What is the primary function of the nacelle?

The primary function of the nacelle is to cover the engine. A nacelle is the housing that encloses the engine on an aircraft, providing protection and supporting various components. This structure is designed to streamline airflow around the engine, reducing drag and contributing to overall aerodynamic efficiency.

While it may also serve other functions, such as housing certain engine components (like the fuel system) or providing structural support, the essential purpose is to encase and safeguard the engine itself. This protective covering is integral to the aircraft's design, ensuring that the engine operates effectively while also minimizing noise and improving the aircraft's performance.

The other options can describe features associated with the engine and nacelle. For example, while an air intake is an essential part of the engine system, it is specifically designed to bring air into the engine rather than being the primary function of the nacelle as a whole. Additionally, the nacelle does not provide lift directly; that is the job of the wings. Lastly, although the nacelle can house the fuel system, this is a secondary function rather than its core purpose.