Newsletter 56 – May 2011

Welcome to the Pipistrel Aircraft update for May 2011

The Pipistrel Taurus G4 is ready for the 2011 CAFE/NASA Green Flight Challenge!

After a very challenging two years of planning, design and development Pipistrel have just publically released preliminary information on their new aircraft which is competing in the upcoming 2011 CAFE/NASA Green Flight Challenge with $1.65 million prize money and the EAA Airventure Electric Flight Challenge with a very cool $60,000 prize money on offer.

The Pipistrel Taurus G4 has rolled out of the Pipistrel factory in Slovenia for the first time a few weeks ago. After two years of extensive development and research the ‘CAFE Racer’ as it has become known, posed for the camera and then rolled off almost silently under electric power for the first taxi testing and start of the flight testing program.

Pipistrel’s involvement and success in the last two CAFE/NASA challenges have taken a 180° turn with the design of this new and very special aircraft which has no similarity with the Virus SW which was successful in the previous two challenges.

This aircraft is completely new;  it’s the first four-place electric aircraft to be flown in the world. The Taurus Electro was similarly the first two-place electric aircraft to be flown in the world some four years earlier.

This unique design has come about by grafting two Pipistrel Taurus aircraft together with a centre section which is some 5 meters (15 feet) wide and includes a centre pylon housing the electric engine and batteries designed to successfully carry this aircraft to the skies and hopefully to the completion of the 2011 CAFE/NASA challenge, the design bears some similarity to the twin Mustang fighter and even White Knight Two.

The aircraft is powered by a 145 kW brushless electric motor which is centrally positioned between both fuselages and drives a large 2 meter (6 feet) custom two-blade propeller. The total wingspan is 21.4 meters (75 feet) making the aircraft wingspan not much smaller than a DC3! as a comparison. The undercarriage is retractable and the aircraft has extremely good gliding capabilities although it is not designed as a glider but as a very efficient aeroplane utilising electric propulsion.

The goal for the development of this aircraft is to enter and hopefully be successful in completing the 2011 CAFE/NASA green flight challenge which is held between July 11 and July 17, 2011 at the Santa Rosa airport in northern California and then also competing in the EAA Airventure Electric Flight Challenge held at this year’s Oshkosh event just a few weeks later.

Pipistrel’s Tine Tomazic has described the aircraft as a “technology demonstrator”. Tine is one of the main development engineers on this project and he is also the test pilot who has put the aircraft through the test flight program. Tine has also lead the design team for the electrical design and control systems in this new aircraft, but he is still very reserved at disclosing the full performance figures and flight capabilities of this exciting new machine before it debuts in the 2011 CAFE/NASA Green Flight Challenge.

Tine has however mentioned that this is ‘the most powerful electric aircraft currently developed, it has the most battery capacity on-board and it is also the first four-place aircraft to be flown under electric power’. The empty weight of the aircraft is 1065 kg with 470 kg of this being batteries, the maximum takeoff weight is 1500 kg giving the aircraft payload of 435 kg making it a real four-seat aircraft.

When quizzed about the future of this aircraft design and the possibility of it entering into production Tine disclosed that the CAFE Racer is purely a proof of concept aircraft which Pipistrel is using as a testbed for many of the same technologies which will be introduced into the recently announced Panthera aircraft which is available with a normal gasoline engine, hybrid engine and also fully electric engine. After the completion of these competitions it is expected the aircraft will be sold to somebody wanting a very unique and one-of design for personal use or to a company wanting to further investigate future propulsion technologies on an already proven airframe with the ability to quickly replace or substitute the propulsion system.

The Pipistrel Taurus G4 will arrive in the USA in the first week of June for registration, certification and ongoing testing before the start of the CAFE Challenge in July.

Safe flying, Michael Coates