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Solar Impulse – given wing by the sun


It was a fatal error of Icarus to approach the sun with his wings of feather and wax, but it is this very sun that is now giving wing to the Swiss solar airplane Solar Impulse. The team working on the circumnavigation of the earth in 2012 includes two alumni of the Bern University of Applied Sciences (BUAS) in Biel, the electrical engineers Stefan Brönnimann and Ueli Kramer.

Stefan Brönnimann

The Solar Impulse project is a real challenge: The airplane takes off and flies autonomously, propelled exclusively by solar energy. Can such a «crazy idea» stimulate developments in the energy sector?

SB: I mainly see new developments in low weight applications. But the greatest benefit for the energy sector is demonstrating the potential of renewable energies to the public at large. If it is possible to fly day and night without any fuel, many other things may be possible as well.

Stefan Brönnimann: You joined Solar Impulse in 2007 and are now in charge of development prototyping up to full production. What motivated you to work in a group that is constantly pushing back the envelope?

It was an amazing experience to be part of the project that began with an empty hangar and resulted in an airplane that actually flies. As the electrical team was rather small, there was considerable job variety. Although there were many exhausting moments – the more you are involved, the more you cannot wait to see it fly!

Ueli Kramer: Have your acquired certain skills at the UAS in Biel which will now prove useful in your career?

I gained a lot of theoretical knowledge during the lessons. But much more important was to apply this theory in my bachelor’s thesis. This experience greatly improved my skill in the practical application of electronics.

Ueli Kramer: At Solar Impulse you are responsible for prototyping and testing electrical units and supporting flight operations. What is your most exciting challenge in your present job?

Dealing with new problems every day and playing an active part in a team with some of the best engineers. It’s also very exciting, of course, to work hand in hand with Claude Nicollier during the flight operations.

The realization of such an outstanding solar aircraft is only possible within an interdisciplinary cooperation. Do you think the UAS has equipped you mentally for your current ambitious tasks?

UK: Studying electronics means moving in a complex and very wide field. So from the start you learn how to think in an interdisciplinary manner. Being adaptable and having an interdisciplinary approach are the most important skills.

SB: In an international project like Solar Impulse different languages and cultures present a huge challenge. The bilingual studies at the UAS and my time spent in Biel greatly helped me to develop a feel for French-speaking people. If you want to read between the lines, you need rather more than just a common language like English!   

Ueli Kramer