Kroeber M4
The Kroeber M4 Köller was a 2-stroke air-cooled horizontally opposed piston engine designed and built by Dr. Kroeber & Sohn G.m.b.H. in Germany in the late 1930s. The M4 proved relatively popular, for powering the ultra-light aircraft and motor-gliders in vogue during the 1920s and 1930s.
Variants
;Kroeber M3 Köller:either a typo or a variant of the M4,;Kroeber M4 Köller:Main production variant
Applications
Data from AEHS: HOAE Kroeber- Grunau Motor-Baby – German motor-glider conversion of a Grunau Baby
- Kocjan Bąk I – Polish motorglider
- Dittmar Condor 'La Falda'
- Möller Stomo 3 – German high-speed ultralight aircraft
- Akaflieg München Mü13M Motormerlin
- ITS-8 – Polish motorglider sic '''Kroeber M3 Köller'''