HB-SIA, Solar Impulse prototype A
With its huge wingspan equal to that of an Airbus A340, and its proportionally tiny weight – that of an average car – the HB-SIA prototype presents physical and aerodynamic features never seen before. These place it in a yet unexplored flight envelope.
Carbon fiber structure, propulsion chain, flight instrumentation, everything has been designed to save energy, to resist the hostile conditions facing airplane and pilot at high altitudes and to marry weight restraints with the required strength.
Solar Impulse is a Swiss long-range solar powered aircraft project being undertaken at the École Polytechnique Fédérale de Lausanne. The project eventually hopes to achieve the first circumnavigation of the Earth by a piloted fixed-wing aircraft using only solar power. The project is led by Swiss psychiatrist and aeronaut Bertrand Piccard, who co-piloted the first balloon to circle the world non-stop, and Swiss businessman André Borschberg.
Piccard initiated the Solar Impulse project in 2003. By 2009, he had assembled a multi-disciplinary team of 50 specialists from six countries, assisted by about 100 outside advisers. The project is financed by a number of private companies. The four main partners are Deutsche Bank, Omega SA, Solvay, and Schindler. Other partners include Bayer MaterialScience, Altran, Swisscom and Swiss Re. Other supporters include Clarins, Semper, Toyota, BKW and STG. The EPFL, the European Space Agency and Dassault have provided additional technical expertise, while Bay Area based SunPower provided the aircraft’s photovoltaic cells.
HB-SIB, the new plane will flight in 2015
It was not built to fly round the world. Its purpose was rather to demonstrate the feasibility of the program by making the first ever whole day-and-night flight without fuel, a task that it accomplished brilliantly in July 2010. The lessons learned by the team are now being applied to the construction of Solar Impulse HB-SIB, which is due to circumnavigate the Earth in 2015.
Question of energy defines the project
At midday, each square meter of land surface receives, in the form of light energy, the equivalent of 1000 watts, or 1.3 horsepower of light power. Over 24 hours, this sun energy averages out at just 250W/m². With 200m² of photovoltaic cells and a 12 % total efficiency of the propulsion chain, the plane’s motors achieve an average power of 8 HP or 6kW.
That’s roughly the amount of power the Wright brothers had available to them in 1903 when they made their first powered flight. And it is with that energy, optimized from the solar panel to the propeller, that Solar Impulse managed to fly day and night without fuel!
FIVE world records established by HB-SIA
Absolute height: 9235 m (30300 ft)
Height gain: 8744 m (28690 ft)
Duration: 26 hours, 10 minutes, 19 seconds
Free Distance along a course: 1116 km (693.5 miles)
Straight distance, pre-declared waypoints: 1099.3 km (683 miles)
Across America 2013: Golden Gate end of April
- Solar Impulse site (solarimpulse.com)
- Solar plane sets off again across US (bbc.co.uk)
- Solar Impulse takes fuel-free flight to Dallas (nbcnews.com)
- Solar Impulse flight across America … (beartales.me)
- Solar Impulse Departs Phoenix, Headed To Dallas (earthtechling.com)
- Solar Impulse airplane is setting solar-powered flight record in Texas (nbcnews.com)
- Solar Impulse: interviewing a man on an 18-hour solar-powered flight (slashgear.com)
- Solar Impulse: Flying from San Francisco to New York City in a solar plane (treehugger.com)