With the introduction of this developement, the "Entwicklungs-Flugzeug" designator EFo was changed to EF. Not much is known about the EF50. It seemed to be a VTOL aircraft design parallel to the Focke-Achgelis Fa269. The most characteristic item of the design is the large diameter of the props, which are extended nearly over the whole wing span. These props were used as rotors during the vertical take off and landing and were turned into horizontal position for forward flights.
Some sources also mention the EF50 as record or racing aircraft. But these sources seemed to be misleaded by the large prop diameter. On the other hand, a Junkers engagement in VTOL or helicopter designs is not known before or following the EF50 design. Junkers had no knowledge in this technologies. Therefore it is questionable, why Junkers started the EF50 study or why the RLM asked Junkers for this design study.