Prototypes are always good if they can prove the weakest link between theory and practice. Then, the heavy industry can have the cake and make it ten times bigger, but the start and beauty of things is in the trial-and-error phase. Such is the case of Zephyr, a solar powered aircraft that took off more than seven days ago and is still aloft.
A manned airplane also powered totally by the sun has been the Impulse, that made a successful 24-hour flight, but Zephyr is a rather military application. It’s been called the “eternal aircraft”, flying over the U.S. Army’s Yuma Proving Ground in Arizona.
It only has 50 kilos (110 lbs) and a 22.5 meters (74 feet) wingspan, is powered by lithium sulphur batteries at night, and 5 people are needed to launch it.
The former unofficial solar powered flight record of 83 hours had been broken by the Zephyr, and now this. It seems the secret lies in the size: the current version is 50 percent bigger than the older ones. I can’t imagine how big should a normal passenger aircraft be in order to fly.