GE CPX38

A new General Electric turboprop engine, derived from the 7,500-shp GE38-1B turboshaft engine, could become available by the middle of the decade. GE has designated the new engine study CPX38, and is basing it on the turboshaft that will power the U.S. Marine Corps’ new heavy-lift helicopter, the Sikorsky CH-53K. This could mean that the CPX38 would be in the 5,000- to 6,000-shp range. The only Western turboprop now in production in that category is the Pratt & Whitney Canada PW150A, which powers the Bombardier Q400.

GE left the high-powered turboprop segment after production of the GE CT7-9-powered Saab 340 ended in 1999. This market, which GE estimates will see 1,800 deliveries in the next 20 years, remains one of the few in which the company does not command a presence. Although the company says it is in discussions with airplane manufacturers, it has not yet named an application for the proposed CPX38. The engine could spawn lower-powered variants to fit both civil and military turboprop applications.

The CPX38 would help the company leverage the significant investment it has made in the GE38-1B turboshaft, which is based on the GE27 technology demonstrator and the U.S. Navy’s T407 turboprop engine. The GE27 served as the basis for the CFE738 turbofan, which powers the Dassault Falcon 2000. GE also has used the derivative-engine approach for the CT7-9 turboprop, which was derived from the CT7-8 turboshaft engine.

Pratt & Whitney Canada is prepared to launch a next-generation turboprop engine for an aircraft in the 90-seat range next year for EIS in 2016, according to VP-Marketing Richard Dussault. Meanwhile, GE Aviation GM-Regional and Large Business Aviation Chuck Nugent said the company continues to develop the CPX38 turboprop engine, which would be a derivative of the GE38 helicopter turboshaft and could be ready for a 2016 EIS.

Speaking to reporters on Tuesday at the Regional Airline Assn. Annual Convention in Nashville, Dussault said P&W Canada has "defined an engine in the 5,000-7,000 shp [shaft horsepower]-class" for a next-generation turboprop. The PW150A powering the Bombardier Q400 offers a maximum 5,071 shp.

The company is aiming for 20% better fuel efficiency compared to the PW100/150 family with an engine that will feature a "brand new core," Dussault explained. In conjunction with Hamilton Sundstrand, P&W Canada is working to develop a "fully integrated propeller system" for the engine, he added.

He noted that P&W Canada plans to test the first components for a next generation turboprop engine this summer. "By the end of next year, we will have run a full core demo," Dussault said. "We're planning to do flight testing as soon as we have a customer."

Nugent said that while there is no formal CPX38 program, the development of the GE38 for Sikorsky Aircraft's CH53K helicopter ordered by the US Marine Corps., which is slated for first flight later this year, would enable GE to quickly transition to launching a next-generation turboprop engine program. "Timing is such that … we could support a 2016 entry into service with our CPX38," he told reporters at the RAA conference.

He added that the CPX38 would deliver "15% lower fuel consumption than [turboprop] aircraft today" and will feature a "completely integrated propulsion system." He noted, "As we talk to airlines around the world, there is a strong interest in turboprops … There is a lot of eagerness on what we can deliver on this product from the airframers also."

Airlines are ready for a stretched turboprop, Dussault asserted: "I think they'd like it tomorrow if they could get it. It's a great way for airlines to reduce their seat mile cost for the aircraft … [With fuel prices rising, it is] increasingly difficult for airlines to earn money on short-haul routes."

ATR CEO Filippo Bagnato recently told ATW, "In the medium term, I’d say five years, there will be an opportunity for an airplane a little bit larger than a 70-seater, and on that we are preparing ourselves to be ready when the requirement will come in a more clear way from the airlines." Bombardier VP-Marketing-Commercial Aircraft Philippe Poutissou has said the manufacturer is "still evaluating the market" for a larger turboprop, but conceded, "The trend with respect to regional aircraft has been to go to larger models and certainly some of our operators would like to see [a stretched Q400] and we’re discussing it with them"(ATW, May 1).

GE Aviation is “ready to go” on a new engine to power 70-90 seat turboprops as well as a next generation regional jet powerplant, and awaits decisions from airframers, says Allen Paxson, the company’s general manager for small commercial engines.

The CPX38 turboprop engine could be ready for operations within 36 months once a manufacturer orders it because the core of the engine would be the same as the GE38 developed for military helicopters, which is being readied for service on CH-53 Marine helicopters in 2015 or 2016, Paxson said May 22 at the Regional Airline Association Annual Convention in Minneapolis.

“We want to leverage that to the turboprop market. We think we have a turboprop engine that’s ready. Obviously, the next step is that we’re looking for an airframe . . . We have been talking with all of the airframers on the turboprop side," he added.

GE Aviation expects a fuel efficiency improvement of about 15% when compared to current Bombardier Q400 engines, although Paxson cautions that the comparison is not exact because of differences in thrust.

But while the engine manufacturer is ready, it is beholden to the airframers, and representatives from ATR and Bombardier seemed in no rush to make a decision about a new turboprop when interviewed at the convention.

Mark Neely, VP of marketing and sales for ATR, says the larger turboprop is “certainly something we continue to look at,” but describes the study as ongoing with more feedback expected from airlines this year. He would not commit to any decisions in 2012, but says most potential customers still want turboprops optimized for the 300 to 350 mile range.

Similarly, Philippe Poutissou, VP, marketing for Bombardier Commercial Aircraft, says the company is studying the desirability and requirements for a higher-capacity Q400.

GE Aviation is working on a new turboprop engine, dubbed the CPX38, to fly on the next generation of 70- to 90-seat turboprops.

The CPX38 will be based on an existing core and could enter the market by the end of the decade—or within three years at the earliest.

“We think the turboprop market is going to continue to be a very vibrant part of regional operations and we are planning to offer an engine in this segment,” GE Aviation regional aviation engine operations GM Allen Paxson said, speaking at the European Regions Airline Assn. (ERA) General Assembly in Dublin.

The CPX38 will be based on the GE38 core, which is going through final testing for an application on the Sikorsky CH-53K Super Stallion helicopter.

“We have an engine today that we believe is ready for an airframe,” Paxson said. “We are in discussions with the airframers on what their needs are going to be. It will be low-risk, on a proven architecture.”

Paxson said GE is aiming for a 15% improvement in specific fuel consumption (SFC) with the CPX38, although “that moves around” depending on optimization. The engine is being tailored for severe operating environments and the target is 99.95% reliability.

The number of blades is likely to increase, compared with today’s typical six-bladed variants. “Currently we are targeting for an eight-bladed prop. The prop diameter may get larger; we are trying to maintain the noise levels. Whether it is six, eight or 10 blades, we’ll work on that as we integrate it with the airframe.”

GE has already incurred the development costs for the GE38 and Paxson said it could take “just one reasonable market” of 400-500 aircraft to launch the CPX38.

“We are continuing to develop the GE38 and putting together partnerships, for the nacelles, etc to make sure we are ready for airframer when need us,” Paxson said. “We expect the CPX38 to come out this decade, if we can find an airframer.”

The lead time, from when the airframe has been identified to final certification, would be about three to four years.

Paxson essentially rules out the potential to re-engine an existing airframe with the CPX38. “This is for a larger size aircraft so really we are looking for an aircraft with a greater max empty weight with 60, 70, 80 or 90 seats, so bigger than the current aircraft today.”