912 iS Sport aircraft combustion engine

The Rotax 912 iS Sport is a four-cylinder, four-stroke aircraft piston engine from BRP-Rotax, with liquid-cooled cylinder heads and air-cooled cylinders, a displacement of 1352 cm³ and a maximum power of 73.5 kW (100 hp). It is a combustion engine for light aircraft, motor gliders and other fixed-wing aircraft, delivered with an engine management system and a propeller speed reduction gearbox, and it is also used as a base for light crewed aircraft and larger fixed-wing platforms that need a gasoline engine.

The key figures are as follows. Maximum power is 73.5 kW (100 hp) at 5800 rpm, which is also the maximum engine speed. Maximum continuous power is 72.0 kW (98 hp) at 5500 rpm, and a further rating of 68.0 kW (92.5 hp) is listed. Torque is 121 Nm at 5800 rpm, 125 Nm at 5500 rpm and 132 Nm at 5000 rpm when running on MOGAS without a hydraulic governor. Bore is 84.0 mm and stroke 61.0 mm. The time between overhauls (TBO) is 2000 hours. For the integrator, the take-off rating fixes the propeller design point, and the continuous rating is the figure used for cruise and mission planning.

Mass is 63.6 kg for the engine with propeller speed reduction gearbox (ratio i = 2.43) and overload clutch. Installation parts are listed separately: the exhaust system 4.8 kg, the engine suspension frame 2.0 kg, the external alternator 3.0 kg, the air guide hood 0.4 kg and the fuel pumps assembly 1.6 kg. A weight budget therefore has to add these items to the engine figure.

The fuel injection and ignition are redundant and electronically controlled, with an eco mode in the engine management system. Lubrication is dry sump with forced circulation, a separate oil tank and automatic valve clearance adjustment by hydraulic tappets. An electric starter is fitted. Fuel must have a minimum of MON 85 or RON 95 (AKI 91); leaded and unleaded fuel, AVGAS 100LL and ethanol 10 blends are listed. An engine configurator and a customised version with neutral black covers are offered by the maker.

Rotax publishes a datasheet for the engine and technical documentation, genuine spare parts and training through its service pages. Typical applications are light sport and general-aviation fixed-wing aircraft, motor gliders and the propulsion of unmanned or optionally piloted fixed-wing platforms where a certified gasoline engine with fuel injection is required.