For the same reason that the use of small engines such as RAW and Daimler proliferated in the early 1920s (limitations of the Treaty of Versailles), there were engines designed by Hermann Haacke, and built in Johannisthal, Berlin.

-The 25/28 CV two-cylinder was used in sports aircraft such as the Dietrich DPVII or the Riesler I. It is the HFM2 model.

“Haacke 28 CV”

-The 35 HP of the same architecture is shown below.

-The HFM2a gave this plus of power. It was used in the first Messerschmitt monoplanes and the Riesler III.

“HFM2a”

-A similar HFM3 is exhibited at the Deutsches Museum Flugwerft Schleisheim.

-This three-cylinder, fan engine gave 40 CV

“Haacke, 3 cylinders”

-They made a group of 60, 90 and 120 CV radial engines. The 5-cylinder radial gave 60 CV and a larger one with ten cylinders (two coupled 5-cylinder engines) gave 120 CV.

“Haacke 60 CV”

From Appendix 9: Hermann Haacke made small aviation engines such as the HMF-2a Two-cylinder that is mentioned in the main text, and from which we now have a clearer picture. We can see the cylinder heads toasted by the burned oil, as they do not have rocker covers.

“El Haacke HMF-2a”

-These engines were built in Johannisthal, Berlin.