The endurance record for an unmanned aerial vehicle flight now officially belongs to Zephyr, the solar powered UAV built by Qinetiq, according to the Fédération Aéronautique Internationale (FAI).

Record claims have been verified by FAI for both duration -- 336h and 22min -- and altitude -- 70,741.5ft -- for the 9 through to 23 July flight.

It handily beat the previous endurance record for unmanned flight, held by the RQ-4A Global Hawk, which stood at 30h and 24min.

Zephyr also passed the Rutan Voyager's record for longest flight by an airplane without refuelling -- 216h, 3min and 44s -- set in December 1986.

An earlier version of the Zephyr logged an 82h 37min sortie in 2008, but the flight was not officially recorded.

Already flown as a 6m (19.7ft) wingspan subscale demonstrator, the new Zephyr design weighs 53kg (117lb) and has a 22.5m (73.8ft) wingspan -- 4m wider than the previous iteration. Its wing area also has been increased by 50 percent by using a wider chord, and new winglets provide improved lift. A new T-tail configuration has also been adopted as a drag-reduction measure.

The new wing houses rechargeable lithium sulphur batteries supplied by Arizona-based Sion Power, with these charged by wing-mounted solar arrays. The UAV also got a new power management system, where individual batteries can be switched off to conserve energy.

Following a dawn hand launch by five people from a test range in Yuma, Arizona, Zephyr climbed to 10,000ft before its autopilot was engaged and it began harvesting solar energy.

For three 8h shifts, a pilot, navigator and flight engineer monitored battery performance and meteorological conditions for the duration of the sortie. The UAV carried a communications payload which could be used by the UK Ministry of Defence on such high-altitude, long-endurance flights.

Source: Flight International