GE Aviation's Czech-built Advanced Turboprop (ATP) engine has been rebranded Catalyst, as the manufacturer readies the new design for critical certification tests relating to ice crystal icing this summer.
The renaming comes more than three years after Textron Aviation selected GE’s 1,300shp (969kW) turboprop to power the Cessna Denali, in a surprise break from the aircraft manufacturer’s long association with the Pratt & Whitney Canada PT6.
“That is such an appropriate name because it is a catalyst for change,” Brad Mottier, vice-president and general manager of GE’s Business, General Aviation and Integrated Systems business, told reporters during a tour of the company’s facility for small turboprop engines in Prague.
The Catalyst so far has the Denali as its only platform, but that could change in the near future. GE expects to announce more applications for 850-1,600shp Catalyst-family engines within two years, Mottier says, declining to elaborate.
After running the first engine to test (FETT) for about 33h since late December, GE has diverted the original Catalyst serial number to launch a research programme.
The FETT is now installed in a 800-channel test rig at the Czech Technical University’s Centre of Aerospace and Space Technology in Prague. In a collaboration with GE, the centre’s researchers will use the engine to develop a database of predictive maintenance requirements for individual turboprop engines. The first test runs in the new rig will begin on 12 or 13 March, GE says.
The second engine to test, which is known within the Catalyst programme as “Engine 5”, is now in final assembly in Prague. Engine 5 will be dedicated to high-altitude testing, which now includes a requirement to certificate turboprops for ice crystal icing.
The new regulation from the US Federal Aviation Administration requires engine manufacturers to size a compressor blisk to survive an impact from an ice ball, says Gordie Follin, GE’s executive manager for the ATP engine.
Such a requirement would require a redesign that would add 1.13kg (2lb) to the Stage 1 blisk and reduce aerodynamic efficiency throughout the engine, Follin says.
However, the FAA has accepted GE’s proposal of a different approach that requires no changes to the design of the blisk. GE has proposed channelling hot oil from a sump on an accessory gearbox to the engine inlet, making it impossible for ice to survive long enough to impact the blisk in the first place, Follin says. That approach will be tested on Engine 5 later this summer in a cold weather facility in Canada.
GE launched the Catalyst programme only two years after acquiring Czech manufacturer Walter, maker of the M601 turboprop – a Soviet-era alternative to the PT6. It was the beginning of an ongoing effort to develop the first successful challenger to P&WC’s popular turboprop.
The selection by the Denali programme rewards GE for packing the Catalyst engine with technologies widely used in transport-class turbofans, but rarely seen in the turboprop-powered commuter market.
The Catalyst’s five-stage compressor boasts a 16:1 compression ratio, raising temperatures inside the core by hundreds of degrees for a normal turboprop engine in the 850-1,640shp power class. GE also inserted variable stator vanes to maximise the compression ratio at high altitude, and used cooled turbine blades so they survive the hotter temperatures.
GE also introduced a full authority digital engine and propeller control system for the Catalyst. The system will gather and transmit data for GE to build reliable models for predictive maintenance, but it will also give pilots a “jet-like experience” in the cockpit, GE says.