After the defeat and the signing of the Treaty of Versailles, Germany was limited in the construction of aircraft, which led to a revival of gliding. One of the pioneers of gliding was Oskar Ursinus, who organized a rally in the Wasserkuppe in 1920. Gliding movement has become a separate sport.
These informal undertakings led to the formation of the Akaflieg (Akademische Fliegergruppe) groups of engineers involved in the theory and practice of aeronautics at the universities of technology. The first groups appeared in 1920 in Aachen, Darmstadt, Berlin-Charlottenburg and later throughout Germany. Subsequently, many members of the groups became pilots in the German Air Force.
In 1924, Junkers engineer Bernhard Schulz developed for Akaflieg Aachen two projects of light multi-purpose aircraft S-7 and S-9 at once . Another engineer from Junkers, Thomas, helped in the development of projects, so sometimes the car was also designated ST-7 and ST-9.
The first aircraft, built in the same year at the Junkers plant in Aachen, was a two-seat cantilever low-wing aircraft equipped with a 24 hp Douglas engine. After the first flights, the engine was changed to a 30-horsepower ABC Scorpion. The two pilots sat side by side in an open cockpit. For ease of placement in the hangar, the S-7 was equipped with removable wings.
The S-9 was completed in 1925 and was a two-seat, high-wing, covered parasol, powered by a 55 hp Siemens-Halske Sh 4 radial five-cylinder engine. (40 kW). The engine mount was made swivel, to facilitate maintenance of the power plant.

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