SWITCH project aims to advance hybrid electric and water enhanced turbofan tech

TOULOUSE, France - Supported by the European Union Clean Aviation Joint Undertaking, MTU Aero Engines AG in Munich, Raytheon Technologies' Pratt & Whitney and Collins Aerospace, GKN Aerospace in Redditch, England, plus Airbus and other companies have announced the formation of a collaborative consortium to develop hybrid-electric and water-enhanced turbofan technology for future aircraft propulsion systems.

With the Sustainable Water-Injecting Turbofan Comprising Hybrid-Electrics (SWITCH) project, the aerospace companies aim to demonstrate the potential of these technologies to improve fuel efficiency and reduce aircraft CO2 emissions by up to 25% compared to today's state-of-the-art propulsion systems for short- and medium-range aircraft.

The SWITCH project is focused on developing a novel propulsion concept built from two technologies: Water Enhanced Turbofan (WET) and hybrid-electric propulsion. By combining these technologies with Pratt & Whitney’s GTF engine architecture, the SWITCH concept aims to enhance efficiency and reduce emissions across the full operating envelope of an aircraft. Technologies developed as part of SWITCH will be fully compatible with cleaner alternative fuels – such as Sustainable Aviation Fuel (SAF) — and will be evaluated for future use with hydrogen.

The hybrid-electric GTF powertrain will enable greater efficiency across all phases of flight by leveraging megawatt class electric motor generators, power electronics, and batteries to optimize the performance of the fuel-burning gas turbine. The WET concept recovers water vapor from the engine exhaust and re-injects it into the combustion chamber to significantly improve fuel efficiency, reduce NOx emissions, and lessen contrail forming emissions. These revolutionary technologies are designed to work together to deliver a step change reduction in emissions and energy use across the full operating system, while maintaining world class reliability and operability.

Airbus in Toulouse, France, will provide key expertise relating to the future integration of SWITCH technologies at the aircraft-level and will support the evaluation of performance benefits including aircraft design and integration of battery and energy management systems. Collins Aerospace in Charlotte, N.C., will provide megawatt-class electric motor generators and power electronics, high-voltage DC distribution and protection, thermal management components and nacelle architectures for the project.

GKN Aerospace will develop various engine structures with all-new functionalities, such as integrated electric machines and heat exchangers.

In addition to aerospace companies, the project is also seeing participation from the DLR German Aerospace Center, plus higher learning institutions Aristotle University of Thessaloniki in Greece; Chalmers University of Technology in Sweden, and the University of Stuttgart in Germany.

"This project will enable us to advance several key technologies on our roadmap to further extend the efficiency of the GTF engine architecture," said Geoff Hunt, senior vice president, Engineering and Technology, at Pratt & Whitney, which is headquartered in East Hartford, Conn. "Given the challenge of reducing the environmental impact of aviation, cross-industry collaboration and public-private partnerships like Clean Aviation will play a vital role in delivering the technology breakthroughs needed to make net zero emissions aviation a reality."