QinetiQ Group PLC (Farnborough, Hampshire, U.K.) reported in July that its composite-airframed Zephyr, a solar-powered, high-altitude/long-endurance (HALE) unmanned air system (UAS), stayed aloft for more than two weeks, exceeding by a large margin the previous UAS record of 30 hours, 24 minutes set in 2001 by Northrop Grumman’s RQ-4A Global Hawk. Launched by hand (see photo) on July 9 at the U.S. Army’s Yuma Proving Ground in Arizona, Zephyr landed on July 23.

QinetiQ claims its “eternal” aircraft has the potential to provide low-cost, persistent surveillance capability over a period of months rather than days, supporting Earth observation and communications relay in a range of defense, security and commercial applications. According to the company, this potential owes much to a breakthrough design that incorporates an entirely new, uniquely shaped 22.5m/74-ft wing and “T” tail.

Advanced Composites Group Ltd. (ACG, Heanor, Derbyshire, U.K.) supplied MTM45-1 carbon fiber/epoxy prepregs for the wing and fuselage frames. This variable-cure-temperature toughened epoxy system, which is optimized for low-pressure vacuum bag processing, also can be autoclave-cured. Zephyr’s two propellers are driven by electric motors, powered by day via wing-mounted, paper-thin amorphous silicon solar arrays. The arrays also recharge lithium-sulphur batteries, supplied by Sion Power Inc. (Tucson, Ariz.), which power the motors at night. The solar power system and lightweight composite structure (total weight slightly more than 50 kg/110 lb) results in an extremely high power-to-weight ratio throughout the day/night cycle, delivering persistent on-station capabilities.