Electric plane in pilots' future?: Oshkosh firm uses batteries to power prototype

Jul. 25--OSHKOSH -- Batteries power cell phones, laptops and kids' toys and could some day, perhaps soon, power airplanes that will be so quiet that only the spinning propellers will make noise. An Oshkosh manufacturer of experimental kit aircraft...


Jul. 25--OSHKOSH -- Batteries power cell phones, laptops and kids' toys and could some day, perhaps soon, power airplanes that will be so quiet that only the spinning propellers will make noise.

An Oshkosh manufacturer of experimental kit aircraft unveiled a plane Tuesday at EAA AirVenture with an electric motor power plant, controller, lithium polymer battery pack and charging system.

Though the innovative technology from Sonex Aircraft isn't ready for sale yet, judging by the reaction of the aviation enthusiasts who crowded around the proof-of-concept plane there's a demand for alternative fuel-powered planes.

"This is so cool," said Jim Reichard of Naperville, Ill. "Good idea."

Sonex founder and President John Monnett said the electric plane will be capable of speeds of up to 135 mph and flight time of 45 minutes to one hour, which would meet the need of most sport fliers who take their planes up for a spin once or twice a week. The plane will likely interest aerobatic pilots, too, though its likely flight time will be 15 to 20 minutes for aerobatic maneuvers.

The goal is for plane owners to "plug it in, fly it an hour, plug it in again and fly it tomorrow," Monnett said.

As the use of batteries in other applications has grown, Sonex's research and development team figured the natural progression was to come up with a way to power a plane using batteries. Though self-launching electric powered gliders are already flying, Sonex is betting on the potential for electric power to attract more pilots.

Tuesday morning, aviation enthusiasts crowded around the open cowling of a yellow Sonex kit-built plane to ogle the black plastic box containing the battery and the red, coffee-can-sized electric motor. Monnett said the proprietary parts of the technology are being kept under wraps while Sonex continues to work on the project.

But what Sonex officials did say is that the lightweight unit is a three-phase, 270-volt, 200-amp motor that will be more than 90% efficient. It uses computer-machined anodized aluminum and nickel-plated steel parts and weighs in at a svelte 50 pounds.

The battery system includes eight lithium polymer battery packs in each of 10 battery safe boxes that will be cooled by foam padding and a cooling inlet that allows air to blow over them. The battery boxes will be removed from the plane and charged individually.

Though batteries are now widely used in the automotive industry's growing hybrid market, the question is what happens when an electric plane's battery system goes dead in the air.

"It's the same thing if you run out of gas in a gasoline-powered plane," said Mark Schaible of Sonex. "You have to monitor your fuel."

Schaible noted that pilots could still guide their plane to safety if the battery runs out of juice.

Reichard is building a $14,000 Sonex kit plane and figures if the battery engine is ready by the time he finishes his aircraft he probably will install one since there would be "no buying gas, no dependence on oil and it'll be smoother and quieter."

Also intrigued by the electric plane was Richard Piatkowski, a retired electrician from Delavan who flies with the Flying Hawks flying club out of Palmyra. But before he gets on board, Piatkowski wants to know the price and how often the batteries would need to be replaced.

"I would definitely be interested in it, but I'm concerned about the cost. The range, too, 45 minutes (flying time) isn't a lot, but it's nice to see you can get by without using fossil fuels," said Piatkowski, who earned his pilot's license in 1976.

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