Hermeus Selects P&W F100 for Hypersonic Darkhorse

 - December 20, 2022, 10:37 AM
Hermeus has selected the Pratt & Whitney F100 turbofan for the turbine portion of its hybrid engine, Chimera II, which will power its Mach 5 Darkhorse uncrewed aerial system. (Photo: Hermeus)

Atlanta-based hypersonic aircraft startup Hermeus has selected the Pratt & Whitney F100 turbofan to integrate into its larger hypersonic engine. The company said the off-the-shelf turbine engine will save it “billions of dollars in research and development costs and years of schedule.”

The F100 turbofan—which recently marked 50 years of service and 30 million flight hours on F-15 and F-16 fighters—will act as the turbine portion of Hermeus’s combined cycle engine named Chimera II, which will be used to power Darkhorse, a Mach 5 hypersonic UAV being developed for defense and intelligence customers. Engine testing is scheduled for 2024. Darkhorse will provide the foundation for the eventual development of the 20-seat Halcyon Mach 5 passenger aircraft.

Chimera II is a turbine-based combined cycle engine that is a hybrid between a turbine and a ramjet, a design that provides for both low-speed and high-speed operation and will allow Darkhorse to use existing airports, something that rocket-based hypersonic vehicles cannot do. The hybrid design is an extension of the smaller Chimera engine Hermeus built for its Quarterhorse demonstration aircraft, which it expects to fly next year. That engine uses the GE J85 engine for its turbine section.

Once the aircraft reaches Mach 3, the engine will bypass incoming air around the turbojet, enabling the ramjet to take over.