Looking like a long, thin balsa-wood glider, Solar Impulse, a manned photovoltaic (PV)-powered airplane, was tested—at night! Ultimately André Borscherg, the founder of the company, plans to fly the plane around the world over a several day period in 2012. The plane should be able to fly for up to 36 hours without stopping.
The Solar Impulse is the first manned PV powered plane to fly overnight and one of a handful of attempts to create a PV aircraft. In the late 1990’s NASA launched its Pathfinder project, and created an unmanned aircraft capable of sustained flight for up to 15 hours with two to five hours of backup battery power. The Pathfinder Plus, a more recent model, has flown to more than 80,000 feet. And NASA’s prototype Helios unmanned PV aircraft has flown to heights of 96,863 feet. NASA believes the planes could fly for up to six months without needing to come down and could be used as suborbital sattellites or for monitoring purposes.
In the end, Impulse achieved its objective. On July 7, the plane made its first attempt to fly through the day and into the night. The Solar Impulse took off from Switzerland’s Payerne military airbase and flew for 26 hours. The plane reached a maximum altitude at 28,000 feet.
Borscherg was the plane’s solo pilot for its first 26-hour flight. He flew the plane until about 9 a.m. (Swiss time), July 8, 2010, and landed the plane at the same base. The plane flies on batteries at night, which are charged by the plane’s PV panels during the day.
PV won’t power your flight across the Atlantic Ocean any time soon but this plane is the most recent attempt to create ultra-light planes capable of running on PV alone. The plane, also known as HB-SIA, has a 64-meter wingspan, which is wider than a 747’s and about three-quarters the length of a football field. Yet it weighs only 1.7 tons, less than a full-sized pickup truck. The plane has four 10-horsepower engines to power its propellers, allowing for a top speed of about 45 miles per hour, which won’t break any records, but it’s a start.