Engine Directory

CFM International

After record airliner sales in 2007 and with the first signs of a global downturn only appearing late in 2008, a year in which the company still produced 1268 engines, CFM International has enjoyed a long period of domination of the market to power single-aisle airliners, dating back to the mid-1980s.

Far from resting on its laurels, the need for greater fuel efficiency has driven CFM to the point where it is poised to drop the single-stage engine architecture of its hugely successful CFM56 design in favour of a two-stage spool in its all-new follow on design, LEAP-X. While two-stage architecture would bring higher fuel efficiency, the trade-off is higher maintenance cost, as compared with existing single-stage designs. As fuel prices soared in 2008, CFM reached the point where the fuel burn advantage of the two-stage high-pressure turbine was sufficient to offset its higher maintenance cost, although the rapid decline in fuel prices since late 2008 will have to some degree redressed the balance towards the single-stage system.

Launched in July 2008, LEAP-X is an entirely new baseline advanced turbofan engine to power future replacements for current narrowbody aircraft expected to enter service towards the end of the next decade. The engine incorporates revolutionary technologies developed over a three-year period as part of the Leap56 technology acquisition programme. Through consolidating the major advances pioneered on the larger GE90 and GEnx designs, including ultra-high-pressure compressor ratios and composite fan materials, CFM expects LEAP-X to redefine the state of the art for single-aisle airliners for decades to come. LEAP-X is expected to reduce the engine contribution to aircraft fuel burn by up to 16% compared with the CFM56 Tech Insertion engines that currently power Airbus A320 family and Boeing Next Generation 737 aircraft. Additional fuel burn improvements are expected once LEAP-X is paired with new aircraft technology. On 15 May 2009 the first LEAP-X engine core was moved to GE's Evendale, Ohio test facility where testing was expected to start in early June. The first run of the full powerplant demonstrator is scheduled for 2012, with certification could be as early as 2016, for a possible Entry Into Service in 2018.

The CFM56 Tech Insertion programme is a comprehensive system upgrade for CFM56-7B engines, which was incorporated in all new -7 production standard engines from mid-June 2007. The programme aims to reduce maintenance costs by up to 12%, specific fuel consumption by 1% and NOx emissions by up to 20%. Flight tests of the Tech Insertion -7B27/3 engine on a 737-800 testbed began in August 2006.

On 28 April 2009 the CFM56-7B Evolution engine enhancement program was announced. Scheduled to enter airline service in mid-2011 to coincide with Boeing Next-Generation 737 airframe improvements announced at the same time. The CFM56-7B Evolution-powered Next-Generation 737 enhanced airplane/engine combination will provide a 2% improvement in fuel consumption, which, in turn, equates to a 2% reduction in carbon emissions. Additionally, the enhanced -7B will provide up to 4% lower maintenance costs, depending on the thrust rating. CFM is using advanced computer codes and three-dimensional design techniques to improve airfoils in the high- and low-pressure turbines to improve engine performance. The company is also improving engine cooling techniques and reducing parts count to achieve lower maintenance costs. The first engine is scheduled to begin ground testing in September 2009. Flight tests of the -7B Evolution configuration are scheduled to begin at GE Aviation facilities in Victorville, California, Certification is expected in the third quarter of 2010. Flight tests on the Next-Generation 737 are planned for later in 2010, followed by aircraft certification and entry into service in mid-2011. Once certified, the Evolution engine will carry the nameplate CFM56-7BE.

Recognising the increasing need to better understand engine material content as assets are evaluated and redistributed throughout the industry, CFM has also developed the TRUengine programme. This identifies engines that have CFM-approved material and repair content and configurations. The qualification is based on information available through records from the engine's most recent shop visit. TRUengine designation will also facilitate CFM's provision of technical product support, while enabling appraisers and potential engine buyers to quickly confirm CFM-approved material content and configurations to engine serial number level.

As for the future, the development of the open rotor engine is also still on the CFM agenda. This is not surprising for a design that promises to deliver 26% lower fuel burn. However, and even though some of the technologies developed for LEAP-X could be applied to the open rotor engine, the design still poses its own technological challenges. CFM expects that it will take time to find solutions to the problems posed by the open rotor engine, notably including the need to reduce the higher noise levels produced: a particular challenge without also increasing fuel burn. In 2009 CFM will begin to investigate the use of innovative new composite technology in fan construction, aimed at reducing both engine weight and blade count, as part of Snecma’s MASCOT research programme.

To amend, update or comment on this profile, contact Ian Joyce at: ian.joyce@flightglobal.com.