GUY NORRIS / LOS ANGELES
Work also begins on "Build3" production standard engine for first A380 shipset
Rolls-Royce has shipped the first Trent 900 to Toulouse for installation on the Airbus A340-300 testbed in preparation for the start of flight tests that are due to begin around mid-May.
Assembly work also started around 16 February on the first "Build3" production-standard engine that will form part of the shipset for the first A380. The entire shipset is due to be delivered to Airbus in the build-up to the planned first flight of the A380 - still officially targeted for the first quarter of 2005.
Certification is also on schedule for the end of October, says Trent 900 chief engineer Rob Savidge, who adds that the A340 flight tests are partially aimed at confirming the initial performance results coming from a ground-test engine under evaluation at the Arnold Engineering Development Center (AEDC) in Tennessee. Specific fuel consumption on the engine at AEDC has been within 1% of guarantees, and was achieved with a "Build1" bill of materials, says Savidge.
The engine has subsequently been fitted with a "Mark 2" high- pressure compressor incorporating longer-life materials and some minor aerodynamic enhancements. The AEDC engine is the third of seven ground-test powerplants involved in the Trent 900 certification and test programme, the first of which is being prepared for water ingestion tests having completed low- and intermediate- pressure (LP/IP) system aerofoil stress surveys.
Development problems have been encountered on the fourth "type test" engine that suffered a low-pressure turbine failure, later attributed to a loose seal segment.
"We had completed 115h of type testing when we had the LP turbine failure," says Savidge, adding that the "problem was solved and a modification for it was developed by the IPT [of Spain] design team, which turned it around quickly". The modification involves axial strengthening of the seal segment and retaining ring to prevent loosening of the segment and nozzle guide vanes, one of which fell out and hit two LPT blades.
Engine five has been used for blade flutter tests and, following nacelle and thrust-reverser work, will undertake the full 2.5kg (5.5lb) bird ingestion test in May. Engine six will undertake a 3,000-cycle endurance test set to run from 20 February until July, while engine seven will be used for the destructive fan blade-off test set for late June. This will evaluate redesigns to the powerplant's inlet and titanium fan casing triggered by results from earlier rig tests.
Source: Flight International
