The project was designed to build a solar-powered aircraft and use it to fly around the world. A short flight was made by the group's prototype in 2009 after year of design and construction. After several longer flights, including a multi-stop flight across Europe, their designers are aiming to go further in the coming years.
The prototype (HB-SIA) flew from Brussels to Paris nonstop in 2011 where it was the guest of honor at the Paris Air Show. That was on the second attempt, as weather forced the plane back on the first try.
Four electric motors propel the plane, but there is a hitch. The current model has a top speed of 43 mph. Not 430, 43 mph. That's about a one-hour trip if you flew it from Altoona to State College.
Current plans have the second build of the plane making the trip in the next couple years, but there are some design issues that need to be overcome before solar power flight will be feasible for mass transit. There would be more than one pilot, changing out every 3-4 days and the solar cells would charge batteries that would run the motors at night.
First is obviously the top speed, which can be fixed using either a high number of motors or stronger motors. The motors would weigh more and would require more energy, so a compromise there has to be made. The overall weight of the plane using modern materials would be about that of an automobile.
The wingspan of a one-seat aircraft like the new solar impulse plane is staggering. At 262.5 feet, it has a larger wingspan than the Airbus A380, which can hold around 500 people.
So solar-powered flight is not in the immediate future, but one day we will advance to the point where solar cells could generate the power needed to transport people across the country using the power of the sun.