zephyr solar powered plane makes an unofficial world record

the UK-built zephyr - a high altitude long endurance unmanned aerial vehicle (UAV) plane -
has set a world record for longest unmanned flight by staying aloft for more than 82 hours.
that time beats the current official world record for unmanned flight set by the
US robot plane global hawk - of 30 hours, 24 minutes - and even zephyr's own previous
best of 54 hours achieved last year.

the trial, which took place between 28 and 31 july 2008, also included the participation
of the UK ministry of defense.

zephyr is an ultra-lightweight carbon-fibre aircraft, that is launched by hand,
with a wingspan of up to 18 metres but weighing just 30 kg.
it was guided by remote control to an operating altitude in excess of 18km (60,000ft),
and then flown on autopilot and via satellite communication.
it tested a communications payload weighing approximately 2kg.
during the day, the plane draws on power supplied by paper-thin amorphous silicon solar arrays,
mounted on its wings, while simultaneously charging batteries used for night operations.
'a lot of effort has gone into power storage and light-weighting the systems,' explained
chris kelleher from UK defence and research firm QinetiQ.

'lithium sulphur is more than double the energy density of the best alternative technology which
is lithium polymer batteries.'

potential applications for zephyr include earth observation and communications relay.
the principal advantage is persistence - that you would be there all the time,' said kelleher.
'a satellite goes over the same part of the earth twice a day - and one of those is at night -
so it's only really getting a snapshot of activity. the zephyr would be watching all day.'

QinetiQ is also developing UAV technology for civilian uses.


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