page_title: Monocoque
section_title: Road vehicles
hierarchical_section_title: Monocoque / Road vehicles
caption_attribution_description: The 1981 McLaren MP4 Formula One car. In the Donington Grand Prix Collection museum, Leics., UK.
context_page_description: Monocoque, also called structural skin, is a structural system in which loads are supported by an object's external skin, similar to an egg shell. The word monocoque is a French term for "single shell" or "single hull".
  First used for boats, a true monocoque carries both tensile and compressive forces within the skin and can be recognised by the absence of a load-carrying internal frame. Few metal aircraft can strictly be regarded as pure monocoques, as they use a metal shell or sheeting reinforced with frames riveted to the skin, but most wooden aircraft are described as monocoques, even though they also incorporate frames.
  By contrast, a semi-monocoque is a hybrid combining a tensile stressed skin and a compressive structure made up of longerons and ribs or frames. Other semi-monocoques, not to be confused with true monocoques, include vehicle unibodies, which tend to be composites, and inflatable shells or balloon tanks, both of which are pressure stabilised.
context_section_description: In motor racing, the safety of the driver depends on the car body, which must meet stringent regulations, and only a few cars have been built with monocoque structures. An aluminum alloy monocoque chassis was first used in the 1962 Lotus 25 Formula 1 race car and McLaren was the first to use carbon-fiber-reinforced polymers to construct the monocoque of the 1981 McLaren MP4/1. In 1990 the Jaguar XJR 15 became the first production car with a carbon-fiber monocoque.
  The term monocoque is frequently misapplied to unibody cars. Commercial car bodies are almost never true monocoques but instead use the unibody system (also referred to as unitary construction, unitary body–chassis or body–frame integral construction), which uses box sections, bulkheads and tubes to provide most of the strength of the vehicle, while the skin adds relatively little strength or stiffness.
caption: 1981 McLaren MP4/1, with a carbon fiber composite monocoque
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