MEGAWATT project

Demonstration of Massive Electric Generation for Aircraft and Wake Adaptive Thruster Technologies

JAXA launched a technology demonstration project called MEGAWATT in FY2025, aiming to take an initiative on the era of passenger jet fleet with megawatt-class electric hybrid propulsion systems by integrating key technologies from Japanese industries. The mission of MEGAWATT is to develop and demonstrate electric hybrid propulsion system for jet aircraft as a highly matured integrated system capable of treating high electric power, thereby enabling Japanese companies to lead the way in electrification businesses by leveraging their innovative technologies. The outcome through this activity will be transferred to Japanese industries and aircraft OEMs, contributing to international standardization efforts, the electrification of next-generation passenger fleet as well as the carbon neutrality.

Wake Adaptive Thruster (WAT) concept

The concept of improving the efficiency of the propulsion system using the BLI (Boundary Layer Ingestion) effect by attaching a propulsion fan on the tail of the fuselage has long been recognized. However, it has yet to be realized, primarily due to the distorted flow near the tail section, which poses significant risks when ingested by conventional turbofan engines. In contrast, the majority of recent proposals for BLI aircraft incorporate electric fans, as their use enhances the feasibility of this concept.

JAXA has proposed a new aerodynamic configuration that solves the problems of BLI aircraft as the WAT (Wake Adaptive Thruster) concept.

On board electric power generation in passenger air fleet

Modern airfleet uses a lot of electricity, not to generate propulsive power, but to power various onboard systems such as air conditioning, galleys, and anti-icing systems. Normally, this electricity is generated by an electric generator attached to the gas turbine engine. As the electric power requirement of aircraft systems increases with each succeeding generation, the capacity of engine-mounted electric generators tends to increase exponentially.

Current engine-mounted generators are field winding types connected to a high-pressure spool via gears, but in the future, more powerful, efficient, and compact generators will be required. To realize a new type of permanent magnet electric generator which extracts power from a low-pressure spool is the key to obtaining the power required by electric propulsion fans.

Key technologies from Japanese domestic industries will lead to a breakthrough in the realization of electric hybrid passenger fleet.

Topics of research and development in the MEGAWATT project

MEGAWATT will develop the main subsystems that are parts of the electric hybrid propulsion system and will conduct assessment of the following designs and technology demonstrations using ground test facilities.

1. Regarding JAXA's unique WAT concept, the effectiveness will be validated through CFD and transonic wind tunnel tests. The results obtained from the technology demonstrations will be used to estimate the performance of the assumed electric hybrid aircraft.
2. MW(megawatt)-class electric generators, motor and several devices will be developed and preliminary tests to confirm the validity of the performance of the components, which will be supplied to the demonstrations, will be conducted.
3. An electric power generation system will be developed, and a demonstration test will be conducted to confirm that a large amount of electric power can be generated from the generator connected to the engine.
4. The electric fan drive system will be developed with a high-altitude environment facility. The ability to generate torque and rotation speed required for an actual aircraft even in a low-pressure environment will be demonstrated.
5. The achievements of the project will be shared with Japanese domestic industries and global stake holders, in addition, the knowledge will be used for international standardization.

June 13, 2025