Oberursel UR II
Type 9-cylinder, single-row, rotary engine Compressor No Reduction Gear Direct drive , right hand tractor Length 85 cm
Operation   4-stroke Bore 112 mm   Compression ratio 6 Height 97 cm
Mixture Carburettor Stroke 170 mm   Fuel consumption 320 gr/hp Width
97 cm
Cooling Air-cooled Displacement 15100 cm3 Oil consumption 55 gr/hp Weight 135 kg
Power output Start 140 hp at 1200 rpm, 120 hp at sea level and 1200 rpm, 110 hp at 1150 rpm (economical)
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