General Electric plans to test a redesigned containment system for the CF34-8C1 engine being developed for the Canadair CRJ700 after earlier fan-rig tests revealed potential flaws. The test is expected to take place at the company's Ruston Gas Turbines site in the UK in September.
In spite of the extended development of the containment collar, GE still expects to stick to the revised development schedule which calls for the initial complete engine to be tested in the first quarter of 1998, and certification in the fourth quarter of 1999.
GE says that the fan-containment system failed on two previous tests, when first a solid aluminium and then a Kevlar collar were used. Another test rig will use a double thickness of Kevlar and aluminium stays, says Frank Klausman, CF34 programme manager.
The containment system has been revised to cope with the higher energy of the -8C1's larger fan. This was increased to 1.17m in diameter (up from 1.11m for the baseline CF34-3B1) and fitted with scaled versions of the CF6-80E1 wide-chord blade to help produce a 50% thrust increase.
The company has also decided to certify the engine to a thrust level of 61kN (13,800lb), at the automatic power reserve setting, an increase of around 3kN over the original plan. This is expected to provide more margin for performance and initial growth, says the engine maker.
The key test of the new fan and revised containment system is scheduled for late in the third quarter of 1998, when the fan stress/blade out test is set to take place on a complete engine.
Other than the containment issues, the -8C1 development has been relatively trouble-free, says GE. Successful tests have been completed on the exhaust system and on the revised aerodynamics of the low-pressure turbine, while the first-phase fan-rig test involved completion of the medium-sized bird ingestion trial.
Source: Flight International
