Newsletter 64 – March 2012

ROTAX, a name that is synonymous with light aircraft, LSA aircraft and even military drones and in a co-operation with Pipistrel today marks a very important milestone in the history for ROTAX with the release of the new fuel injected 912 iS aircraft engine.

This new engine the ROTAX 912 iS produces 100 hp from what is basically the same engine core as the 912 ULS with the exception that the carburettors are gone, now replaced with modern fuel injection. This relieves the engine from carburettor imbalance and provides perfect start-up/shutdown and idle just like a modern car. The choke has gone and the engine responsiveness has been increased substantially along with a 21% reduction in fuel consumption over the existing 912 100 hp engine.

As the world’s leading supplier of aircraft engines for Ultralight and LSA aircraft, ROTAX aircraft engines have truly revolutionized the aircraft industry. The popularity of these engines continues to soar higher and higher, from the original two-stroke engines through to the modern four stroke engines ROTAX produce an engine for just about every aviation application and many hundreds of non-aviation applications.

The 4-stroke 4-cylinder boxer engines we are now familiar with and known as the ROTAX 912 series started development in 1984 having advanced technology and superior weight/performance ratio and have propelled experimental, Ultralight, LSA aircraft and motorgliders for many years gaining themselves an enviable reputation for reliability, low noise, fuel efficiency and most important actually reaching the TBO times. ROTAX aircraft engines are available in two configurations including fully certified engines as well as noncertified engines; both are very similar and enjoy a fantastic reputation.

Today is a significant milestone for both Pipistrel and ROTAX with the release of the 912 iS engine, ROTAX have chosen Pipistrel as the 912 iS release customer and the engine has been fitted and tested on the award-winning Pipistrel Virus SW aircraft. Those that have flown the aircraft report increased smoothness, faster throttle response, lower idle and most importantly for the environment less fuel consumption for this exciting new engine.

Now a little history lesson.

1920    The company was founded in Dresden, Germany as ROTAX-WERK AG.

1930    Taken over by Fichtel & Sachs AG, the company transfers its operations to Schweinfurt/Germany.

1943    The company’s operations are relocated to Wels, Austria.

1947    The company’s operations get relocated to Gunskirchen near Wels.

1959    This year sees LOHNERWERKE GmbH of Vienna acquiring a majority shareholding.

1962    For the first time, a ROTAX engine is installed in a Ski-Doo snowmobile developed by bombardier.

1970    This year sees integration of Bombardier and ROTAX. The former Bombardier Inc. branch BRP, now an independent company, uses ROTAX engines in its motorcycles, personal water craft, and snowmobiles.

1977    High orders of snowmobile spare engines ROTAX 185, 248, 284, 294 are also used in Ultralight aircraft.

1978    Ultralight engines 501, 505 developed (based on snowmobile engine 503).

1982    The company begins development of ROTAX 4-stroke aircraft engines, a landmark in ROTAX history.

1983    The company starts producing ROTAX motorcycle engines for APRILIA.

1984    Start of sales of ROTAX 912 engines.

1988    The company starts producing ROTAX marine engines for Bombardier Sea-Doo watercraft.

1989    Type certificate for ROTAX 912A

1993    The company starts producing ROTAX motorcycle engines for BMW, Germany.

1994    Type certificate for ROTAX 912F.

1996    Type certificate for ROTAX 914F.

1998    Type certificate for ROTAX 912S.

1998    The company starts producing ROTAX engines for Bombardier ATVs.

2000    The company begins initiation of The ROTAX Quality Production System (RQPS).

2001    Launching of ROTAX 4-TEC 4-stroke engines for Sea-Doo watercraft.

2002    This year witnesses the launch of the new 2-stroke semi-direct electronic injection technology: ROTAX 2-TEC engines for Ski-Doo snowmobiles, plus the launch of the ROTAX Kart RM1 with direct drive (without chain).

2003    Sale of Recreational Products Group by Bombardier Inc.; Foundation of Bombardier Recreational Products Inc. (BRP) with BRP-ROTAX as part of the new company.

2003    Approving BRP-ROTAX as International Design Organization according to JAR-21, the European Joint Aviation Authorities (JAA).

2005    85th anniversary of ROTAX is celebrated and 35 years with BRP.

2005    912 / 914 Series compliant to Light Sport Aircraft ASTM Standards.

2006    Production of the 6 millionth ROTAX engine.

2006    582 engine compliant to Light Sport Aircraft ASTM standards.

2008    ROTAX stars manufacturing the 1125 cc Helicon liquid-cooled, four-stroke, fuel-injected 72˚ V-Twin for the Buell Motorcycle Company.

2009    912 Series TBO (Time Between Overhauls) increased from 1500 hours to 2000 hours

2010    914 Series TBO increased from 1200 hours to 2000 hours

2012    Release of the new ROTAX 912 IS engine

More than 150,000 ROTAX Aircraft Engines have been sold since 1973. Today, ROTAX manufacture the 582 engine series (2-stroke) and the 912 / 914 engine family (4-stroke). All these engines are approved for use with Ethanol 10 fuel, MOGAS and AVGAS.

Considering the approved usage of MOGAS and the low fuel consumption the fuel costs of a ROTAX 912 series engine are up to 50 % lower than for a comparable 100 hp air-cooled piston engine. With low operating costs, leading class power to weight ratio, well known reliability, it is no surprise that ROTAX Aircraft Engines are the first choice of more than 200 aircraft manufacturers worldwide and today Pipistrel is proud to be involved as the release aircraft manufacturer for this new exciting milestone for sport aviation.



The three-year development period included more than 1,000 hours on the test bench and 700 test hours in the air, BRP stated. The revamped engine is now in production and being delivered to OEMs with production slated to ramp up in May 2012.

BRP engineers modified just about everything on the old 912, and have incorporated technology enhancements such as a fuel injection system instead of the dual carburetors and digital ECU to the to ensure optimal fuel and air mixture at any altitude. The same aircraft now will feature much longer flight range, lower operating costs, and CO2 emission reduction. The new 912iS also has the same 2,000 hours TBO.

The biggest advantage of the new engine according to the manufacturer is lower fuel consumption – 21 percent less than the carbureted version. Pilots will also benefit from the wide use of the new engine management. Other advantages of the 912iS: no manual choke, no carburetor icing, and having to synchronize two carbs is no longer required.

Fuel injection is more precise, thanks to the ECU that constantly optimizes the air-to-fuel mixture resulting in better efficiency with lower pollution. Sensors monitor engine – airbox – vacuum, exhaust gas temperature, ambient air pressure, inlet air temperature, liquid coolant temperature, and throttle position. The engine self-adjusts for different atmospheric conditions and altitude.

Externally the 912iS has a new “green” look with green-painted cylinder head covers, and on the upper side of the cylinder heads, green plastic covers that hide the most evident difference: the metal fuel rails and double fuel injectors on each cylinder head. Even if the Rotax folks say that the “i” engine has a same size (actually they say it is a “bit” smaller), the area on top of the cylinders now looks bigger and a little bit taller than on the 912S. The upper-rear portion of the engine has a fancy, plastic, car-like airbox with a single throttle body and air filter. The engine block is now painted black, along with the rear engine end with the new generator.

A lot has changed under the hood. The engineers have modified cooling of the liquid-cooled heads that was needed for the implementation of the fuel injection system. The lower portion of the engine block features a deeper “V” form and the crankshaft has been modified, along with several other small details.

Unlike the proven Rotax 912S, the 912iS has a lot of electronics on board. There are three new boxes containing dual (electric) fuel pumps, the fuse box, and the ECU controller. Even omitting two carburetors, the engine dry weight increased almost 9 pounds (15 pounds if the twin fuel pumps and other equipment are included). That means 140 pounds total dry weight.

The electrical system underwent major changes compared to the carbureted engine. The electrical “powerplant” (generator) now delivers 430 watts of electric power and consists of two separate generator blocks that use the same single rotor. One is only dedicated to the ECU (13 amps) and the second is serving the aircraft electrical system with 30 amps. The generator is now the “wet” type, meaning it’s inside the engine immersed/cooled by the crankcase oil. The “i” engine uses the battery only for cranking the engine, which means battery loss in flight doesn’t affect the engine operation. The engine is, of course, fully redundant, having two independent and redundant ECUs that drive double injectors and double spark plugs for each cylinder.

Safe flying, Michael Coates