BEIJING 2008
Plane that flies on solar power

Swiss adventurers Bertrand Piccard and Andre Borschberg promote their prototype at the Beijing Olympics. They hope they can circumnavigate the world in 2011.
By Barbara Demick, Los Angeles Times Staff Writer
August 24, 2008

BEIJING -- It has the wingspan of a commercial airliner, the weight of an automobile and solar panels to provide enough electricity to light a very large Christmas tree.

If this strange contraption actually flies, for some it will be as great a feat as anything achieved at the 2008 Olympics.

Bertrand Piccard, a Swiss psychiatrist best known for his 1999 trip around the world in a balloon, is trying to repeat the journey in a solar-powered airplane. He and a partner, Swiss engineer Andre Borschberg, came to promote the project at the Olympics, hoping to raise money -- though they won't say how much the project will cost -- to obtain technical assistance and, if nothing else, secure landing rights from the Chinese government.

Their ambitions go far beyond getting their airplane off the ground. They see the craft as something of a billboard promoting solar energy.

Piccard's around-the-world journey in 1999 relied not only on wind, but propane gas -- 4 tons was used to keep the balloon aloft.

"It gave me the wish to fly around the world with no fuel," he said last week during a talk with reporters. "If you could fly around the world without the fear of running out of fuel, you would have a freedom that is almost perpetual."

In 1981, U.S. engineer Paul MacCready flew a solar-powered airplane across the English Channel and inventors have been tinkering with the technology ever since. But previous models of solar planes could fly only by day.

"They showed mostly the limits of solar energy rather than the potential," Borsch- berg said.

Piccard and Borschberg are developing a prototype at a former military base in Dubendorf, Switzerland. Its wings, which span about 198 feet, are covered with photovoltaic cells to convert sunlight into electricity. At night, the plane will run on excess electricity stored in batteries. The engineering challenge is to generate enough power to fly the plane and charge the batteries and to keep the weight under 3,500 pounds, about the same as a mid-size car.

"To fly day and night, we need a very efficient aircraft," Borschberg said.

A replica of the aircraft is on display at an Olympic pavilion sponsored by Omega, the Swiss watch company, which is one of the benefactors of the project. Suspended from the ceiling, the plane gets quizzical, sometimes skeptical looks.

"I think it will be a challenge. You have to make all the parts small enough and light enough. But if they can do that, it will fly," said You Changfu, a specialist in solar energy at Beijing's Qinghua University.

Piccard and Borschberg hope to conduct a test run of the single-pilot plane in the spring and by 2011 have a slightly larger two-pilot version to fly around the world.

The plane should be able to fly perpetually, unlike its pilots. When circumnavigating the globe, the pilots will have to land every few days to replenish food, water and oxygen.

To keep the airplane light, Piccard and his team said, the pilots will have few creature comforts. During the day, the plane is expected to climb to nearly 30,000 feet, but by night it should glide at about 6,500 feet to conserve battery life. Average speed will be 42 mph to conserve electricity. The journey will run west to east, against the direction of Earth's rotation, to maximize exposure to sunlight.


With such limitations, it will be a long haul before the solar-powered plane has any practical use.

But Piccard, 50, who comes from a family of adventurers, sees his plane not so much as a vehicle for getting from, say, Zurich to Beijing, but as a metaphor for renewable energy.

"The pilot will have one goal -- to reach the next sunrise before his batteries are empty. If his batteries are empty sooner, the plane will not be able to land and it will crash," Piccard said. "If we don't find a renewable source of energy before sunrise, our economy will crash."

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Solar plane makes record flight
By Jonathan Amos
Science reporter, BBC News

Solar plane's 3 day 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.

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 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.


• 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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