Nacelles or pods are streamlined enclosures used on multi-engine aircraft primarily to house the engines. They are located below, or at the leading edge of the wing or on the tail of the aircraft.
An engine nacelle or pod consists of skin, cowling, structural members, a fire-wall, and engine mounts. Skins and cowlings cover the outside of the nacelle. Both are usually made of sheet aluminum alloy, stainless steel, or titanium. Regardless of the material used, the skin is usually attached to the framework by rivets.
The framework can consist of structural members similar to those are of the fuselage. The framework would include length ways members, such as longerons and stringers, and width ways/vertical members, such as bulkheads, rings, and formers.
A nacelle or pod also contains a firewall, which separates the engine compartment from the rest of the aircraft. This bulkhead is usually made of stainless steel, or titanium sheet metal.