Monday 19 February 2018

Slow but steady solar-powered plane could herald era of batteries

Solar Impulse 2 began its globe-circling trip last year (AP)
Solar Impulse 2 began its globe-circling trip last year (AP)

Chris Michaud

An airplane powered solely by energy from the sun headed across the Atlantic early yesterday, on one of the longest legs of the first-ever flight around the globe without using a drop of fuel.

The spindly, single-seat Solar Impulse 2 left New York's John F Kennedy International Airport at about 2.30am on a trip expected to take up to 90 hours, the 15th leg of its round-the-world journey.

The craft is in some ways a throwback to the early years of flight, with the latest transatlantic crossing recalling John Alcock and Arthur Brown's 1919 journey that famously ended in a Galway bog.

On the current trip, Swiss aviators Bertrand Piccard and Andre Borschberg have been taking turns piloting the plane, which has more than 17,000 solar cells built into wings whose span exceeds that of a Boeing 747, with Piccard at the controls for the transatlantic flight.

The airplane's slow cruising speed, similar to that of a car, has required both men to take up meditation and hypnosis as part of training to stay alert for long periods.

Solar Impulse 2 is due to land some time on Thursday in Spain or France, with the precise location to be determined later depending on weather conditions, said Elizabeth Banta, a spokeswoman for the project team.

The carbon-fibre, propeller-driven plane has four solar-powered engines and four batteries to store surplus energy.

It weighs the same as a family car and can climb to 28,000 feet (8,500 m).

The team behind Solar Impulse - part of a campaign to build support for clean energy technologies - hopes to complete the circumnavigation in Abu Dhabi, where the journey began in March 2015.

Piccard and Borschberg completed a multi-flight crossing of the United States with an earlier version of the plane in 2013.

Borschberg set an endurance record for the longest non-stop solo flight last July in a 118-hour trans-Pacific crossing from Japan to Hawaii.

Piccard's trans-Pacific crossing this year, reaching San Francisco after a flight of nearly three days, took more than three times the 18 hours celebrated airwomen Amelia Earhart took to fly solo from Hawaii to California in the 1930s.

The propeller-driven Solar Impulse is slow, but potentially revolutionary.

Its four engines are powered solely by energy collected from solar cells built into its wings.

That requires a wingspan exceeding that of a Boeing 747, but the carbon-fibre plane is much lighter. The aircraft can cruise at speeds of 34 to 62 mph (55 to 100 kph), around 10 times less than conventional flights.

Surplus power is stored in four batteries during the day, to keep the plane aloft on extreme long-distance flights.

In a precursor of their globe-circling quest, the two men completed a multi-flight crossing of the United States with an earlier version of the solar plane in 2013.

Battery damage sustained during the crossing kept the aircraft grounded for nine months.

The Swiss team's ultimate goal is to achieve the first round-the-world solar-powered flight, part of its campaign to bolster support for clean energy technologies.

The team hopes eventually to complete its circumnavigation in the United Arab Emirates, the starting point for the journey back in March 2015.

The trip has been slow going, battery damage kept the aircraft grounded for nine months. (Reuters)

Irish Independent

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