An Engine With Commercial Airline Smarts For GA

By Kathryn B. Creedy

There’s a new kid in town when it comes to engines and that is GE which introduced its Advanced Turboprop (ATP) last November and which is now powering the new Cessna Denali. That, in itself is impressive since it won that application against both Pratt & Whitney Canada and Honeywell.

But if you are going to compete with the 800-pound gorilla otherwise known as Pratt & Whitney Canada’s PT6 engine you better have something different. And according to General Manager Advanced Turboprop Engines Business and General Aviation and Integrated Systems Paul Corkery that’s exactly what GE has.

“We’re big on the commercial side but we thought the market needed a new centerline engine using the proven technology to manage the risk,” he told Aero-News Network recounting the eight advances that make the engine different. “What we are doing is bringing a step change performance that will make a difference especially for the 700-mile-and-below market. This has more technology for the space than has ever been done before. It will have 15% better specific fuel consumption, 20% lower mission fuel burn and 33% longer time between overhauls.”

He pointed to the compressor and its higher pressure ratio at between 10:1 and 16:1. The compact four-stage axial, single-stage centrifugal compressor delivers high efficiency in a very compact design. In addition it has variable geometry compressor stator vanes to ensure maximum performance and robust operations during all phases of flight.

It has a compact, reverse flow combustor and advanced fuel nozzles enabling efficient combustion, reduced emissions and soot and coking for reduced maintenance. The high-pressure turbine is two stages driving the engine compressor and single-crystal technology and internal air-cooling passages affording high temp operations, maximizing efficiency and power extraction.

The three-stage power turbine connects to the propeller gearbox, providing power to the propeller and maximizing the power extraction and efficiency. The gearbox uses planetary gears to supply power generated to the propeller at a significantly reduced RPM. There will be multiple versions of the gearbox to handle various RPM and SHP combinations from 840-1,650 shp. An accessory gearbox is driven by the engine core and provides mechanical power for engine accessories.

The the Integrated Propulsion Control features a dual channel, full authority digital engine and propeller control coordinating and optimizing engine/propeller operation. “We call it a digital twin,” said Corkery, who explained it mirrors the actual engine. “With this we can model your individual engine which is a unique idea for this space. We can tell the operator how to maintain the aircraft in a rough environment or a normal environment. We do this for our commercial engines and it gives us a lot of insight on how the engine is being operated and how to optimize for a specific mission. That is a big difference than what is already on the market. What excites me is we’ve come to a point where we are not just collecting data but are putting analytics to it to personalize and customize it for an individual operator’s actual missions.”

Corkery is sanguine about the challenge it faces and frankly admires what Pratt & Whitney Canada has done in the market.

“The competition has done a great job,” he said. “They are well run but its time to bring a technological step change into the market. This is a clean-sheet design using proven technology. This is a brand new centerline engine not a derivative. He already have the H series which goes to about 800 shp but we saw the need for something between 840 and 1,600.”

Production and development is completely Euro-centric gathering talent from its operations in Italy, Poland and the Czech Republic. In fact you could say the genesis of the program lies in its 2008 acquisition of Czech manufacturer Walter, which gave it insights into the general aviation market that GE lacked. The program is now fully staffed at 400 engineers culled from the three countries, impressive since the engine was just announced at November’s NBAA.

“We’ll fire the first engine at the end of 2017 and deliver the first engine to Cessna for the Denali and the end of 2018 for flight testing,” he said. “That will take about a year so we will have it certified by the end of 2019.”

The company has a lot riding on its engine including the fate of the Denali itself. “We are the new kid on the block and we know people are watching,” he said. “We also know we have to earn our way. We are humble but confident. At the end of the day we have to deliver promised performance on time to our customer because they have bet on us. We have to show the market that we can deliver.”

While the new engine is rightly aimed at the GA market, it seems perfectly timed to respond to a growing business aviation segment that is now pretty much flying under the radar and that is the small, charter/scheduled subscription airlines that are addressing a critical need in the marketplace.

Since the 1990s small communities have been abandoned by the commercial airlines. Since the advent of new airline pilot training rules, that abandonment has considerably quickened and has become a crisis in many communities that would otherwise warrant service were it not for the pilot shortage. What has really suffered is intra-regional service and intra-state service in such large states as California, Texas and Florida. In the past few years, new companies, such as Surf Air, Imagine Air, Linear Air and many others have developed to connect small-town business travelers directly to their ultimate destination. Passengers on these new operations pay a monthly subscription fee in an all-you-can-fly business model.

What is interesting about these fledgling “airlines” is the fact that 60% of their passengers are new to business aviation which indicates they are meeting a need. What they are doing is what business aviation has always done and that is give time back to the traveler now stuck in the commercial airline maze called the hub and spoke system which saps efficiency like energy on a hot, humid day.

Executives from small regionals have already spotted the market opportunity but have complained they lack an aircraft needed to exploit the market.

Corkery is aware of the potential for the ATP market for just these applications which would, of course, replay GE’s role in the post-deregulation regional airline industry when its venerable CT7 was used to power the Saab 340.

(Image from file)

FMI: www.ge.com