They won NASA challenges for efficiency in 2007 and 2008, produce a two-seat aircraft that cruises at 147 knots on 100 hp, and now Pipistrel aims to achieve 400 passenger miles per gallon (equivalent) in their Taurus Electro G4. Pipistrel claims the twin-bodied G4 (two Taurus Electro G2 motorglider fuselages connected by a common75-ft wing) is the heaviest manned electric-powered aircraft ever built. It weighs in at 1.5 metric tons (more than 3,300 pounds), including 800 pounds of people, more than 1,100 pounds of lithium polymer high energy density batteries and supporting technology, plus the airframe. There are no plans to create a commercial product from the G4. The plan is to use it to win NASA’s Green Flight Challenge, scheduled for Sept. 25 – Oct. 3, 2011, and then adapt the powerplant for another airframe — one that is intended for commercial production and a 200 knot cruise.
NASA’s Green Flight Challenge charges entrants with beating an equivalent fuel efficiency of 200 passenger miles per gallon (miles per gallon multiplied by passengers carried) while achieving 100 mph or better over 20 miles. Pipistrel hopes to double the mark. It will be using a NASA equation to convert battery use to gallons for the sake of the competition. If the company achieves its goal, the 80kW water-cooled motor and powerplant system proven in the G4 will be further developed for use in the company’s Panthera airframe. Unlike the G4, the Panthera is conventional in appearance, but similarly mated to an efficiency optimized airframe. Panthera is expected to fly for the first time in December 2011, powered by a Lycoming IO-390. The company is targeting EASA certification of the Panthera in 2013, with deliveries to follow in the second half of that year. Pricing for the aircraft is expected to fall in at roughly 300,000 Euros (currently about $430,000). Following the piston-powered Panthera, Pipistrel says it will develop a hybrid-electric powered version and an all-electric version capable of 215 nautical miles in cruise.