1946 – The first Unimog prototype
In 1946 the "Prototype 1" Unimog completed its first test drive. Chief designer Heinrich Rößler himself was at the wheel, and he tested the prototype, which had no cab and was fully laden with wood, on rough forest roads near Schwäbisch-Gmünd. The creation of the Unimog is closely linked to the difficult situation in the post-war period, when Germany was suffering supply shortages. In 1945 and 1946, there was a dire lack of food. It was this situation that gave Albert Friedrich, who for many years was head of aircraft engine development at Daimler-Benz AG, the idea of an agricultural motorised vehicle which could help to increase agricultural productivity.
After the war ended, Friedrich had renewed his contacts with Erhard & Söhne, a metal construction company and supplier of Daimler-Benz in Schwäbisch-Gmünd, and in December 1945 the department responsible for the agricultural market began work. Friedrich passed the leadership of the project on to his former subordinate, designer Heinrich Rößler, who took up the post on 2 January 1946. In only a few weeks, a new overall design was developed, with the engine and gearbox positioned directly to the right of the vehicle's centre. This meant that the torque tubes – which protect the drive shafts – could be at right angles to the axles. As a result, only four drive joints were needed for the chassis. This was a brilliant design which, 75 years later, is still used for the Unimog of the highly mobile U 4023/U 5023 series. In March 1946, Hans Zabel from Gaggenau, who had been part of the project from the beginning, coined the term Unimog (Universal-Motor-Gerät, i.e. universally applicable motorised machine) and in October 1946 the vehicle was taken on its first test drive.