Boeing has conducted the second test flight of its Phantom Eye unmanned combat air vehicle (UCAV) to demonstrate its long-range endurance capabilities at Nasa's Dryden Flight Research Center at Edwards Air Force Base (AFB) in California, US.
During testing, the liquid hydrogen-powered UCAV was able to carry out intelligence, surveillance and reconnaissance (ISR) operations at higher-altitudes for up to four days without refuelling.
Climbing above an altitude of 8,000ft, the UCAV stayed airborne for 66 minutes at a cruising speed of 62k before landing, eventually bettering the results of its initial test flight.
Phantom Eye had remained aloft for 28 minutes, at speeds of up to 62k, after reaching an altitude of 4,080ft during the first test flight in June 2012.
Boeing Phantom Works president Darryl Davis said the Phantom Eye's capabilities, affordability and flexibility are expected to attract global customers, despite the current combination of geopolitical and economic issues.
"No other system holds the promise of offering on-demand, persistent ISR and communications to any region in the world, rapidly responding to natural disasters and national security issues," Davis added.
Phantom Eye programme manager Drew Mallow said: "This flight, in a more demanding high-altitude flight envelope, successfully demonstrated Phantom Eye's manoeuvrability, endurance and landing capabilities."
The UCAV had successfully completed taxi testing at Edwards AFB earlier this month.
Designed and manufactured by Boeing Phantom Works under a self-funded programme, Phantom Eye is a high-altitude long-endurance (HALE) designed to assist the US military in conducting ISR missions in Afghanistan.
Featuring a wing-span of 150ft, the fixed-wing UAV will cruise at 150k, carry up to 450lb and stay aloft at altitudes of 65,000ft for up to four days, while performing surveillance across a large area.
Image: Phantom Eye UAS during its second test flight at Nasa's Dryden Flight Research Center at Edwards AFB in California, US. Photo courtesy of Boeing.