RTX today announced it has completed a significant milestone in the development of its hybrid-electric STEP-Tech (Scalable Turboelectric Powertrain Technology) demonstrator. The company has successfully validated sustained operation of the thermal engine, electrical generator, battery system and propulsors to demonstrate energy transfer between these components through the high-voltage electrical network.

As a modular demonstrator program, STEP-Tech is intended for prototyping future distributed propulsion concepts in the 100-500kW class, with capability to scale to 1MW and beyond. These concepts could have application for a range of next-generation platforms, including advanced air mobility vehicles, high-speed electric Vertical Take-Off and Landing aircraft and blended wing body aircraft.

"When combined with RTX's other hybrid-electric demonstrator programs, STEP-Tech positions us to offer advanced propulsion technologies that enable greater fuel efficiency across all future aircraft segments, from advanced air mobility to large commercial," said Juan de Bedout, chief technology officer for RTX. "These new hybrid-electric architectures are key to our strategy for supporting the aviation industry's goal of reduced carbon emissions and more sustainable flight."

RTX has validated the capability of STEP-Tech's battery system to start the thermal engine and use electrical power produced by the turbogenerator to charge the batteries used to drive the propulsor motors. This follows previous tests of each of STEP-Tech's system components, including the first engine run at partial power and the electrical system integration test. All tests were conducted at the RTX Technology Research Center in East Hartford, Connecticut, which features a class-leading 800-volt electrical architecture designed for aerospace applications.

In addition to STEP-Tech, RTX's other hybrid-electric propulsion programs address a range of future aircraft applications up to single-aisle, including the RTX Hybrid-Electric Flight Demonstrator, supported by the governments of Canada and Quebec, and the SWITCH project, which is supported by the European Union's Clean Aviation Joint Undertaking.