Pipistrel Flies The First 4-Seat Electric Aircraft In The World

The Tarus G4 ... the first 4-seat electric aircraft in the world ... took off Thursday morning at 0700 local time from Wittman Field in Oshkosh, WI. Pipistrel, the developer of the G4, said the flight was the result of long and demanding work nearly of a nearly 30-member team of developers and constructors.

The aircraft was developed in order to compete at the next NASA challenge, called CAFE Green Flight Challenge 2011. This year, the competition prize pool amounts to $ 1.65 million dollars. The competition will be held during the fifth annual CAFE Electric Aircraft Symposium held in Santa Rosa, California.

The aircraft was first presented to the public at the Oshkosh Airventure in July this year. According to the informal vote by the visitors, it was the 9th most attractive aircraft on display among 15,000 exhibited airplanes. Each year, the EAA awards a virtual “Dead Grass Award” prize (for the most viewed exhibit) to the ten aircraft with most votes.

But everything was not so easy. The electric propulsion represents an unknown factor so it presented quite some trouble for Pipistrel. It was a great challenge even to import the aircraft into the United States because it is powered by 450 pounds of lithium-polymer batteries, which can in certain circumstances be highly flammable. It was also extremely difficult to find an insurance company in the U.S. which was prepared to insure such aircraft.

The company also had to find an American test pilot - the FAA requests that the first test flights must be performed by an American test pilot and CAFÉ competition rules also demand an American pilot to fly the aircraft at the race. Fortunately, the Taurus G4 received huge media interest during the exhibition in Oshkosh, so consequentially, the team managed to find an insurance company and convince it to accept the insurance challenge.

After the Airventure expo, when the huge airport complex emptied, the friendly airport crew allowed Pipistrel to use the airport hangar and runway for testing. Thus the Pipistrel team achieved the historic flight Thursday morning.

Pipistrel's new, twin-fuselage plane was created by combining two Taurus G2 fuselages, connected by a 5-meter-long spar. A 145-kilowatt brushless electric motor, developed for the new Pipistrel's 4-seat aircraft Panthera, is mounted between the passenger pods and drives a six-foot-diameter, two-blade propeller in tractor configuration. Taurus 4’s full wingspan is about 75 feet. The undercarriage is retractable which enables good gliding ratio and low drag, paramount for the success at the competition. Despite not being intended as a glider, the superb aerodynamic profile gives the G4 an edge over the competition, since the goals of the challenge are mostly aeroefficiency and economic flight.

“The Taurus G4 NASA Racer is a technology demonstrator,” said Tine Tomažic, Pipistrel development engineer and the leader of the G4 development team. “It is the first-ever electric four-place aircraft, the most powerful electric aircraft with most battery capacity on board.” He declined to disclose just what that capacity is (it is a race secret), nor did he disclose the aircraft’s “very high glide ratio” other than to say it’s more than 30 at cruise speed (100 mph). These and other aircraft details will be released at the GFC, he said.

All components of the aircraft have been developed and made by Pipistrel. Aerodynamic studies have been entrusted to prof. dr. Gregor Veble, Head of Research at Pipistrel. The construction of the aircraft was accomplished by dr. Vid Plevnik in cooperation with engineer Rado Kikelj. The development of composite technology parts and systems was done by Sašo Kolar and  Franci Popit with their teams. The most challenging part, namely the development of electronic systems and their regulation as well as the system for charging the batteries were developed by engineer Jure Tomažic with his team.

FMI: www.pipistrel.si