RTX today announced the completion of the preliminary design review for the hybrid-electric propulsion demonstrator engine being developed as part of the SWITCH project, supported by the European Union's Clean Aviation Joint Undertaking (Clean Aviation). By combining two Collins Aerospace megawatt-class electric motor generators within a Pratt & Whitney GTF™ engine, the hybrid-electric propulsion system aims to enhance engine efficiency across all phases of flight, offering the potential to reduce fuel burn and emissions for future short- and medium-range aircraft.

"Completing the preliminary design review is a significant milestone toward demonstrating the potential of hybrid-electric technology to further enhance the performance and efficiency of next generation aircraft propulsion systems," said Juan de Bedout, chief technology officer, RTX. "We are leveraging our growing expertise in the field of hybrid-electric propulsion, including close collaboration between Pratt & Whitney, Collins Aerospace and all members of the SWITCH consortium."

The SWITCH hybrid-electric propulsion system comprises two megawatt-class electric motor generators mounted on the low spool and high spool of the GTF engine, along with associated motor controllers, high voltage wiring and batteries. Testing of the electric powertrain is planned to take place at Collins' state-of-the-art electric power systems development facility, The Grid, in Rockford, IL, before assembly and test of the full-scale GTF demonstrator engine.

The SWITCH project (Sustainable Water Injecting Turbofan Comprising Hybrid-Electrics) is a collaborative consortium including MTU Aero Engines AG, Pratt & Whitney, Collins Aerospace, GKN Aerospace and Airbus, and aims to demonstrate the potential of hybrid-electric and water-enhanced turbofan technologies to enable improvements in aircraft fuel efficiency and reduced emissions.

Hybrid-electric propulsion is a key part of RTX's technology roadmap for enabling more sustainable aviation. In addition to SWITCH, RTX is advancing hybrid-electric technologies through multiple demonstrator programs applicable to a variety of future aircraft platforms, including STEP-Tech and the RTX Hybrid-Electric Flight Demonstrator, supported by the governments of Canada and Quebec.