Solvay’s Solstick PVDF Solef polymer film was used to tape together the solar cells and provide an aerodynamically-efficient wing.
Si2 weighs 2,300kg (5,070 lb), around the same as a small van.
Solar Impulse 2 about to touch down after its first flight on June 2, 2014.
Solar Impulse 2 will cruise at 27,887 ft (8,500 m) during the day and 4,291 ft (1,500 m) at night.
On the morning of June 2, 2014 the Solar Impulse 2 (HB-HIB) completed its maiden flight at Payerne in Switzerland. Test pilot Marcus Scherdel flew the solar-powered aircraft for two hours 17 minutes, during which he reached a maximum height of 5,500ft (1,670m) at an average speed over the ground of 30kt (56km/h). Several additional flights will be undertaken during the coming months to certify the aircraft, which has some significant differences from the original Solar Impulse (HB-HIA), which first flew in December 2009. The aircraft was unveiled on April 9 with a larger, 72m (236 ft 2 in) wingspan, but weighing just 2,300kg (5,071 lb). Solar Impulse 2 is central to a goal of circumnavigating the globe in 2015 solely powered by sunlight, using 17,248 solar cells on its wings and efficient energy storage devices.
Andre Borschberg (left) and Bernard Piccard, who will fly Si2 round the world.
Wind tunnel tests helped to finesse Si2's aerodynamic performance.