About Featured Expert: Hermeus

Hermeus develops high-Mach and hypersonic aircraft technologies for defense and national security applications. Its work brings together aircraft design, propulsion, autonomous flight systems, advanced manufacturing and flight testing within a development approach centered on building and flying progressively more capable vehicles.

The company’s Quarterhorse program is structured as a series of uncrewed aircraft, with each vehicle used to validate specific technical requirements and inform the next stage of development. Quarterhorse Mk 1, powered by a GE J85 engine, completed flight testing at Edwards Air Force Base in May 2025. The aircraft was developed to demonstrate high-speed takeoff and landing and to validate the flight controls, ground operations and supporting systems required for later high-Mach platforms. Quarterhorse Mk 2.1 marked the next major step in that progression. Powered by a Pratt & Whitney F100 engine and comparable in scale to an F-16, the aircraft completed its first flight in March 2026 and achieved supersonic flight in May 2026. The current Quarterhorse series is being used to expand flight performance and collect aerodynamic, propulsion, structural and control-system data at increasingly higher speeds.

Hermeus - Featured Expert Logo - Aerospace Technology MonthlyHermeus is also advancing turbine-based combined-cycle propulsion through its Chimera engine architecture. Chimera combines a turbine engine with a ramjet, allowing the aircraft to operate from conventional runways, accelerate through the supersonic range and transition to ramjet propulsion at higher speeds. The company has also developed inlet precooler technology to reduce the temperature of incoming air as flight speed increases, extending the operating range of the turbine engine. These propulsion and aircraft-development programs support Hermeus’ longer-term work on Darkhorse, a planned reusable hypersonic uncrewed aircraft for defense and national security missions. Darkhorse is being developed around Chimera II, a larger turbine-based combined-cycle system that incorporates the Pratt & Whitney F100 engine core.

The company supports these programs through vertically integrated engineering, manufacturing, avionics, software and test operations. Its Atlanta headquarters houses primary engineering, manufacturing and operations teams, while its Los Angeles facility supports complex engineering, analysis and subassembly work. In Jacksonville, Florida, the High Enthalpy Air-Breathing Test facility is being developed for engine and propulsion-subsystem testing, including the F100 and Chimera systems.

Hermeus’ broader expertise lies in connecting propulsion development, aircraft integration and frequent flight testing within the same program structure. That approach allows technical findings from one vehicle to move directly into the design and operation of the next, while building the systems, facilities and manufacturing experience required for increasingly capable high-speed aircraft.

Founded in 2018 and headquartered in Atlanta, Georgia, Hermeus maintains additional operations in Jacksonville, Los Angeles, Washington, D.C., and New Mexico. Its expertise spans high-speed aerodynamics, turbine-based combined-cycle propulsion, autonomous aircraft systems, advanced manufacturing and flight testing. To learn more about Hermeus and its work in high-Mach aircraft development, please click here.

(Editor’s Note: All trademarks mentioned in this article, including company names, product names, and logos, are the property of their respective owners. Use of these trademarks is for informational purposes only and does not imply any endorsement.)

Molly Bakewell Chamberlin
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