Plane & Pilot
Tuesday, June 21, 2011

A New Era Dawns: Electric Flight

An update on airplanes in production, competition prizes and R&D

Big-Bucks Electric Marathon

Joining the competition money prize list is the 2011 CAFE/NASA Green Flight Challenge, with a whopping $1,650,000 prize to be awarded. Comparative Aircraft Flight Efficiency Foundation (CAFE), presents a daunting challenge: The contestants must fly a 200-mile course in no longer than two hours. Here's the catch: They can use no more than the energy equivalent of a single gallon of gas per occupant. The plane that uses the least amount of power, whether it's gas, biodiesel, hydrogen (in an electricity-producing fuel cell) or battery, will be the winner.

As of press time, half of the 12 confirmed entries for the July race were pure electrics:
• PC-Aero Elektra One
• Feuling GFC
• Windward Performance GosHawk
• eGenius (flown by Sunseeker's Eric Raymond)
• Phoenix Air's PhoEnix (one-off mutation of the LSA motorglider, flown by Jim Lee). It's a two-seater, so it can use up to twice the maximum energy potential of one gallon of gas.
• Pipistrel Taurus Electro G4. With four seats, legal to carry up to four gallons' worth of electrical energy.

Later in the month, EAA's Oshkosh AirVenture will offer its own Electric Flight Challenge, and award $60,000 to the individual or corporation demonstrating the most promising level of achievement in electric-powered flight. Not to be outdone, Europe has the CAFE-like Paris-Madrid Green Aviation Challenge to reward the aircraft that uses the lowest amount of energy on the trip.

Building Up A Charge

So many projects, so few pages: Several sailplane manufacturers, capitalizing on models that stay aloft with a miser's expenditure of fuel, are converting them to electric power, or creating new self-launcher models.

Noteworthy are Italy's Alisport Silent 2 Targa single seater, sporting a retractable propeller, the Air Energy AE-1 Silent with a 13 kW (17 hp) motor that brings 400 fpm of climb, and the Windreich Arcus-E, a two-seat production sailplane with a 42 kW motor (56 hp) and enough battery storage for up to one hour and 10 minutes. Time to get that glider rating!

Many also are available, gas-powered or unpowered. One, the Alatus-ME ultralight sailplane, can be packed up like a hang glider and carried on a car top, yet has an impressive 27:1 glide ratio and a 127 fpm sink rate. Current cost: $50,000.

R&D continues apace: Long-time kit maker and Oshkosh 2010 LEAP winner Sonex first flew its electric Waiex in late 2010. Helicopter giant Sikorsky has its Project Firefly electric eggbeater demonstrator, which may fly this year. Boeing has its Fuel Cell Demonstrator (FCD) to explore the utility and applications of fuel cell-powered electric propulsion. Another fuel-cell bird is the Italian SkySpark, which flew successfully in 2009.


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