In a historical first, RTX subsidiary Pratt & Whitney has signed a licensing deal with another company to manufacture the F100-PW-229 engine.
The agreement will see Hermeus, a startup developing aerospace hypersonic platforms, obtain the right to assemble its own F100 engines.
Hermeus uses the F100 engine, which powers the F-15 and F-16 fighter jet series, as part of the mechanism that will enable the Quarterhorse family of unmanned aircraft to reach high Mach speeds.
The startup is developing its own engine, called “Chimera”, which combines a precooled F100 engine with a ramjet. This is because the ramjet, which is a type of engine with no moving parts designed for very high supersonic speeds, needs acceleration before it can generate thrust.
Once fully developed, Chimera is expected to power the upcoming versions of the Quarterhorse aircraft. So far, Hermeus has successfully tested Quarterhorse Mk 1, which uses a GE J85 jet engine, and Quarterhorse Mk 2 and Mk 2.1, which are fitted with a precooled F100 but not yet a ramjet component.
Quarterhorse Mk 2.1 broke the sound barrier for the first time on May 26, 2026, hitting Mach 1.21 during a flight test over the White Sands Missile Range, New Mexico.
Besides the implications for Hermeus’ industrial plan, the two companies highlighted the agreement for the diversification and expansion of US advanced manufacturing capabilities in the field of defense.
“Meeting future operational needs requires expanding America’s capacity to build the engines our warfighters rely on,” said Zach Shore, CEO of Hermeus in a press release issued on September 15, 2026. “Pratt & Whitney built the standard for fighter propulsion. By becoming a licensed manufacturer of the F100, Hermeus expands domestic engine capacity for the broader defense industrial base and becomes one of the few vertically integrated airframers with the in-house propulsion capability required to scale Quarterhorse.”