Editing Airframe (section)

==History==

[[File:Airframe (4 types).PNG|thumb|520px|Four types of airframe construction: (1) Truss with canvas, (2) Truss with corrugate plate, (3) [[Monocoque]] construction, (4) [[Semi-monocoque]] construction.]]

Modern airframe history began in the [[United States]] during the [[Wright Flyer|Wright Flyer's]] maiden flight, showing the potential of [[Fixed-wing aircraft|fixed-wing designs]] in aircraft.

In 1912 the [[Deperdussin Monocoque]] pioneered the light, strong and streamlined [[monocoque]] fuselage formed of thin [[plywood]] layers over a circular frame, achieving {{convert|130|mph|km/h|abbr=on|order=flip}}.<ref name=AW161121>{{cite news |url= http://aviationweek.com/commercial-aviation/designs-changed-way-aircraft-are-built |title= Designs That Changed The Way Aircraft Are Built |date= Nov 21, 2016 |author= Graham Warwick |work= Aviation Week & Space Technology}}</ref><ref name=ASM0807>{{cite news |url= http://www.airspacemag.com/history-of-flight/airplanes-that-transformed-aviation-46502830/?all |title= Airplanes that Transformed Aviation |date= July 2008 |author= Richard P. Hallion |work= Air & space magazine |publisher= Smithsonian}}</ref>

=== First World War ===
Many early developments were spurred by [[military]] needs during [[World War I]]. Well known [[aircraft]] from that era include the Dutch designer [[Anthony Fokker]]'s combat aircraft for the [[German Empire]]'s {{lang|de|[[Luftstreitkräfte]]}}, and U.S. [[Glenn Curtiss|Curtiss]] [[flying boat]]s and the German/Austrian Taube [[monoplanes]]. These used hybrid wood and metal structures.

By the 1915/16 timeframe, the German [[Luft-Fahrzeug-Gesellschaft]] firm had devised a fully [[monocoque]] 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<ref>{{cite book |title=German Combat Planes: A Comprehensive Survey and History of the Development of German Military Aircraft from 1914 to 1945 |author1=Wagner, Ray  |author2=Nowarra, Heinz  |name-list-style=amp |year=1971 |publisher=Doubleday |location=New York |pages=75 & 76 }}</ref> - this first appeared on the 1916 [[LFG Roland C.II]], and would later be licensed to [[Pfalz Flugzeugwerke]] for its D-series biplane fighters.

In 1916 the German [[Albatros D.III]] biplane fighters featured [[semi-monocoque]] fuselages with load-bearing plywood skin panels glued to longitudinal [[longeron]]s and [[Bulkhead (partition)|bulkhead]]s; it was replaced by the prevalent [[stressed skin]] structural configuration as [[metal]] replaced wood.<ref name=AW161121/> Similar methods to the Albatros firm's concept were used by both [[Hannoversche Waggonfabrik]] for their light two-seat [[Hannover CL.II|CL.II]] through [[Hannover CL.V|CL.V]] designs, and by [[Siemens-Schuckert]] for their later [[Siemens-Schuckert D.III]] and higher-performance [[Siemens-Schuckert D.IV|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.{{Original research inline|date=May 2018}}

German engineer [[Hugo Junkers]] first flew all-metal airframes in 1915 with the all-metal, [[cantilever]]-wing, stressed-skin monoplane [[Junkers J 1]] made of [[steel]].<ref name=AW161121/> It developed further with lighter weight [[duralumin]], invented by [[Alfred Wilm]] in Germany before the war; in the airframe of the [[Junkers D.I]] of 1918, whose techniques were adopted almost unchanged after the war by both American engineer [[William Bushnell Stout]] and Soviet aerospace engineer [[Andrei Tupolev]], proving to be useful for aircraft [[Tupolev ANT-20|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]] made of [[Duralumin]] as the D.I had been; 300 were built, along with the first four-[[aircraft engine|engine]], all-metal [[passenger aircraft]], the sole [[Zeppelin-Staaken E-4/20]].<ref name=AW161121/><ref name=ASM0807/> [[Commercial aircraft]] development during the 1920s and 1930s focused on monoplane designs using [[Radial engine]]s. Some were produced as single copies or in small quantity such as the [[Spirit of St. Louis]] flown across the [[Atlantic]] by [[Charles Lindbergh]] in 1927. William Stout designed the all-metal [[Ford Trimotor]]s in 1926.<ref>{{cite book |author= David A. Weiss |title= The Saga of the Tin Goose |publisher= Cumberland Enterprises |year= 1996 }}</ref>

The [[Hall XFH]] naval fighter [[prototype]] flown in 1929 was the first aircraft with a [[rivet]]ed metal fuselage : an aluminium skin over steel tubing, Hall also pioneered [[flush rivet]]s and [[butt joint]]s between skin panels in the [[Hall PH]] [[flying boat]] also flying in 1929.<ref name=AW161121/> Based on the Italian [[Savoia-Marchetti S.56]], the 1931 [[Budd BB-1 Pioneer]] experimental flying boat was constructed of corrosion-resistant [[stainless steel]] assembled with newly developed [[spot welding]] by U.S. railcar maker [[Budd Company]].<ref name=AW161121/>

The original Junkers corrugated duralumin-covered airframe philosophy culminated in the 1932-origin [[Junkers Ju 52]] trimotor airliner, used throughout World War II by the Nazi German [[Luftwaffe]] for transport and paratroop needs. Andrei Tupolev's designs in [[Joseph Stalin]]'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]] in 1934, and [[Donald Wills Douglas, Sr.|Donald Douglas]]' firms developed the iconic [[Douglas DC-3]] twin-engined airliner in 1936.<ref>{{cite book |author= Peter M. Bowers |title= The DC-3: 50 Years of Legendary Flight |publisher= Tab Books |year= 1986 }}</ref> 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]] was specifically constructed with [[cabin pressurization]] to undergo extensive high-altitude flight tests, paving the way for the [[Boeing 307 Stratoliner]], which would be the first aircraft with a pressurized cabin to enter commercial service.<ref name=ASM0807/>

[[File:Vickers Wellington Mark X, HE239 'NA-Y', of No. 428 Squadron RCAF (April 1943).png|thumb|[[Vickers Wellington|Wellington Mark X]] showing the [[geodesic airframe]] construction and the level of punishment it could withstand while maintaining airworthiness]]

=== Second World War ===
During [[World War II]], military needs again dominated airframe designs. Among the best known were the US [[C-47 Skytrain]], [[B-17 Flying Fortress]], [[B-25 Mitchell]] and [[P-38 Lightning]], and British [[Vickers Wellington]] that used a geodesic construction method, and [[Avro Lancaster]], all revamps of original designs from the 1930s. The first [[Jet aircraft|jets]] were produced during the war but not made in large quantity.

Due to wartime scarcity of aluminium, the [[de Havilland Mosquito]] fighter-bomber was built from wood—plywood facings [[Wood glue|bonded]] to a [[balsawood]] core and formed using [[Molding (process)|mold]]s to produce monocoque structures, leading to the development of metal-to-metal [[Adhesive|bonding]] used later for the [[de Havilland Comet]] and [[Fokker F27]] and [[Fokker F28|F28]].<ref name=AW161121/>

=== Postwar ===

Postwar commercial airframe design focused on [[airliner]]s, on [[turboprop]] engines, and then on [[jet engine]]s. The generally higher speeds and [[tensile stress]]es of turboprops and jets were major challenges.<ref>{{cite book |author= Charles D. Bright |title= The Jet Makers: the Aerospace Industry from 1945 to 1972 |publisher= Regents Press of Kansas |year=1978 |url= http://www.generalatomic.com/jetmakers/index.html }}</ref> Newly developed [[aluminium]] [[alloy]]s with [[copper]], [[magnesium]] and [[zinc]] were critical to these designs.<ref>{{cite book |work= Key to Metals Database |title= Aircraft and Aerospace Applications |publisher= INI International |year= 2005 |url= http://www.key-to-metals.com/PrintArticle.asp?ID=96 |url-status= dead |archive-url= https://web.archive.org/web/20060308194218/http://www.key-to-metals.com/PrintArticle.asp?ID=96 |archive-date= 2006-03-08 }}</ref>

Flown in 1952 and designed to cruise at Mach 2 where [[skin friction]] required its [[heat]] resistance, the [[Douglas X-3 Stiletto]] was the first [[titanium]] aircraft but it was underpowered and barely [[supersonic]]; the Mach 3.2 [[Lockheed A-12]] and [[Lockheed SR-71|SR-71]] were also mainly titanium, as was the cancelled [[Boeing 2707]] Mach 2.7 [[supersonic transport]].<ref name=AW161121/>

Because heat-resistant titanium is hard to weld and difficult to work with, welded [[nickel steel]] was used for the Mach 2.8 [[Mikoyan-Gurevich MiG-25]] fighter, first flown in 1964; and the Mach 3.1 [[North American XB-70 Valkyrie]] used brazed [[stainless steel]] [[Honeycomb structure|honeycomb]] panels and titanium but was cancelled by the time it flew in 1964.<ref name=AW161121/>

A [[computer-aided design]] system was developed in 1969 for the [[McDonnell Douglas F-15 Eagle]], which first flew in 1974 alongside the [[Grumman F-14 Tomcat]] and both used [[boron fiber]] composites in the tails; less expensive [[carbon fiber reinforced polymer]] were used for wing skins on the [[McDonnell Douglas AV-8B Harrier II]], [[McDonnell Douglas F/A-18 Hornet|F/A-18 Hornet]] and [[Northrop Grumman B-2 Spirit]].<ref name=AW161121/>

=== Modern era ===
[[File:Shuttle Carrier Aircraft interior bulkhead.jpg|thumb|right|Rough interior of a [[Boeing 747]] airframe]]
[[File:Wing with one spar.JPG|thumb|Wing structure with [[Rib (aircraft)|rib]]s and one [[Spar (aviation)|spar]]]]

The vertical stabilizer of the [[Airbus A310]]-300, first flown in 1985, was the first carbon-fiber primary structure used in a [[commercial aircraft]]; composites are increasingly used since in Airbus airliners: the horizontal stabilizer of the [[Airbus A320|A320]] in 1987 and [[Airbus A330|A330]]/[[Airbus A340|A340]] in 1994, and the center wing-box and aft fuselage of the [[Airbus A380|A380]] in 2005.<ref name="AW161121" />

The [[Cirrus SR20]], [[type certificate]]d in 1998, was the first widely produced [[general aviation]] aircraft manufactured with all-composite construction, followed by several other [[light aircraft]] in the 2000s.<ref>{{cite news |url= http://www.flyingmag.com/photo-gallery/photos/top-100-airplanes-platinum-edition?pnid=44581 |title= Top 100 Airplanes:Platinum Edition |work= Flying |date= November 11, 2013 |page= 11}}</ref>

The [[Boeing 787]], first flown in 2009, was the first commercial aircraft with 50% of its structure weight made of carbon-fiber composites, along with 20% aluminium and 15% titanium: the material allows for a lower-drag, higher [[wing aspect ratio]] and higher cabin pressurization; the competing [[Airbus A350]], flown in 2013, is 53% carbon-fiber by structure weight.<ref name=AW161121/> It has a one-piece carbon fiber fuselage, said to replace "1,200 sheets of aluminium and 40,000 rivets."<ref>{{cite web |author= Leslie Wayne |title= Boeing Bets the House on Its 787 Dreamliner |work= New York Times |date= May 7, 2006 |url= https://www.nytimes.com/2006/05/07/business/yourmoney/07boeing.html }}</ref>

The 2013 [[Bombardier CSeries]] 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]].<ref name=AW161121/> In 2016, the [[Cirrus Vision SF50]] became the first certified [[Business jet|light jet]] made entirely from carbon-fiber composites.

In February 2017, Airbus installed a [[3D printing]] machine for titanium  aircraft structural parts using [[electron beam additive manufacturing]] from [[Sciaky, Inc.]]<ref>{{cite news |url= http://aviationweek.com/technology/airbus-3-d-print-airframe-structures |title= Airbus To 3-D Print Airframe Structures |date= Jan 11, 2017 |author= Graham Warwick |work= Aviation Week & Space Technology}}</ref>

{| class="wikitable"
|+ Airliner composition by mass<ref>{{cite journal |last1=Woidasky |first1=Jörg |last2=Klinke |first2=Christian |last3=Jeanvré |first3=Sebastian |title=Materials Stock of the Civilian Aircraft Fleet |journal=Recycling |date=5 November 2017 |volume=2 |issue=4 |pages=21 |doi=10.3390/recycling2040021 |doi-access=free}}</ref>
! Material
! B747 !! B767 !! B757 !! B777 !! B787 !! A300B4
|-
! Aluminium
| 81% || 80% || 78% || 70% || 20% || 77% 
|-
! Steel
| 13% || 14% || 12% || 11% || 10% || 12% 
|-
! Titanium
| 4% || 2% || 6% || 7% || 15% || 4% 
|-
! Composites
| 1% || 3% || 3% || 11% || 50% || 4% 
|-
! Other
| 1% || 1% || 1% || 1% || 5% || 3% 
|}