On March 9th André Borschberg, a Swiss fighter pilot and
engineer, took off from Abu Dhabi at the controls of this
flimsy solar-powered aircraft, Solar Impulse 2, on the
first leg of a journey around the world. Despite its 72-
metre wingspan, the plane has room for but a single
pilot—a job Mr Borschberg will share with Bertrand
Piccard, a psychiatrist and balloonist who helped start
the Solar Impulse project a dozen years ago. Flying east,
the two will take turns to complete the 12 legs of the trip
over (they hope) the next five months. The most difficult
stretches, such as an 8,170km flight across the Pacific
from Nanjing to Hawaii, mean spending five days
continuously aloft. The plan is to climb during the day to
8,500 metres while the 17,248 solar cells on the plane’s
wings and fuselage both drive the four propellers and
top up the batteries. At night the pilot will descend
gradually to 1,500 metres, eking out the electricity until
sunrise as he does so.


source: www.economist.com/news/science-and-technology/21646174-solar-powered-plane-takes?fsrc=scn/fb/te/pe/ed/asolarpoweredplanetakesoff