Rieseler soon succeeded in interesting the RLM in his ideas for controlled vertical flight and managed to get a contract to develop the RI, a simple helicopter design with a pair of contra-rotating coaxial rotors powered by a 90 hp HM504 engine. Construction of the RI was done by Rieseler's engineer Otto Steue. By the Spring of 1936 Rieseler began testing the RI in tethered flights and by the Summer it was ready for its first free flight. Riesler invited his friend Flugkaptain Johannes Mohn to fly the RI. Mohn reported that the RI the helicopter was unlike anything he had ever flown before. Be adjusting the engine throttle he soon succeeded in hovering the RI to a height of 49 feet. The R1 was tested almost daily. Mohn claims to have reached a top speed of 99 mph. Engine overheating problems prevented flights from lasted any longer then 15 to 20 minutes. Mohn was not happy with the  flight characteristics in the horizontal flight which led to re-designs and to changes of the tail unit.

A demonstration was arranged for the benefit of Ernst Udet on September 3rd, 1936. Mohn took off vertically to a height of 197 feet, turned the helicopter 360 degrees and landed after a flight of 16 minutes. After the engine had cooled, Mohn took off again to demonstrate a full circuit flight. When Mohn throttled the engine down to land, the engine stalled and the R1 crashed into a heap of twisted metal. Udet joked, "You can't impress me with that! I am quite capable of producing a crash myself". Mohn survived the crash with broken ribs.

It is believed that the R1 was rebuilt and handed over to the DVL, where testing was carried out in 1937. Little else is known on the faith of the RI.

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