What does a monocoque fuselage primarily rely on for strength?

A monocoque fuselage design primarily relies on the skin or covering for its structural strength. In this design, the outer layer of the fuselage bears the loads imposed upon it, eliminating the need for extensive internal framing. The skin is engineered to handle both tensile and compressive stresses, allowing it to support the forces experienced during flight. This design approach leads to a reduction in weight and can improve aerodynamics, as the structure is streamlined without significant interruptions from internal supports.

In contrast, internal framing is a key characteristic of a semi-monocoque design, where the framework provides additional strength. Struts and ribs, commonly found in other structural configurations, offer support and shape to a frame rather than being the primary load-bearing elements in a monocoque design. Lastly, while composite materials can be utilized in monocoque constructions for weight savings and enhanced strength, the primary reliance on the monocoque structure itself is on the skin or covering.