In 1973, the Boeing 737 used three carbon fiber composite materials for its spoilers: T300/2544, T300/5209, and AS/3501. This marked the first application of carbon fiber materials in civil aviation, laying the foundation for its widespread use in subsequent civil aircraft.Prior to this, in 1970, the Boeing 707 used boron fiber/epoxy resin composite materials for its leading-edge flaps. This was the first application of composite materials in civil aircraft, although boron fiber is not a type of carbon fiber. The Boeing 787 was the world's first civil jet airliner to use carbon fiber composites as the primary material, with carbon fiber composites accounting for approximately 50% of the entire aircraft.

Weight reduction and energy saving while possessing high-strength structure

Carbon fiber and its composites (CFRP) are key materials for upgrading civil aviation, with their core role being to replace traditional aluminum alloys and titanium alloys. Data shows that every 1% reduction in passenger aircraft weight can reduce fuel consumption by 0.7%, and every 1kg reduction can save over $10,000 in fuel costs over the aircraft's entire lifecycle. CFRP not only meets the requirements of "lightweight and low-energy consumption" but also ensures structural reliability through its superior performance, making it a crucial support for civil aircraft upgrades.

Fuselage, wings, and engine core components

(I) Fuselage Main Structure: Integrated Molding Achieves High-Efficiency Weight ReductionThe fuselage is a core area for carbon fiber applications. Over 60% of the fuselage skin of the Boeing 787 uses CFRP, and the Airbus A350 fuselage panels also extensively use this material. Through integrated molding technology, the density is only 1.7g/cm³ (approximately half that of aluminum alloy), resulting in an overall weight reduction of 20%-30%. Simultaneously, its fatigue life is 3-5 times that of aluminum alloy, reducing the number of rivets and maintenance frequency.The domestically produced C919 large passenger aircraft uses resin-based carbon fiber materials in 15% of its fuselage structure, achieving an overall weight reduction of 7%.The rear fuselage and horizontal and vertical tail, among other main load-bearing components, use high-performance T800 grade carbon fiber, which is 80% lighter than traditional materials at the same strength.(II) Wings and Tail: High Modulus Properties Adapt to Flight RequirementsWings and tails require extremely high rigidity and lightweight materials, which carbon fiber perfectly meets. The Airbus A350 wing spars and Boeing 787 vertical tail both utilize CFRP, whose high modulus (40% higher than aluminum alloys) effectively resists bending caused by lift during flight. Through fiber layup optimization, a precise match between lightweight wingtips and high load-bearing capacity at the wing root can be achieved, contributing to a 35% weight reduction in the wing.In terms of technological innovation, the Ant Carbon company uses an integrated composite material outer wing box, achieving a 5.6% weight reduction through process innovation, while the matching composite material winglets further reduce weight by 20%.

(III) Engines and Supporting Components: High Temperature Resistance + High Radar Transmission – Dual AdvantagesEngineers and supporting components have stringent requirements for material performance, and modified carbon fiber exhibits significant advantages. The Trent 1000 engine nacelle uses modified CFRP, which can withstand temperatures of 300-500℃ and is 40% lighter than a metal nacelle;the Airbus A320neo radome is made of CFRP, with a radar transmittance exceeding 90%, ensuring stable radar signals. The LEAP-X1C engine, adapted for the domestically produced C919 large passenger aircraft, also uses carbon fiber composite fan blades, further improving fuel efficiency.Currently, the application of carbon fiber in the civil aviation field is constrained by cost (aerospace-grade carbon fiber costs several thousand yuan per kilogram) and maintenance technology (requiring high-precision detection of internal damage). However, with breakthroughs in technologies such as large-tow carbon fiber and thermoplastic composite materials,it is gradually penetrating into more civil aircraft structures and will become a core material support for next-generation passenger aircraft such as all-wing designs in the future.