CFM International plans to begin crosswind tests of its experimental swept fan blade design in June, as it approaches the half-way point of its three-year Tech56 advanced technology development effort.
Tech56 is aimed at improving the CFM56 engine family across the full 20,000-35,000lb thrust (89-156kN) range, as well as providing the technology platform for an all-new engine should it be needed to compete against Pratt & Whitney's proposed PW8000.
Targets for the programme include 15-20% lower cost of ownership, 15-20% lower maintenance costs and 4-7% better fuel burn than the CFM56-7 and -5B, depending on fan diameter. The initiative is also aimed at reducing cumulative noise levels by up to 20dB for the higher thrust engines and by up to 27dB for the smaller engines. Emissions will be driven down to as much as 50% below current regulatory limits.
Tests of the swept fan, mounted on "what is really a CFM56-7 core", will take place at the Peebles test site in Ohio, says CFM56 programme executive Mike Benzekein. The swept, wide chord blade is being developed to generate higher thrust for a given diameter, as well as to reduce fuel consumption by up to 1%. It is also expected to produce weight savings of up to 68kg (150lb) compared with a conventional blade set. In a CFM56-7 sized application, Benzekein says the new fan will generate between 1,500lb and 2,000lb more thrust.
Fatigue tests of the swept fan began last year, as did initial containment tests. Large bird impact tests were also completed, says CFM. The 1999 plan calls for performance and fan stability tests, cross wind tests and a full size blade release.
This year will also see the completion of static and fatigue tests on the company's load reduction device (LRD). This automatically "decouples" the entire fan assembly from the rest of the engine in the event of a blade out failure.
The LRD, which passed a proof-of-concept test on a GE90-sized fan rig in the UK last year, allows overall structural weight to be reduced by up to 90kg per engine, says CFM. One application being considered is the 115,000lb-thrust GE90 growth version planned for Boeing's 777-200X/300X.
Source: Flight International
