Future flights: fuel for liftoff, batteries at 30,000 feet

OSHKOSH, Wis. — An electric airliner?

Imagine a hyper-efficient aircraft as large as a Boeing 737, although weighing much less. It would run quieter and cleaner than any other commercial plane, requiring two-thirds less energy, according to NASA-funded research.

The hybrid-powered jetliner of the future would operate on batteries or jet fuel, depending on whether it's cruising or taking off and climbing, when the most thrust is required.

The concept of electric aircraft generated a resounding buzz amid the drone of pistons and the roar of gas-turbine jet engines at the Experimental Aircraft Association's annual AirVenture air show that wrapped up Sunday at Wittman Regional Airport in Oshkosh.

Boeing is working on a concept plane called the SUGAR Volt that would use turbine engines and electric motors connected to the fans to propel the electric airliner more efficiently. On flights of up to 900 miles, the SUGAR Volt would cruise almost exclusively on battery power, said Marty Bradley, a technical fellow at Boeing's Research and Technology division in Huntington Beach, Calif.

An electric propulsion system would help slash the amount of fuel burned as well as noise around airports by about 70 percent compared to today's airliner fleet, say aerospace researchers who believe they can have such a flying machine up and running by about 2035.

That's a critical environmental issue. The number of commercial flights will double or triple within 50 years, according to some estimates.

"We want to make the airline industry less sensitive to high fuel prices, as well as address air pollution and noise," Bradley said.

On a smaller scale, a competition is under way to develop by next year a personal commuter aircraft that operates on electricity or fuel cells and can average at least 100 mph on a 200-mile flight while achieving greater than 200 passenger mpg. The Green Flight Challenge, sponsored by NASA and the CAFE Foundation, offers a $1.5 million first prize for the aircraft with the best performance.

Some competing teams presented their designs at the Oshkosh air show. Participants included aerospace engineers and students at Embry-Riddle Aeronautical University, Georgia Tech, Penn State University and the University of Colorado.

"The concept is winnable. The engineering still needs to get done," said Jack Langelaan, an assistant professor at Penn State.

Small planes or jumbos, disadvantages include the weight of battery packs and the lack of range that current battery technology provides.

Among the major challenges is improving the amount of power a battery can store for a given weight, said Stephen Beecher, director of advanced technology for power management at GE Aviation.

"You've got to replace a tank of gas with some other fuel source that is not combustible and that you can change somehow to electrical energy," Beecher said.

Electric propulsion will be a "game-changer and transform aeronautics in the next 20 to 30 years," predicted Mark Moore, an aerospace engineer and conceptual design expert at NASA. Moore said the first breakthroughs will occur with small aircraft, personal air vehicles that will replace the automobile on some trips; an expansion of unmanned aerial vehicles, currently used by the military, to civilian use; followed by much more environmentally responsible commercial transport planes.

Moore and his NASA colleagues are developing a one-person, all-electric aircraft called the Puffin Gridlock Commuter. The 12-foot-long Puffin would take off and land vertically and be powered by an electric motor and rotors. The goal is to produce one-tenth as much noise as the quietest helicopter today, he said.

"It means being able to take off and land closer to where you live and work in a much more community-friendly, lower-emissions aircraft," Moore said.

"If we are able to do that, we can get away from the idea that the only way to get around in an on-demand way is through cars and ground congestion," he added. "More people will be able to take advantage of the expansive country that we have."