Unlike the fate of very small jets and other technology programs in the aerospace industry that got a plethora of attention both from within the industry and outside observers after being identified as "the next great" technology trend that would change flight as we know it, there is no doubt that UAVs are here to stay. No matter that drones in a simplistic form have been around almost since the Wright Brothers, UAVs as we know them today have evolved to encompass many intricate forms, missions, and applications.
QinetiQ is just one out of both established companies and start-ups that has invested much time and money into providing autonomy and independence to aircraft, particularly, at least most recently, its solar-powered high-altitude long endurance (HALE) Zephyr UAV.
“Zephyr is the world's first and only truly persistent aeroplane,” said Neville Salkeld, MD of QinetiQ’s U.K. Technology Solutions Group. "We’ve proved that this aircraft is capable of providing a cost-effective, persistent [electro-optic/IR] surveillance, and communications capability. Not only is Zephyr game-changing technology, it is also significantly more cost-effective to manufacture and deploy than traditional aircraft and satellites."
Billed as being easy to transport in a standard road transport container, once launched the Zephyr was designed to remain at altitudes in excess of 18 km above a general area for weeks, if not months, 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 refueling or servicing, which helps minimize the logistical supply chain, extending its operational capability and appeal. Its zero emissions contribute to an environmentally friendly footprint.
Most recently, a Zephyr was launched July 9 at the U.S. Army's Yuma Proving Ground in Arizona. It stayed aloft for 14 days and nights (336 h and 22 min) continuously, achieving the objective of the trial and setting a number of performance and altitude records. It was brought back down to Earth the morning of July 23.
For the trial in Yuma, Zephyr carried a communications payload configured to meet the needs of the U.K. Ministry of Defence. In addition to the obvious defense and security applications, commercial uses include environmental research, monitoring crops and pollution, providing tactical intelligence over disaster zones or forest fires, and delivering mobile communications capabilities in remote areas.
According to Chris Kelleher, QinetiQ’s Chief Designer, “Zephyr will transform the delivery of current services such as communications and lead to many new applications that 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 team brought this entire 'one-shot' flight together [to demonstrate] we can operate both the aircraft and its ultralight utility payload routinely for long duration flights.
“We’ve also had to design for temperatures of around plus 40ºC on the ground to below -75ºC at altitude [at] ever-changing weather systems including storms and high winds—and Zephyr took them all in its stride.”
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, 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.
For its work and achievements, QinetiQ rightly wants some recognition. An official from the Federation Aeronautique Internationale (FAI), the world air sports federation, monitored the tests at Yuma. After the Zephyr was back on the ground, QinetiQ filed for three new world records from FAI, including quadrupling its own unofficial world record for longest duration unmanned flight (82 h, 37 min, set in 2008) and surpassing the current official world record for the longest flight for an unmanned air system (set at 30 h, 24 min by Northrop Grumman's RQ-4A Global Hawk in March 2001).
Zephyr also is believed to have flown longer, nonstop and without refueling, than any other aircraft—having significantly passed the Rutan Voyager milestone of 9 days (216 h, 3 min, and 44 s airborne) set in December 1986.
Around 50% larger than the previous version, the most recent incarnation of Zephyr incorporates an entirely new wing design with a total wingspan of 22.5 m 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 ultralightweight carbon fiber design allows it to weigh in at just over 50 kg.