Editing Aileron (section)

== History ==
[[File:Aerial Locomotion coverpage, 1864.jpg|thumb|left|upright|Boulton's 1864 paper, "On Aërial Locomotion" describing several designs including ailerons]]

The name "aileron", from French, meaning "little wing", also refers to [[Flight feather#Primaries|the extremities of a bird's wings]] used to control their flight.<ref name="Etymology" /><ref name="Larousse" /> It first appeared in print in the 7th edition of Cassell's French-English Dictionary of 1877, with its lead meaning of "small wing".<ref>Parkin 1964, p. 66.</ref> In the context of powered airplanes it appears in print about 1908.  Prior to that, ailerons were often referred to as [[Rudder#Aircraft rudders|rudders]], their older technical sibling,  with no distinction between their orientations and functions, or more descriptively as ''horizontal rudders'' (in French, ''gouvernails horizontaux''). Among the earliest printed aeronautical use of 'aileron' was that in the French aviation journal ''[[L'Aérophile]]'' of 1908.<ref name="Air & Space Mag-2009.09-Crouch" />

Ailerons had more or less completely supplanted other forms of lateral control, such as [[wing warping]], by about 1915, well after the function of the rudder and [[Elevator (aircraft)|elevator]] flight controls had been largely standardised. Although there were previously many conflicting claims over who first invented the aileron and its function, i.e., lateral or roll control,<ref name="Air & Space Mag-2009.09-Crouch" /> the flight control device was invented and described by the British scientist and metaphysicist [[Matthew Piers Watt Boulton]] in his 1864 paper ''On Aërial Locomotion''. He was the first to patent an aileron control system in 1868.<ref name="Air & Space Mag-2009.09-Crouch" /><ref name="Magoun" /><ref name="Aerospaceweb-Yoon.1" /><ref name="Gibbs-Smith 1960" />

Boulton's description of his lateral flight control system was "the first record we have of appreciation of the necessity for active lateral control as distinguished from [passive lateral stability].... With this invention of Boulton's we have the birth of the present-day three torque method of airborne control" as was praised by [[Charles M. Manly|Charles Manly]].<ref name="TLS-2009.05.01-Kinzer" /> This was also endorsed by C.H. Gibbs-Smith.<ref name="Flight-1956.05.11-Gibbs-Smith" /><ref name="Flight-1960.09.16" />  Boulton's British patent, No. 392 of 1868, issued about 35 years before ailerons were "reinvented" in France, became forgotten and lost from sight until after the flight control device was in general use.<ref name="Aerospaceweb-Yoon.2" />{{refn|.

Aviation historian C.H. Gibbs-Smith wrote that the aileron was "....one of the most remarkable inventions... of aeronautical history, which was immediately lost sight of".<ref name="Air & Space Mag-2009.09-Crouch" />

|group="Note"}} Gibbs-Smith stated on several occasions that if the Boulton patent had been revealed at the time of the [[Wright brothers]]' legal filings, they might not have been able to claim priority of invention for the lateral control of flying machines. The fact that the Wright brothers were able to gain a patent in 1906 did not invalidate Boulton's lost and forgotten invention.<ref name="Flight-1956.05.11-Gibbs-Smith" />

Ailerons were not used on manned aircraft until they were employed on [[Robert Esnault-Pelterie]]'s glider in 1904,<ref name="Air & Space Mag-2009.09-Crouch" /><ref name="Ransom" /> although in 1871 a French military engineer, [[Charles Renard]], built and flew an unmanned glider incorporating ailerons on each side (which he termed 'winglets'), activated by a Boulton-style pendulum controlled single-axis autopilot device.<ref name="Bullmer.a">Bullmer 2009, p. 20.</ref>

The pioneering U.S. aeronautical engineer [[Octave Chanute]] published descriptions and drawings of the [[Wright brothers]]' [[Wright Glider#1902 glider|1902 glider]] in the leading aviation periodical of the day, ''[[L'Aérophile]]'', in 1903. This prompted Esnault-Pelterie, a French military engineer, to build a Wright-style glider in 1904 that used ailerons in lieu of [[wing warping]].<ref name="Air & Space Mag-2009.09-Crouch" /> The French journal ''L'Aérophile'' then published photos of the ailerons on Esnault-Pelterie's glider which were included in his June 1905 article, and its ailerons were widely copied afterward.<ref name="Gibbs-Smith 1960" /><ref name="Aérophile-1905.06-Esnault-Pelterie" /><ref name="Parkin.b" />

The Wright brothers used wing warping instead of ailerons for roll control on their glider in 1902, and about 1904 their [[Wright Flyer II|Flyer II]] was the only aircraft of its time able to do a coordinated banked turn. During the early years of powered flight the Wrights had better roll control on their designs than airplanes that used movable surfaces. From 1908, as aileron designs were refined it became clear that ailerons were much more effective and practical than wing warping. Ailerons also had the advantage of not weakening the airplane's wing structure as did the wing warping technique,<ref name="Air & Space Mag-2009.09-Crouch" /> which was one reason for Esnault-Pelterie's decision to switch to ailerons.<ref name="Parkin.b" />

By 1911 most biplanes used ailerons rather than wing warping—by 1915 ailerons had become almost universal on monoplanes as well. The U.S. Government, frustrated by the lack of its country's aeronautical advances in the years leading up to [[World War I]], enforced a [[patent pool]] effectively putting an end to the [[Wright brothers patent war]].<ref name="Ipbiz" /><ref name="Buckeye Institute" /><ref name="NASA History" /> The Wright company quietly changed its aircraft flight controls from wing warping to the use of ailerons at that time as well.

=== Other early aileron designers ===

Others who were previously thought to have been the first to introduce ailerons included:

* American [[John J. Montgomery]] included spring-loaded trailing edge flaps on his second glider (1885): these were operable by the pilot as ailerons. In 1886 his third glider design used rotation of the entire wing rather than just a trailing edge portion for roll control. By his own accounts all of these changes in addition to his use of an elevator for pitch control provided "entire control of the machine in the wind, preventing it from upsetting."<ref>Harwood, CS and Fogel, GB "Quest for Flight: John J. Montgomery and the Dawn of Aviation in the West," University of Oklahoma Press, 2012. pp. 36–45.</ref>
* New Zealander [[Richard Pearse]] reputedly made a powered flight in a monoplane that included small ailerons as early as 1902, but his claims are controversial—and sometimes inconsistent—and, even by his own reports, his aircraft were not well controlled.

[[File:Bulgarien Farman M.F.7.jpg|thumb|right|A 1912 [[Farman HF.20]] biplane with [[Aileron#Single acting ailerons|single acting ailerons]] hinged from the rear spar. The ailerons hang down when at rest and are pushed up into position when flying by the force of the air, being pulled down by cable to provide control.]]

* In 1906 [[Alberto Santos-Dumont]]'s [[Santos-Dumont 14-bis|14-bis]] was one of the earliest (if not ''the'' earliest) engine-powered, aileron-equipped aircraft to fly, as it was modified to have added octagonal-planform interplane ailerons in its outermost wing bays [[Santos-Dumont 14-bis#Concluding flights, and the inclusion of ailerons|on November 12]] of that year for its concluding flight sessions at the [[Chateau de Bagatelle]]'s grounds; but those roll control surfaces were not true "trailing-edge" ailerons hinged directly to the wing panels' framework—for the 14-bis, these were instead pivoted around a horizontal axis centred on the ''forward'' outboard interplane struts, and protruded forward past the wings' leading edges - said to be very much like those on [[Robert Esnault-Pelterie]]'s 1904 biplane glider design.<ref>Harrison, James P. [https://books.google.com/books?id=sIk_T6F63NYC ''Mastering the Sky: A History of Aviation from Ancient Times to the Present''], Da Capo Press, 2000, p. 48, {{ISBN|1885119682}}, {{ISBN|978-1885119681}}.</ref> 
* On May 18, 1908, engineer and aircraft designer [[Frederick Walker Baldwin|Frederick Baldwin]], a member of the [[Aerial Experiment Association]] headed by [[Alexander Graham Bell]], flew their first aileron-controlled aircraft, the [[AEA White Wing]],<ref name="Aerospaceweb-Yoon.1" /> which was later copied by the U.S. aeronautical pioneer [[Glenn Curtiss]]<ref>Parkin 1964, pp. 54–69.</ref> the same year, with the [[AEA June Bug|AEA ''June Bug'']].
* [[Henry Farman]]'s ailerons on his 1909 [[Farman III]] were the first to resemble ailerons on modern aircraft as they were hinged directly to the wing planform structure, and thus were viewed as having a reasonable claim as the ancestor of the modern-day aileron.<ref name="Aerospaceweb-Yoon.1" />
* Wingtip ailerons were also used on the contemporary [[Bleriot VIII]]—the first known flightworthy aircraft to use the joystick and rudder bar pioneering form of [[Flight control system|modern flight controls]]<ref name="Crouch 1982" /> in a single airframe, and the 1911-vintage [[Curtiss Model D]] [[Pusher configuration|pusher]] biplane had spanwise rectangular interplane ailerons of a similar nature to those on the final form of the [[Santos-Dumont 14-bis]],<ref name="Parkin.b" /> but mounted on, and pivoted from the outer ''rear'' interplane struts instead.
* Another very late contestant included the American, [[William Whitney Christmas]], who claimed to have invented the aileron in the 1914 patent for what would become the [[Christmas Bullet]] which was built in 1918.<ref name="Aerospaceweb-Yoon.3" /> Both "Bullet" prototypes crashed during their first "flights" when their wings broke off in flight due to [[Aeroelasticity|flutter]] as a result of being deliberately unbraced.

=== Patents and lawsuits ===

The Wright Brothers' Ohio patent attorney [[Harry Aubrey Toulmin, Sr.|Henry Toulmin]] filed an expansive patent application and on May 22, 1906, the brothers were granted U.S. Patent 821393.<ref name="Wright brothers patent 821393" /> The patent's importance lay in its claim of a new and useful method of ''controlling'' an airplane. The patent application included the claim for the lateral control of aircraft flight that was not limited to wing warping, but through any manipulation of the "....angular relations of the lateral margins of the airplanes [wings].... varied in opposite directions".  Thus the patent explicitly stated that other methods besides wing-warping could be used for adjusting the outer portions of an airplane's wings to different angles on its right and left sides to achieve lateral roll control. [[John J. Montgomery]] was granted U.S. Patent 831173 <ref>{{cite web|url=https://patents.google.com/patent/US831173|title=U.S. Patent #831,173}}</ref> at nearly the same time for his methods of wing warping. Both the Wright Brothers patent and Montgomery's patent were reviewed and approved by the same patent examiner at the United States Patent Office, William Townsend.<ref>Harwood CS, Fogel GB, "Quest for Flight: John J. Montgomery and the Dawn of Aviation in the West, University of Oklahoma Press, 2012. p. 124.</ref> At the time Townsend indicated that both methods of wing warping were invented independently and were sufficiently different to each justify their own patent award.

Multiple U.S. court decisions favoured the expansive Wright patent, which the Wright Brothers sought to enforce with licensing fees starting from $1,000 per airplane,<ref name="Air & Space Mag-2009.09-Crouch" /><ref name="Hayes" /> and said to range up to $1,000 per day.<ref name="Casey-preface" /> According to Louis S. Casey, a former curator of the [[National Air and Space Museum|Smithsonian Air & Space Museum]] in Washington, D.C., and other researchers, due to the patent they had received the Wrights stood firmly on the position that all flying using lateral roll control, anywhere in the world, would only be conducted under license by them.<ref name="Casey-preface" />

The Wrights subsequently became embroiled with numerous lawsuits they launched against aircraft builders who used lateral flight controls, and the brothers were consequently blamed for playing "...a major role in the lack of growth and aviation industry competition in the United States comparative to other nations like Germany leading up to and during World War I".<ref name="Hayes" /> Years of protracted legal conflict ensued with many other aircraft builders until the U.S. entered World War I, when the government imposed a legislated agreement among the parties which resulted in royalty payments of 1% to the Wrights.<ref name="Casey-preface" />

{{Further|Wright brothers patent war}}

=== Ongoing controversy ===

There are still conflicting claims today over who first invented the aileron. Other 19th century engineers and scientists, including [[Charles Renard]], [[Alphonse Pénaud]], and [[Louis Pierre Mouillard|Louis Mouillard]], had described similar flight control surfaces. Another technique for lateral flight control, [[wing warping]], was also described or experimented with by several people including [[Jean-Marie Le Bris]], [[John Joseph Montgomery|John Montgomery]], [[Clement Ader]], [[Edson Fessenden Gallaudet|Edson Gallaudet]], D.D. Wells, and Hugo Mattullath.<ref name="Air & Space Mag-2009.09-Crouch" /><ref name="Harwood" /> Aviation historian [[Charles Harvard Gibbs-Smith|C.H. Gibbs-Smith]] wrote that the aileron was "....one of the most remarkable inventions... of aeronautical history, which was immediately lost sight of".<ref name="Air & Space Mag-2009.09-Crouch" />

In 1906 the [[Wright brothers]] obtained a patent not for the invention of an airplane (which had existed for a number of decades in the form of gliders) but for the invention of a system of aerodynamic control that manipulated a flying machine's surfaces, including lateral flight control,<ref name="Flying Machine patent" /> although [[Rudder#Aircraft rudders|rudders]], [[Elevator (aircraft)|elevators]] and ailerons had previously been invented.