Solar Airplane Attempting To Circumnavigate The Globe Takes Off From Tulsa, Okla.

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Solar Impulse 2, the experimental plane attempting to circumnavigate the world using only the sun's power, has taken off from Tulsa on the latest leg of its journey.

The team says the flight to Dayton, Ohio — the 12th stage of the journey around the globe — is expected to take 18 hours, landing at approximately 11p.m. local time.

They're aiming to promote clean energy. "We have built an experimental aircraft that we use to explore not only altitudes, but also unknown territories within the realm of clean technology and creative team building," the team has said.

Time to board! #Si2 is like an old friend and each flight we do together to prove #futureisclean is magical ☀️ pic.twitter.com/pViroiclYX — André Borschberg (@andreborschberg) May 21, 2016

Swiss pilots Bertrand Piccard and Andre Borschberg alternate legs of the aircraft, with Borschberg at the controls during today's flight over the U.S. He's been tweeting during his journey, including this snapshot of the sun rising over Oklahoma.

On board of @solarimpulse enjoying sun rise over oklahoma pic.twitter.com/pssrBy5yfG — André Borschberg (@andreborschberg) May 21, 2016

Borschberg also paid tribute to the Wright Brothers – the famed aviation pioneers who hailed from today's destination, Dayton. He also notes that "today is a great day as 89 years ago, Charles Lindbergh landed in Paris Le Bourget. A very special moment for me."

.@WrightBrosNPS had the mindset to try w/o the fear of failing to make the impossible possible like we did with #Si2 pic.twitter.com/zFYGM6zFcW — André Borschberg (@andreborschberg) May 21, 2016

You can follow a live stream of the journey here:

The aircraft has a wingspan wider than a Boeing 747 but weighs no more than a mid-sized car. It doesn't handle well in gusty winds. The team says it "spent a week in Tulsa International Airport until they found a clear weather window to allow them to continue their flights across the U.S."

As The Two-Way has reported, "the fuel-free flight project started in March 2015, but it was put on hold in July after the plane's batteries developed problems during a five-day flight from Japan to Hawaii. It resumed its journey last month, completing a three-day trip from Hawaii to Mountain View, Calif."