Home' Asian Aviation : AAV June 2010 Contents 16 AsianAviation | JUNE 2010
The commercial aviation sector will
see a clutch of new aircra designs
entering ser vice over the next decade
or so, including the Boeing 787,
Airbus A350XWB, Bombardier
CSeries and Comac C919.
All of these programmes aim to tap the latest engine
technolog y to o er signi cant leaps in performance,
fuel-e ciency and reductions in noise and emissions.
Furthermore, Boeing and Airbus are both considering
the future of their single-aisle o erings, pondering
successor programmes to the highly successful Boeing
737 and Airbus A320 families while considering
o ering the existing aircra with a new engine as a
more e cient interim solution for carriers that do not
want to wait for an all-new design.
As reported elsewhere in this issue (see feature, pages
24-25), Airbus may make a decision within months
to proceed with the so-called A320 New Engine
Option (NEO), which it hopes will be su ciently
attractive to undermine the business case for the all-
new Bombardier CSeries. e Canadian aircra will
be designed to seat 110 to 149 passengers, competing
directly with smaller variants of the A320 family.
Airbus is looking to evolutionary engine solutions
such as CFM International's Leap-X and Pratt &
Whitney's Geared Turbofan (GTF) PurePower
P1000G as potential powerplants for the A320 NEO.
The manufacturer sees a market window of
opportunity for such a re-engined aircra in about
2015. Then, by the end of the next decade, the
manufacturer will be in a position to proceed with
designs emerging from the current A30X study into
an all-new, future single-aisle model that could even be
powered by open-rotor engines, now in the early stages
CFM International, the joint venture of General
Electric and Snecma best known for its CFM56
turbofan family, last year nalised the architecture
of its Leap-X turbofan. Since then, the manufacturer
has been carrying out testing in the second phase of
demonstrations on the rst engine core, known as the
CFM plans to certi cate the engine in 2014, prior to
entry into service in 2016 on the Chinese-developed
Comac C919 jetliner. With Airbus and Boeing
looking at new single-aisle designs closer to 2020, the
manufacturer has said this would give it more time to
re ne the engine's technolog y and add more e cient
components to make it a credible candidate to power
the next generation of narrowbodies.
e LEAP-X is designed to burn 16 percent less fuel
than the CFM56, with up to 60 percent lower nitrous
oxide (NOx) emissions and noise levels at 15dB below
the current standard.
e new turbofan will have a bypass ratio of about
10, compared with its predecessor's gure of 5 to 6. It
will also have a core pressure ratio of 22 -- double that
of the current engine -- with a two-stage high-pressure
(HP) turbine driving a 10-stage HP compressor. e
low-pressure (LP) turbine blades will be made of
ceramic matrix composite (CMC) materials, saving
about 150kg (330lb) of weight, the manufacturer says.
e rst eCore had completed more than 30 hours
of testing as of the end of April, and was scheduled to
be nished by mid-May. It is the rst of three test units
being built, with the second expected to begin testing
CFM plans to have a full engine demonstrator
running in 2012, according to company executives.
A crucial element of the new engine is its 18-blade,
1.8m diameter composite fan and casing. e fan is
produced using three-dimensional woven resin transfer
moulding, which allows the blades to be carefully
shaped for optimum aerodynamic e ciency. e new
material also allows a weight saving of about 450kg
per aircra , as well as bolstering durability and fatigue
resistance, the manufacturer says.
In the first quarter of 2009, the company began
ground-testing a woven RTM fan on a CFM56-5C
engine core at its Villaroche facility in France, with
acoustic and crosswind trials following in the second
quarter at GE's Peebles site.
e rst results from those tests were "in line with
expectations" CFM said late last year, adding that the
results would be used to develop the second generation
of fan designs. Endurance trials were then carried out
in Villaroche in the second half of last year.
The company is working to optimise blade
aerodynamics in the LP turbine by going through
multiple stages of computational uid dynamic design
and analysis. e turbine with its CMC blades, is to be
demonstrated on a CFM56-7B engine core this year.
e eCore design builds on all the experience CFM
has from previous HP cores -- from the GE90, through
the GEnx, to CFM56 technolog y enhancements
developed under the TECH56 programme -- to
yield a high level of compressor e ciency and stall-
free operation "with a high level of probability", the
e company began initial eCore testing in mid-
2009 at GE's altitude test facility. e manufacturer
sais at the time that those tests would analyse
aerodynamics, performance, aeromechanical response,
operability and the performance of the engine's new
Twin-Annular Premixing Swirler II (TAPS II)
combustor, which improves the e ciency of fuel burn
and reduces harmful emissions.
TAPS II is a more advanced version of the TAPS
combustor found in GE's GEnx engine, which is to
power the Boeing 787 and 747-8. e new combustor
will be key to achieving the engine's target 50-60
percent reduction in NOx emissions.
CFM says it is also looking beyond the LEAP-X, at
open rotor engine architecture.
"With an open rotor you can add 10 percent
more fuel-burn bene ts, so getting to a 26 percent
reduction," says Fabienne Lacorre, the manufacturer's
New engines promise leap in economy
The next 10 years will see several new jetliners enter into service, featuring the latest engine technology
developments that will yield significant economic and environmental advantages over today's powerplants,
writes Andrzej Jeziorski.
The Leap-X engine will power the
Chinese-developed Comac C919 jetliner.
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