One of the most exciting pieces of innovation in the past several years is Solar Impulse, the solar-powered airplane that has flown across the United States. Then, it made a 26-hour non-stop flight over Switzerland, closing the loop on potentially continuous solar-powered flight, quieting skeptics and proving once and for all that solar-powered flight is a reality.
As with all popular things, the sequel has been announced, and the stakes have been raised. Why fly from one country to another when you could fly around the world? The Solar Impulse 2 plans to take off from the Persian Gulf, heading out over India and wrapping itself around the world, only touching down to switch pilots (which seems fair).
The aircraft has a 236-foot wingspan, and is covered in 17,238 solar cells. That’s wider than a 747 (with 17,238 more solar cells than one), but the cockpit only holds one person at a time. It’s made of carbon fiber and weighs just 5,000 pounds, with engines that are 90 percent more efficient than the turbofans that drive commercial jets. During the flight, the plane will cruise at 28,000 feet to soak up the Sun during the day, dropping down to 16,000 feet at night. It only goes 40 mph, so the trip around the world will take 20 to 25, including time spent switching between pilots.
The pilots won't be having a pleasant time of it in flight: the aircraft is not equipped with heating or air conditioning, and the toilet is built directly into the seat. Sounds like quite a sacrifice for these guys, but it's for science, and for a possible future in which we fly on solar power alone. Obviously, given the speed, weight and discomfort of Solar Impulse 2, that day is quite a ways off for most of us. That said, if these men can pilot an airplane around the world using nothing but solar power, then it’s safe to say we’ve reached a new age of aviation.
The video below has more details.