Perpetual fossil fuel-free flight nears reality as Solar Impulse completes first-ever solar powered night flight
(photo: Solar Impulse)
Thu 8 July 2010 – The solar-powered Solar Impulse has made the longest and highest ever flight of its kind, touching down at its Payerne, Switzerland airfield base this morning after flying for more than 26 hours. Taking off early yesterday morning, the plane’s 12,000 solar cells stored enough energy to keep it flying through the night before touching down at 9am local time this morning. It is an important milestone for an eventual transatlantic crossing and round-the-world flight on a second prototype to be built this summer. Solar power is unlikely to find its way into commercial airliner operations in the foreseeable future but as the project’s founder Bertrand Piccard points out, the flight is a symbolic achievement on the path towards a carbon-free aviation industry.
The Solar Impulse, code-named HB-SIA, weighs little more than a medium-sized car but has a wingspan of 63.4 metres, equivalent to that of an Airbus A340 aircraft, and just a metre short of a Boeing 747-400 jumbo. The plane is powered by four 10 HP electric engines. With 200m² of photovoltaic cells and a 12% total efficiency of the propulsion chain, the plane’s motors manage an average power of no more than 8 HP or 6kW – roughly the amount of power the Wright brothers had available to them in 1903 when they made their first powered flight.
The average speed of the flight was a leisurely 23 knots (26.5mph), with a maximum speed of 68 knots (78mph), and the plane reached a maximum altitude of 8564 metres (28,100 feet).
“During the whole of the flight, I just sat there and watched the battery charge level rise and rise,” said André Borschberg, CEO and co-founder of the Solar Impulse project and pilot of the flight. “Sitting in a plane producing more energy than it consumes is a fantastic feeling.”
Bertrand Piccard, who initiated the project in 1999 following his circumnavigation of the world in a balloon, said of the flight: “This is a highly symbolic moment: flying by night using solar power is a stunning manifestation of the potential that clean technologies offer today to reduce the dependency of our society on fossil fuels.”