Rolls-Royce this week confirmed plans to develop new-generation turbogenerator technology that will be the basis for small engines to power hybrid-electric aircraft. The aero engines group announced on June 22 that its Rolls-Royce Electrical unit will expand its product portfolio to support new aircraft needing greater range and payload than current battery technology can support with all-electric propulsion systems, like those the company is developing for partners such as eVTOL aircraft makers Vertical Aerospace and Eve.
The turbogenerator technology Rolls-Royce is working on will be scalable to serve power requirements of between 500 and 1200 kW. It will be used either to recharge batteries after the aircraft takes off or to power propellers directly.
The program is being led by engineers in Germany, Norway, and Hungary. It is receiving undisclosed amounts of financial support from the German government’s Ministry of Economic Affairs and Climate Action.
“Rolls-Royce will be the leading provider of all-electric and hybrid-electric power and propulsion systems for advanced air mobility and will scale this technology over time to larger platforms,” said Rolls-Royce Electrical president Rob Watson. “As part of our strategy, we are looking at offering the complete sustainable solution for our customers. This means extending routes that electric flight can support through our turbogenerator technology. This will advance hybrid-electric flight and mean more passengers will be able to travel farther on low to net zero emissions aircraft.”
Rolls-Royce’s customer business director, Matheu Parr, told FutureFlight that the company wants aircraft developers to know it is ready to collaborate with them to define and develop propulsion systems meeting their needs. He estimated that it will be able to start delivering new hybrid-electric engines from the mid to late part of this decade. He said these could be used to extend the range of eVTOL and eSTOL aircraft.
Last year, during ground tests at Rolls-Royce’s Bristol facility in the UK, the company achieved a key milestone of generating more than a megawatt (1 MW) of power with its Power Generation System 1. Its goal is to generate a power output of 2.5 MW in further testing.
This test generator, which Rolls-Royce says is about the size of a beer keg, incorporates one of the group’s AE2100 turbofan engines, as well as special controls and a thermal management system. At its Dahlewitz site in Germany, the company has been testing a smaller 250-kW gas turbine but has concluded that this won’t deliver the level of performance needed for future hybrid-electric aircraft.
Rolls-Royce Electrical was formed after the group’s acquisition of Siemens’s electric and hybrid-electric aerospace propulsion activities in 2019. The company is already working with Italy’s Tecnam on an all-electric version of its P2012 commuter aircraft called the P-Volt. It is also partnered with Embraer and Norwegian airline Wideroe to develop plans for an electric regional airliner.