Quarterhorse
Overview
An iterative program of unmanned, remotely piloted test aircraft designed to unlock high-speed flight one step at a time. Hermeus says the Quarterhorse program spans four aircraft, each purpose-built to validate a specific technical challenge and feed the next build.
Mk 1 flew at Edwards AFB in May 2025. Mk 2.1, roughly F-16-sized and powered by a Pratt & Whitney F100, flew in February 2026 and on its third flight from Spaceport America hit Mach 1.21 on May 26, 2026, becoming the first privately-developed unmanned supersonic jet and clearing FAA approval for up to seven supersonic flights through year-end. Hermeus says Mk 2.2 is in build and targeted to reach Mach 1.6 in summer 2026, with Mk 2.3 aiming for Mach 3 in 2027 and a Chimera-powered hypersonic Mk 3 before 2030.