We've already heard how batteries that are built into the structure of items – such as cars or satellites – could help extend run times without increasing bulk. Now, the flight time of a drone has been almost doubled, thanks to such "structural batteries."

Case Western Reserve University's Prof. Vikas Prakash started with a 7-foot-long (2.1-m), single-propeller, fiberglass-bodied fixed-wing drone. Over the course of three years, he proceeded to develop an energy-storage system in which battery cells were incorporated into the autonomous aircraft's 6-foot (1.8-m) wingspan.

The idea was that this setup would not only boost the amount of energy stored onboard, but that it could do so without sacrificing cargo space or adding much weight. Such technology would allow drones to either fly farther and for longer periods of time, or to carry additional sensors or other heavier payloads.

In previous tests performed at Ohio's Springfield-Beckley Municipal Airport, using a regular wing and the drone's standard battery pack, the aircraft was able to fly for a maximum of 91 minutes before needing a recharge. Late this February, however, it was tested with the battery wing swapped in. This change allowed it to remain airborne for a total of 171 minutes – almost three hours.

"This test demonstrates that the use of structural battery is a winning concept," says Prakash. "This will allow our crafts to fly longer and/or carry heavier payloads without compromising fuselage space."

Ultimately, it is hoped that such technology could be used not only in drones, but in a fully-electric passenger-carrying regional jet.

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