400 miles per gallon, in a plane


Just before soaring like a graceful bird over a mesmerized crowd at Moffett Field on Monday, a Slovenian-built electric plane was declared the most efficient airplane in the world and won the biggest money-prize in aviation history: $1.3 million, donated by Google.

The Pipistrel Taurus G4 made its record-breaking 200 mile flight over Sonoma County last week. The twin-fuselage design carried an unprecedented payload for an electric plane, four passengers and 1,000 pounds of lithium-polymer batteries. And it was pulled by the most powerful electric motor ever put in an airplane, with 194 horsepower, according to Pipistrel officials.

At an average speed of 100 miles per hour, the result was the electric equivalent of 101 miles per gallon of gasoline, or 403.5 "passenger miles per gallon," as the competition multiplied each plane's mileage by the number of seats.

Google sponsored the contest, which provided $1.65 million in prize money to the contestants, including $80,000 for the second place E-Genius plane, an electric two-seater from Stuttgart University in Germany which achieved 375.8 passenger miles per gallon.

The event was organized by NASA and the Comparative Aircraft Flight Efficiency Foundation. The foundation has been running such contests since the gas crisis of the 1970s, when 20 miles per gallon was a major feat for a plane. Technology has changed rapidly.

"Two years ago, the thought of flying 200 miles at 100 miles per hour in an electric aircraft was pure science fiction," said Jack Langelaan, leader of Team

The Slovakian-built Pipistrel was flown by David Morss of Redwood City and Robin Reid of Independence, Ore. Concrete blocks took the place of two additional passengers. The Pipistrel was the only plane in the competition that could hold more than two passengers.

The E-Genius and the Taurus G4 were the main contenders in the event as the only purely electric planes.

In comparison to the electric planes, a gasoline-powered entry from Florida, the Phoenix, was able to achieve 94.3 passenger miles per gallon with two passengers. Like the other planes in the event, the Phoenix is based on a glider. It weighs half what the electric planes do at just 754 pounds when empty.

Aviation journalist Dean Sigler was enthusiastic about what may be a bigger accomplishment than most people realize, even in the aviation world.

"If your car were going 100 miles per hour you wouldn't get anywhere near that efficiency," Sigler said.


Like this comment
Posted by Lorrie
a resident of Old Mountain View
on Oct 10, 2011 at 2:45 pm

Unlike cars, airplanes can go straight. No winding roads on the way to Tahoe. That saves over 25% of the distance in addition to the speed advantage.

Like this comment
Posted by ugh
a resident of Blossom Valley
on Oct 10, 2011 at 11:13 pm

so they copy one of Burt Rutan;s designs, put an electric engine and 1000lbs of LiPo cells in and win $1.3M. pretty cool, but hardly revolutionary.

Like this comment
Posted by Jeff
a resident of Old Mountain View
on Oct 11, 2011 at 4:43 pm

Dear ugh, so you really think that looks like the Rutan design? Only very generally, with several very big differences. You are missing a great deal in your rush to make a dismissive remark.

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Posted by ugh
a resident of Blossom Valley
on Oct 11, 2011 at 9:24 pm

I just don't get it... what about the design is revolutionary? OK, so it is a variation in the Rutan Voyager/global-flyer twin boom concept, but with an electric motor. I'm sure there is something to it, as it won what was a stiff competition, but the article gives no clues as to why it was the victor... it would be like saying an internal combustion engine passenger car won a competition with 200mpg, without any insight into what they did differently.

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Posted by Alex M.
a resident of Willowgate
on Oct 11, 2011 at 9:44 pm

Actually Pipistrel is a rather innovative aircraft company in its own right. They don't need to copy other designs. Their web site Web Link is interesting, especially the "extreme flight" events that their aircraft compete in. An earlier version of their Taurus (not the twin-boom G4 but a more conventional looking electric sailplane) won the Lindbergh competition earlier this year. Unfortunately their site doesn't have any information on the G4 yet, that I could find.

Sorry, but further commenting on this topic has been closed.

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