The Frankfurter Flugzeugbau Max Gerner GmbH was taken over by the Adler-Weke AG 1/1 1934. A special branch , the Adler Flugzugbau, was created. Josef Jacobs was appointed manager working together with Hans Gustav Röhr, the Technical Manager of the Adler-Werke. Jacobs was an ace from WW 1 with 41 kills and had the Pour-le-merite. Together with Ing. Walter Schilo, former head of Siemens & Halske Werksflugerprobung (Testing departmen of aircraft engines). The serie production of the Gerner light plane as Type G IIRb was started at once. Already at the Deutschlandsflug in June 1934 14 G IIRb took part.
Because of a crash, the 2 pilots were killed, an investigation was started by the RLM. This led to a stop of all flying with this type. A total rebuilt was neccesary, swept backward wings - larger rudder, ailerons, elevator - new structural calculations to achieve a higher flying weight. The new type was named G IIRc. Was accepted early 1935 but only a few were built. The Adler could not compete with the new modern designs. The Gerner company was by itself again from early 1935. Totally was 31 aircraft built.
From Wikipedia
The Adler Works take over Max Gerner
The company Adler, formerly Heinrich Kleyer AG, also based in Frankfurt, which was successful not only with its bicycles and sewing machines, but above all with its motor vehicles Adler Trumpf and Trumpf Junior, strived, like many other companies in Germany, to create another mainstay in the promising field of aviation. The company had already been active in this field since 1909. The fact that two war pilots, Franz Röhr as chief designer and Josef Jacobs as director, had great influence at Adler and initiated the takeover of Gerner's company, was certainly conducive to this endeavour. Jacobs now became head of the entire aircraft construction division, while Gerner, now permanently employed by Adler, continued to be responsible for his aircraft. Through Jacob's efforts, sales of Gerner aircraft soon increased considerably. During this time, the G II Rb underwent some significant changes. Not only did the shape of the tail units change, away from the previous rectangular basic shape to the trapezoidal shape, but the landing gear was also significantly improved, with long-stroke Faudi shock absorbers, which were now supported by the upper chord of the fuselage. As a result, the track width was increased from only 1.2 m to 1.6 m. In addition, there were the more modern low-pressure wheels. The Gerner aircraft were thus apparently on the right track.
After a G II R, Wnr. 7, D-2293, had already crashed from a height of about 60 m on 10 March 1933 and a second aircraft, D-2833 (presumably Wnr. 14), had crashed under similar circumstances on 22 February 1934, the already mentioned crash at the beginning of the Deutschlandflug drew the attention of the Reich Ministry of Aviation (RLM). All aircraft of the type were banned with effect from 1 July 1934 and an investigation was ordered, in which the E-Stelle Rechlin was also involved. The main causes turned out to be disturbances in the air flow behind the tank located in the upper wing, which caused practically the entire tail unit to lose its effect when it was pulled over and the aircraft smeared over one wing. Furthermore, there was too much tail heaviness. These results forced an immediate redesign, which resulted in an aircraft that was greatly altered, at least in appearance, and was now designated the G II Rc. What was new was not the 8° sweep back of the wings to eliminate the center of gravity problem, but also significant aerodynamic improvements, e.g. by enlarging the tail. Although the first aircraft of this version did not receive its certification until April 1935, the production of this version (or the modification of existing aircraft) must have started earlier, because otherwise five Gerner aircraft, now called Adler steel aircraft, would not have been able to take part in the 1935 Germany flight a month later.
Because the economic result in the aircraft sector obviously fell short of the expectations of the management of the Adlerwerke and the further prospects were clouded due to the crashes and the resulting closure, Adler declared the separation from Gerner on 30 April 1935 after lengthy negotiations. He obviously continued to work, now again under his own responsibility as a sole proprietorship, but apparently was able to sell fewer and fewer aircraft. In total, only a little more than fifty aircraft were built, of which six were G IIs, 34 G II Rb and only 13 G II Rc. It is not known when the last Gerner was taken out of service.
