Engine manufacturer Rotax will this year begin delivering ASTM and certificated versions of a new four-stroke, four-cylinder piston 912iS engine, with monitoring capabilities typically found only in more advanced turbofan engines.
The advanced technology offerings, developed for Rotax by Rockwell Collins, include an engine control unit (ECU), the functional equivalent of a full-authority digital engine controller (FADEC) for the fuel-injected 100hp (74kW) engine, and engine monitoring unit (EMU) that records data and provides telemetry to the cockpit.
A FADEC for a commercially available Rotax engine has been a long time coming. Starting in the early 1990s, Aurora Flight Sciences began developing digital controllers for Rotax engines for unmanned aircraft using algorithms developed by David Vos, now senior director of UAS and control technologies at Rockwell Collins.
The work later continued with Vos's start-up company, Athena Technologies, and transferred to Rockwell Collins when it purchased Athena in 2008.
Coupled with an ECU that can cut fuel burn by 21% at cruise power compared with the carburetted version of the 912, the 912iS features a data monitoring function through the EMU that will allow pilots to monitor details of engine performance never before available for small piston engines.
The EMU itself is connected to cockpit displays using a four-wire "CANaerospace" network protocol developed by Germany-based Stock Flight Systems. Company owner Michael Stock says the EMU records engine data at 10Hz and stores the data on an SD card of up to 16Mb size, allowing for 500h of recording. Owners can download an analysis program from Rotax to evaluate the data, or obtain the information via service centres.
In addition to various typical engine performance parameters, the EMU will also record latitude, longitude, airspeed and universal time using a built-in GPS/Galileo receiver built by Swiss company u-blox. Along with giving pilots the means to view flight tracks post-flight, the data could help with engine analysis by linking engine operating parameters with phase of flight, data that could be particularly useful in accident or incident investigations, says Stock.
Rotax expects to finish the internal documentation required for ASTM compliance in June and expects European Aviation Safety Agency certification approval in June or July. Rotax says the engine will cost 10-18% more than the carburetted 912 engine, depending on the aircraft model and installation.
Source: Flight International
