When pilots John Alcock and Arthur Brown became the first to fly a plane non-stop across the Atlantic 97 years ago, incentives included a 拢10,000 prize put up by aviation-mad owner Alfred Harmsworth, worth about $1 million today.
Such competitions spurred innovation and helped usher in the global aviation system we have today, which has utterly transformed the world.
Attempts to set flight records continue 鈥� but are less about cash prizes, and certainly less to do with shrinking the world.
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A case in point is the Swiss-led attempt to circumnavigate the globe in the sun-powered aircraft . This, too, is poised to cross the Atlantic, but will take five days rather than the 15 hours Alcock and Brown clocked up in June 1919.
With 17,000 solar cells covering iridescent wings as broad as a jumbo jet鈥檚, and more than half a tonne of lithium batteries to store solar power and keep its four electric motors going at night, it鈥檚 effectively an outsized, motorised glider with cramped room for just one.
It is no proto-airliner: it only weighs as much as a large car. And that comparison is apt, because its potential for sparking a revolution in the near term lies in more efficient electric motors and batteries with high energy density that could transform life on the ground, as we try to shake off fossil-fuel dependence and seek more efficient ways to store solar energy for use at night.
As the plane鈥檚 creators state, everyone could use the same technologies on the ground to halve global energy consumption, save natural resources and improve quality of life.
Flight hazards
But pushing the limits of electric flight to make this point in the skies was never going to be easy.
Solar Impulse 2 began its circumnavigation in Abu Dhabi in March 2015, flying to Oman, India, Myanmar, China and Japan. Its greatest feat followed that June, when it flew 7200 kilometres for five days from Japan to Hawaii. This won exhausted pilot Andr茅 Borschberg a world record for of any kind, and also that for the longest solar-powered flight.
But celebrations were short-lived. Postflight analysis found the batteries lost storage capacity after overheating, so Borschberg鈥檚 flight team faced a stark choice: risk flying over US cities to reach New York with maybe too little power to escape from, say, weather trouble; or delay for four months while new batteries were shipped to Hawaii and flight-tested. That delay would push them into autumn, when days would be too short for solar-powered flight 鈥� adding a further four months to their grounding.
Neither was an attractive option, but they decided to delay until April 2016 and replace the batteries at huge cost. 鈥淚f you fly over people, you don鈥檛 want to take any risks,鈥� says Borschberg.
But they may have been overcautious: once the overheated batteries had been shipped back to their assembly plant in Germany, says Borschberg, engineers discovered they were undamaged and could have been used to carry on flying. They had lost just 1 per cent of their storage capacity 鈥� well within safety margins.
Such mystery battery problems suggest that solar-powered flight is a work in progress, with many unknowns to iron out. But pushing the technology to its limits in this way will undoubtedly lead to lessons that prove useful down on the ground.
Delays aside, this global flight is not about speed but the politics of energy. It鈥檚 a slow revolution 鈥� but a welcome one.
