In an extremely advanced design, a single-unit steel "bathtub" that ran from just behind the propeller to the rear crew position acted not only as armour, but also as both the main fuselage structure and engine mounting in one unit, engine access being provided by twin vertically-hinged, aft-swinging triple-piece armor-steel panels, one on either side of the nose. The armour was 5 millimetres (0.20 in) thick and weighed 470 kilograms (1,040 lb). It protected the crew, the engine, the fuel tanks, and radio equipment (when fitted). The flight control surfaces were connected to the aircraft's controls by push–rods and bellcranks — not with the usual steel cable control connections of the era — as push-rods were less likely to be severed by ground fire.
There was a significant size difference between the upper and lower wings - the upper wing had a total area of 386.3 square feet (35.89 m2), over double the total area of the lower wing - 147.2 square feet (13.68 m2). This is a form of biplane known as a Sesquiplane.
The aircraft had two fuel tanks with a total capacity of around 120 litres (32 US gal). The main tank (divided into two parts for redundancy) was supplemented by a smaller, 30-litre (7.9 US gal) "gravity tank". This was intended to supply fuel to the engine by Gravity feed in the event of an engine fuel pump failure; it contained enough fuel for thirty minutes on full power. There was a manual fuel pump for use when the gravity tank became exhausted.
The aircraft could be disassembled into its main components: wings, fuselage, undercarriage, and tail, to make it easier to transport by rail or road. A ground crew of six to eight could re–assemble the aircraft and have it ready for flight within four to six hours. The wings were covered with 0.19 millimetres (0.0075 in) thick aluminum skin which could be easily dented so great care had to be taken when handling the aircraft on the ground.