x Abu Dhabi, UAEFriday 28 July 2017

Solar-powered plane flies in dark, bringing joy to pilots and backers

A solar-powered plane has completed the first 24-hour flight using only the sun's energy, going through the night on power stored in batteries.

It's back to Earth in Payerne, Switzerland, for Solar Impulse's solar-powered prototype airplane after success on a  24-hour flight.
It's back to Earth in Payerne, Switzerland, for Solar Impulse's solar-powered prototype airplane after success on a 24-hour flight.

LONDON // A solar-powered plane has completed the first 24-hour flight using only the sun's energy, going through the night on power stored in batteries. The experimental Solar Impulse made a picture-perfect landing at 11am UAE time yesterday at an airfield 50km from Bern. Its designers now plan to make a larger, more advanced aircraft in which they hope to circumnavigate the globe in 2013.

André Borschberg, 57, a former Swiss air force fighter pilot, was at the controls of the plane in a bathtub-sized cockpit for the historic flight. He said afterwards that he had experienced "an extraordinary night", describing the flight as the most incredible adventure of his 40-year flying career. "Just sitting there and watching the battery charge level rise and rise thanks to the sun ? and then that suspense, not knowing whether we were going to manage to stay up in the air the whole night," he said.

"And finally the joy of seeing the sun rise and feeling the energy beginning to circulate in the solar panels again." The plane, with its 63-metre wingspan and 12,000 solar cells, is not so much designed to prove the viability of solar-powered flight but, rather, to act as a test bed for the viability of new, environment-friendly technologies. Bertrand Piccard, co-founder of the project and himself a record-setting balloonist, told the exhausted pilot after he had landed: "When you took off, it was another era. "You land in a new era where people understand that, with renewable energy, you can do impossible things."

Mr Borschberg had taken off from the Payerne airfield just over 24 hours earlier, having to abort the flight last week because of a faulty transmitter. He circled over the Jura Mountains west of the Swiss Alps in clear skies, the solar panels soaking up the energy to power the four electric turbine engines and storing excess power in the batteries that were to keep the aircraft flying through the night.

The pilot said the plane had survived low-level turbulence and thermal winds, while he had endured freezing conditions during the night that had prevented him from drinking because his supplies of water had frozen solid. Mr Borschberg had maintained a special diet, practised yoga and studied meditation to help cope with the sleepless solitude of spending, in total, more than 26 hours in the cramped cockpit.

When the sun rose again, the plane's batteries still had three hours of power left in them, considerably more than anticipated. The aircraft landed to cheers and whoops of joy from hundreds of happy project workers and spectators. "That was the moment that proved the mission was successful - we made it," Mr Piccard said. "It's the first time ever that a solar airplane has flown through the night.

"Nothing can prevent us from another day and night, and the myth of perpetual flight." Mr Piccard, who, with co-pilot Brian Jones, was the first person to circle the Earth non-stop in a hot air balloon, added: "It's much more than just an aeronautical adventure; it's a technological demonstration of what we can offer society in terms of renewable energy. "We want to promote the implementation of the same technologies in cars, heating systems, computers, air conditioning, etc."

It has taken seven years and US$88 million (Dh323m) for Solar Impulse's 50 engineers and technicians, supported by 100 scientists and experts, to realise their dream of a 24-hour flight. The project team's next goal is to stage a 36-hour flight while they embark on building a more advanced model of the plane to circle the globe in five stages. dsapsted@thenational.ae