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Being Electric Doesn’t Keep This Plane From Serious Aerobatics

Friday, 5. July 2013 - 12:57

The Airbus A380 is among the biggest stars here at the Paris Air Show, but no less impressive is the sleek electric aerobatic trainer that is its distant cousin. The E-Fan is the brainchild of Didier Esteyne, an engineer and pilot with a knack for electric aircraft. Two years ago he unveiled an electric version of the diminutive Cri-Cri, which made its debut here last year. Esteyne worked with EADS — corporate parent to Airbus — on the Cri-Cri, and the two decided to team up again on what became the E-Fan.

The project got the green light in October, and Esteyne has been working frantically to finish the plane in time for Paris. This is the 50th anniversary of the show, which draws everyone in the aerospace industry to the airport where Charles Lindbergh landed after flying solo across the Atlantic in 1927. There’s always plenty of new technology on display here, and the E-Fan is at the leading edge of electric aviation.

Its most unusual aspect is the ducted fan propulsion. Rather than use a traditional propeller driven by an electric motor like other electric airplanes we’ve seen (and flown), Esteyne uses a pair of motors with ducted fans — essentially small propellers within a cowling.

“The idea was to have a little motor, with the good thrust,” Esteyne said, standing next to his airplane. The arrangement allows him to get sufficient thrust for flight using much less power than typically found in a two-seater of this size. The upside to that is, of course, the ability to use a smaller battery pack, thereby saving weight — and money. “This plane, with these dimensions, can fly with 20 kilowatts [per side], easy,” he said.

This approach is quite different than we’ve seen from the likes of, say, electric pioneer Chip Yates, who has installed a 193-kilowatt motor in the 200-mph electric airplane he built. The E-Fan will accommodate more powerful motors, Esteyne said, and a final configuration has not been set.

The E-Fan has a wingspan of just over 31 feet and a maximum weight of 1,212 pounds. Juice is stored in a pair of 250 volt, 40 amp-hour multi-cell lithium ion battery packs in each wing root. Esteyne says the current setup provides an hour’s flying at about 110 mph. To maximize flight time, one main landing gear wheel has a small electric motor that can propel the airplane up to 35 mph, which is more efficient than using thrust to taxi.

The airplane is designed as a trainer, and, as with the Cri-Cri, it is capable of aerobatics. Start doing a lot of loops and barrel rolls, though, and your range falls to 30 minutes because of the power needed for vertical flight and other maneuvers. Half an hour may not sound like much, but that’s about all the aerobatic flight the average pilot can handle anyway.

Basic taxi training has gone well, and Esteyne hopes to make an inaugural flight this fall. The goal is to see the plane certified for flight instruction and general aviation use.

Jason Paur

Source: 
www.wired.com
Tags: 
E-Fan
electric aviation