Sikorsky unveiled renderings of its HEX concept hybrid-electric and autonomous tilt-wing technology demonstration aircraft on Tuesday at Heli-Expo 2024. First flight is planned for 2026 and design goals include a range greater than 500 nm, high speed, and a 9,000-pound maximum gross weight.
Developed in collaboration with GE, the design features a 1.2-megawatt GE turbogenerator propulsion pack, integrated flight and motor controls developed under Sikorsky’s Matrix program, and electric motors and power electronics developed by Sikorsky.
Paul Lemmo, Sikorsky's president, said the design will reduce emissions, optimize engine performance, provide a quieter flight experience, improve safety of flight, and save on production and operating costs while contributing to sustainable flight. Lemmo called HEX “transformative for us.”
“We plan to apply learnings from HEX to both existing products and new aircraft in the future,” he said, adding that it will “serve as a testbed for demonstrating autonomy and hybrid propulsion, form the foundation for future product development across a range of configurations, and create opportunities for customer engagement and experimentation.”
Lemmo said HEX would be used to fulfill the goals of “three emerging mission concepts” that include advanced air mobility, agile logistics, and collaboration with uncrewed aerial systems (UAS), as well as incorporating safety-enhancing automation and flight controls for crewed and uncrewed applications.
Sikorsky is currently testing a 600-kilowatt motor being designed for the hybrid system and plans to place it in a testbed power plant system in 2025. According to Lemmo, the company tested first-generation electric motors and power electronics last year and already had conducted flight testing of a subscale proof-of-concept aircraft.
He said Sikorsky put a tilt-wing design in the mix, as well as more traditional-looking helicopters, to meet potential customer needs for both vertical and horizontal flight, and he made it clear that the company envisioned “a family of systems that are safer, more reliable, easier to maintain, and can fly farther and faster at lower cost” for both civil and military customers.
“Our future is not just confined to rotor blades,” Lemmo said, adding that HEX was one of two testbeds the Sikorsky Innovations team will be developing, building, and flying over the next five years.
Lemmo said Sikorsky remains committed to its compound, contra-rotating rotor X2 technology, even in light of the Army’s recent decision to cancel the future attack and reconnaissance aircraft (FARA) program, noting that the company had spent $1 billion developing it over the last 15 years. He added that there remains a possibility that Sikorsky’s entry in FARA, the RaiderX, could still fly since there are still unspent FARA funds.
“We have had multiple countries in Asia and Europe interested in the technology. We remain in dialogue with some of those countries about how this could proceed into a program for their next-generation helicopters,” Lemmo said. “We remain very enthusiastic about the technology and believe it's very mature. We built four generations of this aircraft. The X2 delivers unprecedented speed, range, and agility that no other helicopter in the world can match, and there's a lot of uses for that.”
Lemmo said Sikorsky continues to think X2 has applications for NATO’s Next Generation Rotorcraft requirement and that the company continues to work with the Italian ministry of defense and Leonardo to study the applicability of X2 technology for that country’s next-generation fast helicopter.