23 Jun 2016 19:25 IST

Electri-flying: Clean aviation takes wing with Solar Impulse

While all-solar flights are impossible as yet, firms have flown small electric planes or larger hybrids

As I write this, the all-solar-powered plane Solar Impulse is somewhere above the Atlantic ocean, making the second-last leg of its global circumnavigation. An amazing feat, indeed. Not an ounce of liquid fuel was used in the entire journey.

So, the question on everybody’s lips is, will ‘solar flying’ ever become the norm in commercial aviation?

Much as you’d like to say nothing is impossible in future, especially in technology — I mean, if we can go to the moon, we could theoretically go to the Jupiter — one would have to admit that solar-powered commercial flying is, at the moment, something like, well, flying to the Jupiter.

Impractical, for now

Somebody calculated that to lift a Boeing 757, you would need solar panels to generate 1,500 times as much energy as they do now. So, hmmm….sigh….solar flights have to be dismissed as impractical for the time being.

Was the Solar Impulse effort a waste? (For those who have missed out on the Solar Impulse adventure, it is a two-seater aircraft with solar panels all over the body and wings and two enthusiasts, a pilot and a doctor, are flying around the world in it, hoping to be ambassadors of green flying.)

No, the Solar Impulse was not a fancy toy in the sky. There is a non-solar part to it as well. How did they fly during the nights? By storing the solar power generated during the day in batteries. That highlights a new flank in aviation — electric flying.

NASA and Airbus efforts

Last week, the US aeronautics and space agency, NASA, gave an official designation to one of its experimental aircraft. The newly-named X-57 is an electric propulsion plane. By the way, the boys there have nicknamed it Maxwell, in the memory of James Clerk Maxwell, the 19th century English scientist who did ground-breaking research into electro-magnetism. The X-57 is part of NASA’s $790-million, 10-year programme called New Aviation Horizon.

NASA’s idea is to develop technologies for electric-powered aviation. Some have described the effort as ‘Tesla in the sky’.

Today, aviation is one of the worst carbon emitters, next only to coal-based power plants. A concerned world is racking its head over which clean fuel can power future aircraft. At the moment there are two answers: cleanly produced electricity and hydrogen. But electricity, stored in batteries, seems to be a little closer to reality.

While NASA’s Maxwell is described in the media as something with potential to change the course of aviation history, across the Atlantic people have moved a little ahead.

Commercial aircraft manufacturer Airbus has demonstrated its first all-electric aircraft, the two-seater E-Fan.

Powered by an array of 250-volt lithium-polymer batteries, the E-Fan made aviation history when it hopped across the English channel, taking 35 minutes for the effort, in July 2015. The E-Fan is expected to go into production in 2017, and the plane will be used for training purposes. However, Airbus wants to bring a four-seater version into production by 2019; the E-Fan 4.0 could be offered for private aircraft ownership.

But that is only for starters.

Hybrid short-haulers

Airbus is working towards bringing a 100-seater electric plane that would nip across short hauls of around 1,000 miles. These may not be all-electric, but hybrid. Conventional (or hydrogen?) engines could power the aircraft while take-off and landing, and electric motors could take over while on the cruise mode.

While the Airbus and NASA endeavours are steps meant to move aviation into a different trajectory, several smaller companies have, for long, been experimenting with and offering electric flying. Two names are noteworthy: Sonex Aircraft LLC, a sports flying company that makes assemble-able kits, and Pipistrel, a manufacturer of light aircraft. Both have had success with battery-powered flying. (Incidentally, Pipistrel won an order in 2011 to supply 194 aircraft to the Indian Air Force, the Indian Navy and the National Cadet Corps —though not for electric-powered aircraft.)

With the tailwinds of climate change blowing stronger, electric flying can be expected to soar. Oil companies, please take note.

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