The Solar Impulse HB-SIA landed to much applause. (Solar Impulse)
The Solar Impulse HB-SIA - the first airplane designed to fly day and night without fuel - left the ground yesterday for the first time. Recent results from ground tests had verified the prototype's controllability, acceleration, braking paths, and engine power.

Test pilot Markus Scherdel took the prototype to its take-off speed, and after about 350 meters of flight at an altitude of one meter, the prototype landed back on Dübendorf Airfield's runway in Switzerland.

The HB-SIA is the first prototype of the Solar Impulse project, and it has been a long-term work in progress. The project was launched in 2003, and years of work, calculations, simulations, and tests by a 70-person team led to its unveiling in June of this year.

Over 12,000 solar cells mounted onto the wing will supply energy to four electric motors with a maximum power of 10 HP each. During the day they will also charge the lithium-polymer batteries (400 kg), which will permit the HB-SIA to fly through the night.

At this stage the solar panels have not yet been connected. With the positive conclusion of this initial “flea hop”, the Solar Impulse HB-SIA will now be dismantled and transported to the airfield at Payerne. Starting in early 2010, the aircraft will be making its first solar test flights, gradually increasing flight duration until it makes its first night flight using solar energy.

The results from the HB-SIA and their analysis will serve to develop and build a second aircraft, the HB-SIB for circumnavigating the word in five stages - each lasting several days - in 2012.

"For over ten years now, I have dreamt of a solar aircraft capable of flying day and night without fuel - and promoting renewable energy. Today, our plane took off and was airborne for the very first time. This is an unbelievable and unforgettable moment," said Bertrand Piccard, President of Solar Impulse. Piccard is also an aeronaut, and made the first non-stop round-the-world balloon flight.

(Solar Impulse)