The Rotax 912 ULS is one of the most popular and trusted aircraft engines in light aviation. In production since the late 1990s, it has earned a reputation for reliability, low weight, efficiency, and versatility, making it a preferred choice for microlights, light sport aircraft, gyroplanes, UAVs, and many experimental/homebuilt planes.
The Rotax 912 ULS is a four-stroke, four-cylinder boxer engine, liquid- and air-cooled, with a displacement of 1352 cm³. It produces 100 horsepower (73.5 kW) at 5800 RPM and features a reduction gearbox that optimizes propeller speed relative to engine RPM. This configuration provides smooth operation, low vibration, and excellent fuel efficiency. The engine is known for its mechanical simplicity and robustness while delivering impressive performance for its weight class.
A major advantage of the 912 ULS is its fuel flexibility. It can operate on both AVGAS 100LL and unleaded automotive gasoline (MOGAS), offering lower operating costs and easier fuel access around the world. Typical fuel consumption is between 15 and 18 liters per hour in cruise, making it one of the most economical engines in its category.
The engine uses a dual ignition system for increased safety and reliability. Cooling is achieved through a combination of liquid-cooled cylinder heads and air-cooled cylinders, ensuring stable operation under high loads and hot conditions. Its low dry weight contributes to excellent weight distribution and payload capacity in small aircraft.
Maintenance is straightforward, and the TBO (Time Between Overhaul) is 2000 hours, reflecting its reliability and high-quality engineering. The 912 ULS is also known for easy starting and smooth running, even in cold conditions, requiring minimal warm-up time compared to older engines.
This engine has powered many well-known aircraft, including the ICP Savannah, Pipistrel Virus, Tecnam P92, Diamond DA20 Katana, and Zenith CH701. Over the years, it has set the benchmark for modern light aircraft engines—fuel-efficient, reliable, lightweight, and versatile.
In summary, the Rotax 912 ULS embodies Rotax’s philosophy of delivering maximum performance with minimum weight and fuel consumption. It remains a cornerstone in the evolution of modern sport and recreational aviation and continues to be one of the most respected and widely used engines in its class.
