Hermeus Corporation

Hermeus was founded in 2018 by four engineers out of Generation Orbit who wanted to build an aircraft that could cross the Atlantic in ninety minutes. The technical bet was propulsion. Chimera, the company's turbine-based combined cycle engine, precools incoming air so a conventional fighter turbojet can keep running well past its normal limit, then routes the flow around that core and lets a ramjet carry the vehicle onward from roughly Mach 3. A prototype demonstrated that turbojet-to-ramjet transition on a ground test stand in 2022, and a second generation Chimera II built around the Pratt and Whitney F100 is the engine meant to push a vehicle past Mach 3.3. Every aircraft on the roadmap descends from that one piece of hardware.

Quarterhorse is the uncrewed flight test line and the near-term business. Mk 0 was a ground rig. Mk 1 flew at Edwards Air Force Base in May 2025 to prove out the landing gear, the autonomy and the takeoff and landing approach. Mk 2.1 first flew on 2 March 2026 and went supersonic on 26 May at Mach 1.21, with Mk 2.2 and Mk 2.3 stepping toward Mach 3 in 2027 and Mk 3 carrying the full Chimera II. The customer is the Defense Innovation Unit. A modification in May 2026 scaled the HyCAT agreement to 219 million dollars, one of the largest awards DIU has made, and it buys repeated high-Mach sorties plus payload carriage and release rather than a single record run. Anduril joined in September 2026 to supply mission autonomy.

Darkhorse is the weapons-relevant design, an uncrewed aircraft intended for volume production and powered by F100-derived Chimera engines for speeds above Mach 5 with a useful payload. Ramjet-X, announced in September 2026, is the cheap end of the same idea, an expendable ramjet test vehicle air-launched from Quarterhorse at around Mach 3 so that seekers, thermal management and mission systems get flown often instead of modeled. The Mission Plane is the larger multipurpose high-Mach platform the company points to beyond those. An earlier passenger aircraft concept called Halcyon still frames how the founders describe the long arc, though the funded work today is military.

Engine manufacturing became a business of its own in September 2026, when Pratt and Whitney licensed Hermeus to build the F100-PW-229, the first time Pratt has granted that license to another American company. It makes Hermeus a second source for an engine that powers F-15 and F-16 variants, against an Air Force projection of more than 180 units a year by fiscal 2034, and it hands the aircraft line control of its own powerplant supply. The company raised a 350 million dollar Series C in April 2026 at a valuation of 1 billion dollars, 200 million in equity led by Khosla Ventures with RTX Ventures, Founders Fund and In-Q-Tel, alongside 150 million in debt, and moved its headquarters from Atlanta to the Los Angeles area at the same time. Atlanta kept its roughly 175 staff and became the production site. Headcount runs near 300 across Atlanta, Los Angeles, Jacksonville and Washington. Zach Shore took over as chief executive in May 2026, with founder AJ Piplica moving to executive chairman.