The
mechanical structure of an
aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines ...
is known as the airframe. This structure is typically considered to include the
fuselage
The fuselage (; from the French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds crew, passengers, or cargo. In single-engine aircraft, it will usually contain an engine as well, although in some amphibious aircraft t ...
,
undercarriage
Undercarriage is the part of a moving vehicle that is underneath the main body of the vehicle. The term originally applied to this part of a horse-drawn carriage, and usage has since broadened to include:
*The landing gear of an aircraft.
*The ch ...
,
empennage
The empennage ( or ), also known as the tail or tail assembly, is a structure at the rear of an aircraft that provides stability during flight, in a way similar to the feathers on an arrow.Crane, Dale: ''Dictionary of Aeronautical Terms, third ed ...
and
wing
A wing is a type of fin that produces lift while moving through air or some other fluid. Accordingly, wings have streamlined cross-sections that are subject to aerodynamic forces and act as airfoils. A wing's aerodynamic efficiency is expres ...
s, and excludes the
propulsion system
Propulsion is the generation of force by any combination of pushing or pulling to modify the translational motion of an object, which is typically a rigid body (or an articulated rigid body) but may also concern a fluid. The term is derived fro ...
.
Airframe design is a field of
aerospace engineering
Aerospace engineering is the primary field of engineering concerned with the development of aircraft and spacecraft. It has two major and overlapping branches: aeronautical engineering and astronautical engineering. Avionics engineering is si ...
that combines
aerodynamics
Aerodynamics, from grc, ἀήρ ''aero'' (air) + grc, δυναμική (dynamics), is the study of the motion of air, particularly when affected by a solid object, such as an airplane wing. It involves topics covered in the field of fluid dyn ...
,
materials technology and
manufacturing
Manufacturing is the creation or production of goods with the help of equipment, labor, machines, tools, and chemical or biological processing or formulation. It is the essence of secondary sector of the economy. The term may refer to a r ...
methods with a focus on weight, strength and
aerodynamic drag
In fluid dynamics, drag (sometimes called air resistance, a type of friction, or fluid resistance, another type of friction or fluid friction) is a force acting opposite to the relative motion of any object moving with respect to a surrounding fl ...
, as well as
reliability
Reliability, reliable, or unreliable may refer to:
Science, technology, and mathematics Computing
* Data reliability (disambiguation), a property of some disk arrays in computer storage
* High availability
* Reliability (computer networking), a ...
and cost.
History
Modern airframe history began in the
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
when a 1903 wood
biplane
A biplane is a fixed-wing aircraft with two main wings stacked one above the other. The first powered, controlled aeroplane to fly, the Wright Flyer, used a biplane wing arrangement, as did many aircraft in the early years of aviation. While ...
made by
Orville and Wilbur Wright showed the potential of
fixed-wing designs.
In 1912 the
Deperdussin Monocoque
The Deperdussin Monocoque was an early racing aircraft built in 1912 by the Aéroplanes Deperdussin, a French aircraft manufacturer started in 1911 and reorganized as the Société Pour L'Aviation et ses Dérivés ( SPAD) in 1913. It is so nam ...
pioneered the light, strong and streamlined
monocoque
Monocoque ( ), also called structural skin, is a structural system in which loads are supported by an object's external skin, in a manner similar to an egg shell. The word ''monocoque'' is a French term for "single shell".
First used for boats, ...
fuselage formed of thin
plywood
Plywood is a material manufactured from thin layers or "plies" of wood veneer that are glued together with adjacent layers having their wood grain rotated up to 90 degrees to one another. It is an engineered wood from the family of manufactured ...
layers over a circular frame, achieving .
First World War
Many early developments were spurred by
military
A military, also known collectively as armed forces, is a heavily armed, highly organized force primarily intended for warfare. It is typically authorized and maintained by a sovereign state, with its members identifiable by their distinct ...
needs during
World War I
World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...
. Well known
aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines ...
from that era include the Dutch designer
Anthony Fokker
Anton Herman Gerard "Anthony" Fokker (6 April 1890 – 23 December 1939) was a Dutch aviation pioneer, aviation entrepreneur, aircraft designer, and aircraft manufacturer. He produced fighter aircraft in Germany during the First World War such ...
's combat aircraft for the
German Empire
The German Empire (),Herbert Tuttle wrote in September 1881 that the term "Reich" does not literally connote an empire as has been commonly assumed by English-speaking people. The term literally denotes an empire – particularly a hereditary ...
's ''
Luftstreitkräfte
The ''Deutsche Luftstreitkräfte'' (, German Air Force)—known before October 1916 as (Flyer Troops)—was the air arm of the Imperial German Army. In English-language sources it is usually referred to as the Imperial German Air Service, alt ...
'', and U.S.
Curtiss
Curtiss Aeroplane and Motor Company (1909 – 1929) was an American aircraft manufacturer originally founded by Glenn Hammond Curtiss and Augustus Moore Herring in Hammondsport, New York. After significant commercial success in its first decade ...
flying boat
A flying boat is a type of fixed-winged seaplane with a hull, allowing it to land on water. It differs from a floatplane in that a flying boat's fuselage is purpose-designed for floatation and contains a hull, while floatplanes rely on fusela ...
s and the German/Austrian Taube
monoplanes
A monoplane is a fixed-wing aircraft configuration with a single mainplane, in contrast to a biplane or other types of multiplanes, which have multiple planes.
A monoplane has inherently the highest efficiency and lowest drag of any wing confi ...
. These used hybrid wood and metal structures.
By the 1915/16 timeframe, the German
Luft-Fahrzeug-Gesellschaft
Luft-Fahrzeug-Gesellschaft, also referred to as LFG, was a German aircraft manufacturer during World War I. They are best known for their various "Roland" designs, notably the Roland C.II ''Walfisch'' (whale), Roland D.II ''haifisch'' (Shark) and ...
firm had devised a fully
monocoque
Monocoque ( ), also called structural skin, is a structural system in which loads are supported by an object's external skin, in a manner similar to an egg shell. The word ''monocoque'' is a French term for "single shell".
First used for boats, ...
all-wood structure with only a skeletal internal frame, using strips of plywood laboriously "wrapped" in a diagonal fashion in up to four layers, around concrete male molds in "left" and "right" halves, known as ''Wickelrumpf'' (wrapped-body) construction - this first appeared on the 1916
LFG Roland C.II
The LFG Roland C.II, usually known as the ''Walfisch'' (Whale), was an advanced German reconnaissance aircraft of World War I. It was manufactured by Luft-Fahrzeug-Gesellschaft G.m.b.H.
Characteristics
The C.II had much lower drag than comparab ...
, and would later be licensed to
Pfalz Flugzeugwerke
Pfalz Flugzeugwerke was a World War I German aircraft manufacturer, located at the Speyer airfield in the Palatinate (German: Pfalz). They are best known for their series of fighters, notably the Pfalz D.III and Pfalz D.XII. The company went ba ...
for its D-series biplane fighters.
In 1916 the German
Albatros D.III
The Albatros D.III was a biplane fighter aircraft used by the Imperial German Army Air Service (''Luftstreitkräfte'') during World War I. A modified licence model was built by Oeffag for the Austro-Hungarian Air Service ( ''Luftfahrtruppen''). T ...
biplane fighters featured
semi-monocoque
The term semi-monocoque or semimonocoque refers to a stressed shell structure that is similar to a true monocoque, but which derives at least some of its strength from conventional reinforcement. Semi-monocoque construction is used for, among ot ...
fuselages with load-bearing plywood skin panels glued to longitudinal
longeron
In engineering, a longeron and stringer is the load-bearing component of a framework.
The term is commonly used in connection with aircraft fuselages and automobile chassis. Longerons are used in conjunction with stringers to form structural ...
s and
bulkheads; it was replaced by the prevalent
stressed skin
In mechanical engineering, stressed skin is a type of rigid construction, intermediate between monocoque and a rigid frame with a non-loaded covering. A stressed skin structure has its compression-taking elements localized and its tension-taking e ...
structural configuration as
metal
A metal (from Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typicall ...
replaced wood.
[
Similar methods to the Albatros firm's concept were used by both ]Hannoversche Waggonfabrik
Hannoversche Waggonfabrik AG was a German aircraft manufacturer of the World War I era. It was known as a railway rolling stock constructor until required by the German government in 1916 to start the construction of aeroplanes. The aircraft branc ...
for their light two-seat CL.II through CL.V designs, and by Siemens-Schuckert
Siemens-Schuckert (or Siemens-Schuckertwerke) was a German electrical engineering company headquartered in Berlin, Erlangen and Nuremberg that was incorporated into the Siemens AG in 1966.
Siemens Schuckert was founded in 1903 when Siemens & Ha ...
for their later Siemens-Schuckert D.III __NOTOC__
The Siemens-Schuckert D.III was a German single-seat fighter built by Siemens-Schuckert Werke. The D.III was a development of the earlier Siemens-Schuckert D.IIc prototype.Green and Swanborough 1994, p. 530. The D.III was an (nearly) equ ...
and higher-performance D.IV biplane fighter designs.
The Albatros D.III construction was of much less complexity than the patented LFG ''Wickelrumpf'' concept for their outer skinning.
German engineer Hugo Junkers
Hugo Junkers (3 February 1859 – 3 February 1935) was a German aircraft engineer and aircraft designer who pioneered the design of all-metal airplanes and flying wings. His company, Junkers Flugzeug- und Motorenwerke AG (Junkers Aircraft and Mo ...
first flew all-metal airframes in 1915 with the all-metal, cantilever
A cantilever is a rigid structural element that extends horizontally and is supported at only one end. Typically it extends from a flat vertical surface such as a wall, to which it must be firmly attached. Like other structural elements, a canti ...
-wing, stressed-skin monoplane Junkers J 1
The Junkers J 1, nicknamed the ''Blechesel'' ("Tin Donkey" or "Sheet Metal Donkey"), was an experimental monoplane aircraft developed by Junkers & Co. It was the world's first all-metal aircraft.
Manufactured early on in the First World War, ...
made of steel
Steel is an alloy made up of iron with added carbon to improve its strength and fracture resistance compared to other forms of iron. Many other elements may be present or added. Stainless steels that are corrosion- and oxidation-resistant ty ...
.[ It developed further with lighter weight ]duralumin
Duralumin (also called duraluminum, duraluminium, duralum, dural(l)ium, or dural) is a trade name for one of the earliest types of age-hardenable aluminium alloys. The term is a combination of '' Dürener'' and ''aluminium''.
Its use as a tra ...
, invented by Alfred Wilm Alfred Wilm (25 June 1869 – 6 August 1937) was a German metallurgist who invented the alloy Al-3.5–5.5%Cu-Mg-Mn, now known as Duralumin which is used extensively in aircraft.
Whilst working in military research NUTZ in Neubabelsberg in 1901, Wi ...
in Germany before the war; in the airframe of the Junkers D.I
The Junkers D.I (factory designation J 9) was a monoplane fighter aircraft produced in Germany late in World War I, significant for becoming the first all-metal fighter to enter service. The prototype, a private venture by Junkers named the J 7, ...
of 1918, whose techniques were adopted almost unchanged after the war by both American engineer William Bushnell Stout
William Bushnell Stout (March 16, 1880 – March 20, 1956) was a pioneering American inventor, engineer, developer and designer whose works in the automotive and aviation fields were groundbreaking. Known by the nickname "Bill", Stout designed an ...
and Soviet aerospace engineer Andrei Tupolev
Andrei Nikolayevich Tupolev (russian: Андрей Николаевич Туполев; – 23 December 1972) was a Russian Empire, Russian and later Soviet Union, Soviet aeronautical engineer known for his pioneering aircraft designs as Di ...
, proving to be useful for aircraft up to 60 meters in wingspan by the 1930s.
Between World wars
The J 1 of 1915, and the D.I fighter of 1918, were followed in 1919 by the first all-metal transport aircraft, the Junkers F.13
The Junkers F 13 was the world's first all-metal transport aircraft, developed in Weimar Republic, Germany at the end of World War I. It was an advanced Cantilever#Aircraft, cantilever-wing monoplane, with enclosed accommodation for four passenge ...
made of Duralumin
Duralumin (also called duraluminum, duraluminium, duralum, dural(l)ium, or dural) is a trade name for one of the earliest types of age-hardenable aluminium alloys. The term is a combination of '' Dürener'' and ''aluminium''.
Its use as a tra ...
as the D.I had been; 300 were built, along with the first four-engine
An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy.
Available energy sources include potential energy (e.g. energy of the Earth's gravitational field as exploited in hydroelectric power gen ...
, all-metal passenger aircraft
An airliner is a type of aircraft for transporting passengers and air cargo. Such aircraft are most often operated by airlines. Although the definition of an airliner can vary from country to country, an airliner is typically defined as an ai ...
, the sole Zeppelin-Staaken E-4/20
The Zeppelin-Staaken E-4/20 was a revolutionary four-engine all-metal passenger monoplane designed in 1917 by Adolf Rohrbach and completed in 1919 at the Zeppelin-Staaken works outside Berlin, Germany. The E-4/20 was the first four-engine, all-m ...
.[ ]Commercial aircraft
An airliner is a type of aircraft for transporting passengers and air cargo. Such aircraft are most often operated by airlines. Although the definition of an airliner can vary from country to country, an airliner is typically defined as an ai ...
development during the 1920s and 1930s focused on monoplane designs using Radial engine
The radial engine is a reciprocating type internal combustion engine configuration in which the cylinders "radiate" outward from a central crankcase like the spokes of a wheel. It resembles a stylized star when viewed from the front, and is ca ...
s. Some were produced as single copies or in small quantity such as the Spirit of St. Louis
The ''Spirit of St. Louis'' (formally the Ryan NYP, registration: N-X-211) is the custom-built, single-engine, single-seat, high-wing monoplane that was flown by Charles Lindbergh on May 20–21, 1927, on the first solo nonstop transatlant ...
flown across the Atlantic
The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe an ...
by Charles Lindbergh
Charles Augustus Lindbergh (February 4, 1902 – August 26, 1974) was an American aviator, military officer, author, inventor, and activist. On May 20–21, 1927, Lindbergh made the first nonstop flight from New York City to Paris, a distance o ...
in 1927. William Stout designed the all-metal Ford Trimotor
The Ford Trimotor (also called the "Tri-Motor", and nicknamed the "Tin Goose") is an American three-engined transport aircraft. Production started in 1925 by the companies of Henry Ford and ended on June 7, 1933, after 199 had been made. It w ...
s in 1926.
The Hall XFH naval fighter prototype
A prototype is an early sample, model, or release of a product built to test a concept or process. It is a term used in a variety of contexts, including semantics, design, electronics, and Software prototyping, software programming. A prototyp ...
flown in 1929 was the first aircraft with a rivet
A rivet is a permanent mechanical fastener. Before being installed, a rivet consists of a smooth cylindrical shaft with a head on one end. The end opposite to the head is called the ''tail''. On installation, the rivet is placed in a punched ...
ed metal fuselage : an aluminum skin over steel tubing, Hall also pioneered flush rivet
A rivet is a permanent mechanical fastener. Before being installed, a rivet consists of a smooth cylindrical shaft with a head on one end. The end opposite to the head is called the ''tail''. On installation, the rivet is placed in a punched ...
s and butt joint
A butt joint is a technique in which two pieces of material are joined by simply placing their ends together without any special shaping. The name "butt joint" comes from the way the material is joined. The butt joint is the simplest joint to ma ...
s between skin panels in the Hall PH
The Hall PH was an American flying boat of the 1930s. It was a twin-engined biplane, developed from the Naval Aircraft Factory PN and could hence trace its lineage back to the Felixstowe flying boats of World War I. The PH was purchased in small n ...
flying boat
A flying boat is a type of fixed-winged seaplane with a hull, allowing it to land on water. It differs from a floatplane in that a flying boat's fuselage is purpose-designed for floatation and contains a hull, while floatplanes rely on fusela ...
also flying in 1929.[ Based on the Italian ]Savoia-Marchetti S.56
The Savoia-Marchetti S.56 was an Italian single-engine biplane flying boat trainer and tourer, built by Savoia-Marchetti.
Of unequal span, the upper longer than the lower, Donald 1997, p.820. of wooden construction. Instructor and student sat s ...
, the 1931 Budd BB-1 Pioneer
The Budd BB-1 Pioneer was an experimental United States flying boat of the 1930s utilizing the Savoia-Marchetti S.56 design. Its framework was constructed entirely of stainless steel, using a newly patented method of welding that alloy.
Devel ...
experimental flying boat was constructed of corrosion-resistant stainless steel
Stainless steel is an alloy of iron that is resistant to rusting and corrosion. It contains at least 11% chromium and may contain elements such as carbon, other nonmetals and metals to obtain other desired properties. Stainless steel's corros ...
assembled with newly developed spot welding
A spot welder
Spot welding (or resistance spot welding) is a type of electric resistance welding used to weld various sheet metal products, through a process in which contacting metal surface points are joined by the heat obtained from resistance ...
by U.S. railcar maker Budd Company
The Budd Company was a 20th-century metal fabricator, a major supplier of body components to the automobile industry, and a manufacturer of stainless steel passenger rail cars, airframes, missile and space vehicles, and various defense products ...
.[
The original Junkers corrugated duralumin-covered airframe philosophy culminated in the 1932-origin ]Junkers Ju 52
The Junkers Ju 52/3m (nicknamed ''Tante Ju'' ("Aunt Ju") and ''Iron Annie'') is a transport aircraft that was designed and manufactured by German aviation company Junkers.
Development of the Ju 52 commenced during 1930, headed by German Aeros ...
trimotor airliner, used throughout World War II by the Nazi German Luftwaffe
The ''Luftwaffe'' () was the aerial-warfare branch of the German ''Wehrmacht'' before and during World War II. Germany's military air arms during World War I, the ''Luftstreitkräfte'' of the Imperial Army and the '' Marine-Fliegerabtei ...
for transport and paratroop needs. Andrei Tupolev's designs in Joseph Stalin
Joseph Vissarionovich Stalin (born Ioseb Besarionis dze Jughashvili; – 5 March 1953) was a Georgian revolutionary and Soviet political leader who led the Soviet Union from 1924 until his death in 1953. He held power as General Secreta ...
's Soviet Union designed a series of all-metal aircraft of steadily increasing size culminating in the largest aircraft of its era, the eight-engined Tupolev ANT-20
The Tupolev ANT-20 ''Maxim Gorky'' (russian: Туполев АНТ-20 "Максим Горький", sometimes romanized as ''Maksim Gorki'') was a Soviet eight-engine aircraft, the largest in the world during the 1930s. Its wingspan was similar t ...
in 1934, and Donald Douglas' firms developed the iconic Douglas DC-3
The Douglas DC-3 is a propeller-driven airliner
manufactured by Douglas Aircraft Company, which had a lasting effect on the airline industry in the 1930s to 1940s and World War II.
It was developed as a larger, improved 14-bed sleeper version ...
twin-engined airliner in 1936. They were among the most successful designs to emerge from the era through the use of all-metal airframes.
In 1937, the Lockheed XC-35
The Lockheed XC-35 is a twin-engine, experimental pressurized airplane. It was the second American aircraft to feature cabin pressurization. It was initially described as a "supercharged cabins" by the Army. The XC-35 was a development of the Lo ...
was specifically constructed with cabin pressurization
Cabin pressurization is a process in which conditioned air is pumped into the cabin of an aircraft or spacecraft in order to create a safe and comfortable environment for passengers and crew flying at high altitudes. For aircraft, this air is ...
to undergo extensive high-altitude flight tests, paving the way for the Boeing 307 Stratoliner
The Boeing Model 307 Stratoliner (or Strato-Clipper in Pan American service, or C-75 in USAAF service) is an American stressed-skin four-engine low-wing tailwheel monoplane airliner derived from the B-17 Flying Fortress bomber, which entered com ...
, which would be the first aircraft with a pressurized cabin to enter commercial service.[
]
Second World War
During World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...
, military needs again dominated airframe designs. Among the best known were the US C-47 Skytrain
The Douglas C-47 Skytrain or Dakota (Royal Air Force, RAF, Royal Australian Air Force, RAAF, Royal Canadian Air Force, RCAF, Royal New Zealand Air Force, RNZAF, and South African Air Force, SAAF designation) is a airlift, military transport ai ...
, B-17 Flying Fortress
The Boeing B-17 Flying Fortress is a four-engined heavy bomber developed in the 1930s for the United States Army Air Corps (USAAC). Relatively fast and high-flying for a bomber of its era, the B-17 was used primarily in the European Theater ...
, B-25 Mitchell
The North American B-25 Mitchell is an American medium bomber that was introduced in 1941 and named in honor of Major General William "Billy" Mitchell, a pioneer of U.S. military aviation. Used by many Allied air forces, the B-25 served in ...
and P-38 Lightning
The Lockheed P-38 Lightning is an American single-seat, twin piston-engined fighter aircraft that was used during World War II. Developed for the United States Army Air Corps by the Lockheed Corporation, the P-38 incorporated a distinctive tw ...
, and British Vickers Wellington
The Vickers Wellington was a British twin-engined, long-range medium bomber. It was designed during the mid-1930s at Brooklands in Weybridge, Surrey. Led by Vickers-Armstrongs' chief designer Rex Pierson; a key feature of the aircraft is its g ...
that used a geodesic construction method, and Avro Lancaster
The Avro Lancaster is a British Second World War heavy bomber. It was designed and manufactured by Avro as a contemporary of the Handley Page Halifax, both bombers having been developed to the same specification, as well as the Short Stirlin ...
, all revamps of original designs from the 1930s. The first jets were produced during the war but not made in large quantity.
Due to wartime scarcity of aluminum, the de Havilland Mosquito
The de Havilland DH.98 Mosquito is a British twin-engined, shoulder-winged, multirole combat aircraft, introduced during the Second World War. Unusual in that its frame was constructed mostly of wood, it was nicknamed the "Wooden Wonder", or ...
fighter-bomber was built from wood—plywood facings bonded to a balsawood
''Ochroma pyramidale'', commonly known as the balsa tree, is a large, fast-growing tree native to the Americas. It is the sole member of the genus ''Ochroma''. The tree is famous for its wide usage in woodworking, with the name ''balsa'' being ...
core and formed using mold
A mold () or mould () is one of the structures certain fungus, fungi can form. The dust-like, colored appearance of molds is due to the formation of Spore#Fungi, spores containing Secondary metabolite#Fungal secondary metabolites, fungal seco ...
s to produce monocoque structures, leading to the development of metal-to-metal bonding used later for the de Havilland Comet
The de Havilland DH.106 Comet was the world's first commercial jet airliner. Developed and manufactured by de Havilland in the United Kingdom, the Comet 1 prototype first flew in 1949. It featured an aerodynamically clean design with four d ...
and Fokker F27
The Fokker F27 Friendship is a turboprop airliner developed and manufactured by the Dutch aircraft manufacturer Fokker. It is the most numerous post-war aircraft manufactured in the Netherlands; the F27 was also one of the most successful Euro ...
and F28.[
]
Postwar
Postwar commercial airframe design focused on airliner
An airliner is a type of aircraft for transporting passengers and air cargo. Such aircraft are most often operated by airlines. Although the definition of an airliner can vary from country to country, an airliner is typically defined as an ...
s, on turboprop
A turboprop is a turbine engine that drives an aircraft propeller.
A turboprop consists of an intake, reduction gearbox, compressor, combustor, turbine, and a propelling nozzle. Air enters the intake and is compressed by the compressor. Fuel ...
engines, and then on jet engine
A jet engine is a type of reaction engine discharging a fast-moving jet of heated gas (usually air) that generates thrust by jet propulsion. While this broad definition can include rocket, Pump-jet, water jet, and hybrid propulsion, the term ...
s. The generally higher speeds and tensile stress
In continuum mechanics, stress is a physical quantity. It is a quantity that describes the magnitude of forces that cause deformation. Stress is defined as ''force per unit area''. When an object is pulled apart by a force it will cause elonga ...
es of turboprops and jets were major challenges. Newly developed aluminum
Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. It has ...
alloy
An alloy is a mixture of chemical elements of which at least one is a metal. Unlike chemical compounds with metallic bases, an alloy will retain all the properties of a metal in the resulting material, such as electrical conductivity, ductility, ...
s with copper
Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkis ...
, magnesium
Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 of the periodic ta ...
and zinc
Zinc is a chemical element with the symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodi ...
were critical to these designs.
Flown in 1952 and designed to cruise at Mach 2 where skin friction
Skin friction drag is a type of aerodynamic or hydrodynamic drag, which is resistant force exerted on an object moving in a fluid. Skin friction drag is caused by the viscosity of fluids and is developed from laminar drag to turbulent drag as a f ...
required its heat
In thermodynamics, heat is defined as the form of energy crossing the boundary of a thermodynamic system by virtue of a temperature difference across the boundary. A thermodynamic system does not ''contain'' heat. Nevertheless, the term is al ...
resistance, the Douglas X-3 Stiletto
The Douglas X-3 Stiletto was a 1950s United States experimental jet aircraft with a slender fuselage and a long tapered nose, manufactured by the Douglas Aircraft Company. Its primary mission was to investigate the design features of an aircraf ...
was the first titanium
Titanium is a chemical element with the symbol Ti and atomic number 22. Found in nature only as an oxide, it can be reduced to produce a lustrous transition metal with a silver color, low density, and high strength, resistant to corrosion in ...
aircraft but it was underpowered and barely supersonic
Supersonic speed is the speed of an object that exceeds the speed of sound ( Mach 1). For objects traveling in dry air of a temperature of 20 °C (68 °F) at sea level, this speed is approximately . Speeds greater than five times ...
; the Mach 3.2 Lockheed A-12
The Lockheed A-12 is a high-altitude, Mach 3+ reconnaissance aircraft built for the United States Central Intelligence Agency (CIA) by Lockheed's Skunk Works, based on the designs of Clarence "Kelly" Johnson. The aircraft was designate ...
and SR-71
The Lockheed SR-71 "Blackbird" is a Range (aeronautics), long-range, high-altitude, Mach number, Mach 3+ military strategy, strategic reconnaissance aircraft developed and manufactured by the American aerospace company Lockheed Corporati ...
were also mainly titanium, as was the cancelled Boeing 2707
The Boeing 2707 was an American supersonic passenger airliner project during the 1960s. After winning a competition for a government-funded contract to build an American supersonic airliner, Boeing began development at its facilities in Seattl ...
Mach 2.7 supersonic transport
A supersonic transport (SST) or a supersonic airliner is a civilian supersonic aircraft designed to transport passengers at speeds greater than the speed of sound. To date, the only SSTs to see regular service have been Concorde and the Tupol ...
.[
Because heat-resistant titanium is hard to weld and difficult to work with, welded ]nickel steel
Nickel is a chemical element with Chemical symbol, symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and Ductility, ductile transition metal. Pure nickel is chemically reactive bu ...
was used for the Mach 2.8 Mikoyan-Gurevich MiG-25
The Mikoyan-Gurevich MiG-25 (russian: Микоян и Гуревич МиГ-25; NATO reporting name: Foxbat) is a supersonic interceptor and reconnaissance aircraft that is among the fastest military aircraft to enter service. Designed by the ...
fighter, first flown in 1964; and the Mach 3.1 North American XB-70 Valkyrie
The North American Aviation XB-70 Valkyrie was the prototype version of the planned B-70 nuclear-armed, deep-penetration supersonic strategic bomber for the United States Air Force Strategic Air Command. Designed in the late 1950s by North Ame ...
used brazed stainless steel
Stainless steel is an alloy of iron that is resistant to rusting and corrosion. It contains at least 11% chromium and may contain elements such as carbon, other nonmetals and metals to obtain other desired properties. Stainless steel's corros ...
honeycomb
A honeycomb is a mass of Triangular prismatic honeycomb#Hexagonal prismatic honeycomb, hexagonal prismatic Beeswax, wax cells built by honey bees in their beehive, nests to contain their larvae and stores of honey and pollen.
beekeeping, Beekee ...
panels and titanium but was cancelled by the time it flew in 1964.[
A ]computer-aided design
Computer-aided design (CAD) is the use of computers (or ) to aid in the creation, modification, analysis, or optimization of a design. This software is used to increase the productivity of the designer, improve the quality of design, improve c ...
system was developed in 1969 for the McDonnell Douglas F-15 Eagle
The McDonnell Douglas F-15 Eagle is an American twin-engine, all-weather tactical fighter aircraft designed by McDonnell Douglas (now part of Boeing). Following reviews of proposals, the United States Air Force selected McDonnell Douglas's ...
, which first flew in 1974 alongside the Grumman F-14 Tomcat
The Grumman F-14 Tomcat is an American carrier-capable supersonic, twin-engine, two-seat, twin-tail, variable-sweep wing fighter aircraft. The Tomcat was developed for the United States Navy's Naval Fighter Experimental (VFX) program after the ...
and both used boron fiber
Boron Fiber (also commonly called boron filament) is an amorphous elemental boron product which represents the major industrial use of elemental (free) boron. Boron fiber manifests a combination of high strength and high elastic modulus.
A co ...
composites in the tails; less expensive carbon fiber reinforced polymer
Carbon fiber-reinforced polymers (American English), carbon-fibre-reinforced polymers (Commonwealth English), carbon-fiber-reinforced plastics, carbon-fiber reinforced-thermoplastic (CFRP, CRP, CFRTP), also known as carbon fiber, carbon compo ...
were used for wing skins on the McDonnell Douglas AV-8B Harrier II
The McDonnell Douglas (now Boeing) AV-8B Harrier II is a single-engine ground-attack aircraft that constitutes the second generation of the Harrier family, capable of vertical or short takeoff and landing (V/STOL). The aircraft is primari ...
, F/A-18 Hornet
The McDonnell Douglas F/A-18 Hornet is an all-weather, twinjet, twin-engine, supersonic aircraft, supersonic, carrier-based aircraft, carrier-capable, Multirole combat aircraft, multirole combat aircraft, designed as both a Fighter aircraft, ...
and Northrop Grumman B-2 Spirit
The Northrop (later Northrop Grumman) B-2 Spirit, also known as the Stealth Bomber, is an American heavy strategic bomber, featuring low-observable stealth technology designed to penetrate dense anti-aircraft defenses. A subsonic flying ...
.[
]
Modern era
Airbus
Airbus SE (; ; ; ) is a European Multinational corporation, multinational aerospace corporation. Airbus designs, manufactures and sells civil and military aerospace manufacturer, aerospace products worldwide and manufactures aircraft througho ...
and Boeing
The Boeing Company () is an American multinational corporation that designs, manufactures, and sells airplanes, rotorcraft, rockets, satellites, telecommunications equipment, and missiles worldwide. The company also provides leasing and product ...
are the dominant assemblers of large jet airliners
A jet airliner or jetliner is an airliner powered by jet engines (passenger jet aircraft). Airliners usually have two or four jet engines; three-engined designs were popular in the 1970s but are less common today. Airliners are commonly cl ...
while ATR ATR may refer to:
Medicine
* Acute transfusion reaction
* Ataxia telangiectasia and Rad3 related, a protein involved in DNA damage repair
Science and mathematics
* Advanced Test Reactor, nuclear research reactor at the Idaho National Laboratory, ...
, Bombardier and Embraer
Embraer S.A. () is a Brazilian multinational aerospace manufacturer that produces commercial, military, executive and agricultural aircraft, and provides aeronautical services. It was founded in 1969 in São José dos Campos, São Paulo, where i ...
lead the regional airliner
A regional airliner or a feederliner is a small airliner that is designed to fly up to 100 passengers on short-haul flights, usually feeding larger carriers' airline hubs from small markets. This class of airliners is typically flown by the re ...
market; many manufacturers produce airframe components.
The vertical stabilizer of the Airbus A310
The Airbus A310 is a wide-body aircraft, designed and manufactured by Airbus Industrie, then a consortium of European aerospace manufacturers.
Airbus had identified a demand for an aircraft smaller than the A300, the first twin-jet wide-bod ...
-300, first flown in 1985, was the first carbon-fiber primary structure used in a commercial aircraft
An airliner is a type of aircraft for transporting passengers and air cargo. Such aircraft are most often operated by airlines. Although the definition of an airliner can vary from country to country, an airliner is typically defined as an ai ...
; composites are increasingly used since in Airbus airliners: the horizontal stabilizer of the A320
The Airbus A320 family is a series of narrow-body airliners developed and produced by Airbus.
The A320 was launched in March 1984, first flew on 22 February 1987, and was introduced in April 1988 by Air France.
The first member of the famil ...
in 1987 and A330
The Airbus A330 is a wide-body aircraft developed and produced by Airbus.
Airbus conceived several derivatives of the A300, its first airliner in the mid-1970s. Then the company began development on the A330 twinjet in parallel with the A340 ...
/A340
The Airbus A340 is a long-range, wide-body passenger airliner that was developed and produced by Airbus.
In the mid-1970s, Airbus conceived several derivatives of the A300, its first airliner, and developed the A340 quadjet in parallel with ...
in 1994, and the center wing-box and aft fuselage of the A380
The Airbus A380 is a large wide-body airliner that was developed and produced by Airbus. It is the world's largest passenger airliner and only full-length double-deck jet airliner.
Airbus studies started in 1988, and the project was annou ...
in 2005.[
The ]Cirrus SR20
The Cirrus SR20 is an American piston-engined, four- or five-seat composite material, composite monoplane built since 1999 by Cirrus Aircraft of Duluth, Minnesota. The aircraft is the company's earliest type certificate, type-certified model, earni ...
, type certificate
A type certificate signifies the airworthiness of a particular category of aircraft, according to its manufacturing design (''type design''). It confirms that the aircraft of a new type intended for serial production, is in compliance with applica ...
d in 1998, was the first widely produced general aviation
General aviation (GA) is defined by the International Civil Aviation Organization (ICAO) as all civil aviation aircraft operations with the exception of commercial air transport or aerial work, which is defined as specialized aviation services ...
aircraft manufactured with all-composite construction, followed by several other light aircraft
A light aircraft is an aircraft that has a maximum gross takeoff weight of or less.Crane, Dale: ''Dictionary of Aeronautical Terms, third edition'', page 308. Aviation Supplies & Academics, 1997.
Light aircraft are used as utility aircraft c ...
in the 2000s.
The Boeing 787
The Boeing 787 Dreamliner is an American wide-body jet airliner developed and manufactured by Boeing Commercial Airplanes.
After dropping its unconventional Sonic Cruiser project, Boeing announced the conventional 7E7 on January 29, 2003, ...
, first flown in 2009, was the first commercial aircraft with 50% of its structure weight made of carbon-fiber composites, along with 20% Aluminum and 15% titanium: the material allows for a lower-drag, higher wing aspect ratio
In aeronautics, the aspect ratio of a wing is the ratio of its span to its mean chord. It is equal to the square of the wingspan divided by the wing area. Thus, a long, narrow wing has a high aspect ratio, whereas a short, wide wing has a low a ...
and higher cabin pressurization; the competing Airbus A350
The Airbus A350 is a long-range, wide-body twin-engine jet airliner developed and produced by Airbus.
The first A350 design proposed by Airbus in 2004, in response to the Boeing 787 Dreamliner, would have been a development of the A330 wi ...
, flown in 2013, is 53% carbon-fiber by structure weight.[ It has a one-piece carbon fiber fuselage, said to replace "1,200 sheets of aluminum and 40,000 rivets."
The 2013 ]Bombardier CSeries
The Airbus A220 is a family of five-abreast narrow-body airliners by Airbus Canada Limited Partnership. It was originally designed by Bombardier and had two years in service as the Bombardier CSeries.
The program was launched on 13 July 2 ...
have a dry-fiber resin transfer infusion wing with a lightweight aluminium-lithium alloy fuselage for damage resistance and repairability, a combination which could be used for future narrow-body aircraft
A narrow-body aircraft or single-aisle aircraft is an airliner arranged along a single aisle, permitting up to 6-abreast seating in a cabin less than in width.
In contrast, a wide-body aircraft is a larger airliner usually configured with mult ...
.[ In 2016, the ]Cirrus Vision SF50
The Cirrus Vision SF50, also known as the Vision Jet, is a single-engine very light jet designed and produced by Cirrus Aircraft of Duluth, Minnesota, United States.
After receiving deposits starting in 2006, Cirrus unveiled an aircraft mock ...
became the first certified light jet
A business jet, private jet, or bizjet is a jet aircraft designed for transporting small groups of people. Business jets may be adapted for other roles, such as the evacuation of casualties or express parcel deliveries, and some are used by pub ...
made entirely from carbon-fiber composites.
In February 2017, Airbus installed a 3D printing
3D printing or additive manufacturing is the Manufacturing, construction of a three-dimensional object from a computer-aided design, CAD model or a digital 3D modeling, 3D model. It can be done in a variety of processes in which material is ...
machine for titanium aircraft structural parts using electron beam additive manufacturing from Sciaky, Inc.
Safety
Airframe production has become an exacting process. Manufacturers operate under strict quality control and government regulations. Departures from established standards become objects of major concern.
A landmark in aeronautical design, the world's first jet airliner
A jet airliner or jetliner is an airliner powered by jet engines (passenger jet aircraft). Airliners usually have two or four jet engines; three-engined designs were popular in the 1970s but are less common today. Airliners are commonly cl ...
, the de Havilland Comet
The de Havilland DH.106 Comet was the world's first commercial jet airliner. Developed and manufactured by de Havilland in the United Kingdom, the Comet 1 prototype first flew in 1949. It featured an aerodynamically clean design with four d ...
, first flew in 1949. Early models suffered from catastrophic airframe metal fatigue
In materials science, fatigue is the initiation and propagation of cracks in a material due to cyclic loading. Once a fatigue crack has initiated, it grows a small amount with each loading cycle, typically producing striations on some parts o ...
, causing a series of widely publicised accidents. The Royal Aircraft Establishment
The Royal Aircraft Establishment (RAE) was a British research establishment, known by several different names during its history, that eventually came under the aegis of the Ministry of Defence (United Kingdom), UK Ministry of Defence (MoD), bef ...
investigation at Farnborough Airport
Farnborough Airport (previously called: TAG Farnborough Airport, RAE Farnborough, ICAO Code EGLF) is an operational business/executive general aviation airport in Farnborough, Rushmoor, Hampshire, England. The airport covers about 8% of Rush ...
founded the science of aircraft crash reconstruction. After 3000 pressurisation cycles in a specially constructed pressure chamber, airframe failure was found to be due to stress concentration, a consequence of the square shaped windows. The windows had been engineered to be glued and riveted, but had been punch riveted only. Unlike drill riveting, the imperfect nature of the hole created by punch riveting may cause the start of fatigue cracks around the rivet.
The Lockheed L-188 Electra
The Lockheed L-188 Electra is an American turboprop airliner built by Lockheed. First flown in 1957, it was the first large turboprop airliner built in the United States. Initial sales were good, but after two fatal crashes that led to expensiv ...
turboprop, first flown in 1957 became a costly lesson in controlling oscillation
Oscillation is the repetitive or periodic variation, typically in time, of some measure about a central value (often a point of equilibrium) or between two or more different states. Familiar examples of oscillation include a swinging pendulum ...
and planning around metal fatigue
In materials science, fatigue is the initiation and propagation of cracks in a material due to cyclic loading. Once a fatigue crack has initiated, it grows a small amount with each loading cycle, typically producing striations on some parts o ...
. Its 1959 crash of Braniff Flight 542 showed the difficulties that the airframe industry and its airline
An airline is a company that provides civil aviation, air transport services for traveling passengers and freight. Airlines use aircraft to supply these services and may form partnerships or Airline alliance, alliances with other airlines for ...
customers can experience when adopting new technology
Technology is the application of knowledge to reach practical goals in a specifiable and reproducible way. The word ''technology'' may also mean the product of such an endeavor. The use of technology is widely prevalent in medicine, science, ...
.
The incident bears comparison with the Airbus A300
The Airbus A300 is a wide-body airliner developed and manufactured by Airbus.
In September 1967, aircraft manufacturers in the United Kingdom, France, and West Germany signed a memorandum of understanding to develop a large airliner.
West G ...
crash on takeoff of the American Airlines Flight 587
American Airlines Flight 587 was a regularly scheduled international passenger flight from John F. Kennedy International Airport to Las Américas International Airport in Santo Domingo, the capital of the Dominican Republic. On November 12, 200 ...
in 2001, after its vertical stabilizer
A vertical stabilizer or tail fin is the static part of the vertical tail of an aircraft. The term is commonly applied to the assembly of both this fixed surface and one or more movable rudders hinged to it. Their role is to provide control, sta ...
broke away from the fuselage
The fuselage (; from the French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds crew, passengers, or cargo. In single-engine aircraft, it will usually contain an engine as well, although in some amphibious aircraft t ...
, called attention to operation, maintenance and design issues involving composite material
A composite material (also called a composition material or shortened to composite, which is the common name) is a material which is produced from two or more constituent materials. These constituent materials have notably dissimilar chemical or ...
s that are used in many recent airframes. The A300 had experienced other structural problems but none of this magnitude.
See also
* Longeron
In engineering, a longeron and stringer is the load-bearing component of a framework.
The term is commonly used in connection with aircraft fuselages and automobile chassis. Longerons are used in conjunction with stringers to form structural ...
* Former
A former is an object, such as a template, gauge or cutting die, which is used to form something such as a boat's hull. Typically, a former gives shape to a structure that may have complex curvature.
A former may become an integral part of the ...
* Chord (aeronautics)
In aeronautics, the chord is an imaginary straight line joining the leading edge and trailing edge of an aerofoil. The chord length is the distance between the trailing edge and the point where the chord intersects the leading edge.L. J. Clanc ...
* Aircraft fairing
An aircraft fairing is a structure whose primary function is to produce a smooth outline and reduce drag.Crane, Dale: ''Dictionary of Aeronautical Terms, Third Edition'', page 206. Aviation Supplies & Academics Inc, Newcastle Washington, 1997. ...
* Vertical stabilizer
A vertical stabilizer or tail fin is the static part of the vertical tail of an aircraft. The term is commonly applied to the assembly of both this fixed surface and one or more movable rudders hinged to it. Their role is to provide control, sta ...
References
Further reading
*
{{Aircraft components
Aircraft components
Structural system