Which component serves as a streamlined housing enclosing dome, barrel, and control assemblies?

• A. barrel
• B. dome
• C. spinner
• D. swashplate

Answer: (C)

The key idea is that there’s a streamlined outer cover that wraps around the rotor head, enclosing the internal parts like the dome, the central barrel, and the control link assemblies. This outer shell is designed to reduce aerodynamic drag while protecting the inner components and keeping them aligned as the blades move.

That outer cover is the spinner. It sits at the hub area and forms a single, smooth profile over the rotor head, so it encloses the dome, barrel, and control assemblies underneath. The dome itself is the cover for the head’s inner workings, the barrel is the central structural piece inside, and the swashplate is part of the control linkage; none of those on their own provide the protective, streamlined housing. The spinner is specifically the component described as that outer streamlined enclosure.