Pratt & Whitney Canada (P&WC) and GE Aviation are working on new-generation turboprop engines for the 90-seat regional aircraft that may be launched in the coming years. While P&WC is studying a clean-sheet design, dubbed Next-Generation Regional Turboprop (NGRT), GE is planning on a derivative of the GE38 turboshaft: the CPX38
The NGRT is being designed for 90-seaters, in the 5,000- to 7,000-shp power range. The precise level of power will depend on the cruise speed and size of the aircraft. “With the same technology, we could go up to 8,000 shp,” said Richard Dussault, Pratt & Whitney Canada’s marketing v-p.
“In April, we started running some stages of the compressor,” Dussault told AIN. As part of a technology demonstration program, P&WC (Hall 4 Stand D12) is designing a core engine that may run as soon as mid-2013. The entire compressor is scheduled to run in January next year. Engineers will endeavor to validate the compressor’s key parameters–airflow, efficiency and pressure ratio–before building the rest of the core.
The core will be made of the compressor, P&WC’s Talon combustor and a high-pressure turbine that will draw elements from the PW1000G geared turbofan. Should the company find a launch customer in the coming months, the core may start running in 2014. If that happens, engineers would use the extra time to design a core that will be more representative of the production configuration.
Flight tests will be part of the development program. At its flight test center at Montreal Mirabel airport, P&WC has added a dedicated pylon, for turboprops and small turbofans, to one of its Boeing 747 SP flying testbeds. “One of our differentiators is our ability to test, validate and certify a complete propulsion system with the nacelle, propeller and accompanying control system,” Dussault emphasized.
Certification could happen in 2017, should the program be launched next year. The NGRT’s main features are fuel burn and maintenance. Over in-service PW100s, it would cut fuel consumption by 20 percent. In addition, maintenance should be simplified thanks to the Fadec’s diagnosis and prognosis capabilities. Time on wing should increase and maintenance costs be cut by 30 percent, according to Dussault.
Meanwhile, GE (Hall 4 Stand B7) is studying its CPX38 turboprop for aircraft “for 70 to 90 seats and higher.” Its power would be in the 4,000- to 6,000-shp range. No hardware change would be needed from a 70- to a 90-seat application, just tailoring the cycle, Tim Varga, GE’s manager of small commercial turboprop programs, explained to AIN.
As the GE38 turboshaft is in development, some tests have been performed for a potential turboprop derivative. Specific high-altitude testing has been done, for example, to measure fuel efficiency and margins. The GE38 is to power the Sikorsky CH-53K heavy twin-engine helicopter.
The CPX38 could enter into service in 2017 if launched now. Typically, such a test program would use four to six test engines, not including flight-test engines, Varga said. He insisted turboprops need to maintain a competitive advantage over turbofans. Therefore, a lot of effort is to focus on cutting fuel burn further.
French engine manufacturer Snecma is understood to be also considering a turboprop for 90-seaters. It did not respond to questions from AIN about the possible program.