Having a plane that can fly continuously without refueling has long been a dream of military planners, but that dream might soon become reality if the QinetiQ Zephyr solar plane lives up to its billing.
An earlier version of the Zephyr managed to stay aloft for almost 3 1/2 days, but in the two years since that feat the design team from QinetiQ has made a host of improvements. They now claim that the latest version can stay aloft indefinitely, and are currently well into second week of an extended test flight to prove it.
Powered entirely by amorphous solar panels no thicker than a sheet of paper, the Zephyr weighs a mere 110 pounds despite its huge 74 foot wingspan. The long spindly wings house batteries that power the Zephyr at night, and which are recharged once daylight returns. By flying above the clouds bad weather shouldn't be an issue, and it seems like the only things limiting the flight's duration are how long the structure can physically hold together, amd how many recharge cycles the batteries can handle.
Look for the Zephyr high over sensitive enemy military installations soon.