Swiss adventurer Bertrand Piccard has unveiled a prototype of the solar-powered plane he hopes eventually to fly around the world.

The vehicle, spanning 61m but weighing just 1,500kg, will undergo trials to prove it can fly through the night.

Dr Piccard, who made history in 1999 by circling the globe non-stop in a balloon, says he wants to demonstrate the potential of renewable energies.

The final version of the plane will try first to cross the Atlantic in 2012. Although the vehicle is expected to be capable of flying non-stop around the globe, Dr Piccard will in fact make five long hops, sharing flying duties with project partner Andre Borschberg.

"The aeroplane could do it theoretically non-stop - but not the pilot," said Dr Piccard. "We should fly at roughly 25 knots and that would make it between 20 and 25 days to go around the world, which is too much for a pilot who has to steer the plane.

"In a balloon you can sleep, because it stays in the air even if you sleep. We believe the maximum for one pilot is five days." The public unveiling on Friday of the HB-SIA took place at Dubendorf airfield near Zürich.

"The real success for Solar Impulse would be to have enough millions of people following the project, being enthusiastic about it, and saying 'if they managed to do it around the world with renewable energies and energy savings, then we should be able to do it in our daily life'."

source : bbc.news.com