New hybrid-electric engines could power next-gen supersonic aircraft

A UK electric powertrain company, Helix, has partnered with US-based supersonic aerospace startup Astro Mechanica to develop the Duality™ hybrid-electric propulsion system aimed at enabling affordable, long-range supersonic flight. This innovative engine architecture combines a turbogenerator core with multiple high-power electric motors, separating the compressor and fan stages from the gas turbine to boost fuel efficiency and reduce operational costs. The system is designed to operate efficiently across a wide speed range, switching between turbofan mode at subsonic speeds, turbojet at low supersonic speeds, and ramjet at higher supersonic speeds, enabling sustained flight above Mach 3. The fourth-generation prototype features four lightweight SPX242-94 electric motors, each delivering up to 400 kW peak power and 470 Nm torque, with continuous output capabilities that meet the extreme demands of supersonic airflow. Helix is also developing custom motors for the next generation of Astro Mechanica’s propulsion system, capable of delivering