Soaring on solar power alone
Aircraft to fly around the world without fossil fuel to make point about climate change
ABU DHABI, United Arab Emirates — With its wings stretched wide to catch the sun’s energy, a Swiss-made solar-powered aircraft took off from Abu Dhabi on Monday in a historic first attempt to fly around the world without fossil fuel.
Solar Impulse founder André Borschberg was at the controls of the single-seat aircraft when it lumbered into the air at the Al Bateen Executive Airport. Borschberg will trade off piloting with Solar Impulse co-founder Bertrand Piccard during layovers on a 35,000-kilometre journey.
Some legs of the trip, such as over the Pacific and Atlantic oceans, will mean five days and five nights of flying solo. The journey will span 25 flight days over five months before the aircraft returns to Abu Dhabi in late July or August.
“It is also exciting because you know, you simulate, you calculate, you imagine, but there is nothing like testing and doing it in real,” Borschberg said.
The Solar Impulse 2 aircraft, a larger version of a single-seat prototype that first flew five years ago, has a wingspan of 72 metres, larger than that of the Boeing 747. Built into the wings are 17,248 ultraefficient solar cells that transfer solar energy to four electrical motors that power the plane’s propellers. The solar cells also recharge four lithium polymer batteries.
At 2,300 kilograms, the Si2 weighs about as much as a minivan or mid-sized truck. An empty Boeing 747, in comparison, weighs 180,000 kilograms.
The Si2 is heading first to nearby Muscat, Oman, where it will land after about 10 hours. A typical passenger jet takes an hour to make the same journey.
Although the aircraft’s average flight speed will be 70 km/h, Piccard says the optimal speed for the lightweight Si2 — made of carbon fibre — is at about 25 knots, or 45 km/h.
Borschberg has been practising yoga and Piccard self-hypnosis in order to calm their minds and manage fatigue during the long solo flights. They aim to rest a maximum of 20 minutes, repeating the naps 12 times over a 24-hour period. Goggles worn over the pilot’s eyes will flash lights to wake him up.
Neither pilot will be able to stand in the cockpit while flying, but the seat reclines for stretching and its cushion can be removed for access to a toilet.
Armbands placed underneath their suits will buzz if the plane isn’t flying level. The plane does not have a pressurized cockpit so Borschberg and Piccard will feel the changes in temperature. The pilot’s blood oxygen levels constantly will be monitored and sent back to ground control.
The plane will reach an altitude of about 8,500 metres during the day to catch the sun’s rays and at night dip to about 1,500 metres when flying over the ocean.
After two stops in India, the Si2 will head to China, where it will stay for a month until the days are longer to catch more of the sun’s energy. It will also make stops in Myanmar, Hawaii, Phoenix, Ariz., and New York’s John F. Kennedy International Airport. The path across the Atlantic will depend on the weather and may include stops in southern Europe or Morocco.
Borschberg and Piccard say the flight is to make the world “confront the Conference on Climate Change of the United Nations, which will define the new Kyoto Protocol in December 2015 in Paris.”