Solar Impulse 2 Plane Takes Off From Egypt On Final Leg Of World Tour (reuters.com)
How long would it take an airplane to fly around the world without using any fuel? About 22 days of actual air time, according to Fusion. Solar Impulse 2, an aircraft which is powered by solar energy, left Egypt on Sunday on the last leg of the first ever-fuel free flight around the world. The team behind it tweeted a few minutes ago that they have completed 91% of the final, last, conclusive flight. Reuters reports: Solar Impulse 2, a spindly single-seat plane, took off from Cairo in darkness en route to Abu Dhabi, its final destination, with a flight expected to take between 48 and 72 hours. The plane, which began its journey in Abu Dhabi in March 2015, has been piloted in turns by Swiss aviators Andre Borschberg and Bertrand Piccard in a campaign to build support for clean energy technologies. "The round the world flight ends in Abu Dhabi, but not the project," Piccard told Reuters a few days before takeoff. Solar Impulse flies without a drop of fuel, its four engines powered solely by energy collected from more than 17,000 solar cells in its wings. It relies on solar energy collected during the day and stored in batteries for electrical energy to fly at night. The carbon fiber plane, with a wingspan exceeding that of a Boeing 747 and the weight of a family car can climb to about 8,500 meters (28,000 feet) and cruise at 55-100 kph (34-62 mph).
Starting in March of 2015 to now isn't 22 days. It may have only been in the air for 22 days, but the trip sounds like it took about 1 and a third years.
No fuel? How does it fly with no fuel??? Magic rays?
That is actually not as "un funny" as it seems.
When the F16 was in the conception phase, they had the idea to disallow certain flight maneuvers. E.g. flying on the back etc. So they had a strict computer trying to interpret the pilots steering commands and keeping the plane in the air and follow that command as close as "reasonable".
Unfortunately they had sign error when calculating the normal vector of the planes orientation on the southern hemisphere.
Result: if you cross the equator the plane thinks you are flying upside down. According to "the rules" that was not allowed and you where flipped around. Then again: the pilot realized the plane is really flying upside down and tried to flip it around: but he could not, as the flight computer was exactly preventing that!
Interestingly this bug was found in the Simulators, before the plane even was flight ready. The idea of so much computer control as abandoned then.
Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.