Solar Impulse 2 Flight Around the World

 

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).

 

LIGHTNESS

Prowess of the engineers led by André Borschberg who managed to build the entire structure proportionately 10 times lighter than that of the best glider. Every gram added had to be deducted somewhere else, to make room for enough batteries on board, and provide a cockpit in which a pilot can live for a week. In the end, it is of the weight of a small van: 2’300kg!

Stimulating innovation in the field of sheets of carbon, which now weigh only a third as much as sheets of printer paper (25 g/m2)

 

ROBUSTNESS

The airframe is made of composite materials: carbon fibre and honeycomb sandwich.

The upper wing surface is covered by a skin consisting of encapsulated solar cells, and the lower surface by a high-strength, flexible skin. 140 carbon-fiber ribs spaced at 50 cm intervals give the wing its aerodynamic cross-section, and also maintain its rigidity.

 

LIVING UP IN THE SKY, FOR DAYS

For the trip’s “long haul flights” the pilot will be living in the 3.8 m3 cockpit for 5 or 6 days and nights in a row.

The cockpit volume provides enough space on board for oxygen supplies, food and survival equipment, whilst also meeting the optimal ergonomic requirements for flights lasting several days.

 

MULTI-PURPOSE SEAT

A multi-purpose seat functions both as reclining berth and toilet.

A parachute and a life-raft are packed into the seat-back. When fully reclined, it allows the pilot to perform physical exercises. It allows more legroom, has an ergonomic inflatable cushion, and has been developed for minimum weight.

 

EXTREME TEMPERATURES

In the absence of any heating, the cockpit and the pilot will be facing extreme temperatures: from +40°C à -40°C!

Bertrand Piccard and André Borschberg are protected against the ambient cold or heat by high-density thermal insulation in the cockpit structure.

 

FOCUS & VIGILANCE TECHNIQUES

Self-hypnosis and meditation techniques allow the pilot to maintain his powers of concentration and vigilance.

 

DIET & MEDICINE

Science-based personalized nutrition has been developed by Nestlé Health Science, to meet the need of 2.4kg (5.2lbs) of food, 2.5l (84.5oz) of water, and 1l (33.8oz) of sports drink per day, during the long legs of the #RTW solar flight. Physicians and specialists of high altitude medicine provide medical advice prior and during flights.

 

REAL TIME FLIGHT MONITORING

In contact with the MCC - Mission Control Center - in Payerne the pilot receives support and flight indications.

Continuous transmission of hundreds of technical parameters via satellite data-link to the MCC. All possible eventualities are simulated by a multidisciplinary team to find the right combination of weather patterns, and pave the way for the solar airplane to enter controlled airspace and prepare for landings at international airports.

 

Information Provided by - http://info.solarimpulse.com/en/our-adventure/building-a-solar-airplane