Hermeus Maps Path to Mach 5 Jet
The company detailed each Quarterhorse prototype it has flown and will build before its planned production aircraft.
Updated on Nov. 8, 2026 in Quantum Computing
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Hermeus has laid out each prototype it has made and will make before its production jet, following a Quarterhorse Mk 2.1 that reached Mach 1.6 in later flights after first going supersonic in May 2026. The production aircraft is intended to reach Mach 5 (3,800 mph).
Why it matters
The sequence of prototypes shows how the company plans to move from ground runway tests to supersonic flight and eventually to hypersonic-class speeds. Its progress is measured against the long-standing goal of reducing travel times on routes such as London to New York.
The Quarterhorse Mk 2.1 uses a Pratt & Whitney F100 engine and reached Mach 1.21 (928 mph) in May 2026 before later flights hit Mach 1.6 (1,227 mph). The Mk 2.2 began testing in September 2026 with the Gryphon precooler-turbine system, and the timeline for the Mk 2.3 and Mk 3 remains unspecified.
The players
Hermeus
Hermeus is an American aerospace company developing hypersonic and supersonic aircraft, including the Quarterhorse prototype series.
The details
Hermeus has built and tested a series of Quarterhorse prototypes, beginning with the Mk 0, which ran up and down the runway over 37 days in late 2023 with a General Electric J-85 engine. The Mk 1 flew over Edwards Air Force Base in spring 2025 to inform controls during takeoff, flight, and landing. Upcoming prototypes will test thermal management and the Chimera II combined-cycle system planned for the Mk 3.
Timeline
Late 2023: Quarterhorse Mk 0 completes its testing period.
Spring 2025: Quarterhorse Mk 1 flies at Edwards Air Force Base.
May 2026: Quarterhorse Mk 2.1 reaches supersonic speeds.
September 2026: Quarterhorse Mk 2.2 begins testing with the Gryphon system.
November 2026: Hermeus details its prototype family tree.
The Tech Race
Hermeus's Gryphon is a precooler-turbine built on the Pratt & Whitney F100 engine, a design that extends an existing military turbofan toward supersonic and hypersonic flight. The company's path from the F100-based Mk 2.1 to the Chimera II combined-cycle system for the Mk 3 marks a departure from purely turbojet-based prototypes.
The program's progress points toward faster air travel, with the production jet targeting Mach 5 and the London to New York trip cut from about 8 hours to roughly 1.5 hours. A civilian version is no longer in play in the foreseeable future, so the near-term benefit is limited to the military and development timelines.
The takeaway
Hermeus's staged prototype approach shows how a hypersonic-class program can be built up through incremental flight tests. Readers following aerospace progress can track each milestone as the company moves toward its production aircraft.
Further reading
Explore more on Quantum Computing developments shaping the next generation of computing.
Source note: This article includes information reported by Autoevolution.
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