Monday, April 15, 2013

Solar plane to head across country


A plane shaped like an immense, spindly dragonfly rests inside Moffett Field's cavernous Hangar 2.

It weighs as much as a car and flies on nothing but sunlight, tapped by 11,628 solar cells coating its wings. And in May, it will leave Moffett on a cross-country trip to New York City in a bid to prove that crazy ideas can sometimes work.


Made by Swiss company Solar Impulse, the plane is a flying experiment, testing new ultralight materials and battery technologies while pushing the limits of solar power.

It is designed to inspire. Pilot Bertrand Piccard, the son of a deep-sea explorer, sees the Solar Impulse plane as a way to motivate budding pioneers in technology and other fields.

"As soon as you start to love the unknown, love the doubts, love the question marks, life becomes an absolutely fabulous adventure, and this is what Solar Impulse is all about," he said Thursday at Moffett. "Of course, Solar Impulse is carrying one pilot and zero passengers. But it's also carrying a lot of messages."

Among those messages: renewable power can be used in ways that many people would consider impossible.

"Together, what we're going to show is that the idea that renewable energy can't fuel the world is wrong," said Tom Werner, CEO of SunPower Corp. The San Jose company supplied the plane's flexible solar cells, each as thick as two strands of hair.

'That's what we do'

"They're shattering myths," Werner said of Piccard and fellow Solar Impulse pilot André Borschberg. "They're destroying conventional thinking. And that's what we do in Silicon Valley."

The plane has already proved itself in the air. In 2010, it flew for 26 hours straight, showing that the battery pack could store enough energy from the solar cells to keep flying through the night. In 2015, Borschberg and Piccard plan to fly around the world.


First, however, they will tackle the United States.

After test flights around the Bay Area in April, the plane will take off in May for Arizona, landing in Phoenix. From there it will travel to Dallas-Fort Worth airport. In all, the team plans five legs between Moffett Field and New York's John F. Kennedy International Airport. At each stop, the plane and its makers will linger for a week to 10 days, showing off the aircraft as an educational tool.

With four propellers, the Solar Impulse plane doesn't have the speed of a jet. And the pilots don't want to fly more than 24 hours on any one leg.

"This airplane could do (the trip) nonstop," said Borschberg, who also serves as the company's CEO. "For safety reasons, the pilot is not as able as the technology, just yet."

Single-person craft

The plane was shipped to Moffett in pieces and assembled inside Hangar 2, whose vast interior was originally designed to hold blimps. The wings, stretching a total of 208 feet, look solid enough, but they're mostly fabric, with solar cells across the top. The cockpit fits one, just barely. The entire plane, pilot included, weighs about 3,525 pounds.

Together, the solar cells can generate up to 45 kilowatts of electricity. That's a little over 10 times the output of a typical home solar system. But it's enough to keep the propellers spinning and charge up the battery pack before nightfall.

The company, which has about 80 employees, is already building another version of the plane for the planned flight around the world. And it is relying on a network of partners to supply the technology that will make that flight possible. A division of the Bayer pharmaceutical company, for example, has provided specialized materials to help lower the plane's weight, including rigid foam in the wing tips and polycarbonate films in the cabin window.

Solar Impulse may not be a harbinger of aviation's future.

Most energy analysts believe aviation will rely on liquid fuels for the foreseeable future. Even the outgoing Piccard demurs a bit when asked if solar will one day be a common way to power planes.

"It would be crazy to answer yes and stupid to answer no," he said. "Because of course today, we cannot imagine having a solar-powered airplane with 200 passengers. But in 1903 (the year of the Wright brothers' first flight) it was exactly the same. And when Charles Lindbergh crossed the Atlantic, he was all alone on board, with an airplane full of gasoline."