bolts mounted through flanges. Flying controls comprised hollow steel tubes, rods and fittings.

The rudders and other control surfaces were fabric covered – on an aluminium alloy frame. The undercarriage was constructed from alloy steel castings and steel stampings. The engines comprised aluminium alloy pressings, drop forged nickel chromium steel crankshafts, chromium steel cylinders and lead-bronze bearings. The complete engine was mounted on a welded steel triangulated structure attached to the front spar.