| SAN FRANCISCO
SAN FRANCISCO May 3 A solar-powered airplane
that developers hope to eventually pilot around the world was
due to take off early on Friday from San Francisco Bay on the
first leg of an attempt to fly across the United States with no
fuel but the sun's energy.
Departure was set for 6 a.m. local time from Moffett Field,
a joint civil-military airport near the south end of San
Francisco, with the spindly looking plane, dubbed the Solar
Impulse, headed first to Phoenix on a slow-speed flight expected
to take 19 hours.
After additional stops in Dallas, St. Louis and Washington,
D.C., with pauses at each destination to wait for favorable
weather, the flight team hopes to conclude the plane's
cross-country voyage in about two months at John F. Kennedy
International Airport in New York.
Swiss pilots and co-founders of the project, Bertrand
Piccard and Andre Borschberg, will take turns flying the plane,
built with a single-seat cockpit, with Piccard slated to be at
the controls for the first flight to Arizona. He is scheduled to
land in Phoenix at 1 a.m. local time on Saturday.
The project began in 2003 with a 10-year budget of 90
million euros ($112 million) and has involved engineers from
Swiss escalator maker Schindler and research aid from
Belgian chemicals group Solvay - backers who want to
test new materials and technologies while also gaining brand
Project organizers say the journey is also intended to boost
worldwide support for the adoption of clean-energy technologies.
With the wingspan of a jumbo jet and weighing the same as a
small car, the Solar Impulse is a test model for a more advanced
aircraft the team plans to build to circumnavigate the globe in
The plane made its first intercontinental flight, from Spain
to Morocco, last June.
SOLAR CELLS BUILT INTO WINGS
The aircraft runs on about the same power as a motor
scooter, propelled by energy collected from 12,000 solar cells
built into the wings that simultaneously recharge batteries with
a storage capacity equivalent to a Tesla electric car.
In that way, the Solar Impulse can fly after dark on solar
energy generated during daylight hours, and will become the
first solar-powered aircraft capable of operating day and night
without fuel to attempt a U.S. coast-to-coast flight.
But the plane is unlikely to set any speed or altitude
records. It can climb gradually to 28,000 feet (8,500 meters)
and flies at an average pace of just 43 miles per hour (69 km
The current plane was designed for flights of up to 24 hours
at a time, but the next model will have to allow for up to five
days and five nights of flying by one pilot - a feat never yet
Meditation and hypnosis were part of the training for the
pilots as they prepared to fly on very little sleep.
Asked about the downside of solar-powered flight at a news
conference in March to unveil the current plane, Piccard
acknowledged there was a price paid for the tiny carrying
capacity and massive wings.
"In that sense, it is not the easiest way to fly," he said.
"But it is the most fabulous way to fly, because the more you
fly, the more energy you have on board."
He added: "We want to inspire as many people as possible to
have that same spirit: to dare, to innovate, to invent."
The plane's four large batteries, attached to the bottom of
the wings along with the plane's tiny motors, account for a
quarter of its overall heft.
The aircraft's lightweight carbon fiber design and wingspan
allow it to conserve energy, but also make the plane vulnerable
to being tipped over.
A ground team of weather specialists, air traffic
controllers and engineers track the plane's speed and battery
levels and help the pilot steer clear of turbulence. Solar
Impulse cannot fly in strong wind, fog, rain or clouds. Its
machinery is not even designed to withstand moisture.