912 iS aircraft combustion engine

The Rotax 912 iS Sport is a four-cylinder, four-stroke aircraft piston engine from BRP-Rotax, rated at 73.5 kW (100 hp) for take-off. It is a combustion engine for light aircraft, with electronic fuel injection and ignition, and is also sold as the 912 iSc Sport version. Its four cylinders are cooled by a combined liquid and air system.

The engine is built for fixed-wing light aviation and similar aircraft that need a piston power plant with an engine management system. Integrators receive it with a propeller speed reduction gearbox, fitted with an overload clutch, and an electric starter.

The main figures are a maximum power of 73.5 kW (100 hp) at 5800 rpm and a maximum continuous power of 72.0 kW (98 hp) at 5500 rpm. Torque is 121 Nm at 5800 rpm and 125 Nm at 5500 rpm. Bore and stroke are 84.0 mm and 61.0 mm, giving a displacement of 1352 cm3. Maximum engine speed is 5800 rpm. The time between overhauls is 2,000 hours. For an integrator, the continuous rating is the figure that sets cruise power, and the shorter take-off rating is for climb.

Mass of the engine with gearbox (ratio 2.43) is 63.6 kg. Installation items are listed separately: exhaust system 4.8 kg, engine suspension frame 2.0 kg, external alternator 3.0 kg, air guide hood 0.4 kg and fuel pumps assembly 1.6 kg. Lubrication is by dry sump forced circulation with a separate oil tank, with hydraulic valve tappets that adjust automatically. The fuel system is redundant, with two channels of injection and ignition, and an eco mode is available. Fuel can be leaded, unleaded, AVGAS 100LL or ethanol 10, with a minimum of MON 85, RON 95 or AKI 91.

Cooling by liquid and air, an engine management system and the gearbox are part of the delivered engine, so the airframe needs mainly the suspension frame, exhaust, intake and fuel supply. Typical applications are light sport and general aviation aeroplanes, motor gliders and other light aircraft, including unmanned airframes of that size class.