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Trent XWB development 'on track'
Development of the Rolls-Royce Trent XWB engine
that will power the Airbus A350 XWB is on track,
according to programme director Chris Cholerton
and chief engineer Chris Young.
Most recently, progress has been demonstrated
by the first run of the 84,000lb-thrust XWB-84
variant during June. In-flight testing of the new
powerplant is set to take place in mid-2011, about
six months ahead of scheduled engine certification.
Definition of the Trent XWB engine concept
took place in 2006, followed by two years'
design integration with Airbus before the engine
configuration was frozen about two years ago. The
powerplant sports a 118in-diameter fan with a low
Other elements of what the manufacturer terms
a "whole-engine design" include the fan-case
mount, optimised bearing-load management and
modulating air systems. The Trent XWB's features
also include "advance aerodynamic compressors,
single-skin combustion casing, and a short, light
low-pressure turbine", the manufacturer says.
Configuration of the companion 93,000lb-thrust
Trent XWB-93 for the A350-1000 should be frozen
in about a year's time, says Rolls-Royce, with initial
runs scheduled for the first half of 2013 -- shortly
before the XWB-84 enters service on the A350-
900. The powerplant is also being developed in
75,000lb-thrust XWB-75 and 79,000lb-thrust
XWB-79 models, with a further, later -79B standard
also in the pipeline, with the prospect of holding its
thrust level in higher air temperatures.
Earlier this year, Rolls-Royce passed its 'Gate 3'
milestone, the third of five planned production-
readiness reviews. The final review is scheduled
for the second quarter of 2012. Preparation for
production also involves "gated" reviews of the
Compared with typical rolls-Royce civil-aircraft
engine programmes, early critical testing sees more
units being run earlier. For example, by January
2011 the manufacturer should have the seventh
XWB powerplant on line. In the past, previous
designs have usually involved about five engines
that typically have taken eight months from first
run to join the programme.
By last month [June], Trent XWBs Nos 2 and 3 were
under construction as Rolls-Royce also kitted up
the fourth and fifth engines. In completing design
of the new engine, the manufacturer has invested
700,000 more design hours than historically has
been usual at this stage.
As it pursues good serviceability, Rolls-Royce has
assessed some 400 Trent XWB parts and has 1,200
"mitigation" plans in progress. It also has assessed
the process capability of more than 10,700 design
features and analysed 130 maintainability aspects.
Advanced three-dimensional computational
fluid-dynamics analysis has been performed on all
Last year the manufacturer completed more
than 20 rig tests, aimed at reducing Trent XWB
programme risks. These have involved many
elements of the engine from compressors, fan, and
turbine to combustors and gearboxes. Engineers
were looking at aerodynamics, flow visualisation
Also progressing well in the Trent XWB
development programme are the engine's
key parameters. Rolls-Royce says that specific
fuel consumption is "on target to meet the
specification", while engine weight at maturity is
likewise projected to be on track.
Noise and emissions are said to be "delivering
specification". Target performance for the A350-
800 and -900 Trent XWB-84 sound levels on arrival
and departure are QC0.5 and 1, respectively,
with the larger A350-1000's Trent XWB-93
engine aiming to meet QC1 and 2 standards. This
status has been validated by "latest Trent engine
measurement", the company says.
"Current status is consistent with [the] guarantee
position," says Rolls-Royce. A low-noise bleed valve
programme for approach noise is "progressing".
Emissions status below CAEP6 limits has been
validated by the latest Phase 5 combustion
testing and Trent XWB rig testing. All this Trent
XWB development has seen a large Rolls-Royce
investment in production facilities, including those
for single-crystal turbine blades and advanced
The supply chain for the new engine is "in place
and delivering", says Rolls-Royce. Globally, 88
suppliers have been selected, along with 12 engine
partners. Some 16 Rolls-Royce plants will also
"feed" the programme.
Before the new engine enters production, Rolls-
Royce plans to prove a new production build-line
concept. Moving lines will be used for Trent XWB
fan-cases and core assembly.
initial composites lay-up. Metal-cutting began about
four months ago, on centre-wingbox attachments.
Caudron says that nal-assembly lines in Toulouse
and Hamburg are taking shape.
In August, Airbus expects to take delivery of the
rst A350 thrust reverser, which will be used for tests
on the second Rolls-Royce Trent XWB at Stennis
in the USA. Tooling for the engine's fan cowl and
torque box ring has been built and a demonstrator
manufactured ahead of completion of the rst cowl
for the engine ight-test bench.
e 280m x 300m A350 nal-assembly hall in
Toulouse, near the A330/A340 production line,
is expected to accommodate at least ten aircra a
month. When completed later this year, the facility
will occupy 7.4 hectares, including 21,000 square
metres to house o ces, stores, supply-chain ser vices,
e manufacturer is getting ready to build A350
wings at the Airbus UK factory in north Wales, where
a 46,000 square-metre plant is being built. For best
use of available volume, the largely composite A350
wings will be constructed "in the horizontal," rather
than "in the vertical" as with previous Airbus wings.
One responsibility for Airbus UK has been a so -
called 'Demobox II' exercise to develop or prove
manufacturing methodologies for the A350 wingbox.
An initial example was designed, manufactured, and
assembled as part of Airbus e orts to 'de-risk' the
wingbox programme and "deliver maturity" and
capacity to adjust production.
Demobox II sought to prove the horizontal-assembly
process, which is replacing the previous vertically
oriented procedure, and to establish automatic
drilling of the A350 wing's bottom skin panel (or
"cover"). e exercise also has ser ved to provide a
training platform for assembly of wing-boxes, ahead
Rolls-Royce completed the first
run of the Trent XWB-84 in June.
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