What kind of material is typically used for the filler in fuselage assemblies?

The correct choice is composite materials, which are frequently utilized as filler in fuselage assemblies due to their lightweight characteristics and high strength-to-weight ratio. Composites often consist of fibers, such as carbon or glass, embedded in a resin matrix, which provides excellent structural stability while minimizing the overall weight of the aircraft.

Moreover, composites can be engineered to offer improved resistance to fatigue and corrosion, essential properties for components that experience significant stress and environmental exposure during flight. The use of composites in aviation is growing, as they allow for design flexibility and can enhance the aerodynamic performance of the fuselage.

On the other hand, metals, while strong, can add considerable weight and are more susceptible to corrosion unless treated appropriately. Plastics do offer advantages in terms of weight and resistance to corrosion but may not provide the required strength for fuselage structural components. Wood, although historically used in aviation, is rarely employed in modern aircraft fuselige assemblies due to its limitations in strength and susceptibility to environmental conditions. Thus, composites emerge as the preferred choice for this application.