October 30, 2007 The Boeing Company has achieved a milestone in the development of its High Altitude Long Endurance (HALE) unmanned aircraft by successfully testing a hydrogen propulsion system in simulated conditions of 65,000 feet. The test, conducted over more than three days using a Ford Motor Company-developed hydrogen engine (a gasoline version of which can be found in the Ford Fusion and Escape Hybrid) is a further step towards the realization of a UAV designed to remain airborne for more than seven days and carry multi-sensor payloads of up to 2,000 pounds.

"This test demonstrates the technical readiness of the hydrogen engine system and confirms the capability breakthrough in flight endurance and altitude that could be realized by a variety of military and commercial customers," said Darryl Davis, vice president and general manager, Boeing Advanced Precision Engagement and Mobility Systems.

Because the the long endurance, propeller-driven autonomous aircraft will be able to maintain a continuous presence over a specific ground location from stratospheric altitudes, its potential applications include border observation, port security and telecommunications as well as battlefield intelligence and surveillance.

The turbocharged internal combustion engine achieved better than expected fuel economy while demonstrating complete airflow and torque control across the engine's operating range.

Boeing is collaborating with Aurora Flight Sciences and Ford to develop the HALE aircraft's propulsion system.

Related reading: AeroVironment’s Global Observer liquid hydrogen powered UAV.