The Solar Impulse 2 is set to fly around the world with no fuel, only by solar power and it is so efficient it could remain in the air forever.
Images © Solar Impulse
The Solar Impulse 2 with 72 meters (236 feets) wingspan, has 7,200 solar cells covering them, is longer than the wings of a Boeing 747 jumbo jet.
It is the only airplane able to fly day and night exclusively on solar power.
According to Solar Impulse:
The chances of succeeding at the first attempt to build a solar airplane capable of flying around the world were judged to be slim, so a more rudimentary prototype, HB-SIA, was first constructed. Lessons learned from this prototype are incorporated in Solar Impulse 2, the Round-The-World Solar Airplane.
This revolutionary single-seater aircraft made of carbon fiber has a 72 meter wingspan (larger than that of the Boeing 747-8I) for a weight of just 2,300 Kg, equivalent to that of a car.
The 17,000 solar cells built into the wing supply four electric motors (17.5 CV each) with renewable energy.
During the day, the solar cells recharge lithium batteries weighing 633 Kg (2077 lbs.) which allow the aircraft to fly at night and therefore to have virtually unlimited autonomy.
Learn more about the challenges of building the Round-the-World Solar Airplane.
I am designing a plane with 100 m span carrying 250 passengers. Could I meet the SI II team ?
That is a solar plane with 2335 m2 surface area !