Electric planes actually aren’t new, from tiny electric model airplanes up to the solar plane that is set to circumnavigate the globe in 2015.
True, the Solar Impulse HB-SIA is a purely solar powered electric plane and not much good for anything other than a proof-of-concept, that is, you wouldn’t load it with cargo and passengers or, gulp, do any acrobatic loops. Acrobatic and trainer planes are small and agile, powerful enough to perform vertical climbs and loops and rolls, everything you’d imagine seeing in a dogfight or air show.
Of course, to generate that kind of power requires engines running on some kind of fossil-derived aviation fuel, but what if you took away the fuel and engines? Could an electric plane perform the same kind of acrobatics? A new electric plane being built by EADS, parent company of Airbus, is meant to do just that, and was unveiled at the Paris Air Show this year.
Of course, the easiest way to get a lot of power is to put in big electric motors and big batteries, both of which add a lot of weight. Weight, of course, is exactly what you want to avoid adding to something that you want to put into the sky, specifically an airplane. In order to get the most out of the smallest battery packs and still have a fairly capable plane, the E-Fan uses a pair small 20kW duct fans which deliver more thrust more efficiently than open propeller designs. Using a more efficient propulsion system allows use of smaller 80kWh lithium-ion battery packs, which gives about an hour flying time at 110mph.
Didier Esteyne, the designer, says the E-Fan electric plane will also be able to do plenty of acrobatic moves, but that flight time would be cut down to about 30 minutes. Thirty minutes flight time might sound bad, but that’s about the limit of the pilots themselves when performing such maneuvers. Final specifications aren’t set, yet, and a maiden flight is expected this fall.