Solar Impulse is the only airplane of perpetual endurance, able to fly day and night on solar power, without a drop of fuel.
http://info.solarimpulse.com/en/our-adv ... mpulse-2//
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.
SOLAR CELLS
More than 17’000 solar cells, collecting up to 340kWh of solar energy per day and representing 269.5 m2!
More precisely 17'248 monocrystalline silicon cells each 135 microns thick mounted on the wings, fuselage and horizontal tailplane, providing the best compromise between lightness, flexibility and efficiency (23%).
In order to maximize the aerodynamical performance, the plane is built with a wingspan of 72m: wider than that of a Boeing 747 Jumbo Jet!
BATTERIES
The energy collected by the solar cells is stored in lithium polymer batteries, whose energy density is optimized to 260 Wh / kg. The batteries are insulated by high-density foam and mounted in the four engine nacelles, with a system to control charging thresholds and temperature. Their total mass amounts to 633 kg, or just over a quarter of the aircraft’s all-up weight.
In order to save energy, the aircraft climbs to 8’500 m during the day and descents to 1,500 m at night.
MOTORS
Average power over 24-hour of a small motorbike (15 hp) with a maximum power of 70 hp (four 17.5 hp engines).
Four brushless, sensorless motors, each generating 17.4 hp (13.5 k), mounted below the wings, and fitted with a reduction gear limiting the rotation speed of a 4 m diameter, two-bladed propeller to 525 rev / min. The entire system is 94% efficient, setting a record for energy efficiency.
SPEED
Solar Impulse can fly at the same speed than a car, between 36 km/h (20 Kts) and 140 km/h (77 Kts).
At sea level: minimum speed of 45 km/h (20 Kts) and maximum speed of 90 km/h (49 Kts).
At maximum altitude: from 57 km/h (31,5 Kts) to 140 km/h (77 Kts).
