It’s a bit of a strange sight- three men running swiftly, each holding up an arm supporting a thin, toy-like aircraft. With one huge shove, the solar-powered, propeller-driven Zephyr-6 soared 60,000 ft into the sky, where it remained for the next 82 hours and 37 minutes. The UK-built plane has set an unofficial world endurance record for a flight by an unmanned aircraft.
Conducted at the US Army’s Yuma Proving Ground in Arizona, the Zephyr-6 flight was a demonstration designed to woo the US military. It flew for more than 3 days on pure sunlight, and by night on solar-powered batteries it had recharged during the day. The flight beats the current official world record set by Northrop Grumman’s Global Hawk in 2001. However, the achievement is technically “unofficial” because the Federation Aeronautique Internationale ( the world air sports federation that sanctions all record attempts) wasn’t involved.
A melange of new technology, the Zephyr soaks up solar power using ultra thin amorphous silicon arrays pasted atop it’s carbon fiber structured wings. As night falls, the plane is propelled by rechargeable lithium-sulphur batteries, which according to a Zephyr-6 developer have more than double the energy density of lithium-ion polymer batteries.
Military officials tend to love all things “unmanned”, especially aircraft like Zephyr-6, which could be used for preliminary surveillance and battlefield communications.