While the wind-powered Greenbird waits for favorable conditions before its land-speed record attempt, another British craft was proclaimed a record-breaker yesterday. The Zephyr-6, a solar-powered plane, flew nonstop for 82 hours and 37 minutes, according to its UK makers.
The propeller-driven craft runs on solar energy, and charges lithium-sulfur batteries by day to keep it aloft at night. Its solar arrays are paper thin and glued to its pair of 30-foot wings. On July 28, three guys hand-launched Zephyr with a running start. Remote controls then guided the plane to its cruising altitude, where a combination of autopilot and satellite correction kicked in until it descended July 31.
The clocked flight soared past the previous record for an unmanned trip (30 hours, 24 minutes), but won’t enter the books. Since this was just a trial run, QinetiQ didn’t try to meet all of the criteria mandated by the Federation Aeronautique Internationale for an official record.
However, the test demonstrated to the US and UK military planners that the super-light 145-pound craft could carry more than four pounds of payload up to 60,000 feet – twice as high as most commercial airliners.
This would see the biggest plane in history take to the sky, powered by the sun and capable of carrying a 450-kilo (1,000-lb.) payload. US commanders say the design must be able to maintain its position over a particular spot on the Earth's surface uninterrupted for five years.
If successful, Zephyr-6's descendants could redefine surveillance:
"The principal advantage is persistence – that you would be there all the time," he told BBC News. "A satellite goes over the same part of the Earth twice a day - and one of those is at night - so it's only really getting a snapshot of activity. Zephyr would be watching all day."
A final Zephyr could be ready to launch in two years.