Unimog R-4, 1697 cm³, 73.5 mm * 100.0 mm, 19 : 1, prechamber Diesel, 19 kW (25 hp), 2250 rpm, front engine, four-wheel drive, single-disk dry clutch, four-speed, later six-speed, later also fully synchronised available, 2 R-gears, identical portal axles f/r, coil springs, shock absorbers, spindle steering, drum brakes, 3.52/1.72/1.63/2.02 m, 6. 50 - 18 (5''), 40 litres, 1,375/1,775 kg, 50 km/h, 13,800 DM (closed), from 1949.

Not in terms of weapons technology does the war produce new things in a very short time, but the more its end approaches, the more the survivors form a picture of a possible future after it. This is probably how the universal motor device came into being. Some vehicles that were later produced in large numbers were thus already created during the war under the strictest secrecy.

In the case of the Unimog, there is also the fact that the main protagonist, Albert Friedrich, was head of aircraft engine development in Berlin-Marienfelde. Once before, Germany lost a war and the first thing that was forbidden by the Allies was the development of aircraft. In addition, the produced four-wheel drive crew car at Daimler-Benz until 1944 may have helped, too.

Added to this may be the plan of the American Secretary of the Treasury Henry Morgenthau in 1944 to de-industrialise Germany and only allow agricultural production. This coincides with the fact that after almost every war lasting several years, there is a large supply gap in the population. All this may have prompted Friedrich to decide that an auxiliary device for agriculture was now most important.

The second person involved in the development of the Unimog is Heinrich Rößler, once assigned to the Berlin factory, although actually a passenger car designer. According to Friedrich's first plans, the vehicle was designed with seats above the front axle and an engine driving the central transmission-distributor unit from the rear.

Anyone who grumbles nowadays about the low top speed of the first Unimog should take a look at the competition from the existing farm tractors, which are considerably slower. The rear wheels are large, also because of the non-driven front wheels. The only possible option is a one hundred percent lock, which often drives the tractor straight ahead over the turned front wheels.

At most, there is a PTO and simple auxiliary tools at the front, but there is no trace of the versatility of the Unimog. Thousands of attachments are said to have been developed for this vehicle to date. The 40 tonnes of the first Unimog cannot be compared with the towing capacity of a similarly large and easily manoeuvrable tractor.

By the end of 1949, with the addition of engineers Freitag and Zabel, a small design team was already in place. Other experts were added, including one for agriculture, who set the track width at 1,270 mm, which made it possible to drive through the rows in a potato field. So there will be some room later to use the 1,435 mm of a railway track.

Among the suppliers are the companies Erhard & Söhne and Boehringer, who later also took over production. The engine was meanwhile provided at the front, clearly protruding into the passenger compartment because of the short snout. The vehicle initially consisted of a ladder frame, only with which it was roadworthy, for the first time in autumn 1946. The planking could be made from flat sheet metal, in the beginning with little effort.

The first engine was that of the Mercedes 170V, a petrol engine, mind you, but like the later Diesel engine of the same vehicle, probably throttled for more torque. For the diesel engine, which did not appear on the market until 1948, the Unimog team was involved in its development at an early stage through test engines. This was very important because the cost of fuel for farms is then much cheaper than for private individuals.

Gradually, the other rights for this 'special vehicle' are also fought for, which then included all the cheapening of an agricultural vehicle. It was not until 1950, however, that the first add-on part for the Unimog was available for purchase, a kind of chipper for the front. At least the laterally projecting shaft with a belt drive could be used for all kinds of implements such as a threshing machine.

As domestic and foreign interest in the Unimog grew, production had to be transferred from Boehringer at the time to the Daimler-Benz plant in Gaggenau under a contract signed in 1950. As a result, further design, marketing and sales were taken over there. Foreign countries also became increasingly interested in the Unimog, especially municipal institutions and the military. Especially the latter and the equipment of the newly formed German military probably connected with it, were probably not Albert Friedrich's intention. He left the project for good in 1950.