General Atomics Aeronautical Systems Inc (GA-ASI) has completed the final qualification test for its new 200 hp heavy fuel engine at its flight test facility at El Mirage in California, the company announced on 19 November 2024.
The Heavy Fuel Engine (HFE) 2.0 has been designed as a highly reliable low-maintenance engine for unmanned aerial vehicles (UAVs) with a 40% increase in service life, providing longer maintenance-free operational periods. The engine will provide the horsepower and electrical power required to meet the demanding performance needs of GA-ASI’s new Gray Eagle 25M medium-altitude, long-endurance (MALE) UAV for multi-domain operations (MDO).
The three-week qualification testing of the HFE 2.0 engine, which was concluded on 13 November 2024, is aligned with the Federal Aviation Administration’s endurance test requirements (FAA 14 CFR 33.49) as the FAA’s primary performance standard for engines to be used in commercial aviation.
“Over the last 18 months HFE 2.0 excelled in strenuous durability testing that included 2,450 full power cycles simulating high-stress conditions during three extensive test profiles of 200, 400, and 651 hours,” GA-ASI stated. “Additionally, the engine completed 50 hours of flight testing across the flight envelope.”
GA-ASI President David R Alexander stated that the final qualification test was “the culmination of the extensive durability and flight test programme for the HFE 2.0 engine”, adding, “It’s been great to see the outstanding test results that have validated the design and development of the HFE 2.0 engine we have worked on so passionately for the past seven years and to bring this world-class engine to the Gray Eagle fleet.”
GA-ASI and its General Atomics Europe affiliate partnered with global leaders in high-performance engines – supported by propulsion technology innovator Cosworth – to develop an engine through the company’s internally funded research and development programme. GA-ASI also brought in General Atomics Electromagnetic Systems to design and build the engine’s dual brushless generator, which will dramatically reduce field maintenance and is designed to be a drop-in replacement for the existing generator. The enhanced generator will deliver over 50% more electrical power to support newly available payloads for the MDO mission.
After completion of the FAA engine endurance test for the HFE 2.0, the next steps call for the US Army certification process to allow authorisation of the engine for use on the existing fleet of GA-ASI Gray Eagle Extended Range (GE ER) UAVs as a replacement for their 180 hp engines, which are reaching the end of their service lives.
The HFE 2.0 is also the cornerstone of the modernised Gray Eagle 25M UAV currently being produced under a US Army-funded programme to support future MDO UAV missions.
