It's a strange bird, with a wingspan that recalls an airliner but able to carry only a single passenger, the pilot. Those wings are upholstered in 12,000 photovoltaic cells, which run the 3,300-pound craft while also charging 880 pounds of batteries meant to keep the propellers turning after the sun goes down. That will be necessary to achieve the Solar Impulse's mission — circumnavigating the planet in one fell swoop. (Well, not quite a fell swoop — the human limitations of having a crew of one means there will be stopovers to swap out adventurers.)
Piccard, an entrepreneurial adventurer with exploration in his genes, told a crowd of 800 that his plane represented not so much a statement about aviation but about the role of renewable energy in general.
"If an aircraft is able to fly day and night without fuel, propelled solely by solar energy, let no one come and claim that it is impossible to do the same thing for motor vehicles, heating and air conditioning systems and computers," the AFP quoted Piccard.
That theme echoes on the Solar Impulse Web site:
"We want a strong symbol capable of striking the minds. In this respect, Solar Impulse will be our ambassador. The message we want to share is that it is essential to develop new technologies to allow our society to reduce its energetic consumption. As it is almost unthinkable that people will accept to diminish their life standards, we must develop efficient equipments that consume less, as well as alternative sources of energy and first of all solar energy."
Expect a night crossing of Switzerland by this "ambassador" sometime next year, and from lessons learned then a second solar aircraft is expected to arise. That's the one that will circle the globe, with liftoff for that flight forecast for 2012.
Piccard likely has a better understanding of the challenges than most — he was the first person to successfully circle the globe nonstop in a balloon.
For the wonks in the house, the solar cells being used will have an estimated efficiency of 20 percent, i.e. a fifth of the solar energy reaching the cells is turned into electricity. "Today there exist more high-performance technologies with up to 30 percent output," according to the Impulse's creators, "but they are also heavy. It is obvious that a significant improvement of this output would also improve the airplane's performance and reduce its wingspan or increase the payload."
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