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these materials are corrosion and fatigue resistant. The limiting factor in the widespread
application of these materials has been their high cost compared to conventional metals. The
Paper presented at the RTO AVT Specialists’ Meeting on “Low Cost Composite Structures”,
held in Loen, Norway, 7-11 May 2001, and published in RTO-MP-069(II).
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application of composite materials for each of the aircraft listed in Figure 1 are reviewed in the
present paper with respect to the following:
• Fighter Aircraft (US) F-16, F-14, F-18,YF-23, F-22, JSF, UCAV
• Fighter Aircraft (Europe) Gripen JAS-39, Mirage 2000, Rafael,
Eurofighter Typhoon, Lavi, DASA Mako
• Fighter Aircraft (Russia) MiG-29, Su series
• Bomber (US) B-2
• Transport (US) KC-135, C-17
• Transport (US- Commercial) B-777, B-767, MD-11
• Transport (Airbus, European) A-320, A-340, A380, Tu-204, ATR42,
Falcon 900, A300-600 ST
• General Aviation Piaggio, Starship, Premier 1
• Rotary Aircraft V-22, Eurocopter Tiger, Comanche
RAH-66, Bell/Agusta BA-609, EH101,
Super Lynx 300, S-92,
Figure 1. Aircraft composite materials usage surveyed.
1. The typical weight fraction of composite structures in military, transport and general aviation
aircraft
2. Factors influencing the use of composite materials
3. Payoffs associated with the applications reviewed
4. Factors limiting the use of composite materials
5. Technology developments in progress to remove the limitations
6. Potential role for composite materials in future airframes.
The following paragraphs describe the results of this review.
Combat Aircraft
The trends in the use of composite materials for US Fighter aircraft are shown by three examples
in Figure 2. The percentage by weight of composite materials used initially (e.g., F-15E) was
small at 2%, but this percentage has since grown to more than 25% for the F-22 which is the
designated replacement for the F-15E. The F-22 has demonstrated the feasibility and benefits of
introducing processes such as RTM (Resin Transfer Molding) to improve the affordability of
composite materials in combat aircraft applications. The use of composite materials in the US
Navy’s F/A-18E/F equals nearly 20% of its structural weight in flight critical parts as shown in
Figure 3. The choice of composite materials in the F/A-18E/F was dictated by a need to reduce
weight and to improve strength, reliability and maintainability in an aircraft carrier environment.
The center and aft fuselage skins and other ancillary structure, such as the speed brake and dorsal
covers, are all-carbon/toughened- epoxy construction in the F/A-18E/F. Carbon fibers, such as
Hexcel’s IM7, with improved strength and stiffness properties are used in the wing and the tail
skins. Although composite materials in general are sensitive to impact damage, toughened
materials such as Fiberite’s 977-3 toughened epoxy system used on the F/A-18E/F have
successfully addressed this threat in operations. The AV-8B uses nearly 25% by weight of
composite materials in its airframe.
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Aluminum
Titanium
Other
1987
49%
17%
2%
32%
29%
21%
31%
19%
16%
39%
24% 21%
Composites
Figure 2. Materials usage trends in US fighter aircraft.
Aluminum
Steel
Titanium
Carbon Epoxy
Other
49
15
13
10
13
100
31
14
21
19
15
100
Carbon Fibers (IM7) Used
in Wing and Tail Skins
Percent of Structural Weight
F/A-18C/D F/A-18E/F Increased Carbon Epoxy
Usage in Center and
Aft Fuselage
High Strength/Durability
(AERMET 100) Used in
and Flap Transmissions
Improved Toughness
Resin (977-3) Used in
All C/E Structural
Applications
Figure 3. Materials distribution for the F-18 E/F aircraft.
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The Eurofighter Typhoon is shown in a cutaway view in Figure 4, and uses composite materials
in the wing skins, forward fuselage, flaperons and the rudder. Eurofighter’s exterior skins are
made of Hexcel’s 8552 toughened epoxy and constitute 70% of the wetted area. Overall, 40% of
the Eurofighter’s structural weight consists of carbon-fiber composite materials. The proportion
of composite parts in Dassault’s combat aircraft has grown steadily over the years, from 7 percent
on the first Mirage 2000 fighters, to over 26 percent on the Rafale. Other fighters built by
European companies such as the Saab Gripen, and EADS’ newly developed “light” fighter Mako
　
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