Solar plane still in China awaiting weather that will permit 5-day flight to Hawaii

The pilots and team prepping the Solar Impulse plane to fly around the world don’t appear to be impulsive about leaving China.

They’ve been here since March 29, stymied by unfavorable weather conditions, which have delayed the solar-powered plane’s next and most dangerous leg – a five-day, 5,070-mile journey to Hawaii.

“The mission team . . . is working really hard to find a window allowing us to depart for the Pacific Ocean,” pilot and Solar Impulse co-leader Bertrand Piccard said Wednesday on Twitter.

When that window will open up is unclear. They’d originally hoped to depart as early as May 5.

Piccard and fellow Swiss pilot Andre Borschberg are taking turns attempting to become the first to fly a solar-powered plane around the world. The one-seater Solar Impulse plane, the product of a decade of work, is completely powered by the rays of the sun and whatever tailwinds it may encounter.

The odd-looking plane, which weighs about as much as a minivan, gets its energy from 17,000 solar cells on its 236-foot-wide wings, which are wider than those on a Boeing 747. The pilots say they are attempting the circumnavigation to demonstrate the potential of renewable energy and ever-changing technological advances.

After starting in Abu Dhabi on March 8, Piccard landed the plane in the southern China city of Chongqing on March 29, the fifth leg of its journey. Piccard and his support team hoped to be there for only a few days, but bad weather delayed the flight to Nanjing, China, until April 20.

The next leg was the longest, more than 5,000 miles across the ocean to Hawaii. So far, the weather has not cooperated.

Conditions have to be just right for Borschberg to attempt the five-day, five-night leg. If the sky is overcast during the morning, it can prevent the plane from recharging its batteries after a nighttime flight. Thunderstorms or heavy crosswinds would force Borschberg to change course, adding to the duration and risk of the flight.

Elke Neumann, media relations officer for Solar Impulse, said the Nanjing takeoff has been delayed for a variety of weather reasons, including two typhoons near the Philippines and concerns about crosswinds.

As of Friday, the plane’s mission control team in Monaco had not identified a possible date when weather forecasts were favorable.

On Friday, the 62-year-old Borschberg was in Japan making arrangements. “Currently in Tokyo to fine tune @solarimpulse strategy to fly over Japanese airspace as soon as weather permits,” he tweeted in the afternoon.

In an interview in Nanjing late last month, Borschberg conceded that it could take some time to find a five-day window in which he could safely fly to Hawaii, a solar-powered Pacific crossing that has never been attempted before.

“You have to respect the forces of nature,” he said. “This is a plane that flies with nature, so you need to have nature on your side.”

Piccard and Borschberg originally had hoped to complete their tag-team, around-the-world flight in five months, returning to Abu Dhabi in August. Because of weather delays in China, that date almost surely will be set back – particularly because they still must cross the Atlantic, where the hurricane season begins June 1.

Global trip would be first powered solely by the sun

A pilot flying alone will attempt to fly a solar-powered aircraft from Nanjing, China, to Hawaii -- the seventh leg in an unprecedented effort to circumnavigate the globe with an aircraft powered only by the sun. The flight across the Pacific is particularly dangerous because it will take the Solar Impulse at least five days to reach Hawaii, during which the lone pilot must remain awake, except for occasional naps of no more than 20 minutes.

Start End Distance Time
#1 Abu Dhabi Muscat 400km 12 hours
#2 Muscat Ahmedabad 1,465km 20 hours
#3 Ahmedabad Varanasi 1,071km 15 hours
#4 Varanasi Mandalay 1,408km 20 hours
#5 Mandalay Chongqing 1,375km 20 hours
#6 Chongqing Nanjing 1,344km 17 hours
#7 Nanjing Hawaii 8,172km 120 hours
#8 Hawaii Phoenix 4,707km 100 hours
#9 Phoenix Midwest* 2,030km 30 hours
#10 Midwest* New York 1,436km 20 hours
#11 New York Europe* 5,739km 120 hours
#12 Europe* Abu Dhabi 5,845km 120 hours
*Exact airport / city still to be determined
Source: Solar Impulse