Powered by the sun, the plane that flew all day... and all night in 26-hour test



A solar-powered plane yesterday completed a record-breaking 26-hour flight - paving the way for an aircraft that could potentially stay airborne for ever.

The Solar Impulse, which flies using four propeller engines powered by solar panels on its huge wings, landed in Switzerland after an epic flight.

It collects so much energy from the sun during the day that it can store electricity to power it through the night.

Engineers behind the experimental single-seat aircraft, which circled Swiss airspace yesterday, are planning to fly it over the Atlantic and eventually around the world, claiming: 'We are now on the verge of perpetual flight.'

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Pilot Andre Borschberg and his engineers on the ground cheered loudly as the plane clocked up 24 hours in the air shortly before 7am Swiss time yesterday.



Former fighter pilot Mr Borschberg then flew back to Payerne airfield, south-west of Bern, and touched down at 9am, 26 hours and nine minutes after he had taken off from the same runway.



It was the longest and highest flight in the history of solar aviation, and reached top speeds of 75mph.



While he was airborne Mr Borschberg, 57, had to use all his skill to avoid lowlevel turbulence and thermal winds over Switzerland's mountains before enduring freezing conditions during the night.



He ended the test flight with a picture-perfect landing to cheers and whoops from hundreds of supporters on the ground as he eased the craft on to the runway.



Helpers rushed to stabilise the plane as it touched down to stop its massive wingspan scraping the ground and toppling over.



After touchdown Mr Borschberg said: 'It was unbelievable, success better than we expected. We almost thought to make it longer.



'But we demonstrated what we wanted to demonstrate so they made me come back. So here I am.' 'We achieved more than we wanted.

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'Everybody is extremely happy. The night is quite long, so to see the first rays of dawn and the sun returning in the morning - that was a gift.'



The plane's wings are covered with solar panels housing thousands of cells designed to collect the energy of the sun's rays and power four electric motors driving wing-mounted propellers.



Clear blue skies meant the prototype aircraft could soak up plenty of solar energy as it flew over the Jura mountains to the west of the Swiss Alps.



But Mr Borschberg still kept within gliding range of his home runway and wore a parachute - just in case. He began cruising at 9,850ft (3,000m) in an attempt to avoid the turbulence and thermal winds that are frequent in the mountains.



He then took the Solar Impulse up to 27,900ft (8,500m) by Wednesday evening, at which point a decision was made to continue through the night using solar power stored in its batteries.



The pilot slowly descended to 4,920ft (1,500m) before midnight, where he stayed until his early-morning landing.

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The first 24-hour test flight proves that the aircraft can collect enough energy from the sun during the day to stay aloft indefinitely, because the solar panels began collecting energy again at dawn, team co-founder Bertrand Piccard said.



'The goal of the project is to have a solar-powered plane flying day and night without fuel,' he added.



After landing, Mr Borschberg embraced Mr Piccard before gingerly unstrapping himself from the bathtub-size cockpit in which he had spent more than a day.



'You land in a new era where people understand that with renewable energy you can do impossible things,' Mr Piccard told the pilot.



The project co-founder, who completed the first non-stop circumnavigation of the globe in a balloon, the Breitling Orbiter III, in 1999, said the next step will be an Atlantic crossing in a second, lighter prototype.



The team aims to fly around the world by 2012. Although the goal is to show that emissions-free air travel is possible, the team has said it does not see solar technology replacing conventional jet-powered planes any time soon.



Instead, the project is designed to test and promote new energy-efficient technologies.

