Junkers F 13

Finnair Junkers F-13

The "Junkers F 13" is the first modern commercial aircraft. Outstanding design features make it an key example of an entire generation of commercial aircraft:
The cabin for the passengers is closed, accommodates four persons, and is equipped with comfortable upholstered seats, heating and illumination. Following the precedent of spacious automobiles used for long-distance journeys in those days, Junkers also referred to his F 13 as an air limousine.

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The wing, with its relatively deep profile, is a low-wing cantilever monoplane and not based on a biplane design with struts and bracing wires, which was common at that time. The drag was reduced considerably by the abandonment of exterior wires, struts and attachment fittings. The low-positioned wing provides increased safety to the passengers in case of emergency landings. When ditching (carrying out emergency landings on water) the aeroplane remained capable of floating for some time.

The framework of the F 13 consists of light alloy profiles and tubes riveted to each other. At the end, this framework is covered with preformed corrugated sheet metal parts. The wing and fuselage framework are built according to the Junkers patent "Monoplane with self-supporting wings" of 1918.

The aeroplane is made entirely of a light metal alloy (duraluminium) and covered with corrugated sheet metal, instead of employing a wood and steel tube construction with fabric covering, which was common in those days. The corrugated sheet metal admits a high inherent stiffness and thus requires only a few interior supporting elements. The light alloy construction makes the F 13 rugged, resistant to climatic conditions, easy to repair, and therefore long lasting.

The open cockpit offers space for two pilots and is equipped with a dual control mechanism for the first time. Thus, the pilots can share the work and take turns at the control on longer flights.

The first flight of the F 13 took place in June 1919. Soon afterwards record flights such as a high-altitude flight with 8 occupants at an altitude of 6,750 m and a non-stop, long-distance flight covering 1,900 km in 12 hours and 10 minutes drew attention to the capability of the new aircraft.

Aeroplanes built as a seaplane version are used for traffic between seaports and for longer flights over water. Here, an F 13 has landed in a bay near Rio de Janeiro (in the background you can see the Sugar Loaf Mountain).

The F 13 contributed considerably to the development of air traffic in the twenties. Many less developed and sparsely populated countries that did not have a developed air traffic system began to rely on the aeroplane for passenger, freight and postal traffic in the twenties and thirties. A total of about 330 F 13s were built in 60 different versions and sold to 30 countries from 1919 until 1932. They were still in use as passenger and freight planes until well into the thirties.

Experience gained in the operation of Junkers airlines was evaluated systematically and employed in design improvements. An entire series of large aeroplanes with corrugated covers evolved from the F 13. The final result was the extraordinarily successful three-engined commercial aeroplane Junkers Ju 52/3 m built in 1932.

The F 13 was a further development of the Junkers W 33 freight plane, whose exterior is similar to its ancestors. Flying a W 33 that had been specially modified for the record breaking attempt, Hermann Köhl, E.G. von Hünefeld and J. Fitzmaurice made the first successful Atlantic crossing from East to West in 1928.