However, deep in the bowels of P&WC's General Aviation organization, a future PT6 replacement effort has been underway for at least two years. Characterized by Saabas as a technology program, the initiative first emerged in public in late 2011. “We're also looking at a technology demonstration as well, particularly in areas that could be a step change,” Saabas says. “We've done demonstrations of some of the basic concepts and we will maybe marry those together. The goal is a 10-15% improvement in fuel burn. The timing of that is also a balance between what we have and where the market needs are going.”
Intriguingly P&WC's initial launch target for the new engine is the low power bracket where the PT6 originally began. “I think we'll start off at the smaller end. It's a different demographic with avgas,” says Saabas, referring to the widespread use of this type of fuel in general aviation. “We will try it out there, without calling it a PT6, and if it is successful, we'll migrate it across. We replaced ourselves on the JT15D with the PW500 and we can do it again with the PT6,” he adds.
If successful, the new engine is expected to be quickly extended up the power range. “We know we have to bring a new game to the table,” says Maria Della Posta, P&WC senior vice president of sales and marketing. “There are also changing market drivers, with new growth from emerging counties and the next generation of pilots. The current market is in need of more power—and when we introduce a new component with more advanced materials that offers more, we make it available to the others. We are bringing to the market things that are useful and practical.”
P&WC remains coy about design details. “There are just some basically smart ideas that have to be tested,” says Saabas, who adds that the engine maker is assuming the “3P” approach to development. “Production, preparedness and processes—we do that with any new product we introduce. But the key thing to the PT6 design and the market was its modularity and the ability to access the hot section on wing [without needing to remove the entire engine]. Those are the kind of features you want to maintain,” he says.
One potential option believed to be under study is a PT6-scale advanced derivative partially based on architectural elements of the recently developed PW210S. Like the PT6, this is a simple engine, with only five major rotating components. These include a two-stage centrifugal compressor driven by a single-stage turbine with a reverse-flow combustor and a free, two-stage power turbine. The power turbine drives the output shaft through a front-mounted combined reduction and accessory gearbox. The PW210 cycle also has more performance and additional temperature margin, making it fundamentally more capable. Equipped with a digital engine control system, it produces 10-20% more power for the same fuel consumption as current-generation engines and could make the logical jumping-off point for the next generation.
The company's recent experience with the development of two new engines, the PW600 for the very light jet market and the PW1000G with its bigger sister company, has given it invaluable insight into designing advanced production systems.
“Clearly, we'd use the PW600 process, just like we did with the new [PW1000G] facility at Mirabel, [Quebec,] where we apply them at a different scale,” says Saabas. The process is adapted from that used by German car maker Audi to build the R8 sports car. “The Audi R8 is a similar weight to the geared turbofan, so the PW1500G [Bombardier CSeries version] conveyer system is the R8 system. We didn't have to build and develop anything new, and we didn't have to shake it down,” he says.
Tap the icon in the digital edition of AW&ST for more on the history of the PT6 and some of the aircraft it powers, including a time line and photos of some unusual applications, or go to AviationWeek.com/pt6