This aircraft would be a clean sheet design; in comparison to the G 24, it would be larger and provide for greater passenger comfort while also being simpler both to operate and maintain.

After extensive wind tunnel experiments Ernst Zindel, the leader of the design team, persuaded Professor Junkers that the gain in speed, provided by reduced air resistance, would not outweigh the increased weight, cost, and complexity of either retractable landing gear or simple wheel fairings.

The majority G 31s flew with foreign air-cooled radial engines in the 500 hp range, which were typically license-built in Germany (see list of variants below).

[5] Duralumin was the most commonly-used material; others include cast electrum and silumin, which were used for relatively low-stressed complicated form pieces, less important fittings, and elements such as the bearing housings.

[6] Corrugated sheets of duralumin covered the exterior of the wing, which was built in the-then typical Junkers technique, its structure comprising a tubular frame.

The majority of instrumentation was on a centre-mounted panel placed between the two pilots; in addition to standard apparatus of the era, it was provisioned with dial indicators for the stabilizer and rudder-adjusting devices, hand pumps, and keys for radiotelegraphy.

The right-hand pilot could, following the removal of the back of their chair, operate the radio switchboard that was suspended behind him in the auxiliary apparatus room.

The central section of the fuselage had a strong framework that was reinforced by a series of bulkheads and transverse frames and entirely covered with corrugated sheet duralumin.

[13] The horizontal empennage of the aircraft was relatively large and provided effective stability even when fully loaded and the centre of gravity trending toward the rear.

In the event of an extended flight with one of the wing engines inactive, the exertions of the constant deflection of the rudders could be offset by a flexible adjusting device.

Powered by Pratt & Whitney Hornets, these differed from the G 31 airliners in having open cockpits and a large hatch in the fuselage roof to accommodate the loading of bulky cargo via crane.

This machine (construction number 3010, registration VH-UOW) was seriously damaged in an accident at Laverton, Victoria on 31 October that year after it careened off the runway and collided with and destroyed the Minister for Air's car.

[citation needed] Unlike the earlier Junkers G 24, the G 31 was not a commercial success; only 13 aircraft were ever sold, as opposed to 54 civilian G 24s along with +30 military derivatives).

[19] Compared to the G 24, it offered greater comfort to its passengers, while in comparison to the more conventional biplane airliners of the 1920s, the G 31 was both faster and safer, the latter aspect being largely attributable to its all-metal construction.

[citation needed] Data from Hugo Junkers Pionier der Luftfahrt – Seine Flugzeuge,[23] National Advisory Committee for Aeronautics[24]General characteristics Performance