Download Pdf [2,03 MB] - MTU Aero Engines

“Our focus is on longevity of the product and
we’re continuously enhancing it to benefit
our customers,” Müllenholz emphasizes.
After the V2500-A1 version had been improved
to become the V2500-A5, the
SelectOne standard constitutes another
step forward. The V2500-A5 is designed to
suit the varying requirements of the A320
family of aircraft; in the 22,000- to 33,000pound
thrust range, there are seven versions
in total. Thanks to its cost effectiveness, reliability
and environmental credentials, the
V2500 has, from its inception, been the
engine of choice for this Airbus family.
MTU’s role in the V2500 program is the fivestage,
low-pressure turbine, which is assembled
at MTU Maintenance Berlin-Brandenburg.
As co-founder of the multinational IAE
engine consortium, the German company is
holding a roughly 11-percent stake in the
V2500. Pratt & Whitney contributes the combustor
and the high-pressure turbine, Rolls-
Royce is responsible for the high-pressure
compressor, and Japanese Aero Engines
Corporation for the fan and low-pressure
compressor.
“The modifications embodied in SelectOne,
as compared with the standard V2500-A5
version, mainly involve the high-pressure
compressor and turbine, as well as the electronic
engine control,” explains MTU’s
Stephan Krinner, V2500 technical program
engineer. The optimized high-pressure com-
Testing of the SelectOne on the wing of a Boeing 747 in Plattsburgh, New York.
pressor now boasts 3D airfoil geometries as
well as improved aerodynamics and airfoil
surface texture. The high-pressure turbine incorporates
new materials and sealing systems.
MTU has adapted its low-pressure turbine
accordingly. “Our specialists optimized the
airfoil angle of attack of the stage three turbine
stator,” explains Werner Striegl, the
V2500 technical program manager. The
German engine manufacturer not only shares
in the development and manufacture of
SelectOne but, as the globally leading
V2500 maintenance provider, also assumes
full repair responsibility.
Before the modified engine was allowed to
fly, it needed to demonstrate its reliability on
the test stand. During the preliminary phase,
three engine tests were on the agenda: the
performance operability test took place in
April 2007 at MTU’s Munich facility to verify
the functionality of the complete SelectOne
engine. “For flight approval, we simulated
cycles on the test stand,” explains Kurt
Scheidt, who at MTU is responsible for commercial
engine testing. “A cycle lasts 10 to
15 minutes, as we’re mainly testing at the
maximum loads occurring during takeoff and
landing.” Upon completion of several weeks
of test stand trials, the engine was stripped
and inspected. Additionally, a telemetry test
and an endurance test took place in the U.S.
at partner Pratt & Whitney’s test facility.
After the ground testing wrapped up successfully
in October 2007, the engine was
flown to America in the cargo bay of a commercial
transport. At Plattsburgh in New
York State, testing on the flying testbed was
scheduled. On the wing of a Boeing 747, the
IAE engine completed 45 flying hours in
seven flights and proved to be in perfect
shape. “The targets were all met and the performance
capabilities attested to in the
ground runs were confirmed,” Scheidt summarizes.
The technically difficult installation
of the test engine for the flight trials was
assisted by MTU instrumentation specialists
on-site. 500 tapping points needed to be
crammed into the engine, no easy job even
for the experts. Says Scheidt: “The whole
complex sensor system had to be accommodated
in a manner such that it was sure not
to interfere with flightworthiness.”
The meticulously accurate preparations made
by all involved paid off: Following successfully
completed flight testing, SelectOne obtained
approval from the U.S. Federal Aviation
Administration (FAA) in December 2007.
But that left the partners little time to relax;
already in February this year SelectOne
underwent further flight trials, this time in
the sky above Toulouse in the south of
France, on the wing of an Airbus A320.
“We’re right on schedule,” Scheidt explains.
Certification by the European authorities is
expected in May this year, in time for the ILA
International Aerospace Exhibition in Berlin.
That paves the way for launching production
in summer. IAE’s first SelectOne production
engine will go to IndiGo Airlines. The
Indian carrier will be equipping a hundred
Airbus A320 family aircraft with the
SelectOne build standard, becoming the
launch customer of the optimized bestseller.
For additional information, contact
Leo Müllenholz
+49 89 1489-3173
For interesting multimedia services
associated with this article, go to:
www.mtu.de/108V2500_E
The SelectOne on MTU Aero Engines’ test facility in Munich. In February 2008 the SelectOne made its first flight in Toulouse – on the wings of an A320.
10 Technology + Science
11