| G 31 | |
|---|---|
 | |
| Junkers G31 | |
| Role | Airliner |
| National origin | Germany |
| Manufacturer | Junkers |
| First flight | 1926 |
| Primary user | Deutsche Luft Hansa |
| Number built | 13 |
The Junkers G 31 was an advanced tri-motor airliner produced in small numbers in Germany in the 1920s. Like other Junkers types, it was an all-metal, low-wing cantilever monoplane. In the mid-1920s, the all-metal construction and an aerodynamically 'clean' configuration were remarkable.
Professor Junkers wanted to follow up on the commercial success of the tri-motor G 24 with a new design that would be larger, more comfortable for passengers, and simpler to operate and maintain. [1]
The G 31 was the first Luft Hansa airliner to feature a flight attendant (Wagner p. 264 [1] ), who served food and drinks (which were not complimentary). This earned the G 31 the nickname 'flying dining car' ('fliegender Speisewagen' in German). Because of its large fuselage, it was also called the flying moving van ('fliegender Möbelwagen' in German). Behind the cockpit were compartments for a radio operator, baggage, and an APU that provided compressed air for main engine starting and drove a generator for electric power. [2] The cabin was divided into three compartments that held eleven regular passenger seats, four jumpseats for passengers, a jumpseat for the steward, and an enclosed lavatory. Instead of the passenger seats, ten beds could be made up for night flying. There was a baggage and freight hold under the cabin. The wings had trailing edge flaps that reduced the landing speed by ten percent (Wagner p. 267 [1] ).
Professor Junkers originally requested the G 31 have landing gear that would retract into the wings. 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 tail skid incorporated a roller, to avoid damage to grass airfields(Wagner p. 262–263 [1] ).
The intended powerplant was three Junkers L5 engines. When these proved too weak, it was suggested to use the Napier Lion, considered to be the best aero engine at the time ("the best engine for the best plane"). This however was too expensive, especially since it would have had to be paid for in convertible currency, not German Reichsmark. Most G 31s flew with foreign air-cooled radial engines in the 500 hp range, which was license-built in Germany (see list of variants below)(Wagner p. 265–267 [1] ).
Originally, the G 31 had been intended to equip Junkers' airline, Junkers Luftverkehr, but this venture was merged into Deutsche Luft Hansa in 1926, and the new airline purchased only eight G 31s, beginning operations in May 1928. They were used on the long-range routes of Luft Hansa, particularly to Scandinavia. They continued in this role until 1935, when replaced by the Junkers Ju 52.
Four other G 31s were sold for freighting cargo in New Guinea. Operated by Guinea Airways, one was owned by the airline itself, while the other three were owned by the Bulolo Gold Dredging Company. 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. [3] In one particular operation, the G 31s were used to airlift eight 3,000 tonne (3,310 ton) dredges (in parts) from Lae to Bulolo. Three of the aircraft were destroyed in a Japanese air raid on Bulolo on 21 January 1942, and the remaining aircraft were pressed into RAAF service ten days later. 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. [4] [5] Although judged beyond repair by the Air Force, it eventually returned to freighter use in New Guinea for some time after the war.
Unlike the earlier Junkers G 24, the G 31 was not a commercial success, with only 13 being sold, as opposed to 54 civilian G 24s (+30 military derivatives)(Wagner p. 267 [1] ). Compared to the G 24 it offered passengers more comfort. Compared to the more usual biplane airliners of the 1920s, the G 31 was faster, and its all-metal construction made it safer. However, the purchase price and operating costs were high. Instead of the newly designed G 31, a developed version of the G 24 might have sold better.
Australia 
Germany 
Data from Wagner p. 269 [1]
General characteristics
Performance
Aircraft of comparable role, configuration, and era
Related lists
Hugo Junkers was a German aircraft engineer and aircraft designer who pioneered the design of all-metal airplanes and flying wings. His company, Junkers Flugzeug- und Motorenwerke AG, was one of the mainstays of the German aircraft industry in the years between World War I and World War II. His multi-engined, all-metal passenger- and freight planes helped establish airlines in Germany and around the world.
The Junkers Ju 52/3m is a transport aircraft that was designed and manufactured by German aviation company Junkers.
The Junkers F 13 was the world's first all-metal transport aircraft, developed in Germany at the end of World War I. It was an advanced cantilever-wing monoplane, with enclosed accommodation for four passengers. 322 planes of the type were manufactured, an exceptionally large number for a commercial airliner of the era, and were operated all over the globe. It was in production for thirteen years and in commercial service for more than thirty.
The Boeing Model 247 is an early American airliner, and one of the first such aircraft to incorporate advances such as all-metal semimonocoque construction, a fully cantilevered wing, and retractable landing gear. Other advanced features included control surface trim tabs, an autopilot and de-icing boots for the wings and tailplane. The 247 first flew on February 8, 1933, and entered service later that year.
The Junkers Ju 90 was a 40-seat, four-engine airliner developed for and used by Deutsche Luft Hansa shortly before World War II. It was based on the rejected Ju 89 bomber. During the war, the Luftwaffe pressed them into service as military transports.
The Junkers Ju 86 was a German monoplane bomber and civilian airliner designed in the early 1930s, and employed by various air forces on both sides during World War II. The civilian model Ju 86B could carry ten passengers. Two were delivered to Swissair and five to Deutsche Luft Hansa. In addition a single civilian Ju 86Z was delivered to Sweden's AB Aerotransport.
Deutsche Luft Hansa A.G. was a German airline. It served as flag carrier of the country during the later years of the Weimar Republic and throughout Nazi Germany, when it had close links to the Nazi Party.
The Junkers W 34 was a German-built, single-engine, passenger and transport aircraft. Developed in the 1920s, it was taken into service in 1926. The passenger version could take a pilot and five passengers. The aircraft was developed from the Junkers W 33. Further development led to the Junkers Ju 46.
The Junkers G 24 was a German three-engine, all-metal low-wing monoplane passenger aircraft manufactured by Junkers from 1925. Junkers F 24 was the designation for single-engine versions of the same aircraft.
The Albatros L 73 was a German twin-engined biplane airliner of the 1920s. Of conventional configuration, it featured a streamlined, boat-like fuselage and engine nacelles. All four manufactured aircraft of that type were operated by Deutsche Luft Hansa, one of which crashed near Babekuhl on 28 May 1928.
The Arado V.1 was a prototype airliner, built in Germany in 1927. It was a single-engine, high-wing braced monoplane with tailwheel undercarriage. It made several long-distance flights, including carrying mail to South America, before being exhibited in Berlin in 1929, when it was bought by Deutsche Luft Hansa.
The Junkers W 33 was a German 1920s single-engine low-wing monoplane transport aircraft that followed Junkers standard practice making extensive use of corrugated aluminium alloy over an aluminium alloy tube frame, that was developed from the similar but slightly smaller Junkers F 13, and evolved into the similar W 34. One example, named Bremen was the first aircraft to complete the much more difficult east–west non-stop heavier-than-air crossing of the Atlantic.
Deutsche Luft-Reederei (D.L.R.), was a German airline established in December 1917 which started operating in 1919.
The Dornier Do R Superwal was a German flying boat airliner of the 1920s.
The Focke-Wulf A 17 Möwe was an airliner built in Germany in the late 1920s. It was a conventional high-wing cantilever monoplane with fixed tailwheel undercarriage. The aircraft provided fully enclosed seating for up to eight passengers and had a separate, fully enclosed flight deck for the two pilots. Most examples flew with Deutsche Luft Hansa, serving until around 1936. In the early 1930s, two A 17s were used for testing the Junkers Jumo 5 diesel engine.
The Heinkel HE 12 was a pontoon-equipped mail plane built in Germany in 1929, designed to be launched by catapult from a liner at sea.
The Junkers Ju 60 was a single engine airliner built in prototype form in Germany in the early 1930s. It was designed to meet a requirement issued by the Reichsverkehrsministerium for a German-built equivalent to the Lockheed Vega with which to equip Deutsche Luft Hansa. The result was a sleek, cantilever monoplane of conventional configuration, with wings skinned in the corrugated duralumin that had been a hallmark of Junkers designs up to this time, although this would be the last Junkers aircraft to have this feature. The main units of the tailwheel undercarriage were retractable.
The Messerschmitt M 24, otherwise known as the BFW M.24, was an airliner developed in Germany in the late 1920s as a further development in the series of designs produced by Messerschmitt, based on the M 18. Like the M 18 and its follow-on, the M 20, it was a high-wing cantilever monoplane with a fully enclosed cabin and fixed tailwheel undercarriage. It was slightly smaller than the M 20, seating only eight passengers instead of the ten that could be carried by the previous aircraft.
The Messerschmitt M 28 was a mail plane developed in Germany in the early 1930s to meet a requirement by Deutsche Luft Hansa. It was a single-engine, low-wing cantilever monoplane of conventional design with an enclosed cockpit and fixed, tailskid undercarriage.
The Sablatnig P.III was an airliner produced in Germany in the early 1920s.
| Authority control databases: National |
|---|
