It doesn’t matter if you drive an electric car, bicycle or use public transport on a day to day basis, your personal carbon footprint always soars when you get in an airplane. While the airline industry has been continually innovating ways of reducing the energy consumption of airplanes through the use of lightweight construction materials and new plane designs, the majority of planes today still rely on the traditional jet engine as their principal means of propulsion. That, for the most part, equates to burning large amounts of aviation fuel.
At this week’s Farnborough International Airshow in the UK however, Airbus — better known for its long-haul A380 double-deck, wide body, four-engine jet airliner — has been demonstrating its greener side with a plane that produces no tailpipe emissions whatsoever.
Enter the E-Fan, an all-electric prototype airplane which can fly for between 45 minutes and an hour on a single charge of its 10 kilowatt-hour lithium polymer battery pack. Powered by a pair of sixty kilowatt motors in turn driving a variable pitch fan, the E-Fan can generate 1.5 kilonewtons of thrust, enough to get it and its two occupants airborne and cruising at a respectable 160 kph (99.4 mph).
When on the ground, the E-Fan is powered by a 6 kilowatt electric motor mounted in the plane’s front wheel. Powerful enough for taxing, it means the main fans are switched off while the plane is on the ground.
Built using ultra-lightweight components, the E-Fan 2.0 isn’t a big plane. In fact, at just 6.67 meters (21.8 feet) in length and with a wingspan of 9.5 meters (31.2 feet) it’s one of the smaller planes you’ll see flying at a major air show. But its ultra lightweight construction is the key to the E-Fan’s airworthiness.
Like electric cars, electric motors have seemed the perfect way to power an airplane. They’re quiet, small, and ultra efficient. They also operate at a wide range of temperatures without any problems. Moreover, a surprising number of people in the airplane world, from jet engineers through to commercial pilots, glider enthusiasts and even helicopter pilots, all drive electric cars when their feet are on the ground, making electric airplanes an inevitable step for the future of air travel.
Like electric cars however, electric airplanes have been held back for years by the battery technology needed to power them. Thankfully, battery technology has finally caught up, at least to the point where an electric airplane is really feasible.
Which brings us nicely to the battery pack that makes the E-Fan fly. Housed along each inboard wing parallel to the cockpit is a series of 250 volt lithium-polymer batteries capable of storing a total of ten kilowatt-hours of power. Sandwiched into the wing itself, the batteries were picked not only for their incredibly light weight but impressive power density.
Already called the “Tesla of the skies” by many commentators, Airbus hopes the E-Fan will eventually be offered in two and four-seat variants, named the E-Fan 2.0 and E-Fan 4.0 respectively. There’s no word on official pricing yet, but rest assured the prototype shown this week in Farnborough — which made its maiden flight back in march — isn’t just a proof of concept for publicity’s sake.
At the time of writing, Airbus says we should see the E-Fan 2.0 make its official debut as a fully-fledged commercial product by 2017. Presumably, the four-seat E-Fan 4.0 will follow behind.
With such limited seating capabilities, the E-Fan will likely become something of a rich person’s plaything, but don’t think that means you’re doomed to be a heavy polluter every time you fly.
That’s because the E-Fan technology is being used in a joint project being developed by a consortium of EADS Innovation Works, Rolls Royce, and Cranfield University called the Distributed Electrical Aerospace Propulsion Project (DEAP).
While still in its early stages, DEAP has already developed something called the E-Thrust, an airplane design which operates as a hybrid aircraft. Capable of carrying up to 90 passengers, the E-Thrust plane would use two sets of powerful electric fans driven by an on-board battery pack alongside a large advanced gas turbine engine located in the tail of the plane. What’s different from a conventional aircraft however is that the turbine wouldn’t be responsible for generating thrust: it would simply be supplementing the on-board battery pack with extra power when needed to power the six electric fans.
During take off and climb, the E-Thrust would use power from the plane’s battery pack alongside power generated by the on-board gas turbine engine to produce the required thrust to lift the plane into the air.
At cruising speed, the gas-turbine would provide most of the power needed to move the plane along, with any supplemental power generated going to recharge the plane’s on-board battery pack. During decent, the turbine would switch off, and the fans would operate in the same way as regenerative braking in an electric car, recapturing energy as the plane descends to recharge its battery pack.
Naturally, the E-Thrust won’t be taking to the skies just yet — nor will it taking you on your next vacation — but in as little as ten years some of our planes, like our cars, will plug in too.
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