There’s a new world record for the longest flight time: 83 hours:

QinetiQ’s Zephyr breaks flight time record for unmanned aircraft

QinetiQ claimed Sunday that its propeller-driven aircraft called Zephyr flew for 83 hours and 37 minutes nonstop, more than doubling the official world record set by Northrop Grumman’s Global Hawk in 2001.

The airplane weighs only 66 pounds. It has solar cells and lithium-sulfur batteries so it can fly at night. It went as high as 60,000 feet.

Even though it weighs so little, it has an 18-meter wingspan and everything possible has been done to remove weight:

Solar plane makes record flight (with video)

Its structure uses ultra-lightweight carbon-fibre material; and the plane flies on solar power generated by amorphous silicon solar arrays no thicker than sheets of paper. These are glued over the aircraft’s wings.

To get through the night, the propellers are powered from lithium-sulphur batteries which are topped up during the day.

“A lot of effort has gone into power storage and light-weighting the systems,” explained Mr Kelleher. “Lithium sulphur is more than double the energy density of the best alternative technology which is lithium polymer batteries.

See also: QinetiQ says it has broken unmanned flight record

[See WR #41]