NEW YORK, July 6 (Reuters) - An airplane entirely powered by the sun embarked on the final leg of a journey across the United States on Saturday, taking off from Washington, D.C., for a roughly 21-hour flight to New York City.
The Solar Impulse, its four propellers driven by energy collected from 12,000 solar cells in its wings that simultaneously recharge batteries for night use, departed Dulles International Airport outside Washington at 4:46 a.m. EDT (0846 GMT), organizers said.
Flight plans call for it to head north over Maryland, Delaware and New Jersey, pass over the Statue of Liberty in New York Harbor and land at John F. Kennedy Airport around 2 a.m. EDT (0600 GMT) on Sunday.
If the spindly experimental aircraft completes the journey as planned, it will be the first solar-powered plane capable of operating day and night to fly across the United States.
The Solar Impulse, with the wingspan of a jumbo jet and the weight of a small car, completed the first leg of the journey from San Francisco to Phoenix in early May and flew later that month from Phoenix to Dallas. From there it flew to St. Louis, stopped briefly in Cincinnati, then flew on to Washington, where is has remained since June 16.
Intended to boost support for clean energy technologies, the project began in 2003 with a 10-year budget of $112 million (90 million euros). It has involved engineers from Swiss escalator maker Schindler and research aid from Belgian chemicals group Solvay. (Reporting by Paul Thomasch; Editing by Eric Beech)