ENGINES.qxp_Finance 19/05/2022 13:19 Page 1
ENGINES
Making Today’s BizAv Engines More Efficient Having looked, previously, at how the leading engine OEMs in Business Aviation are focusing on reducing emissions and noise pollution, Chris Kjelgaard discusses how digital monitoring is helping make powerplants more efficient today…
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ne of the most significant developments in Business and General Aviation engine design in recent times, amounting to little less than an operational revolution, is the advent of computerized engine control and sensor-driven digital monitoring of engine performance and health. From a pilot’s viewpoint, the availability of Full Authority Digital Engine Control (FADEC) improves engine efficiency and engine performance alike. FADEC also helps reduce pilot workload in terms of the frequency of control adjustments pilots have to make to keep the engine(s) operating optimally throughout every phase of flight. FADEC makes the adjustments automatically. “Look at the PT6 E-Series, as an example,” says Nicholas Kanellias, Vice President, General Aviation for Pratt & Whitney Canada. (Note: The PT6 E-Series engine powers the Pilatus PC-12 NGX, and also the new Daher TBM 960 single engine turboprop aircraft). “The electronic engine control (EEC) provides full digital envelope protection, and is able to make the necessary adjustments to optimize and deliver the correct engine power throughout the flight.” Specifically, he explains, the EEC monitors more than 100 parameters continuously, and key engine and aircraft data are used to optimize the engine’s operation and deliver the power needed throughout the flight. “In fact, the EEC acts as a sort of cruise control,
68 Vol 26 Issue 6 2022 AVBUYER MAGAZINE
leveling out the engine’s demand on power, and thus on fuel. And, since the engine is electronically [rather than mechanically] controlled, there are fewer parts to maintain,” Kanellias adds.
Increased Fuel Efficiency
The sophistication of the latest generation of computerized FADEC, the third generation, has allowed manufacturers to introduce two new control technologies into their business and commercial turbofan engines that increase fuel efficiency yet more and reduce emissions still further. These technologies are: active turbine blade-tip clearance management; and modulated blade cooling. Both use cooling air pathways, but they do so in different ways and the pathways are in different parts of the engine. Active blade-tip clearance: works by feeding cooling air through pathways in the turbine casing which contains the turbine blade stages, in order to actively slightly expand or shrink the interior diameter of the casing. The expansion or shrinkage (controlled automatically) ensures that the tips of the turbine blades are as near to touching the interior of the casing as they can be without actually doing so, every moment of the flight. This minimizes the amounts of exhaust gas which can spill over the edges of the turbine blades without doing the useful work of turning the blades to drive the highwww.AVBUYER.com
