Solar-powered aircraft to attempt round the world flight

A solar-powered aircraft that will attempt to fly round the world next March was revealed in Switzerland this afternoon. It will fly day and night without fuel only using solar electricity and batteries to keep it in the air.

The Solar Impulse2 aircraft will demonstrate just how far one can go without fuel, said Bertrand Piccard and André Borschberg who founded the Solar Impulse project more than a decade ago.

They and their commercial supporters revealed this second version today in Payerne, Switzerland. An earlier prototype showed back in 2010 that it was possible to fly day and night on solar power. And more recently it made a coast-to-coast multi-stage journey across the US.

The Solar Impulse has a wingspan of 72 metres, equal to the largest passenger aircraft, with its huge wings carrying the 17,200 solar cells. These power electric motors during the day that drive four propellers to give it lift, but at night it is all down to the batteries to keep the aircraft aloft.

It weighs in at a hefty 2.3 tonnes but this is considered exceptionally light compared to a typical jet aircraft its size. Even at that weight it can still take off under its own power and without any fuel.

The original designs for the single-seater were completed by the École Polytechnique Fédérale de Lausanne. The first plane has flown to Spain and Morocco and managed a 36 hour flight that included nine hours of night flying.

Much advanced technology has gone into the aircraft from chief sponsor Swiss company ABB, the largest engineering company in the world, and companies such as Bayer through its materials science division. The aircraft needs the technology, for example to cope with temperatures that can fluctuate from minus 40 at night up to 40 degrees during the day.

Bertrand Piccard has a history for such aeronautic attempts. He co-piloted the first balloon to circle the world non-stop. His partner in the adventure André Borschberg is a Swiss businessman. The plan to make a multistage circumnavigation of the Earth in 20 to 25 days in March 2015.