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Pipistrel Ajdovšcina was established in 1987 as the first private aircraft producer in former Yugoslavia. It is hard for those of us living in a free society to imagine that before that, under the totalitarian Yugoslavian regime, private aviation was virtually non-existent and it was almost unimaginable for private individuals to make aircraft at home; alternative aviation really was alternative then. Being a private aircraft producer doesn’t seem like a particularly big deal these days, but by offering an alternative to military aviation and army-regulated sports airfields 25 years ago, Pipistrel could rightfully claim to have pioneered alternative flying in Slovenia.

The airfield where Pipistrel first began flying belonged to the army, which meant that any ultralight pilots who wanted to fly had to do so in secret. They had to wait until the regular army pilots had finished flying for the day, locked up the hangars and left, before sneaking in an hour or two of flying before darkness fell.

The name “Pipistrel” actually came about as an indirect result of the restrictions on private flying. This was because, at first, Pipistrel produced only powered hang-gliders. The fact that these triangular-shaped aircraft only flew late in the evenings prompted locals to start jokingly calling them “bats”—the Latin word for which is pipistrellus.

Pipistrel’s powered hang-gliders were the company’s first big sales success, with more than 500 sold by 1995. As successful as the hang-gliders were, Pipistrel realised it would have to diversify and offer more products to customers if it were to grow, and saw ultralights as the right direction to go.

Back then, many ultralight aircraft were not too different from hang-gliders, made mainly of tubes and fabric. Pipistrel decided it wanted to offer something different—more sophisticated—and produced an aircraft that would give glider pilots the freedom to go gliding on their own, with no need for an aero-tow or a helper at the wing tip.

Enter the Sinus

The result was the Sinus—the world’s first ever two-seat motor glider to qualify as an ultralight aircraft. It was a revolutionary design: it was the first production ultralight aircraft made of composite material and it looked like a “real’ aeroplane. Not surprisingly, this brought international recognition for Pipistrel, which received more than 100 orders for the aircraft in its first year of production.

Now fitted with an 80-hp Rotax 912 engine (the first models used the two-stroke Rotax 503), the Sinus is fast, quiet, economical and versatile; for example, it can be used for lengthy cross-country flights (up to 650 nm), gliding, pilot training, aerial photography or simple recreational flying.

In 2004, a Sinus became the first ultralight aircraft to fly around the world. Pipistrel takes pride in the fact that the only modification necessary to the record-breaking aeroplane was to have bigger fuel tanks fitted.

Developing the Virus

During the four years following the Sinus’s introduction, Pipistrel received a lot of feedback from around the world. As a result, it developed a new aircraft, based on the Sinus, which it called the Virus. The new Virus, with a shorter wing (12 metres, instead of the Sinus’s 15 metres), a nose-wheel landing gear and a strengthened airframe, was optimised more for flight training.

Following the company’s practice of constant evolution and development, it subsequently modified the design further to produce the Virus SW (short wing). The Virus SW is available in three different versions: the Virus SW 80 and Virus SW 100 featuring the Rotax 912 UL2 (80 hp) and Rotax 912 ULS (100 hp) engines respectively and now, the Virus SW with Rotax 912 iS fuel injected engine for which Pipistrel was the release manufacturer.

The 100-hp Virus SW 100 is capable of a maximum speed of 160 knots and has a 75% cruise speed of 147 knots, making it the fastest ultralight aircraft in the world. In 2007, the Virus SW won several categories in the NASA Personal Air Vehicle Challenge, including the overall Vantage Prize. In 2008, it claimed the main prize in the NASA General Aviation Challenge for a combination of its low noise, low fuel consumption and manoeuvrability, and prizes for the shortest takeoff distance and best angle of climb.

Pipistrel has now produced more than 400 Sinus/Virus aircraft of various models.

The Taurus

The evolution of the Sinus into the Virus and then the Virus SW pleased the powered-flight fraternity and progressively cemented Pipistrel’s place as a leading light aircraft manufacturer. However, many glider pilots, who had praised the Sinus’s versatility, expressed a desire for even more “glider-like” features than the Sinus and wanted an aircraft with an even better glide ratio that would be more like a “real” glider.

In 2004, Pipistrel answered their requests by producing the Taurus—a side-by-side two-seat self-launching glider, which Pipistrel describes as the aircraft that the Sinus would have been had the technology been available in 1995.

Fitted with a Rotax 503 engine and retractable propeller, the Taurus expands significantly on the Sinus’s capability as a glider and has an outstanding glide ratio of 41:1—contributed to by its side-by-side seating configuration, in which the fuselage contour actually contributes to lift.

Pipistrel has also produced an electric version of the Taurus—the Taurus Electro, which is capable of climbing to 4,000 feet after self-launching. The American magazine Popular Science named the Taurus Electro as one of the ten most important aerospace innovations of the year in 2008. In 2010, the Taurus Electro won the gold medal for innovative design at the Biennial of Industrial Design awards and, in 2011, it won the Lindbergh Prize for the best electric aircraft. The Pipistrel Taurus G4, a modified double-fuselage Taurus, (featured in a previous issue of Pacific Wings) also won the prestigious NASA Green Flight Challenge in 2011.

The Apis

Following on from the success of the two-seat Taurus, Pipistrel introduced a single-seat self-launching glider known as the Apis (Latin for Bee), which has a glide ratio of 40:1. The Apis holds 10 world records in its class.

By the end of 2011, more than 100 Taurus/Apis aircraft had been sold around the world.

The Panthera

Early in 2009, Pipistrel began developing an entirely new four-seat aircraft. Every facet of the aircraft’s design has been developed in-house by the ten-person research and development team, and six people in the prototyping department.

Built of carbon-fibre, the new aircraft—the Panthera—is a high-performance four-seat touring aircraft with retractable landing gear. From the start, Pipistrel wanted its trademark high efficiency incorporated into a comfortable and aesthetically pleasing design that also had to be robust enough for operation from grass runways. The flaps and sturdy titanium trailing-link landing gear are all electrically operated.

Even the basic configuration of the aircraft is innovative, featuring a cross between a low- and mid-mounted wing. Pipistrel says this allows for a minimal cross-section that produces as little drag as possible while still accommodating the retractable landing gear and providing a comfortable cabin for four passengers. Every Panthera will be equipped with an integrated ballistic parachute rescue system as standard.

Pipistrel says that the final aerodynamic shape is more efficient than any competing aircraft so that the Panthera will have better performance and lower fuel consumption, and produce less noise than the competition.

A notable feature of the Panthera design is its modular propulsion system. The same aircraft can be equipped with an electric, a hybrid or a regular piston engine.

The Panthera’s cabin features two front doors and a single rear door, all of which open in “gull-wing” fashion. The wide cabin is designed for comfort and, with no front side pillars, the shape of the windows provides excellent visibility. The instrument panel is all glass, with three main LCD displays (the hybrid and electric versions have an additional display for the power management systems).

The piston-engine version of the Panthera uses the 210-hp Lycoming IO-390 engine, while the electric and hybrid versions use electric engines of 150 kW (100 kW continuous). The hybrid drive is identical to the electric version but with the addition of a piston-powered generator. Both the electric and the hybrid versions allow for quiet aircraft operation in the vicinity of populated areas. The batteries in the electric version are sufficient for more than two hours of flight.

Pipistrel specifically wanted the Panthera to be a true four-seater for long-distance travelling, unlike many so-called “four-seat” aircraft from other manufacturers in the past, which have typically been unable to travel any distance when carrying four people.

Pipistrel has just begun building a new facility in Gorizia, Italy, for serial production of the Panthera. When completed, the new facility will encompass 10,000 m² of floor space. In addition to Panthera production, the new facility will also house an aircraft service and maintenance operation, and a flying school. When it is fully operational, the new complex (valued at approximately €5 million) will employ up to 200 people.

The predicted price for a new Panthera is approximately €400,000. Pipistrel expects to produce around 20 aircraft in the first year of production, and plans to increase production steadily to a rate of around 200 aircraft per year by the fifth year.

In addition to the numerous awards won by Pipistrel’s aircraft over the years, the company’s founder and general manager, Ivo Boscarol, has been recognised internationally and locally for his significant contributions to industry and aviation. Among other awards, Mr Boscarol was named the Slovenian entrepreneur of the year in 2003. He received the award of the Slovenian Chamber of Commerce in 2004, the Slovenian Design Month Award in 2008, and in 2009, he was chosen as the only Slovenian entrepreneur to represent Slovenia for the International SME Week in Brussels. In 2005, he was awarded the FAI Paul Tissandier diploma for making an outstanding contribution to the field of aviation.

The Alpha

Encouraged by the success of the Virus, Pipistrel recently developed an even simpler aircraft known as the Alpha, specifically intended for flight training. Pipistrel set itself a number of important goals with the Alpha. It had to be strong and durable, easy to fly, with benign stall characteristics, easy to service, have easy access to its cockpit, it had to have tricycle landing gear, good brakes, a ballistic parachute and dual controls, a quiet cockpit, good heating and ventilation, and approved strobes and lighting. Most importantly, the Alpha had to be affordable to buy and economical to operate.

With an 80-hp Rotax engine, it has a higher cruise speed than past generations of general aviation two-seat trainers, but sips only around 10–12 litres an hour. Thus, despite having smaller tanks than the Sinus and Virus, it still has a respectable range of around 400 nm. The Alpha also has excellent short-field performance, with a takeoff roll of only around 150 metres; without the wheel spats of its siblings, the Alpha is even more suitable for grass or dirt strips.

The price of a new Alpha is only approximately €59,000, or around NZ$100,000.

Building new aircraft

When Pipistrel develops any new aircraft, it makes the first five prototypes in-house, designing and building every piece from scratch. This way, the company says it knows how every piece is built and how it will behave, and it has greater control over how the completed aircraft will behave in the real world. Once an aircraft has been tested, the design is “frozen” (i.e. not subject to further changes). Pipistrel then produces the complete documentation, chooses the production materials and decides what technology it will incorporate, makes the necessary production moulds, trains the workers and outsources production of certain parts to subcontractors.

The company maintains strict records of parts and personnel to ensure quality and safety standards throughout the process. At the end of any process, the workers involved have to sign an inspection sheet. At the end of the day, a quality control manager checks all the processes again and signs every inspection sheet. Modelled on a production system patented by Toyota, there are multiple other safety and quality control measures in place in a system that Pipistrel believes is unique in the aviation industry.

Once an aircraft is finished, it is flown for at least five hours by one of Pipistrel’s test pilots to ensure everything is functioning correctly before the aircraft is released to a customer.

ECOlution—the Pipistrel philosophy

The Pipistrel company describes its philosophy of “ECOlution” as one of sustainable and ecologically sound evolution that it applies to every aspect of its operation. Each one of its aircraft is designed from the outset to be as aerodynamically clean and smooth as possible. Eliminating drag and making an aircraft glide better, reduces the amount of power needed to fly. Less power needs less fuel and produces less noise, and less fuel means less CO₂.

The company’s ECOlution goes well beyond its aircraft designs and it stands to reason that environmentally-friendly aeroplanes can only come from environmentally-friendly manufacturing facilities. Pipistrel’s modern state-of-the-art facility in Ajdovšcina was designed to incorporate every rationally practical form of renewable energy. A great deal of planning went into producing a building that was intended to be completely energy self-sufficient with no emissions and no pollution.

One of the main ideas was to cover the entire roof of the building with photovoltaic solar panels. This required careful planning to orient the building’s axis and set the roof panels at the optimum angle to ensure maximum output during the sunniest months (May to September).

A challenge that had to be overcome to incorporate solar panels was the wind. Ajdovšcina is famous for a very strong local wind called the “Burja”, which can often exceed 200 km/h. Such strong winds would tear conventionally-fixed solar panels from the roof, so Pipistrel had to develop special brackets to secure them—which involved using the company’s virtual wind tunnel to test the design. All the careful designing, planning and testing paid off, and the roof of the building now houses the largest solar power plant in Slovenia.

In keeping with Pipistrel’s ECOlution philosophy, it was essential that the building had to fulfil its ecological function regardless of whether it was economically justified. This thinking defied the “norms” of construction, and challenged engineers and contractors.

The greatest challenge wasn’t the position of the building or the construction of its roof or carefully insulated walls, but assimilating and integrating the various energy systems in the building. Pipistrel needed to choose different energy sources carefully and pick the best available systems to control and manipulate the energy. This was no easy task, especially since the new building had to be linked with the heating and cooling systems within the existing older building. With more than ten independent energy systems in the two buildings, it was difficult to link them all into one centrally supervised and functional unit.

Extra care was taken to insulate the new facility against thermal losses. Both the roof and walls incorporate polyurethane “sandwich” panels with excellent insulation qualities, and the doors and windows are made of modern plastic materials.

The air-conditioning and heating systems both make use of glycol-filled pipes embedded in the concrete floor. The fluid is heated or cooled as appropriate by geo-exchange ground-source heat pumps.

Lighting is regulated according to the amount of daylight, while rooms are located within the building according to the tasks they must fulfil; for example, classrooms face south to receive maximum daylight, while storage rooms are in the centre of the building because they don’t need much natural light.

All major glass surfaces face north to prevent too much heat entering the building during the summer months, while the south-facing windows are covered with extended roofs or balconies. During the summer months, when the sun is higher in the sky, the extended roof provides shade for the windows and only lets diffuse light enter while keeping heat out. During the winter, the lower position of the sun in the sky allows direct sunlight to enter the building and provides additional heat.

The building’s ventilation uses energy recuperators, and the air from the welding workshop is cleaned with the help of de-ionisation.

All these systems are regulated by a central control system that calculates and regulates all the input and output parameters in the most efficient way possible.

The overall result is a building that is totally energy self-sufficient. Pipistrel claims that this results in savings of more than 180 tons of CO₂ and 95,000 kWh of energy each year.

Projects and collaboration

Pipistrel works with numerous other companies and agencies to advance aviation technology. One example is Pipistrel’s collaboration with the University of Nova Gorica to develop the application of organic solar cells to uneven surfaces. Organic solar cells represent a step forward in photovoltaic technology, as they are flexible and cheaper to produce than the commonly known silicon-based panels. Pipistrel’s engineers are researching and building prototype devices to demonstrate efficient ways of applying organic solar cell material to various bent and uneven surfaces and materials.

Another of Pipistrel’s cooperative efforts—this time with the University of Stuttgart’s Institute of Aircraft Design—is the development of a hydrogen fuel cell-powered aircraft, known as the Hydrogenius. The Hydrogenius, which is based on the Pipistrel Taurus, is intended to demonstrate the viability of pure hydrogen fuel cell-based propulsion in future aircraft.

Pipistrel in New Zealand—Alan and Donna Clarke

Today, Pipistrel aircraft are operating in 50 countries, and the company has a network of dealers and representatives in 35 countries around the world. The wide dealer network enables Pipistrel to offer personalised service to customers in a way that is relevant to their respective local conditions.

In New Zealand, Pipistrel’s distributors are Alan and Donna Clarke, who are based in Kerikeri. Alan has significant aviation experience; he learnt to fly in South Canterbury in the late 1960s and gained his commercial licence at the age of 19. After a period spent instructing, he began agricultural flying in North Canterbury before moving to Africa, where he flew for several years variously in Rhodesia, Mozambique and South Africa.

In 1977, Alan began flying helicopters in the USA but completed his helicopter qualifications back in New Zealand, where he met his wife, Donna. Alan continued a nomadic seasonal flying lifestyle for the next few years, including time spent flying helicopters on oil-support operations in South Africa.

In 1984, by the time the Clarkes returned to New Zealand (where Alan resumed agricultural flying), he had amassed more than 10,500 hours.

A career change saw Alan move into the world of finance. He became an authorised financial adviser and has written a book entitled Retire Richer.

Despite his success in the finance industry (which continues today), Alan’s passion for flight lured him back into aviation in 2004, when he decided to buy a new microlight aircraft. Wanting a “real” aeroplane and not a “toy”, he travelled to Australia to assess the Pipistrel Sinus and decided it more than met his requirements.

His experience with the Sinus and the Pipistrel company encouraged Alan to become a distributor for Pipistrel in New Zealand. Alan and Donna have now flown more than 400 hours in their Sinus, including several long-distance cross-country flights to the lower South Island. Alan says he has become more of a glider pilot than a powered pilot since flying the Sinus, spending much of his airtime with the engine switched off. He says he is a big fan of the Rotax 912 engine, which he describes as smooth and reliable, and he says it always starts in the air when needed.

The timing for Alan becoming a dealer for an aircraft type new to New Zealand—followed not long afterwards by a global financial crisis—did not do great things for sales initially, but recently, Alan says New Zealand sales have “come to life”, with this year’s orders already exceeding all previous years combined.

Alan suspects the increasing sales might have something to do with the growing recognition of Pipistrel’s credibility as a leading manufacturer and the many awards won by its aircraft for innovation and efficiency.

Panthera’s Pacific Wings connection

Early this year, Pipistrel ran an international competition for the design of a new livery for its first Panthera. The winning designer would be awarded a €1,000 cash prize and have his or her signature on the aircraft. That first Panthera would subsequently be displayed at air-shows around Europe wearing its winning livery.

The company wanted a design that enhanced the Panthera’s lines and unique characteristics; specifically, the brief was that it should reflect luxury, sportiness, speed, efficiency/environmental friendliness and safety.

Pipistrel received a total of 160 designs from around the world, including one from Pacific Wings’ own Anna Gaskell—the design genius responsible for our layout each month.

The quality of entries for the competition was so high that Pipistrel amended its original prize offer. At the end of preliminary judging, the company selected three designs that the judges liked so much that they decided to award the three finalists €500 each. Each of the three finalists was then asked to submit refined versions of their designs incorporating requests and suggestions from Pipistrel. The company then chose the best of those three and awarded that designer an additional €500.

The eventual winner of the competition was…our very own Anna Gaskell!

Pacific Wings would like to congratulate Anna on her outstanding design. As thrilled as we are that Anna’s design won the competition, it did not come as too much of a surprise, in view of her greatly appreciated eye for aesthetics and ability to interpret design briefs.

Anna is unquestionably the most vital link in Pacific Wings’ monthly publishing process and thus we could not be more thrilled than to see her recognised by her success in this international competition.

For Anna to have her signature attached to such a beautiful new aeroplane that will be displayed at major aviation events around Europe wearing her livery is a major achievement and something she should be very proud of—as we are of her.

Bloody well done, Anna!