Bombardier's proposed CSeries sets in motion competition to power next-generation of single-aisle airliners

The race to develop new-centreline engines for the next generation of Airbus and Boeing narrowbodies may be kicked off earlier than expected following the revelation of higher-than-predicted thrust requirements for Bombardier's newly unveiled CSeries airliner.

More surprisingly, the troubled Pratt & Whitney PW6000 will not formally be offered for the CSeries despite being in the right 20,000lb thrust class (89kN). P&W president Louis Chenevert says "International Aero Engines [IAE] is our route to market" for the Bombardier aircraft, but this does not mean the end of the PW6000 or the search for new applications.

P&W says the longer-range, lower-cycle design needs of the CSeries make the PW6000 unsuitable for the role. IAE president Mark King confirms that the multinational company is "preparing to move to the next generation", and adds the CSeries is "the first [application] we can see in sharp focus. We have started negotiations with Bombardier, and our shareholders are supporting the V2500 as our route to market. We see it as a very positive development towards the next generation of V2500 family."

However, CFM International is more cautious. Although it is also talking to Bombardier, it says the longer-term focus remains on studies of a new-centreline engine for a higher thrust bracket aimed at service entry from around 2012.

"We held a kick-off meeting last week and we hope to be in a position by early next year to decide on a technical plan to be ready for a launch in early 2008," says CFMI president Pierre Fabre. The outline schedule "means we would have to focus on new technology work between now and 2007". For the Bombardier requirement, Fabre says: "You are not going to see a GE or Snecma engine, but maybe a CFM. What is the answer? We don't know."

Although CFMI's Tech 56 technology investment effort will be used to update the CFM56 engine in the interim, Fabre says forthcoming noise requirements are the driver.

He adds: "Airbus and Boeing could make the A320 and 737 evolve, but what we tend to believe is that noise pressure will be such that a significant step will have to be implemented - and that will be a driver for a new engine."

He adds: "The consensus is that 2012 could be the entry into service of a new-centreline engine." The initial target would be a family in the 23,000-35,000lb thrust range (compared with the current 20,000-33,000lb), aimed at noise levels below Stage 4. "That's effectively a 25dB cut with today's reliability, which is a huge challenge," says executive vice-president Bill Clapper. "It's a big movement in the state of the art."

Early concepts that could be included in the study are a contra-rotating, two-stage fan, further fan-case treatment innovations and reduced stage numbers. "It would need a new, higher bypass, and that doesn't fit under the wing of the A320 and 737," he adds.

The overall thrust requirement, and therefore noise emissions, could be reduced by lower take-off weights which CFMI says may be achievable with advanced, composite structures likely to feature in the next- generation airframes.



Source: Flight International