Composites are super materials made by combining two or more materials together in a structured pattern. This gives them special properties that the individual materials do not have of their own.
Many composites used in aviation are made by reinforcing a plastic polymer resin with strong fibers like carbon, glass, or aramid (similar to Kevlar). The resin acts like a glue holding the reinforcing fibers together in the desired shape.
The fibers provide the strength and stiffness, while the resin transfers loads between the fibers and protects them from damage. Altering the fiber orientation, type, and volume means engineers can tailor a composite’s mechanical properties in different directions.
Why Use Composites in Airplanes?
According to the experts over at Aerodine Composites, there are two main reasons why aviation composites are ideal for airplanes; they are much lighter than traditional metals but just as strong and stiff.
Lighter Weight
Since airplanes need to overcome gravity’s downward pull to generate lift, being lightweight is incredibly important. Lightweight airframes need less thrust from the engines to fly the same distance as heavier ones.
Advanced composites like carbon fiber reinforced polymers (CFRP) can be up to 30% lighter than aluminum alloys used for traditional metallic airframes. This huge weight savings means airplanes can carry more passengers, cargo, and fuel while burning less fuel overall.
High Strength and Stiffness
Despite being lightweight, modern composites are engineered to be incredibly strong, stiff, and durable. The plastic resin helps evenly spread out forces across the embedded fiber reinforcement.
These high strength-to-weight properties allow engineers to design safer, more damage-tolerant airframes that better withstand bird strikes, lightning strikes, and minor impacts during operation.
Composites in Modern Airliners
Today’s biggest airliners, like the Boeing 787 Dreamliner and the Airbus A350 XWB, take full advantage of composites, actually using them for over 50% of their airframe structures and wings.
For example, the 787’s entire fuselage barrel is made from composite sections joined with aerospace adhesives, doing away with thousands of rivets and fasteners. The plane’s composite wing covers made from CFRP replace what used to be over 50,000 separate aluminum parts. This allowed Boeing to create a lighter, smoother wing that can flex and bend more for improved aerodynamics.
Older generation wide-body jets like the Boeing 777 also incorporate composites in the tail cone, rear pressure bulkhead, flooring, and interior components to reduce weight.
Other Composite Applications
In addition to the main airframe and wings, composites excel in many other aviation applications:
- Engine cowlings, nacelles, and fan blades
- Landing gear doors and actuation mechanisms
- Control surfaces like ailerons, elevators, and rudders
- Propellers on smaller turboprop aircraft
- Interior cabin components like sidewalls, overhead bins, and entertainment system monuments
- Helicopter rotor blades, fuselage sections, and transmission housings
The future really does look incredibly promising for even more widespread use of advanced composites in aircraft. Researchers are continuously developing new higher performing and lower cost carbon fibers, thermoplastic resins, and manufacturing processes.
These next-generation materials and techniques could allow composites to be utilized in primary structural components like wing spars and beams that currently use metals because of cost and design constraints.
Conclusion: A Winning Combination of Benefits
Advanced composites offer an unbeatable combination of light weight yet high strength and stiffness for modern aircraft designers to leverage. This powerful mix enhances fuel efficiency while simultaneously improving damage tolerance and safety.
As aerospace companies and researchers continue pushing the boundaries of new composite materials, manufacturing methods, and optimized structural designs, we will undoubtedly see these “super materials” used in more and more aircraft components and systems.