Two seat fighter
Two seat reconnaissance
1 Oberursel  U III
Length 6,65 m,  span 11,45 m, wing area 21,00 m2
Length 7,70 m, span 12,00 m
Empty 570 kg, flying weight 200 kg
Max. speed 180 km/h, range 170 km
Only parts of fuselage and wing finished. Cancelled
Junkers J3
Following the experiences of the J1 and J2, Junkers realized, that the iron structure of his aircraft was to heavy to fullfill the demand for satisfying climb performance as well as maneuvering. Therefore he advised Dr. Mader to think about the utilization of Duralumin, which reduces the weight for about 60% compared to iron structures. While Mader, Reuter and Brandenburg were engaged in the construction of the new aircraft design, named J3, Steudel was responsible for the research of new production technologies for the utilization of Duralumin.

The developement of the J3 were privately financed by Junkers and ICO without any support by IDFLIEG or the German government. Two versions of the J3 were designed, a single seated fighter aircraft and double seated battle aircraft. In late summer 1916 the production of the single seated J3 prototype was started at Dessau. The fuselage tube construction and the complete wing with corrugated Duralumin panels were already finished, when Junkers ran into financial difficulties for this project and in October 1916 the further project was stopped. Even if the J3 did not become the world's first aircraft, which was built from light metals, all calculations proofed, that the utilization of Duralumin was heading towards lighter metal aircraft, which offer convenient performances compared to the conventional wooden and textile covered aircraft.

The wing and fuselage sections, which were already mounted, were later transfered to the Junkers Educational Exhibition, where they remain until they were destroyed during an air raid against Dessau in 1945.