Oberursel produced the 110 hp model, supposedly without authorization in Germany. The Oberursel Ur.II was a straight copy of the Le Rhône, but the Le Rhône was preferred over the Oberursel due to the materials used in the French product. However, by July 1918 there was a shortage in Germany of castor oil,[1] a plant-derived lubricant that the rotaries required as it could not be easily dissolved into the fuel, and because it possessed lubrication qualities superior to mineral oils of the day.[5] A new Voltol-based lubricant, derived from mineral oil, was substituted and was blamed for engine failures on rotary-engined German fighters such as the Fokker E.V which used the Oberursel Ur.II. It has been suggested that without proper lubricants, the Le Rhône rotary would have been equally failure-prone
Used by the LFG V.19

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