News & Current Affairs

August 24, 2008

Solar plane makes record flight

Solar plane makes record flight

A UK-built solar-powered plane has set an unofficial world endurance record for a flight by an unmanned aircraft.

The Zephyr-6, as it is known, stayed aloft for more than three days,
running through the night on batteries it had recharged in sunlight.

The flight was a demonstration for the US military, which is
looking for new types of technology to support its troops on the
ground.

Craft like Zephyr might make ideal platforms for reconnaissance.

They could also be used to relay battlefield communications.

Chris Kelleher, from UK defence and research firm QinetiQ, said
Unmanned Aerial Vehicles (UAVs) offer advantages over traditional
aircraft and even satellites.

“The principal advantage is persistence – that you would be
there all the time,” he told BBC News. “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. Zephyr would be watching
all day.”

Deployment close

The latest flight was conducted at the US Army’s Yuma Proving Ground in Arizona.

The Zephyr flew non-stop for 82 hours, 37 minutes.

Altitude infographic NOT TO SCALE (BBC)

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.

However, the Yuma mark remains “unofficial” because QinetiQ did
not involve the FAI (Federation Aeronautique Internationale), the world
air sports federation, which sanctions all record attempts.

The US Department of Defense funded the demonstration flight
under its Joint Capability Technology Demonstration (JCTD) programme.

This programme is designed to advance the technologies American commanders would most like to see in the field.

“We think Zephyr is very close to an operational system – within
the next two years is what we’re aiming for,” Mr Kelleher said. “We
have one more step of improvements; we trying to design a robust and
reliable system that will really sit up there for months; and we want
to push the performance.”

Energy density

The trial, which took place between 28 and 31 July, also included the participation of the UK Ministry of Defence.

The 30kg Zephyr 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.

Zephyr (QinetiQ)

Zephyr should be in commanders’ hands within two years

At first sight, the propeller-driven Zephyr looks to be just another
model aircraft, and it is even launched by hand. But this “pilotless”
vehicle with its 18-metre wingspan incorporates world-leading
technologies.

Its structure uses ultra-lightweight carbon-fibre material; and
the plane flies on solar power generated by amorphous silicon solar
arrays no thicker than sheets of paper. These are glued over the
aircraft’s wings.

To get through the night, the propellers are powered from lithium-sulphur batteries which are topped up during the day.

“A lot of effort has gone into power storage and light-weighting
the systems,” explained Mr Kelleher. “Lithium sulphur is more than
double the energy density of the best alternative technology which is
lithium polymer batteries.

“They are an exceptional performer. We’ve worked with the Sion
Corporation. They’ve had them in development for years. We’re actually
the first application in the world for them.”

Vulture venture

Zephyr has demonstrated that it can cope with extremes of
temperature – from the blistering 45C heat found at ground level in
Arizona’s Sonoran Desert, to the minus 70C chill experienced at
altitudes of more than 18km (60,000ft).

The engineers from the Farnborough-based company are now
collaborating with the American aerospace giant Boeing on a defence
project codenamed Vulture.

This would see the biggest plane in history take to the sky,
powered by the sun and capable of carrying a 450-kilo (1,000lb)
payload.

US commanders say the design must be able to maintain its
position over a particular spot on the Earth’s surface uninterrupted
for five years.

QinetiQ is also developing UAV technology for civilian uses.

It has been working recently with Aberystwyth University on
field monitoring trials, plotting areas of ground that may or may not
need fertiliser applications.

Zephyr (QinetiQ)
Lightweight plane (30-34kg/70lb) is launched by hand
Coms or surveillance payload of about 2kg (4.5lb)
Flies autonomously and can climb to more than 18km (60,000ft)
By day, Zephyr flies on solar power and recharges its batteries
Advanced amorphous silicon solar arrays supplied by Unisolar
Rechargeable lithium-sulphur batteries supplied by Sion Corp
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5 Comments »

  1. Does anybody have any idea what speed this vehicle attained?

    Could 450kg support a single human passenger, including water and an air pressurization system?

    If so, this could be the future of personal air travel…

    Comment by dnamax — August 24, 2008 @ 10:50 pm

  2. Now, if only they could design a
    similar UAV made of carbon fiber
    and astrogel, it would be about 1/4
    the weight of the present one.

    Comment by dr burke — August 25, 2008 @ 12:54 am

  3. I don’t understand why they couldn’t fill the
    wings with nitrogen for lift? Also, when the Sun heats the nitrogen gas, it will expand and then it could be compress by a small on board compressor, for storage. When Sun goes down,the gas is released back into the system to turn a small turbine to provide a charging current, to the electric engines. And the gas output of the turbine, is released back into the wings to await another heating/cooling cycle.

    Much like the heating/cooling cycle of a refrigerator. And it would be self contained and reusable day after day. One would think

    dr burke

    Comment by dr burke — August 25, 2008 @ 1:05 am

  4. I’m sorry, in addition, I meant to say that will eliminate or greatly reduce the weight of li-ion batteries for night time flying; except for
    a few backup batteries, just in case the
    inner workings fail and juice is needed for
    guidance/control/navigation situations.

    dr burke

    Comment by dr burke — August 25, 2008 @ 1:15 am

  5. One more thing to consider, put the nitrogen gas under high pressure(?), to enhance the
    compressor/turbine cycle. As a matter of
    fact, you could also eliminate the solar
    cells and use only a closed system, of heat,
    expansion, compression, turbine cycles to
    fly the UAV. One would think.

    Comment by dr burke — August 25, 2008 @ 1:31 am


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