LE BOURGET—A stealthy flying wing aircraft powered by a hybrid diesel-electric engine will be built and flown by General Atomics Aeronautical Systems Inc. (GA-ASI) by 2026 to demonstrate a new level of endurance for future uncrewed combat air vehicles (UCAVs), CEO David Alexander said June 21. 

The newly revealed plans to build and fly the 13,000-lb. Gambit 4 come several months after GA-ASI detailed the configuration of the unique hybrid propulsion system and long-endurance, stealthy Gambit 4 UCAV.

“We want to fly it,” Alexander said, speaking to Aerospace DAILY at the Paris Air Show here. “You won’t be able to get that next step unless you get up there and show it works.”

GA-ASI intends to self-fund the Gambit 4 prototype through initial flight testing, then use the results to search for external funding sources, Alexander said. 

The Gambit 4 proposes an advanced new propulsion system, with the Heavy Fuel Engine (HFE) 2.0 as the basis for the prime mover of electric thrusters. The HFE itself is derived from the Thielert Centurion, an aircraft propulsion variant of the Mercedes-Benz OM668 automotive engine.

The 400-hp HFE 2.0 will deliver about 360 kW of power to electric motors, with a pair of 50-kW boosters available for takeoff power and payloads. 

The combination of the propulsion system and the aerodynamic design of the Gambit 4 should produce an aircraft with about 60 hr. of endurance.

The Gambit 4 design marks a departure from the rest of GA-ASI’s Gambit series, which includes members focused on strike, surveillance and training missions. The first three members are based on a common chassis and avionics system, with interchangeable wings, inlets and exhaust systems depending on the mission. 

The Air Force Research Laboratory selected GA-ASI in 2021 to develop the Off-Board Sensing Station (OBSS). The program intends to test an uncrewed aircraft system with interchangeable features.