You're probably not going to live to see an electric 747 landing at O'Hare, but a growing number of aeronautical engineers believe electric airplanes are the future of general aviation.

They may be right.

These engineers work at places like NASA and say the battery and fuel cell technology that is pushing automobiles beyond internal combustion will do the same for light aircraft.

One company leading the way is Pipistrel and its Taurus Electro, which uses a 30 kilowatt motor to take off then glides silently on air currents. It's already received a dozen orders for the plane and plans to begin delivering them by year's end.

"We have this technology," says Tine Tomazic, the company's test pilot. "It's here now."



Electric aircraft trace their history to 1884 and the La France, a dirigible powered by chromium-chloride batteries and 7.5-horsepower motor. It flew five miles in 23 minutes to become the first airship to take off and land from the same point.

Ninety-six years later, the solar-electric Gossamer Penguin made its first flight on Aug. 7, 1980. Solar Challenger flew 163 miles from Paris, France to Dover, England in 5 hours and 23 minutes about a year later.

Solar panels gave way to the first manned battery-electric flight on July 16, 2006, when students at Tokyo Institute of Technology built an airplane powered by 160 AA batteries. It flew almost 1,300 feet in 59 seconds. Last month, Boeing successfully tested a hybrid hydrogen fuel cell-lithium ion battery airplane. The plane flew for 20 minutes using power generated by fuel cells alone.

The Taurus Electra mates an electric motor to a glider with a 48-foot wingspan. The lithium-polymer battery pack weighs 101 pounds and provides enough power to climb to 6,000 feet at a climb rate of 560 feet per minute. Pipistrel CEO Ivo

Boscarol says the battery pack recharges about as quickly as a cell phone and the Taurus Electro offers the same performance as the gasoline-powered Taurus. It will sell for around $100,000.

Pipistrel spent 1 million Euros (about $1.5 million at today's exchange rate) developing the Taurus Electro; the European Union contributed about one-third that amount to the project.

The engineers, pilots and academics who attended the Electric Aircraft Symposium in San Francisco say advancements in battery technology, composite materials and electric motors will make electric airplanes like the

Taurus Electro increasingly common. AC Propulsion, for example, is developing an 15 kilowatt motor that is 17 inches in diameter and weighs 18 pounds; it hopes to see the motors used in the Solar Impulse solar-electric airplane that will attempt to fly for 36 hours straight sometime next year.

Mark Moore, an engineer at NASA Langley Research Center, says electric motors offer many benefits over internal combustion, including zero emissions, greater efficiency and improved reliability. This allows "all kinds of freedom of design" and "new and exciting possibilities."

There are still some bugs to be worked out, not the least of which is the limited range afforded by current battery technology. Greg Cole, an engineer and designer at Windward Performance, says even the best batteries don't offer more than one hour of flight time, but he expects that to double within five years. Hydrogen fuel cells are another possibility for extended range, although they remain fairly far over the horizon.

Electric aircraft advocates say two things will spur innovation and help bring electric aircraft to general aviation. The first is a proposed "Green Prize" competition by the CAFE Foundation to reward the first airplane capable of 100 mph and the equivalent of 100 mpg. The second is the Experimental Aircraft Association's request that the Federal Aviation Administration to allow the use of electric motors in ultralight and light sport aircraft.

“The EAA community is committed to this direction,” said engineer and lifetime EAA member Craig Willen. "Man can and will develop electric propulsion for flight."

Pictures and video of the Taurus Electro courtesy Pipistrel.

http://www.youtube.com/watch?v=sIAe8ZFn_yg