After 14 nights in the air, QinetiQ prepares to land its Zephyr solar powered unmanned aircraft

Zephyr was launched on 09 July and is currently still flying above the US Army's Yuma Proving Ground in Arizona. Today Zephyr will have been aloft for 14 nights continuously, achieving the objective of the trial and setting a number of performance and altitude records. At this point QinetiQ's Zephyr team in Yuma will bring the aircraft back to earth.

An official from the Federation Aeronautique Internationale (FAI), the world air sports federation, has been monitoring progress at the Yuma Proving Ground and when Zephyr is back on the ground he looks set to be able to confirm a number of new world records. This includes quadrupling its own unofficial world record for longest duration unmanned flight (82 hours, 37 minutes set in 2008) and surpassing the current official world record for the longest flight for an unmanned air system (set at 30 hours 24 minutes by Northrop Grumman's RQ-4A Global Hawk on 22 March 2001). Zephyr will also have flown longer, non-stop and without refuelling, than any other aeroplane - having significantly passed the Rutan Voyager milestone of 9 days (216hours) 3 minutes and 44 seconds airborne, set in December 1986.

"Zephyr is the world's first and only truly persistent aeroplane," said Neville Salkeld, MD of QinetiQ's UK Technology Solutions Group. "We are really proud of the team's achievement which has been supported by expertise from across the QinetiQ business and beyond. We've now proved that this amazing aircraft is capable of providing a cost effective, persistent surveillance and communications capability measured in terms of weeks, if not months. Not only is Zephyr game-changing technology, it is also significantly more cost effective to manufacture and deploy than traditional aircraft and satellites."

Easy to transport in a standard road transport container, once launched Zephyr can remain above a general area for weeks, if not months, at a time delivering vital capability at a fraction of the cost of satellites and significantly more cost effectively than other ‘conventionally powered' manned or unmanned aircraft. Zephyr also does not need to return to base at regular intervals for re-fuelling or servicing which helps minimise the logistical supply chain, extending its operational capability and appeal. Its zero emissions also make it exceptionally environmentally friendly.

For the trial in Yuma Zephyr is carrying a communications payload configured to meet the needs of the UK Ministry of Defence. In addition to the obvious defence and security applications, commercial uses include environmental research; monitoring crops and pollution; providing tactical intelligence over disaster zones or forest fires; plus delivering mobile communications capabilities in remote areas.

Chris Kelleher, QinetiQ's chief designer said: "We have designed, built and delivered what will be remembered as a milestone in aviation history. Zephyr will transform the delivery of current services such as communications, and lead to many new applications which are not possible or affordable by other means.

"The brand-new ‘production ready' Zephyr airframe incorporates totally new approaches to aerodynamics, structures, propulsion, avionics, flight controls, power system management, thermal control, ground control station design and payload, as well as overall operating processes. Our outstanding team has brought this entire 'one-shot' flight together at the first time of asking, demonstrating we can operate both the aircraft and its ultra-light utility payload routinely for long duration flights.

"We've also had to design for temperatures of around plus 40ºC on the ground to below minus 75ºC at altitude, ever changing weather systems including storms and high winds - and Zephyr took them all in its stride. It is a truly fantastic achievement."

Launched by hand, the aircraft flies by day on solar power delivered by amorphous silicon solar arrays, supplied by Uni-Solar, no thicker than sheets of paper that cover the aircraft's wings. These are also used to recharge the lithium-sulphur batteries, supplied by Sion Power Inc, which are used to power the aircraft by night. Together they provide an extremely high power to weight ratio on a continuous day/night cycle, thereby delivering persistent on station capabilities.

Around 50% larger than the previous version, Zephyr incorporates an entirely new wing design with a total wingspan of 22.5m to accommodate more batteries that are combined with a totally new integrated power management system. The entirely new aerodynamic shape also helps to reduce drag and improve performance. Zephyr's ultra-lightweight carbon fibre design means it weighs in at just over 50Kg.