Boeing's Phantom Works offered a first glimpse of Phantom Eye, the hydrogen-powered unmanned demonstrator built to stay aloft at 65,000ft (19,800m) for up to four days at a time, on 12 July in St. Louis, Missouri.

In September, Phantom Eye will move to NASA's Dryden Flight Research Center at Edwards AFB, California, to begin a series of ground and taxi tests in preparation for its maiden flight in the first quarter of 2011. The debut flight is expected to last 4-8h.

"We still have a ways to go," says Drew Mallow, Phantom Eye programme manager, including continuing wing testing, integration work and one additional structural test.

PhantomEye Unveil 
 © Boeing

Boeing's Phantom Works has been pushing hard to maintain a stringent self-imposed schedule, Mallow says, demonstrating not only the technology but also Boeing's rapid prototyping abilities.

"It is a perfect example of turning an idea into a reality. It defines our rapid prototyping efforts and will demonstrate the art-of-the-possible when it comes to persistent intelligence, surveillance and reconnaissance," says Darryl Davis, president of Boeing Phantom Works. "Phantom Eye is the first of its kind and could open up a whole new market in collecting data and communications."

Phantom Eye has a 45.7m (150ft) wingspan, will cruise at around 150kt (277km/h) and can carry up to a 205kg (450lb) payload. It is powered by two 2.3-litre, four-cylinder engines originally designed for a Ford Ranger pick-up truck, each with 150hp (111kW).

"The hydrogen propulsion system will be the key to Phantom Eye's success," Mallow says. "It is very efficient and offers great fuel economy, and its only by-product is water, so it's also a 'green' aircraft."

The engines and propulsion system have undergone component testing in an altitude chamber, says Bill Norby, hydrogen systems integration manager, making sure the aircraft will be able to maintain combustion at such a high altitude for long periods of time.

"One of the most vexing problems to solve so far was the oil consumption with the new turbo charger," he says. "It was not a difficult problem to solve, but it was time consuming to work through the data, balancing pressure and capacity."

Source: Flight International