The Solar Impulse aircraft known as HB-SIA is in the middle of its first 24-hour flight including a complete day/night cycle. The aircraft took off from its home airfield in Payerne, Switzerland, shortly before 7 a.m. local time on Wednesday (1 a.m. Eastern time). It will spend the day climbing to an altitude to nearly 28,000 feet (8,500 meters) while charging its batteries.
Just before sunset, pilot André Borschberg will decide whether or not to continue the flight through the night. Once darkness falls over the Swiss countryside, the aircraft will fly on battery power. If the night flight is attempted, Borschberg will very slowly descend to around 5,000 feet (1,500 meters) before making a dawn landing back at the home airfield in Payerne.
HB-SIA (its Swiss aircraft identifier) is a prototype design powered by four, 10-horsepower electric motors with a cruise speed of roughly 40 miles per hour (70 km/h). A total of 11,628 solar cells power the motors and charge polymer lithium batteries. With a wingspan of 208 feet (63.40 meters), the delicate aircraft rivals a jumbo jet in width, but only weighs 3,520 pounds (1,600 kilograms).
The Solar Impulse team is using today's flight to test both the aircraft and pilot capabilities that will be used when the around the world flight is attempted in 2012. By using sunshine to climb to altitude and charge batteries, the airplane will be able to fly for up to 36 hours at a time, limited only by pilot fatigue.
By flying at night, Bertrand Piccard, the man behind the Solar Impulse program, hopes to show that a solar-powered airplane is more than just a stunt. On the Solar Impulse blog posted before today's flight started, it was noted that Piccard had given a pep talk to the team reminding them "this airplane is here to prove that renewable energies are not just pornography for tree huggers."
The public can follow the flight in real time with video, graphs showing the aircraft's flight and power data, as well as a simulated cockpit of sorts showing the location.
Photo: Solar Impulse
