Solar Impulse took off from Phoenix at 4:47 local time this morning, headed to Dallas.
The entirely sun-powered airplane was making the second leg of its cross-country journey, which began in Silicon Valley on May 3, with André Borschberg in the not-so-roomy pilot’s seat. You can follow the flight in real-time on the Solar Impulse site.
This leg of the flight to Dallas Fort Worth International Airport will be an estimated 868 miles, the Solar Impulse team said, which would make it the longest solar-powered flight in history. Borschberg piloted Solar Impulse to the current record – officially, 693 miles in free distance or 683 miles by a stricter standard that uses predeclared waypoints – when he flew from Payerne, Switzerland, to Madrid last June.
Solar Impulse departed this morning after more than two weeks in Phoenix, with part of that time a planned layover for public events but the last several days spent waiting for appropriate flying conditions.
The willowy, 3,500-pound plane, with a 208-foot wingspan, needs just the right weather window to safely make its fuel-free way along, traveling at elevations of up to 25,000 feet but at ground speeds merely in the mid-30s mph. The plane also has to time its journey in order to arrive at busy DFW at a time that won’t be too disruptive to air traffic – expected to be 1 a.m. local time on Thursday, some 20 hours after takeoff from Phoenix.
After Dallas, Solar Impulse intends to head to St. Louis, then Washington, D.C., and then finishing up in New York City around the Fourth of July.
Ultimately, Borschberg and fellow pilot Betrand Piccard (he flew the first leg of this trip, and will take the next one, too) hope to circumnavigate the globe in a new Solar Impulse craft, with a bigger, more comfortable cockpit, based on the HB-SIA they are taking across North America after successful flights last year in Europe.
They were pointing at 2014 for that global attempt, but when the wing spar on the under-development HB-SIB was damaged in construction, they pushed the round-the-world flight to 2015 – and that’s when the decision was made to bring the HB-SIA to the U.S.
The revolutionary carbon fiber solar airplane has 12,000 solar cells built into its wings that recharge a set of four 400-kilo lithium batteries housed in the engine pods during flight. The plane averages about 8 horsepower—similar to what the Wright Brothers managed when they first flew in 1903.