A UK company specialising in electric powertrains has recently teamed up with a supersonic aerospace startup from the US to make a new hybrid-electric engine designed to enable affordable, long-range supersonic flight.
To build the DualityTM hybrid-electric propulsion system, Helix, headquartered in Milton Keynes, partnered with Astro Mechanica, based in California. The combined-cycle propulsion system is designed to enable efficient Mach-3, long-range supersonic flight at commercially viable costs.
The new jet engine architecture for supersonic flights. Image: Helix/Astro Mechanica.
Unlike conventional jet engines, DualityTM combines a turbogenerator core with multiple power-dense electric motors and separates the compressor and fan stages from the gas turbine.
“We are incredibly proud that our electric motors are powering DualityTM, given its potential to reshape aviation and aerospace,” said Derek Jordanou-Bailey, Helix’s aerospace chief engineer.
Next-gen supersonic engine
The DualityTM system is designed to boost fuel efficiency, addressing one of the most pressing economic challenges in supersonic flights, which travel faster than the speed of sound, exceeding 1,225km/h at sea level.
The fourth-generation prototype uses four SPX242-94 electric motors to drive its two-stage compressor. Each weighs a mere 31.3kgs, yet delivers up to 400 kilowatts (kW) of peak power and 470 newton metres of torque (Nm).
This unusually high power-to-weight ratio allows the propulsor to meet the extreme demands of supersonic airflow. The motors can sustain 300kW and 286Nm of torque continuously, enabling consistent thrust across a wide operational envelope.
Helix and Astro Mechanica’s solution will power supersonic jet engines. Image: Helix/Astro Mechanica.
“For decades, Helix has worked at the very cutting-edge of electric powertrain technology and are now a critical enabler in electrification journey of many high-performance sectors,” explained Derek Jordanou-Bailey.
The hybrid-electric architecture can switch between turbofan at subsonic speeds, turbojet at low supersonic speeds, and a ramjet at supersonic speeds. This flexibility helps maximise efficiency across various flight conditions, making it effective from takeoff through speeds above Mach 3.
The UK firm is also building custom motors for the fifth generation of Astro Mechanica’s propulsion system. These will be used to power the turbogenerator in this full-scale engine.
Supersonic made viable
The new motors will deliver 900kW of continuous power in both generator and propulsion modes. At peak performance, they can reach 950kW at speeds up to 20,000 revolutions per minute (rpm).
It will also be able to deliver a maximum torque output of 575 newton-metres. According to Helix, to ensure reliable performance in extreme environments, a new motor-isolation system has been developed specifically for high-altitude operation.
The new jet engine architecture for supersonic flights. Image: Helix/Astro Mechanica.
Jordanou-Bailey stated that Helix’s radial flux motors are a critical enabling tech for Astro Mechanica’s propulsion system. With their exceptional power density, the motors allow both the turbogenerator and propulsor to operate with the efficiency required to realise the DualityTM engine’s step-change in aviation.
“Astro Mechanica’s engine shows that our unrivalled power density stands to completely transform the engineering and economics of whole industries,” Jordanou-Bailey concluded in a press release.
With advanced airframe design, Astro Mechanica is developing the world’s first supersonic aircraft capable of transpacific flight. The goal is to make high-speed, long-range travel commercially viable.