Home' Asian Aviation : AAV July August 2011 Contents Trent XWB engine testing
Eight Rolls-Royce (R-R) Trent XWBs are being
used in the powerplant test programme, which
involves engine serial numbers 20990 and 20001
to 2007 -- although engines are not being test-run
Trent XWB 20990 -- R-R planned to complete
engine "pass-o " tests with this unit, its most
highly instrumented ight-test engine ever, by
June. e tests will precede in- ight trials aboard
the Airbus A340 ying test bed.
20001 -- is engine will be equipped with
strain-gauged fan blades for bird-ingestion tests
that will begin with a "medium" bird in trials
that were expected to continue in July with a
"large" specimen. e powerplant has been used
for earlier performance-envelope expansion,
operability trials, and compressor-functional
20002 -- R-R is using Trent XWB 20001 on
Derby s Test Bed 58 for integration of aircra -
interface systems. Low-pressure turbine testing in
May was to be followed by thermal and emissions
trials, integration of buyer-furnished equipment,
and water-ingestion trials by late June.
20003 -- Engine cyclic tests are scheduled to be
conducted with this unit.
20004 -- Endurance testing began with Trent XWB
20004 in June. e work was said to involve "lots of
hours" at high speed and high thrust to con rm the
design s maturity.
20005 -- UK and US tests on this engine have
included utter and cross-wind operations. It also
was part of thermal-survey work at Derby, which
has provided positive results in the shape of lower-
than-predicted disc-cavity temperatures. US trials
have involved fan strain-gauging, noise, and thrust-
20006 -- This unit was being reconfigured in
anticipation of altitude testing scheduled to start in
the US in August. e engine was used earlier for the
validation of low-, intermediate-, and high-pressure
bearing loads, oil-system optimisation, sea-level
performance, and variable-frequency generators.
20007 -- Intermediate-pressure turbine strain-gauge
and thermal testing will be performed on the nal
the blades rotate at higher speeds toward the rear
of the engine s intermediate-pressure (IP) stage.
Performance retention, speci cally fuel burn, will
be enhanced through the use of increased overall
pressure ratios in the two-stage IP turbine (IPT).
Speci c fuel consumption has been "excellent, better
than expected", says Cholerton.
e Trent 900 has provided the source for the
Trent XWB s low-pressure turbine (LPT), a nine-
inches-shorter scaled version of that on the A380
engine. e reduced weight of the LPT ser ves to
o set that the heavier IPT.
R-R has introduced composites material for the
rear fan case, which is supplied by new partner ATK
and for which development has gone well, according
to Young. To make moving nished engines easier,
the manufacturer has also produced a "transportation
stand", which permits a simpler separation of the core
from the fan case before the powerplant is shipped by
air to Toulouse.
The engine company has been preoccupied
with efforts to deliver
engine maturity at --
or in advance of -- the
says Trent XWB
Chris Cholerton. R-R
has "matured" in-
house design processes,
analysing any disruptive
events that have taken
place in the Trent engine
fleet and applying the
lessons from previous
failure modes to ensure reliability.
"Failure-mode effects and critical analysis
(FMECA)" and the Pareto principle -- the tendency
for, say, 20 percent of causal events to generate perhaps
80 percent of resultant e ects -- have been applied to
400 parts and led to 1,200 "mitigation plans".
In an effort to reproduce in-ser vice operating
conditions, the manufacturer has made signi cant
investments in computing capacity to support
component and systems testing, Cholerton says.
Important contributions have come from R-R s
environment-friendly, high-temperature E3E
(efficiency, environment, economy) two -shaft
technolog y demonstrator engines.
By July, R-R expected to have completed four more
Trent XWBs to complement its initial four units.
e company has been increasing the momentum
of testing ahead of ight trials of one engine on an
Airbus A340 ying-testbed (FTB) later this year.
Cholerton says early testing has gone "very, very
well". Compared with the initial 84,000lb thrust
required in ser vice, much higher thrust levels of over
100,000lb have been demonstrated on the rst unit.
R-R has invested increased resources into early
development stages of the Trent XWB, including
proof-of-concept work. All the design modules
are said to have been validated by the "highly
instrumented" engines, on which the company
measures more than 1,500 parameters (including ,
for example, overall gas ow). e XWB has yielded
the "best-ever Trent performance" results, according
Ahead of the Paris show, more than 60 rig-test
programmes had been completed as R-R worked
to establish reliability. Much of the testing is said to
have been pushed to "extreme limits" -- the company
having increased diagnostic capacity and begun
investigating mechanical behaviour early in the
R-R had also completed a large proportion of
emissions-control reliability testing before June.
In anticipation of nal humidity inspection and
checks, it had completed inspections and product-
assessment tests of humidity, thermal, and vibration
Young says functional operation has been
"excellent", while the IP compressor (on which one
of the four rows of guide vanes has been xed) has
demonstrated a "very good" surge margin. A key step
in progress toward the Trent XWB s rst ight will
The Trent XWB has yielded the "best-ever Trent performance"
results, according to Chief Engineer Chris Young.
32 AsianAviation | JULY-AUGUST 2011
The 118-inch-diameter fan on the Trent XWB
is the largest on a Rolls-Royce engine to date.
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