First round-the-world solar powered flight to take place in 2015 as Solar Impulse 2 is unveiled
Solar Impulse 2
Mon 14 Apr 2014 – The Solar Impulse team have unveiled the second version of their aircraft that has been designed to complete the world’s first round-the-world solar-powered flight. The two co-founders – explorer Bertrand Piccard and engineer André Borschberg – will take turns to fly Solar Impulse 2 eastwards from continent to continent starting in March 2015 from the Gulf area. As well as a feat of aviation innovation, the aim of the project is to promote clean technology around the world. With a technical team of 80 specialists, it has so far taken 12 years of calculations, simulations, construction and testing. With a weight of just 2,300kg, the single-seater aircraft has a huge wingspan of 72 metres – longer than the wingspan of a Boeing 747 and only 8 metres shorter than the Airbus A380. The wings, fuselage and horizontal tailplane contain 17,248 highly-efficient solar cells, each only 135 microns thick, the same as a human hair.
“A vision counts for nothing unless it is backed up by action,” said Piccard. “with eight world records for Solar Impulse 1, the first solar aircraft capable of flying during the night, crossing two continents and flying over the United States, we have shown that clean technologies and renewable energies can accomplish the impossible.”
Test flights of Solar Impulse 2 are due to take place next month, followed by training flights over Switzerland. The attempt on the round-the-world flight will take the aircraft over the Arabian Sea and follow a route over India, Burma, China, the Pacific Ocean, the United States, the Atlantic Ocean and Southern Europe or North Africa before returning to its departure point. Landings will be made every few days to change pilots and to allow for public events with governments, schools and universities.
To complete the flight, the aircraft will have to achieve an aviation first of flying without fuel with only one pilot for five consecutive days and nights over oceans from one continent to another. Borschberg said the flight would be as much a human as a technological feat. “Solar Impulse 2 will have virtually unlimited autonomy, and now we need to make sure the pilot is as sustainable as his aircraft.”
The 3.8 cubic metre cockpit has been designed to accommodate a pilot for a week but for maximum energy efficiency it is not pressurised or heated, a challenge for the pilot who will have to endure temperature ranges from minus 40 to plus 40 degrees C, although the cabin is protected by high-density thermal insulation.
Take-offs and landings will be carried out at night to avoid turbulence and winds, with the aircraft climbing to 8,500m during the day and descending to 1,500m at night to save energy. The industry-leading efficiency of the monocrystalline silicon solar cells at 22.7% compares with a typical efficiency of 16% for solar panels used on homes. The best are those used on satellites – 30% – but these are too heavy for the aircraft.
The main backers for the Solar Impulse project are Solvay, Omega, Schindler and ABB, with aeronautical partners including IATA, ACI, Dassault and Eurocontrol.