Flying high with Rotax engines

On water, on land and in the air!

In the turbulent years of the 1970s, the business that had started with stationary engines and continued with engines for two-wheel machines and karts moves into the development of aircraft engines. Aviation is the last bastion, the one sector that Rotax’ innovation and commitment has not yet conquered. It is not the Gunskirchen staff themselves who make the first attempts at flying hang gliders and ultralight aircraft. North American companies misappropriate snowmobile engines for use in ultralight aircraft. Illegal usage in the as yet unregulated light aircraft sector, mostly as a body-mounted engine with no intake or exhaust system and inadequate equipment, becomes a risky undertaking. Safety concerns, the irresponsible use of company products by third parties and a potential new business opportunity also prompt discussions in Gunskirchen. Rotax acknowledges its responsibility and starts developing its own aircraft engines in record time. The engineers visit air shows, build links with manufacturers and step by step acquire the expertise required to adapt Rotax engines to the operating conditions for aircraft. The criteria rapidly become clear: A high level of reliability, the “complete package” of engine, transmission, fixtures, intake and exhaust systems, and producer support are all soon delivered by Rotax. 

The glider community, initially considered “Fetzen-Flieger” (“rag fliers”) quickly becomes a high tech sector thanks to high-performance Rotax engines. (Envato Elements)

The Rotax 642 aircraft engine leads the way

Under the leadership of Karl Bablich, then Engine Maintenance Manager and an enthusiastic pilot, Rotax develops the expertise to build tailor-made engines that are licensed by the aviation authority. It starts with a modified snowmobile engine, whose two fan-cooled cylinders deliver 40 HP and which is deployed from now on as aircraft engine Type 642. Due to the different environment, the requirements for aircraft engines are especially complex and demanding. “Aircraft engines need to deliver high levels of power for low levels of weight and be twice as safe when it comes to electrics and hydraulics. And of course, that was a bit different from snowmobile engines. Once again, we brought our engine development up to a higher level,” remembers Johann Rapberger, former Manager of the Rotax Design Department. And innovation, commitment and precision really raises the game! Rotax quickly becomes popular, especially with gliders. Whereas gliders started by being pulled by winches or tow planes, their new retracting power units make these light aircraft are more mobile and flexible. A joint project with Finnish manufacturer Eiri Avion is even more favorably received. “The Finnish manufacturer of the PIK-20, Eiri Avion, approached us in 1976 to ask us to develop an engine for a PIK-20E. We then made the appropriate modifications to the Rotax Type 503,” remembers Dietrich Weiß, who worked in project planning at the time. In subsequent years, the Rotax 503 UL and its larger cousin, the 582 UL, became some of Gunskirchen’s most successful products. This engine type (503) replaces the popular but higher capacity Type 642 and over the years is used in a wide variety of products. Just like industrial engines – such as drills or water pumps – snowmobiles and ultralight aircraft use the 34 HP engine. And for decades: The engine’s performance is upgraded further to 52 HP in the 1990s, at which point noise emissions are also reduced. By the end of the long and successful history of this engine, more than 150,000 have rolled off the production line!

The modified 642 snowmobile engine can be said to be the forerunner of Rotax aircraft engines. (BPR-Rotax company archives)

Market leadership in the UL sector

By the late 1980s, four out of five ultralight aircraft (ULs) are powered by Rotax engines. The company has secured market leadership, albeit at a high price. The design requirements of individual producers are diverse and specific, with the effect that purchase order quantities are generally not sufficient to enable the then two-stroke UL engines to be mass produced cost-effectively. One proposed way out of this economic dilemma is a new engine type. On the initiative of Heinz Lippitsch, the divergent requirements are consolidated and Rotax ultimately brings all the aviation sector’s ideas together into its new four-stroke engine, the Type 912, creating the basis for a generation of high-performance engines that are compatible with many different models and sectors. The successors and redesigns made to the 2017 version of the 915 iS aircraft engine make it the ultimate in performance, consumption and quality!

Steady (further) development

Rotax has had an impressively long and intensive history of production for the aviation sector since 1973. Over 180,000 aircraft engines have left the works in Gunskirchen, underlining the popularity of the engines for the special demands made by the aviation sector. Many aircraft types, including the Ikarus, Scheibe, Falke SF-24C, Super Dimona, Kantana, Sky Arrow and Tecnam-P92 use Rotax engines. More than 250 aircraft manufacturers – which make up around 80 % of all manufacturers worldwide – put their trust in Gunskirchen performance and quality standards. “The market launch of the Rotax 912 Series was a major step forward for us and the development of our business, and of small aircraft, and remains a key contribution to cutting-edge aviation technology in general,” explains Eduard Franz, CEO and owner of Franz Aircraft Engines Vertriebs GmbH in an interview, giving Rotax’ dedication the best possible report card. It is not only partners, customers and pilots who are delighted with Rotax engines. The company’s endeavors in the development of aircraft engines are also recognized at institutional level, with the European Union Safety Agency (EASA) awarding it Design Organization Approval (DOA) and Production Organization Approval (POA) certification in 2003 and 2005.

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