Siemens' eAircraft electric aircraft power unit has 180 staff and develops propulsion systems in Munich and Erlangen in Germany and Budapest in Hungary.
The deal is expected to be completed by the end of the year.
"Our eAircraft team, under the leadership of Frank Anton, has made aviation history several times in the past ten years and is a pioneer in electric and hybrid-electric systems for aircraft," said Roland Busch, CTO and COO of Siemens. "With Rolls-Royce, we've found a perfect home for this business and have placed its expertise in the hands of one of Airbus' close partners. We will continue to cooperate with Rolls-Royce, in particular by making our digital solutions portfolio available in order to facilitate this major step toward sustainable, lower-emission aviation."
eAircraft has been working with Airbus since 2016 to create prototypes for propulsion systems that range from under one hundred to several thousand kilowatts, for example for the Airbus air taxi, the CityAirbus.
Roll-Royce has also been working with Siemens and Airbus on a hybrid-electric propulsion for commercial aircraft. The E-Fan X hybrid-electric technology demonstrator is expected to fly next year on a BAe 146 flying testbed, with one of the aircraft’s four gas turbine engines replaced by a two megawatt electric motor. “The E-Fan X enables us to build on our wealth of electrical expertise to revolutionise flight and welcome in the third generation of aviation," said Paul Stein, Rolls-Royce, Chief Technology Officer.