The Siemens & Halske Sh.IIIa engine represents the latest development of the rotary engine arrangement widely used for aircraft propulsion in the early period of aviation, from 1908 to 1918. Despite of some drawbacks, the Sh. III was a technically advanced engine for its time, capable of remarkable performances in terms of maximum power output, specific fuel consumption and mass-to-power ratio. In September 1918, a Siemens-Schuckert D.IV equipped with the engine Sh.IIIa did record a remarkable performance for those times, reaching the altitude of 8100 meters from the ground in 36 minutes.