The new solar airplane Solar Impulse 2 of the Swiss pilots Bertrand Piccard and André Borschberg is ready. After about three years of construction it was presented in the Swiss town Payerne. After a testing phase it will start its several monthlong journey around the world in April 2015.
The 4 motors have each 17HP and are 94% energy efficient, they accelerate the plane to a max. speed of about 100 MPH. Here is a video of the construction of the entire plane:
The pilots will travel in an altitude of 28000 feet and will have to survive temperatures as low as -40°F – there is no heating on board.