For all the advancements made in solar power technology, developing an airplane that could harvest enough of the sun's energy to not only be flown for extended periods, but take another person along for the ride has proven a difficult task. The team at Solar Flight recently took on this challenge, unveiling its plans for what would be the world's first two-seater solar aircraft, the Sunseeker Duo. Today, the company announced that it has spent the last few months testing the plane's flight performance and the results hold some promise for helping achieve its lofty ambitions.

Solar Flight's latest endeavor first caught our attention back in October 2012, when project leader Eric Raymond announced plans to manufacture a solar airplane powerful and aerodynamic enough to carry two people. A successful Kickstarter campaign has brought Raymond one step closer to fulfilling this vision, completing construction and taking flight with the Sunseeker Duo on December 17, 2013.

In the time since, the team has tested the different aspects of the plane's performance such as monitoring the battery system, motor, propeller, folding hub mechanism and landing gear retraction systems. Some instability during unpowered test flights was initially observed, prompting the addition of extra solar cells to the horizontal stabilizer.

Solar Flights now reports that the craft has good control authority both in the air and on the ground and outperforms its previous iteration, the Sunseeker II, in every aspect. The company says that the Duo is capable of cruising directly on solar power with two people for periods of 12 hours or more.

The Sunseeker Duo has a wingspan of 22 meters (72 ft) and weight of 280 kg (617.3 lb). 1,510 solar cells line the wings and tail surfaces, gathering the sun's energy to be stored in the lithium-polymer battery pack located in the fuselage. The plane's motor has a maximum output of 25 kW, more than the team had initially hoped for.

"The lithium batteries today have seven times more capacity than the nickel cadmium batteries we used in Sunseeker I," says Raymond. "When we first sketched the concept for this airplane, we couldn’t imagine solar cells with greater than 20 percent efficiency. These technologies are a dream come true."

The focus of Solar Flights in developing the Sunseeker Duo has not only been to overcome several design and technological challenges, but to produce something that can serve as a high performing, practical aircraft.

"We are working very hard to have the airplane tested and ready for passenger flights by this summer," says Irene Raymond, the wife and project partner of Eric. "No sight is more captivating than Earth from above. It will be even more beautiful from the cockpit of a solar powered airplane."

You can see the Sunseeker Duo take flight in the video below.

Source: Solar Flight

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