Solar-powered loitering UAV a "go"

The Boeing Co. on Sept. 14 signed an agreement with the Defense Advanced Research Projects Agency (DARPA) to develop and fly the SolarEagle unmanned aircraft for the Vulture II demonstration program.

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The Boeing Co. (Chicago, Ill.) on Sept. 14 signed an agreement with the Defense Advanced Research Projects Agency (DARPA, Arlington, Va.) to develop and fly the SolarEagle unmanned aircraft for the Vulture II demonstration program. Under the terms of the $89 million (USD) Vulture II agreement, Boeing will develop a full-scale flight demonstrator, including the critical power system and structures technologies. Key suppliers for the program include Versa Power Systems (Littleton, Colo.) and QinetiQ North America Operations (McLean, Va.). SolarEagle will make its first demonstration flight in 2014.

According to Boeing’s Pat O’Neil, Boeing Phantom Works program manager for Vulture II, the SolarEagle is a large unmanned aircraft designed to remain, eventually, on station at stratospheric altitudes for at least five years. “That’s a daunting task,” O’Neil admits, but he contends that “Boeing has a highly reliable solar-electric design that will meet the challenge in order to perform persistent communications, intelligence, surveillance and reconnaissance missions from altitudes above 60,000 ft [18,288m].”

The goals for the SolarEagle demonstrator concept include the capacity to remain aloft in the upper atmosphere for 30 days, harvest solar energy during the day, store that energy in fuel cells and use the stored energy through the night. The aircraft will have highly efficient electric motors and propellers and a high-aspect-ratio, 400-ft/122m wing that will permit a very large wing-mounted solar collection array as well as superior aerodynamic performance.

SolarEagle is one of Phantom Works’ several rapid prototyping efforts. Others include Phantom Ray, a fighter-sized, unmanned advanced-technology demonstrator, and the hydrogen-powered Phantom Eye demonstrator, a HALE (high-altitude, long-endurance) aircraft designed to stay aloft for up to four days. Both are scheduled for first flights in 2011.

Meanwhile, the composites-intensive Solar Impulse aircraft made its first flight across Switzerland on Sept. 22, powered solely by solar energy. The prototype, built by Solar Impulse SA (Lausanne, Switzerland) and piloted by André Borschberg, flew from its base in Payerne to Geneva International Airport and back twice in two days. Borschberg, Solar Impulse CEO and cofounder, says “The Swiss solar flights represent a major step forward for our team, taking us away from our customary airspace.” The next major milestones for Solar Impulse are international flights scheduled for next year, a transatlantic flight in 2012, and circumnavigation of the world in 2013, says the team.