Rotax says the new 912iS fuel-injected 100hp (75kW) engine it plans to begin delivering for light sport aircraft (LSA) in May will have 21% better fuel efficiency than the carburetted 912S and 30-70% better than traditional four-cylinder, four-stroke piston engines in the LSA sector.
The key component of the new engine is a Rockwell Collins electronic dual-channel engine control unit (ECU) that uses sensors to self-adjust the engine for optimum operation independent of altitude and atmospheric conditions.
Fuel injection will also remove concerns over induction system icing that can be a problem in carburetted engines at certain temperature and humidity conditions. Rotax engines, which feature dual carburettors, also need the mechanical devices balanced about every 200h for best fuel burn, a practice that will no longer be required with the 912iS.
Maintenance should also become more predictable with the ECU, which monitors engine and control system health, "detecting and mitigating potential faults and failures", Rockwell Collins says.
Based on a typical high-power fuel burn of 19 litres/h (5 USgal/h) for the Rotax 912S, the 912iS should burn 21% less, or about 15litres/h. The reduction equates to more than 20% fewer carbon emissions produced. The 912iS will cost around $12,000 more than its stablemate.
Several OEMs plan to offer the engine, including LSA market leader Flight Design with its new CTLSi model, available mid-year. Other manufacturers who have been testing or plan to offer the new engine include Evektor, Pipistrel and Tecnam.
Rotax is also working on a certificated version of the engine, which will be a likely candidate for aircraft such as the popular Tecnam P2006T twin-engined light aircraft.