Monocoque (French for "single" (mono) and "shell" (coque)) is a construction technique that supports structural load using an object's external skin. French ( français,) is a Romance language spoken around the world by 118 million people as a native language and by about 180 to 260 million people This stands in contrast with using an internal framework (or truss) that is then covered with a non-load-bearing skin. In Architecture and Structural engineering, a truss is a structure comprising one or more triangular units constructed with straight slender members whose Monocoque construction was first widely used in aircraft, starting in the 1930s. The 1930s were described as an abrupt shift to more radical and conservative lifestyles as countries were struggling to find a solution to the Great Depression.

Structural skin is another term for the same concept.

Unibody, or unitary construction, is a related construction technique for automobiles in which the body is integrated into a single unit with the chassis rather than having a separate body-on-frame. A chassis (plural "chassis" (ˈʃæːsiː ˈtʃæːsiː consists of a framework that supports an inanimate object analogous to an Animal 's Body-on-frame is an Automobile construction technology Mounting a separate body to a rigid frame which supports the Drivetrain was the original method of building The welded "Unit Body" is the predominant automobile construction technology today.

View of the inside of the tail cone of a Murphy Moose homebuilt aircraft under construction, showing the semi-monocoque design

Aircraft

Early aircraft were built up from an internal frame, typically of wood or steel tubing, which was then covered (or skinned) with fabric to give it a smooth surface. The Murphy Moose is a large high-wing utility Monoplane designed to handle nearly any Airfield under any conditions Also known as amateur-built aircraft or kit planes, homebuilt aircraft are constructed by persons for whom this is not a professional activity Wood is hard fibrous lignified structural tissue produced as secondary Xylem in the stems of Woody plants notably trees but also shrubs Steel is an Alloy consisting mostly of Iron, with a Carbon content between 0 A textile is a flexible material comprised of a network of natural or artificial Fibres often referred to as thread or Yarn. The materials vary; some builders used sheet metal or plywood for the skin. Sheet metal is simply Metal formed into thin and flat pieces It is one of the fundamental forms used in Metalworking, and can be cut and bent into a variety Plywood is a type of Engineered board made from thin sheets of Wood, called plies or veneers In all of these designs the idea of load-bearing structures with separate skins remained.

In 1916 LFG introduced their Roland C.II, which used a fuselage made of "bent" plywood, forming both the external skinning as well as the main load bearing surface. Luft-Fahrzeug-Gesellschaft, universally referred to as LFG, was a World War I German aircraft manufacturer The LFG Roland CII, usually known as the Walfisch (Whale was an advanced German reconnaissance aircraft of World War I manufactured by Luft-Fahrzeug-Gesellschaft Plywood is a type of Engineered board made from thin sheets of Wood, called plies or veneers This made the plane immensely strong in comparison with contemporary designs, although it was also quite heavy. Similar designs were also produced by Pfalz Flugzeugwerke, who had originally built the Roland under license. Pfalz Flugzeugwerke was a World War I German aircraft manufacturer located at the Speyer airfield in the Rhineland-Palatinate.

By the late 1920s the price of aluminium (specifically duralumin) started dropping considerably and many manufacturers started using it to replace the internal framing, and in some cases, the external skin. The 1920s is sometimes referred to as the " Jazz Age " or the " Roaring Twenties " when speaking about the United States and Canada WikipediaNaming Duralumin (also called duraluminum, duraluminium or dural) is the trade name of one of the earliest types of age-hardenable Aluminium alloys A classic example of such a design is the Ford Trimotor, which retained the old type structure with new materials. WikipediaWikiProject Aircraft. Please see WikipediaWikiProject Aircraft/page content for recommended layout The structure of the plane consists of a trusswork of U-shaped aluminium beams, with a thin skin of aluminium riveted on top, using skin corrugations instead of wing ribs and fuselage stringers. A rivet is a mechanical Fastener. Before it is installed it consists of a smooth cylindrical shaft with a head on one end

When these designs started appearing it was realized that the skin itself had significant structural properties of its own. With a sufficient thickness, one could do away with all of the internal structure. However this would be even heavier than the framing would have been. At thinner gauges the skin could easily provide the structure for tension and shear loads (metal resists being pulled apart quite well), and if bent into a curve or pipe, it became quite strong against bending loads as well. The only loading it could not handle on its own—at least for thin "skins"—was compression. Combining this sort of structural skin with a greatly reduced internal stiffening to provide strength against buckling in compression led to what is known as "semi-monocoque". In Engineering, buckling is a failure mode characterized by a sudden failure of a structural member subjected to high Compressive stresses where

This converged with higher engine power and greater attention to streamlining to create faster aircraft; this required a stiff skin to support them on the passing air. The maximized torsional stiffness was also important to avoid aerolastic problems in the transition from the well-braced biplane construction. Aeroelasticity is the science which studies the interaction among inertial, elastic, and aerodynamic forces An outstanding early example is the Douglas DC-3, the first aircraft that could move cargo without a subsidy. At the beginning of World War II the technique was still being established and many aircraft still used mixed construction. World War II, or the Second World War, (often abbreviated WWII) was a global military conflict which involved a majority of the world's nations, including By the end, all high-performance planes were monocoque or semi-monocoque, while many lower-performance general aviation aircraft (such as the Piper PA-20 Pacer and Taylorcraft) still employed internal frame construction. General aviation (abbr GA) is one of two categories of Civil aviation. Piper Aircraft Inc, is a manufacturer of General aviation Aircraft, located at the Vero Beach Municipal Airport in Vero Beach Florida The PA-20 Pacer is a four-place strut braced high-wing light aircraft that was built by Piper Aircraft in the post- World War II period Taylorcraft Aviation is an airplane Manufacturer that has been producing aircraft for almost seventy years in several locations For the more dispersed loads of even slower aircraft, such as hang gliders and the Gossamer human powered series, a return to external wire bracing was one key to success. When loads are light, it costs proportionately more to provide stiffness against buckling over the same distance, so it pays to concentrate the compression loads into a few masts and as such, using tension members for most of the shape. Bicycle wheels, and even modern tents, use tension members to brace the compression parts against buckling. Where lightweight torsional resistance is the primary need, monocoque construction shows to advantage at lighter loadings than when it is used as a beam.

One disastrous result of metal monocoque aircraft design was the metal fatigue failures of the De Havilland Comet. WikipediaWikiProject Aircraft. Please see WikipediaWikiProject Aircraft/page content for recommended layout Once the process of metal fatigue was verified as the culprit, structural changes (like avoiding stress concentrations due to sharp corners) were incorporated to reduce this danger. Aircraft before and since have been safe, even with longer cracks, but regular inspections are still needed to detect them early. When one is found, all parts from that batch are traced and checked carefully or replaced. De Havilland had previously built thousands of wooden monocoque jet aircraft, the Vampires, copying their very successful Mosquito structure.

Composite aircraft have led to additional advances in monocoque construction. Composite materials (or composites for short are engineered Materials made from two or more constituent materials with significantly different physical or chemical By layering the materials in certain ways, the structure can have high strength and stiffness in one direction while not wasting material in another, making them ideal for wing structures. They can also be built to be flexible in useful ways, and no heavier or stiffer than needed at any point. Helicopter blades are now just twisted to adjust the cyclic pitch, instead of being mounted on a pivot.

Automobiles

X-ray drawing of the 1942 Nash 600 body design. The Nash 600 was an automobile manufactured by the Nash-Kelvinator Corporation of Kenosha Wisconsin from 1940 through the 1949 model year

The first automotive application of the monocoque technique was 1923's Lancia Lambda. The Lancia Lambda was an innovative Automobile produced from 1922 through 1931 Chrysler and Citroën built the first mass-produced monocoque vehicles, both in 1934, with the innovative Chrysler Airflow and the Traction Avant, respectively, and General Motors followed with the Opel Olympia in 1935. Chrysler LLC is an American Automobile manufacturer that has been producing Automobiles since 1925 Citroën (pronounced See-Troh-Enn is a French Automobile manufacturer, founded in 1919 by André Citroën. The Chrysler Airflow was an Automobile produced by the Chrysler Corporation from 1934 to 1937 The Citroën Traction Avant was an Automobile produced by the French manufacturer Citroën. General Motors Corporation ( GM) ( is a multinational automobile manufacturer founded in 1908 and headquartered in the United States. The Opel Olympia is a Small family car produced by the German automaker Opel from 1935 to 1940 from 1947 to 1953 and again from 1967 to 1970

In the post-war period the technique became more widely used. Nash Motors introduced this type of construction in 1941 with the new 600, generally credited with being the first popular mass-produced unibody construction automobile made in the United States. Also see Kelvinator and American Motors Corporation Nash Motors was an Automobile manufacturer based in Kenosha Wisconsin, in The all-welded steel with sturdy bridge-like girders that arched front to rear made for greater strength, safety, and longer life. A bridge is a Structure built to span a Gorge, Valley, Road, railroad track, River, Body of water A girder is a support beam used in Construction. Girders often have an I beam cross section for strength but may also have a box shape Z shape Nash engineers claimed that about 500 pounds of excess weight was cut out (compared to body-on-frame automobiles) and the body's lower air drag helped it to achieve excellent gas mileage for its day. In Fluid dynamics, drag (sometimes called fluid resistance) is the force that resists the movement of a Solid object through a Fluid (a Prophetically, the company's 1942 news release text attached to the X-ray drawing describes how ". A news release, media release, press release or press statement is a written or recorded Communication directed at members of the News . . all auto bodies will built . . . as this some day. . . " The Alec Issigonis Morris Minor of 1948 featured a monocoque body. Sir Alexander Arnold Constantine Issigonis, CBE, FRS (November 18 1906&ndashOctober 2 1988 was a Greek - British designer The revolutionary Morris Minor was launched at the Earls Court Motor Show on 20 September, 1948. The Hudson Hornet, along with the rest of Hudson range, featured a monocoque body at the same time. The Hudson Hornet is an automobile that was produced by the Hudson Motor Car Company of Detroit Michigan between 1951 and 1954

Other automakers incorporated this type of construction and the terms unit body and unibody became more common in general use. The automotive industry is the industry involved in the design development manufacture marketing and sale of Motor vehicles In 2007 more than 73 million motor vehicles The Ford Consul was the first Ford built in England using a unibody. Ford Consul (1951–1956 The Consul was first shown at the 1950 London Motor Show and was the start of Ford of Britain's successful attack on the family saloon car market and replaced American Motors (AMC) continued its engineering heritage from Nash and Hudson with breakthroughs such as in 1963 of combining separate parts into single stampings. American Motors Corporation (AMC was an American automobile company formed on January 14 1954 by the merger of the Nash-Kelvinator Corporation Also see Kelvinator and American Motors Corporation Nash Motors was an Automobile manufacturer based in Kenosha Wisconsin, in The Hudson Motor Car Company made Hudson and other brand Automobiles in Detroit Michigan, from 1909 to 1954 The Rambler Classic had "uniside" door surrounds from a single stamping of steel that reduced weight and assembly costs, as well as increasing structural rigidity and improving door fitment. The Rambler Classic was an intermediate sized automobile that was built and sold by American Motors Corporation (AMC from 1961 to 1966

Spot welded unibody construction is now the dominant technique in automobiles, though some vehicles (particularly trucks) still use the older body-on-frame technique. Spot welding is a type of Resistance welding used to weld various sheet Metal products This article is about the semi-truck For the North American use of the word see Pickup truck. Body-on-frame is an Automobile construction technology Mounting a separate body to a rigid frame which supports the Drivetrain was the original method of building

Some American automobiles, such as the 1967-81 Chevrolet Camaro and Pontiac Firebird, 1968-79 Chevrolet Nova and virtually all Chrysler Corporation automobiles from 1960 until the early 1980s, used a compromise design with a partial monocoque combined with a subframe carrying the front end and powertrain. The Chevrolet Camaro is a " Pony car " made in North America by the Chevrolet Motor Division of General Motors. The Pontiac Firebird was a Pony car built by the Pontiac division of General Motors between 1967 and 2002 The Chevrolet Nova or Chevy II was an American Compact car introduced by the Chevrolet division of General Motors in 1962 Chrysler LLC is an American Automobile manufacturer that has been producing Automobiles since 1925 A subframe is a structural component of a vehicle such as an Automobile or an Aircraft, that uses a discrete separate structure within a larger Body-on-frame The intention was to provide some of the rigidity and strength of a unibody while easing manufacture, although the results were mixed, in large part because the powertrain subframe contained the greatest single portion of the vehicle's overall mass, and thus movement of the subframe relative to the rest of the body could cause distortion and vibration. Subframes or partial subframes are still sometimes employed in otherwise monocoque construction, typically as a way of isolating the vibration and noise of powertrain or suspension components from the rest of the vehicle.

In automobiles, it is now common to see true monocoque frames, where the structural members around the window and door frames are built by folding the skin material several times. In these situations the main concerns are spreading the load evenly, having no holes for corrosion to start, and reducing the overall workload. Corrosion means the breaking down of essential properties in a material due to Chemical reactions with its surroundings Compared to older techniques, in which a body is bolted to a frame, monocoque cars are less expensive, lighter, more rigid, and can be more protective of occupants in a crash when appropriately designed.

Monocoque shell of Panoz DP01 Champ Car. The Panoz DP01 is the recently introduced Champ Car World Series spec race car that was used in the 2007 season Champ Car, was the name for a class and specification of cars used in American Championship Car Racing for many decades primarily for use in the Indianapolis

Monocoque design is so sophisticated that windshield and rear window glass now often make an important contribution to the designed structural strength of automobiles. The windshield or windscreen of an Aircraft, Automobile, Bus, Motorcycle, or Tram is the front Window Unfortunately, when a vehicle with a unibody design is involved in a serious accident, it may be more difficult to repair than a vehicle with a full frame. Rust is also more of a problem, since the structural metal is part of the load bearing structure making it more vulnerable, and must be repaired by cutting-out and welding rather than by simply bolting on new parts (as would be the case for a separate chassis). Older cars with separate chassis can still pass vehicle inspection tests (such as the British MoT) with quite advanced rust in the sills (rocker panels) and pillars, whereas in more modern cars these parts are structural and would lead to a test failure. See also Vehicle inspection The Ministry of Transport test (more usually MOT - pronounced by spelling out the letters is an annual test In the United States, in the majority of the states which require safety inspections, vehicles will not pass inspection if rust has perforated components such as rocker panels, floor pans, or pillars - regardless of the type of body construction.

Monocoque designs are favored amongst high-performance cars and racing cars today for their overall structural integrity and the fact that one can design a monocoque out of lightweight materials such as carbon fiber and expect the resulting vehicle to be light, stiff, and stable at high speeds and in tight corners. These types of particularly advanced monocoques can even be molded to create diffusers and ground effects which generate huge amounts of downforce.

Architecture

Architects occasionally take advantage of the increasing sophistication of monocoque technology in their building projects. Using monocoque technology in buildings allows for interior spaces without columns and load-bearing walls; this creates more spatial and programmatic openness inside.

Many 1950s and 1960s UK underground protected nuclear bunkers were constructed as reinforced concrete monocoque structures for their inherrant strength, robustness and protective factors. A military bunker is a hardened shelter often buried partly or fully underground designed to protect the inhabitants from falling bombs or other attacks Often described as "underground submarines" in that, if they were dug up and placed in water, they would have floated and stayed waterproof.

Future Systems, a firm based in the United Kingdom, designed The NatWest Media Centre for Lords Cricket Ground in 1999. Future Systems is a London -based architectural and design practice headed by Directors Jan Kaplický and Amanda Levete. The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom, the UK or Britain,is a Sovereign state located It is a monocoque structure (in aluminium). It was manufactured by Pendennis Shipyard in Falmouth, drawing on the company's boatbuilding experience.

Neil Denari is another architect who experiments with monocoque structures in much of his work. Neil Denari (b Fort Worth Texas September 03 1957 is an American architect professor and author

An igloo (and any uniform dome) is of full monocoque design, while a geodesic dome is a hybrid design, combining monocoque and frame elements. An igloo ( Inuit language: iglu, Inuktitut syllabics: ᐃᒡᓗ "house" plural iglooit or igluit, but in English A geodesic dome is an almost spherical shell structure based on a network of Great circles ( Geodesics lying approximately on the surface of a Sphere Quonset huts, hogans, and yurts are more examples. A hogan (hoʊˈgɑːn from Navajo hooghan, hoːɣan is the primary traditional home of the Navajo people. A yurt is a portable Felt -covered wood lattice -framed dwelling structure used by Nomads in the Steppes of Central Asia.

Boats and ships

Small boats, like kayaks and canoes, are typically of monocoque construction, while large ships tend to have frames. A kayak is a small human-powered Boat. It typically has a covered deck and a cockpit covered by a Spraydeck. A canoe is a small narrow Boat, typically human-powered though it may also be powered by sails or small electric or gas motors Mid-sized ships and boats (including submarines) may be of either design, or a hybrid of the two. A submarine is a Watercraft that can operate independently below water as distinct from a Submersible that has only limited underwater capability

Bicycles

Primarily due to the widespread use of carbon fibre in bicycle frame construction, monocoque framesets are becoming increasingly common. The American company Kestrel USA pioneered the use of carbon fibre monocoques in bike frame manufacture in the 1980s, and since then the technique has become increasingly widely used due to its stiffness and light weight. Kestrel is an American Bicycle Manufacturer headquartered in Santa Cruz California specializing in high-end bikes for Triathlon, Items such as seatposts and other components are now employing the same technique.

Motorcycles

A Grand Prix motorcycle racing monocoque motorcycle was developed in 1967 by Ossa, a Spanish motorcycle brand. Overview A Road Racing World Championship Grand Prix was first organized by the Fédération Internationale de Motocyclisme (FIM in 1949 MotorCycle is the title of a 1993 album by Rock band Daniel Amos, released on BAI Records. This article recaps the 1967 Grand Prix motorcycle racing season Ossa was a Spanish Motorcycle manufacturer which was active from 1924 to 1982 best known for lightweight two-stroke-engined bikes used in Observed Trials Honda also experimented with a monocoque motorcycle in 1979 with its NR500. () is a Multinational corporation, engine Manufacturer and engineering corporation headquartered in Japan. The 1979 Grand Prix motorcycle racing season was the 31st FIM NR500 was an innovative racing Motorcycle developed by Honda HRC in 1978 to compete in Grand Prix motorcycle racing. Monocoque construction has begun to see application in motorcycle chassis production, for example, the 2005 model year Kawasaki Ninja ZX-14. The Kawasaki Ninja ZX-14 ( ZZR1400 in Europe and Japan is a Hyper sport Motorcycle manufactured by Kawasaki Heavy Industries and is currently

Scooters

Scooters produced by Vespa and other companies are made from a pressed steel monocoque frame. This page is very closely monitored and additions of external links if not discussed first are removed quickly Steel is an Alloy consisting mostly of Iron, with a Carbon content between 0 This innovative design lead to the light weight and high fuel economy of scooters, and contributed to their popularity. Fuel economy in automobiles is the amount of Fuel required to move the Automobile over a given Distance. A scooter is a style of two-wheeled motor vehicle traditionally defined by characteristics such as a step-through frame wheels less than 16" in diameter and an engine located

Rockets

First-stage view of the Falcon I.

The Falcon I rocket recently developed by SpaceX uses a graduated monocoque, flight pressure-stabilized design for its first stage. The Falcon 1 is a partially reusable Launch system designed and manufactured by SpaceX. Space Exploration Technologies Corporation ( SpaceX) is an American space-transportation Startup company founded by PayPal co-founder Elon This pressure-stabilized design is also used by the Atlas II rocket. Atlas II was a member of the Atlas family of Launch vehicles which evolved from the successful Atlas missile program of the 1950s

See also

• Backbone chassis
• Body-on-frame
• Coachbuilder
• Monokote a plastic model aircraft coating. Backbone chassis is a type of an automobile construction Chassis that is similar to the Body-on-frame design Body-on-frame is an Automobile construction technology Mounting a separate body to a rigid frame which supports the Drivetrain was the original method of building Bus manufacturingA coachbuilder is a manufacturer of bodies for Carriages or Automobiles The trade dates back several centuries Monokote is a commercially available light weight plastic shrink wrap film available in various color schemes with an adhesive on one side used to cover and form the surfaces of a
• Strut Bar
• Spaceframe
• Superleggera

References