CFMI Claims Success with Tech56
But Targets Still More Improvements

Having completed months of testing under its Tech56 engine improvement program, CFM International says it's seeing payoff and expects to pursue additional upgrades to its CFM56 family.
So far none of the technologies have found their way onto production engines, but CFM International is planning to take several of the technologies that have shown promise into more complex testing in the coming months. The overriding goals of the project are to simplify designs to cut production costs, and obtain better efficiency to reduce operating cost and pollution.

Among technologies that have completed early testing is a solid 61-inch swept wide-chord fan blade on a CFM56-7 that should be more efficient than the current blade design. CFM also has successfully rig-tested a six-stage high-pressure compressor. A second version of the device is now undergoing additional tests.

Similarly, a twin angular, pre-swirl combustor that did well in initial testing is now undergoing another series of evaluations. A new fuel nozzle design will be incorporated into TAPS later this year. Brush seals assessed on a CFM56-5B are seen as potentially reducing leakage 40% over current seal designs. Among the turbine activities is an on-going evaluation of a third-generation low-pressure turbine design with 35% fewer parts.

On the horizon, CFM hopes to begin testing a hollow 68-inch swept fan on a CFM56-5C this month. It is slated for performance and crosswind testing, and, next summer, a full-scale engine blade-out test. Early next year, the company will examine a new booster design in the CFM56-5B with the hope of eliminating variable bleed valves.

In a separate effort, the first CFM56-5C/P is slated to start ground testing in November, with the hope of achieving certification late next year to enter service on the Airbus A340 in 2003. The engine for A340-200/300s features three-dimensional aerodynamic high-pressure compressor and the high-pressure turbine the company first developed for the A320's CFM56-5B/P. Additionally, it could get a new stage one low-pressure turbine nozzle that is still early in development.

CFM plans to offer the ­5C/P to current A340 users as a kit upgrade. The engine should deliver 1% better specific fuel consumption over the ­5C4 and a 13-degree increase in exhaust gas temperature.