Longest unmanned flight-world record set by  Zephyr plane

[Sep 10] LONDON, UK--A lightweight, solar-powered plane built by British defence and security technology company QinetiQ has broken a world record for unmanned flight by staying aloft for 54 hours, the firm said Monday.
  The Zephyr, which has an 18-metre (59-feet) wingspan and weighs just 30 kilogrammes (66 pounds), smashed the previous best of 30 hours 24 minutes by nearly a whole day, flying to a maximum height of 58,355 feet.

   It then flew a second time, again beating the previous benchmark set by a jet-powered US Air Force plane six years ago with a time of 33 hours 43 minutes to a height of 52,247 feet.

    The researchers believe it is the first time a solar-powered craft has flown under its own power through two nights.

   Paul Davey, Zephyr business development director at QinetiQ, said that even if they do not clinch the new record, the aircraft had secured its place in the annals of unmanned aerial vehicle (UAV) development.

  "Both flights were achieved in the face of thunderstorms and debilitating heat in the hostile environment of the New Mexico high desert in the summertime," he said.

   "They have proved that an autonomous UAV can be operated on solar electric power for the duration required to support persistent military operations."

   By day, the Zephyr is powered by solar panels on its wings. Daylight sun also recharges lithium sulphur batteries that keep it aloft at night.