Milton Keynes, UK – 01 December 2025 – Helix, the UK manufacturer renowned for producing the world’s most power-dense electric motors and inverters, has partnered with California-based aerospace innovator Astro Mechanica to supply electric motors for its groundbreaking Duality™ engine. This proprietary dual-use propulsion system promises to make supersonic flight more efficient, versatile, and economically viable than ever before.
Currently, the Duality™ engine employs four Helix SPX242-94 motors, each capable of 400kW peak power and 470Nm maximum torque, while weighing just 31.3kg. These motors drive the engine’s 2-stage propulsor compressor, providing an extraordinary combination of power density and efficiency. Helix is now designing next-generation custom motors for Astro Mechanica’s fifth-generation engine, which will deliver 900kW of continuous power in both generator and propulsion modes, weighing 61.5kg per unit. Peak performance is projected at 950kW with 575Nm of torque, optimized for extreme-altitude operation.
A Hybrid-Electric Breakthrough in Aviation
Duality™’s hybrid-electric architecture separates the propulsion unit from the turboshaft core. A gas turbine-driven turbogenerator powers the four Helix motors in the propulsors, enabling the engine to mimic a turbofan at subsonic speeds, a turbojet at lower supersonic speeds, and transition to a ramjet at very high supersonic speeds. This adaptability ensures optimal efficiency across a wide range of flight conditions, creating a combined-cycle turboelectric adaptive engine capable of cruising from takeoff to Mach 3+.
When paired with Astro Mechanica’s advanced airframe design, the Duality™ engine could enable the world’s first supersonic aircraft with transpacific capability, unlocking applications in national defence, orbital launch, long-range cargo delivery, and potentially commercial supersonic passenger travel.
Helix: The Power Behind High-Performance Electric Propulsion
Helix’s radial flux motors are critical to achieving Duality™’s step-change in aviation efficiency. Their unrivalled power density enables the turbogenerator and propulsor to operate at peak efficiency, making a supersonic, dual-use propulsion system technically and economically feasible.
Derek Jordanou-Bailey, Aerospace Chief Engineer at Helix, commented:
“We are incredibly proud that our electric motors are powering Duality™. For decades, Helix has been at the cutting edge of electric powertrain technology, and now we are helping redefine what is possible in aerospace. Astro Mechanica’s engine demonstrates that our technology can completely transform both engineering and economic models across industries.”
Helix’s expertise is rooted in high-performance motorsport applications. Its systems power Formula E teams and record-breaking hypercars, including the McMurtry Spéirling, Lotus Evija, Czinger 21c, and Aston Martin Valkyrie. In recent years, Helix has expanded into aerospace, defence, and marine sectors, supplying propulsion for vertical take-off and landing vehicles, space launch providers, racing boats, yachts, and defence platforms spanning land, sea, and air.
Looking Ahead
Astro Mechanica is testing its fourth-generation Duality™ prototype, with first flight anticipated within three years. Over the next decade, the company aims to make supersonic passenger travel as accessible and affordable as today’s commercial air travel. Helix will continue to collaborate closely with Astro Mechanica, providing the power-dense technology required to push aviation technology into a new era.
With Helix at its core, Astro Mechanica’s Duality™ engine represents a landmark in hybrid-electric aviation, bringing the vision of efficient, long-range supersonic flight closer to reality than ever before.
