Solar Impulse project

Solar Impulse is a European long-range solar powered plane project being undertaken at the École Polytechnique Fédérale de Lausanne. The project is promoted by Bertrand Piccard, who co-piloted the first balloon to circle the world non-stop. This project hopes to repeat that feat using only solar power. The first aircraft, bearing the Swiss aircraft registration code of HB-SIA, is a one-seater, capable of taking off under its own power, and intended to remain airborne up to 36 hours. Building on the experience of this prototype, a slightly larger follow-on design (HB-SIB) is planned to make circumnavigation of the globe in 20–25 days.



Design and development

Piccard initiated the Solar Impulse project in 2003, but since then the team has grown to a multi-disciplinary team of 50 specialists from six countries, assisted by about 100 outside advisers.

The project is partially financed by private companies such as Solvay, Omega SA, Deutsche Bank, Bayer MaterialScience, Altran and Swisscom. The EPFL, the European Space Agency (ESA) and Dassault provide technical expertise.

Achieved timeline
2003: Feasibility study at the École Polytechnique Fédérale de Lausanne.
2004–2005: Development of the concept.
2006: Simulation of long-haul flights.
2006–09: Prototype.
2009: First flight of prototype

Planned timeline
2009–10: Test flights with prototype
2011: Building HB-SIB
2011–12: Test flights
2012: Circumnavigation flight


Planned second aeroplane (HB-SIB)

HB-SIB, the Swiss registration code borne by the second Solar Impulse aeroplane, is planned for completion in 2011, with a pressurized cockpit and advanced avionics to allow for trans-continental and trans-oceanic flights.

The wingspan of HB-SIB will be 80 m (260 ft), slightly wider than the wingspan of an Airbus A380, the largest passenger airliner in the world.

The cockpit will include cabin pressurization, supplemental oxygen and various environmental support to the pilot to allow a cruise altitude of 12,000 metres (39,000 ft).

The team hopes that a round-the-world flight will be possible in 2012. The flight would circle the world in the northern hemisphere near the equator. Five stops are planned to change pilots. Each leg will last three to four days, limited by the physiology of the human pilot.

Once improved battery efficiency makes it possible to reduce the weight, a two-seater is envisaged to make a non-stop circumnavigation.


General characteristics
Crew: 1
Payload: Lithium-ion batteries: 450 kg, (capacity: 200 Wh/kg = 90 KWh)
Length: 21.85 m (71.7 ft)
Wingspan: 63.4 m (208 ft)
Height: 6.40 m (21.0 ft)
Wing area: 11,628 photovoltaic cells: 200 m2 (2,200 sq ft)
Loaded weight: 1600 kg (3,500 lb)
Max takeoff weight: 2000 kg (4,400 lb)
Powerplant: 4× electric motors, (10 HP) each
Take-off speed: 35 kilometres per hour (22 mph)

Performance
Cruise speed: 70 kilometres per hour (43 mph)
Endurance: 36 hours
Service ceiling: 8,500 m (27,900 ft) Maximum altitude: 12,000 metres (39,000 ft)