25 June 1919: Junkers-Fokker Aktiengesellschaft test pilot Emil Monz made the first flight of the Junkers F.13 at Dessau, Saxony-Anhalt, Germany. It was the first airplane to be built of all-metal construction specifically for commercial passenger service. Named Herta in honor of Professor Hugo Junkers’ oldest daughter, the prototype carried identification marks D 183.
Designed by Chief Engineer Otto Reuter, the F.13 was a single engine monoplane with a corrugated duralumin skin over a duralumin structure. It had a flight crew of two and four passengers could be carried in a comfortable enclosed cabin of the same size as automobiles of the time. The single wing was cantilevered and, unusually for the time, used no braces or support wires.
The prototype had a wingspan of 14.47 meters (47 feet, 5.7 inches). The wingspan was increased to 14.82 meters (48 feet, 7.5 inches) in production airplanes. The airplane was 9.59 meters (31 feet, 5.6 inches) long and 4.10 meters (13 feet, 5.4 inches) high. It had a maximum takeoff weight of 1,800 kilograms (3,968 pounds).
The first F.13 was powered by a 14.778 liter (901.81 cubic inch) water-cooled Mercedes D.IIIa single overhead cam inline six-cylinder direct-drive engine with two valves per cylinder and a compression ratio of 4.64:1. It produced 174 horsepower at 1,400 r.p.m., and drove a two-bladed, fixed-pitch laminated wood propeller. The D.IIIa weighed 660.0 pounds (299.4 kilograms). (Production airplanes used BMW and Junkers engines.)
The F.13 had a maximum speed of 170 kilometers per hour (106 miles per hour).
In production from 1919 to 1932, a total of 332 Junkers F.13s were built. Some remained in service in the late 1930s.
Herta was later renamed Nightingale and its registration markings changed to D 1.
Emil Monz died 18 February 1921 when the Junkers F.13 that he was flying, D 128, crashed in a snowstorm enroute to Stuttgart.
© 2017, Bryan R. Swopesby