Paris Air Show

P&WC’s work on C Series leads to bizjet possibilities

 - June 14, 2007, 6:37 AM

Having passed responsibility for an engine for the planned Bombardier C Series 110- to 149-seat jetliner to its U.S. parent, Pratt & Whitney Canada (P&WC) says time devoted to the exercise has not been wasted. Rather, it is contributing to work on a 10,000- to 14,000-pound-thrust design–dubbed X10–aimed at a future generation of large business and corporate jets.

Work on a C Series engine moved south of the U.S./Canada border after Bombardier discussions with airlines drove power requirements beyond the 20,000-pound-thrust threshold that defines respective P&WC and parent company Pratt & Whitney product ranges. The Canadian subsidiary’s facilities in Quebec do not have, for example, the test cell or lifting capacity to handle engines of the emerging size required for the proposed new airliner–which otherwise would have become its largest offering.

P&WC is now applying its initial C Series design experience to continuing research and development (R&D) efforts that involve 18 engine projects, including as many as seven new designs, according to executive vice president John Saabas. The balance of activity comprises mainly variants of current products that will offer, for example, new power settings.

Saabas said the X10 program, which could produce an engine to power a new Bombardier family, Cessna’s large-cabin concept or Dassault’s super-midsize long-range jet, represented “an example of taking a compressor and scaling it up and down, so we can re-use some C Series work.” This project had a potential application on a future turboprop engine more powerful than the current PW100 regional airliner powerplant “if we ever want one that big,” said Saabas.

Separately, a five-year, C$1.5 billion program of R&D investment that began in 2006 will cover work that will include development of combustion, emissions, materials, manufacturing and noise technologies that will contribute to existing products as well as next-generation engines.

Suppliers of turboprop-powered regional airliners have enjoyed a market renaissance during the recent positive economic cycle, which historically has driven demand for passenger capacity, leading to higher production rates and increased turboprop design activity. Saabas said build rates for the PW100, which powers ATR and Bombardier regional airliners, have “doubled since 2003, so we are almost [back to the] early-1990s’ good times.”

On the subject of future new turboprops, Saabas said, “We are at the drawing board right now; [there are] no concrete plans, but this could be a very viable business opportunity.” He said advanced design work that involved “exciting” fuel-burn and emissions projections could lead to improved turboprop performance. “It is a question of investment versus return.”

Meanwhile, PW&C is continuing to improve durability of the PW100 family, which is not yet “a mature design.” Saabas confirmed that P&WC is working with ATR to provide a 4-percent increase in power for operations at high temperatures or at high-altitude airfields.

The engine company has almost completed development and expected the new PW120 variant to be certified “in the short term.” He expects to see more aircraft sales to areas such as India, where rough airstrips were not conducive to
jet operations.

Saabas is encouraged by the strength of ATR and Bombardier regional airliner order backlogs–“70 to 80” and “more than 100,” respectively–and said the recent high price of fuel has confirmed the advantage of turboprop over turbofan equipment on 500-mile routes.

P&WC has an established technology-development process that sees successive designs benefiting from previous work. For example, the compressor for the PW210 turboshaft helicopter engine was based on that used in the PW600 turbofan.

Current P&WC R&D initiatives follow the earlier advanced turbine fan integrator (ATFI) program. Begun “six or seven years ago when fuel prices were much lower,” that effort produced the geared-fan technology for a possible future 700- to 1,000-shp turboprop demonstrated here at Le Bourget during the 2003 Salon.

The ATFI work also had demonstrated an engine core similar to that now proposed for the X10, as well as new combustor technology with NOx emissions some 10 percent better than the latest CAEP standards. The program proved to be “a very good test vehicle” that still offered some technology-demonstration concepts for optimized fuel burn, “but [engine] architecture has moved on,” said Saabas.
He acknowledged P&WC efforts to enhance current customer support. “We are working hard to improve how we work with customers who need a reliable and very fast response, so we are trying to revamp back-office support to respond more quickly.

After more than 45 years’ development, the ubiquitous PT6 turboprop remains a dynamic program, as Saabas explained, saying P&WC has “a couple of derivatives in the mill,” with an emerging requirement for variant offering “almost 2,500 shp.” Having “doubled since 2003,” overall P&WC engine production is expected to reach some 3,000 units this year, with a projected 20-percent increase to “a 3,500-type figure” in 2008.

With such continuing increases, Saabas is well aware of the demand being made
on P&WC’s suppliers. “It’s always a challenge, because when you grow [suppliers] must grow with you, but we’ve done it for the past three years,” concluded Saabas.