Hoffman Rotor made a 7-cylinder rotary radial that gave 60 hp. It was installed on the Sommer monoplane, made by Deutsche Sommer Flugzeugwerke.

“Picture of the Sommer with its Hoffmann engine” (PeT)

From Appendix 10: We have located an engine of this brand on the Deutsche Sommer monoplane aircraft. Of 60 CV and the year 1911.

“The Deutsche Sommer with the rotary engine”

-The Hoffmann-Rotor is a 7-cylinder rotary engine.

-In the text appears the same photo in negative for not having authorization. Now we have it from another source.

"Enlargement to discover the rotary engine"

From Appendix 12: Through a German publication, now we have a picture of the engine on the airplane that appears in the main text. This 7-cylinder engine was designed by George Hoffmann and gave 60 CV.

“George Hoffmann and his engine” (PiP-Flu)