Slovenian aircraft manufacturer Pipistrel is entering next month's NASA/CAFE Green Flight Challenge with an unusual electric airplane built in mere months specifically for the competition.

The Taurus G4 is a test bed to develop a high-power electric propulsion system. It features twin fuselages, room for four and the biggest electric motor we've seen bolted to an airframe. In a nod to the early days of aviation, when new designs went from idea to runway in just weeks or months, the airplane came together remarkably quickly.

"The airplane was designed and built in the course of four months," Pipistrel's Tine Tomazic told us at the big Airventure airshow, adding that the G4 was built specifically for the NASA/CAFE Green Flight Challenge. "Its sizing and aerodynamic features, as well as the power train and battery capacity were matched to the requirements."

The competition, which begins Sept. 25, is aimed at developing highly fuel-efficient, yet practical, aircraft. Competitors must fly at least 200 miles in less than two hours while averaging at least 200 seat miles per gallon. With its four seats, Tomazic believes the Taurus G4 has a distinct advantage if Pipistrel can meet the performance requirements.

Tomazic works in research and development for Pipistrel and is coordinating its Green Flight Challenge effort. The Taurus G4 was built entirely in house, and mostly of carbon fiber with some Kevlar here and there. It is essentially a pair of Pipistrel's Taurus self-launch glider fuselages joined by a single wing.

But the most interesting part is the powerplant.

Mounted between the fuselages is a 150 kilowatt (200 horsepower) electric motor. It is the most powerful electric motor seen thus far in an all-electric airplane design.

All that power requires plenty of energy. The Taurus G4 carries more than 1,100 pounds of lithium polymer batteries. Tomazic wouldn't elaborate on the details, but says there is more than 75 kilowatt-hours available via the company's proprietary management system.

The airframe is very light. Although the aircraft weighs roughly 2,350 pounds empty, nearly half of that is the battery. Maximum takeoff weight is 3,300 pounds.

Tomazic says the airplane is purely a demonstrator, with no plans for production.

"The configuration is not classic, so I doubt people would like it as their private plane," he says.

Pipistrel is using the G4 to develop the motor, battery and power management system for a more traditional design. The company sees great potential in the drivetrain.

"This would be an ideal power level to be put in a bigger, three- or four-seat airplane," Tomazic says. "A performance airplane."

Pipistrel has been around 25 years and produces several light sport aircraft and motor gliders. The Taurus Electro is a self-launch glider powered by a small electric motor, which helps the pilot attain sufficient altitude for soaring. But Tomazic mentions the company's new Panthera as the plane slated to receive the powertrain being developed on the Taurus G4.

This sleek four-seat aircraft is aimed more at traditional aircraft rather than as a soaring airplane. Tomazic says the plane should make its first flight by the end of the year; he expects to see deliveries by the middle of 2013.

The airplane's motor glider roots are evident in the long, high aspect ratio wings.

The rapid pace of development we're seeing in electric airplanes has drawn comparisons to the early days of aviation, when new ideas and designs came quickly. Tomazic says the comparison isn't lost on anyone, and evolving technology requires moving quickly to bring ideas to market.

"I think we're sort of in the dawn of electric flight, maybe compared to the times after the First World War," Tomazic says. "A lot will happen, there will be many hits and misses. But in the end somebody will get it right and we'll be on track."

Pipistrel continues to cover its bases developing gasoline powered airplanes in parallel with electric airplanes. Like other companies, even hybrid power is in the works.

The company is no stranger to the Green Flight Challenge, which recently received a big sponsorship from Google. The company won the contest in 2007 and 2008 and could be the team to beat this year.

Photos: Jason Paur/Wired.com