JEC COMPOSITES MAGAZINE - Issue #106 - July 2016 - 19

Fig. 1: Estimates of demand for composites by type (carbon, glass and
aramid fibre reinforced plastics), for use in aircraft engines from 2005 to
2017, in metric tons (Source: Toho Tenax America - November 2012)

Aero Engine - IAE (Pratt &
Whitney United States, 25%,
Pratt & Whitney Aero Engines
International GmbH Switzerland, 24.5%, MTU Aero Engines Germany, 25.25%, and the
Japanese Aero Engine Corporation, which consists of Kawasaki
Heavy Industries, IshikawajimaHarima Heavy Industries and
Mitsubishi Heavy Industries,
25.25%); and Engine Alliance
(a 50-50 joint venture between
GE and Pratt & Whitney of
United Technologies Corp.).
In May 2015, CFM International (GE/Safran) held 69% of
engine orders for narrow-body
aircraft (type A320 or B737,
successors or competitors),
compared with 20% by IAE,
meaning that GE and Safran

each hold a third of the market.
For wide bodies (type A380,
A350, B747, B777, etc.), GE
leads again with 49% of market
share by itself, or 53% if you
include its participation in CFM
International. For regional jets,
its market share reaches 66%.
In terms of number of engines
ordered in all commercial aviation segments lumped together,
GE outstrips the others with
44%, followed by Safran with
21%, Pratt& Whitney with 15%,
and Rolls-Royce with 12% (see
Figure 3).

CFM International's LEAP
Of the latest engines to come
out, or about to, the LEAP is
one of the most emblematic
for the use of composites. This

new engine went airborne for
the first time on an A320neo
in May 2015, two days before
scheduled according to the fiveyear development plan (Figure
4) - an event that is rare enough
to be worthy of note, as aircraft
planning schedules usually
tend to be extended due to the
complexity and criticality of the
parts to be produced.
Composites are used heavily in
the LEAP engine to lower its
fuel consumption and reduce its
CO2 emissions. CFM estimates
that the use of composites reduces the weight of each aircraft
by up to 450 kg.
The LEAP consists of 3Dbraided carbon-fibre fan blades
and fan case (manufactured
by Albany Engineered Composites) and ceramic-matrix
composite shrouds in the highpressure turbine. According to
the designers, a LEAP fan blade
(made using RTM) is so strong
that it can support the weight of
an Airbus A350 or a Boeing 787
by itself, and the carbon fan case
(from 1.76 to 1.98 metres in
diameter depending on the engine version) is 30% lighter than
an aluminium solution. The
lower weight of these components is not the only advantage,
as they are also more durable.
Also according to CFM Inter-

national, manufacturing each
blade requires 150,000 miles of
carbon fibre. Given that the fibre
used is Hexcel's IM7 and that
the 6K tow has a linear density
of 0.223 g/m, this means that it
takes 8.97 kilograms of carbon
per blade. There are 18 blades
in the engine, for a total of some
162 kg of carbon, to which
you have to add the quantity
required for the containment
case, also made of carbon - and
according to the publisher's own
estimates, this could be as much
as 80 kilos. That is more than
250 kg of carbon per engine.
For the ceramic matrix composites (CMC), the SiC/SiC
solution was chosen. Although
OEMs themselves rarely invest
in raw-material production any
more, these continuous silicon
carbide fibres are manufactured
by NGS Advanced Fibers Co.,
Ltd. (a joint-venture between
Nippon Carbone, GE Aviation and Safran) - proof that
the development of the fibres
(sold under the brand name
Nicalon™) has been particularly
crucial. In the high-pressure
turbine, the main-stage shroud
is made of ceramic-matrix
composite, providing weight reduction and higher temperature
reliability. According to NASA,
SiC/SiC CMC in extreme
conditions have a number of

Fig. 2: Aircraft engine delivery and sales forecast over the 2015-2034 period

No106 July 2016 /

jec composites magazine 19
Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #106 - July 2016
