General Atomics Aeronautical Systems, Inc. (GA-ASI) conducted the first flight of its new 200-horsepower heavy fuel engine on a Gray Eagle aircraft at its El Mirage flight facility on May 9, 2023. The Heavy Fuel Engine (HFE) 2.0 is being considered by the U.S. Army to become the fleet replacement for the current 180-horsepower engine used by the Gray Eagle Extended Range (GE-ER) Unmanned Aircraft System (UAS). HFE 2.0 is also the cornerstone of the modernized Gray Eagle 25M (GE-25M) aircraft currently being developed under a U.S. Army-funded program to support future Multi-Domain Operations (MDO) missions.

GA-ASI initiated the Internal Research and Development program that led to HFE 2.0 in 2016 with the goal of designing and developing a more reliable and durable engine that would also address diminishing manufacturing sources for aviation heavy fuel engines and components. GA-ASI and its affiliate General Atomics Europe partnered with global leaders in high-performance engines—supported by propulsion technology innovator Cosworth—to develop an engine with increased horsepower, durability, and reliability. GA-ASI also brought in General Atomics Electromagnetic Systems (GA-EMS) to design and build the engine's dual brushless generators, which will dramatically reduce field maintenance and deliver over 50 percent more electrical power for new payloads and mission capabilities.

"We're very excited to see GE-ER powered by this new state-of-the-art propulsion system," said GA-ASI President Dave Alexander. "In order to ensure the highest reliability and durability, we brought together a world-class team from across industry and leveraged our extensive HFE experience to deliver this solution. We're proud to make this engine available to our U.S. Army customer."

The design effort was focused on reducing field maintenance and extending the time between engine replacement by 40 percent over the current engine.

HFE 2.0 will continue to undergo planned IRAD flight tests and begin qualification testing this year.