First flying machine

There are conflicting views as to what was the first flying machine. This kind of controversy of invention is not limited to flight. For example, debates over the tallest building tend to break into debates around what constitutes a building and what is the most important measure of such structures' height. In the same way some records of flying machines can come down to the exact definition of what, for example, constitutes a "flying machine", or "flight", or even "first".

Claims to first piloted flight by date

Pre-19th century

*According to Aulus Gellius, Archytas, the Ancient Greek philosopher, mathematician, astronomer, statesman, and strategist, was reputed to have designed and built the first artificial, self-propelled flying device, a bird-shaped model propelled by a jet of what was probably steam, said to have actually flown some 200 meters. [Aulus Gellius, "Attic Nights", Book X, 12.9 at [http://penelope.uchicago.edu/Thayer/E/Roman/Texts/Gellius/10*.html LacusCurtius] ] [ [http://www.tmth.edu.gr/en/aet/1/14.html ARCHYTAS OF TARENTUM, Technology Museum of Thessaloniki, Macedonia, Greece] ] This machine, which its inventor called "The Pigeon" (Greek: "Περιστέρα" "Peristera"), may have been suspended on a wire or pivot for its flight. [Modern rocketry [http://www.pressconnects.com/apps/pbcs.dll/article?AID=/20070104/NEWS02/701040323/1006/] ] [Automata history [http://automata.co.uk/History%20page.htm] ]
* Anonymous, Chang'an, China, according to 1st century records the first human in the air, using feathery wings — 19 CE [（天凤六年）或言能飞，一日千里，可窥匈奴。莽辄试之，取大鸟翮为两翼，头与身皆著毛，通引环纽，飞数百步堕。(Rendering: [In the 6th year of Tianfeng, 19] there is a statement about a flight, made at a swift speed, to spy on the Xiongnu. The contraption was lightly built, with two big wings like those of a bird, and feather over the head and body. The flight ran for a few hundred paces, and fell.) "Book of Han", 99.]
* Zhuge Liang, China, traditionally credited with invention of the Kongming lantern, which was the first hot air balloon, though not suitable for human transportation. — 2-3rd century CE.
* Yuan Huangtou, Ye, China, first manned kite glide to take off from a tower — 559 CE [（永定三年）使元黄头与诸囚自金凤台各乘纸鸱以飞，黄头独能至紫陌乃堕，仍付御史中丞毕义云饿杀之。(Rendering: [In the 3rd year of Yongding, 559] , Gao Yang conducted an experiment by having Yuan Huangtou and a few prisoners launch themselves from a tower in Ye, capital of the Northern Qi. Yuan Huangtou was the only one who survived from this flight, as he glided over the city-wall and fell at Zimo [western segment of Ye] safely, but he was later executed.) Zizhi Tongjian 167 and Beishi 19.]
* Abbas Ibn Firnas (aka Armen Firman), al-Andalus, first parachute flight — 852
* Abbas Ibn Firnas, (aka Armen Firman), al-Andalus, first manned glider flight, ended in crash. — 875 [Lynn Townsend White, Jr. (Spring, 1961). "Eilmer of Malmesbury, an Eleventh Century Aviator: A Case Study of Technological Innovation, Its Context and Tradition", "Technology and Culture" 2 (2), p. 97-111 [100-101] .] [ [http://www.saudiaramcoworld.com/issue/196401/first.flights.htm First Flights] , "Saudi Aramco World", January-February 1964, p. 8-9.]
* Eilmer of Malmesbury, England, a monk who flew a glider from an Abbey in the early 11th century
* Hezarfen Ahmet Celebi, Istanbul, Turkey, first successful manned glider flight. — 1630-1632 [Arslan Terzioglu (2007). "The First Attempts of Flight, Automatic Machines, Submarines and Rocket Technology in Turkish History", "The Turks" (ed. H. C. Guzel), p. 804-810.]
* Lagari Hasan Çelebi, Turkey, first manned rocket aircraft — 1633
* Pilâtre de Rozier, Paris, France, first trip by a human in a free-flying balloon (the Montgolfière). 9 km covered in 25 minutes. October 15, 1783

19th century

* Hans Andreas Navrestad, Norway — 1825
*:Allegedly flew manned glider.
* John Stringfellow, England — 1848
*:First heavier than air powered flight, accomplished by an unmanned steam powered monoplane of convert|10|ft|m|sing=on wingspan. In 1868, he flew a powered monoplane model a few dozen feet at an exhibition at the Crystal Palace in London.
* George Cayley, England — 1853
*:First Western human glide. Cayley also made the first scientific studies into the aerodynamic forces on a winged flying machine and produced designs incorporating a fuselage, wings, stabilizing tail and control surfaces. He is considered the "Father" of aeronautical engineering, and modern airplanes use principles he discovered, such as separate systems for lift and thrust and the cambered wing.
* Jean-Marie Le Bris, France, flight in 1856
*:Jean-Marie Le Bris was the first to fly higher than his point of departure, by having his glider pulled by a horse on a beach, against the wind.
* Jan Wnek, Poland — controlled flights 1866 - 1869.
*:Jan Wnek controlled his glider by twisting the wing's trailing edge via strings attached to stirrups at his feet. [http://www.dziecidodzieci.republika.pl/wnekfr.htm] Church records only -- Krakow Museum unwilling to allow verification.
* Goodman Household, South Africa, 1871
*: Goodman built and flew his own glider over one hundred meters. The story is that he crashed breaking both glider and a leg. The event took place in the Kwazulu Natal Midlands near Curry's Post in 1871 and is recorded variously in legend and local literature. [ [http://www.sapfa.org.za/history/history_1.php The History of Aviation in South Africa] Flight in South Africa in the 1870's - Fact or myth. South African Power Flying Association. Accessed May 2008.]
* Félix du Temple de la Croix, France, 1874.
*: First take-off of a manned and powered aircraft, from a downsloped ramp, resulting in a brief hop a few feet above the ground.
* John Joseph Montgomery, United States of America 1883
*: First controlled glider flight in the United States, from a hillside near Otay, California.
* Alexander Feodorovich Mozhaiski, Russian Empire — 1884
*: First powered hop by a manned multi-engine (steam) fixed-wing aircraft, 60-100 feet (20-30 meters), from a downsloped ramp.
* Clement Ader, France — October 9 1890
*:He reportedly made the first manned, powered, heavier-than-air flight of a significant distance (50 m) but insignificant altitude from level ground in his bat-winged monoplane, the Eole. Seven years later, the Avion III (a different machine) was said to be flown upon 300 metres (in fact just lifted off the ground, and loose control. The event was not publicized until many years later, as it had been a military secret. The events were poorly documented, the aeroplane not suited to have been controlled; there was no further development. Later in life Ader claimed to have flown the Avion II in 1891 for over 200 meters.
* Otto Lilienthal, Germany — 1891
*:The German "Glider King" was a pioneer of human aviation—the first person to make controlled untethered glides repeatedly and the first to be photographed flying a heavier-than-air machine. He made about 2,000 glides until his death August 10, 1896 from injuries in a glider crash the day before.
* Hiram Stevens Maxim, United Kingdom — 1894
*:The American inventor of the machine gun built a very large 3.5 ton flying machine that ran on a track and was propelled by powerful twin naphtha fueled steam engines. He made several tests in the huge biplane that were well recorded and reported. On July 31st, 1894 he made a record breaking speed run at 42 miles per hour. The machine lifted from the convert|1800|ft|m|sing=on track and broke a restraining mechanism, crashing after a short uncontrolled flight just above the ground.
* Samuel Pierpont Langley, United States — May 6 1896
*:First sustained flight by a heavier-than-air powered, unmanned aircraft: the Number 5 model, driven by a miniature steam engine, flew half a mile in 90 seconds over the Potomac River near Washington, D.C. In November the Number 6 flew more than five thousand feet. Langley's full-size manned powered Aerodrome failed twice in October and December 1903.
* Octave Chanute, United States — Summer 1896
*: Designer of first rectangular wing strut-braced biplane (originally tri-plane) hang glider, a configuration that strongly influenced the Wright brothers. Flown successfully at the Indiana shore of Lake Michigan, U.S. by his proteges, including Augustus Herring, for distances exceeding convert|100|ft|m.
* Carl Rickard Nyberg, Sweden — 1897
*:Managed a few short jumps in his Flugan, a steam powered, manned aircraft
* Gustave Whitehead, United States — 1899
*:Reportedly flew a steam-powered monoplane about half a mile and crashed into a three-story building in Pittsburgh in April or May 1899, according to a witness who gave a statement in 1934 and said he was the passenger. [Gustave Whitehead's Flying Machines [http://gustavewhitehead.org/affidavits_-_1934/affidavit:_louis_darvarich_.html Affidavit: Louis Darvarich - July 19, 1934] ] cite web|url=http://www.weisskopf.de/history.htm|title=Aviation Pioneer Gustave Whitehead ] [cite web|url=http://www.deepsky.com/~firstflight/Pages/devine.html|title=Martin Devine - August 15, 1936 ] [cite web|url=http://www.deepsky.com/~firstflight/Pages/daravich.html|title=Louis Darvarich - July 19, 1934 ]
* Percy Pilcher, Scotland — 1899
*:Pioneer British glider/plane builder and pilot; protege of Lilienthal; killed in 1899 when his fourth glider crashed shortly before the intended public test of his powered triplane. Cranfield University built a replica of the triplane in 2003 from drawings in Philip Jarrett's book "Another Icarus". Test pilot Bill Brooks successfully flew it several times, staying airborne up to 1 minute and 25 seconds.
* Augustus Moore Herring, United States — 1899
*:Attached a compressed air motor to a biplane hang glider and flew about convert|70|ft|m.

20th century

* Dr Wilhelm Kress, Austria — 1901
*: Tested Drachenflieger, tandem monoplane seaplane similar to Samuel Langley, which made brief airborne hops but could not sustain itself.
* Gustave Whitehead, United States — August 14, 1901
*: First publicized account of a flight by an aeroplane heavier than air propelled by its own motor - Whitehead No. 21. Reports were published in the "New York Herald", and the "Bridgeport (CT) Herald". The event was reportedly witnessed by several people, one of them a reporter for the "Bridgeport Herald". Children and youngsters who were present signed affidavits about 30 years later about what they saw. Reports said he started on the wheels from a flat surface, flew 800 meters at 15 meter height, and landed softly on the wheels.
* Lyman Gilmore, United States — May 15, 1902
*: Gilmore claimed to be the first person to fly a powered aircraft (a steam-powered glider). No witnesses. But he was an able inventor, rotary snow plow, 8-cylinder rotary motor, etc..
* Gustave Whitehead, United States — January 17, 1902
*: Whitehead claimed two spectacular flights on January 17 1902 in his improved Number 22, with a 40 Horsepower (30 kilowatt) motor instead of the 20 hp (15 kW) in the Number 21 aircraft and aluminium instead of bamboo. In two published letters that he wrote to "American Inventor" magazine, [ [http://www.deepsky.com/~firstflight/Pages/article4.html Whitehead letters to "American Inventor" magazine] . Accessed December 24 2007.] he said the flights took place over Long Island Sound and covered distances of about two miles (3 kilometers) and seven mi (11 km) at heights up to 200 ft (61 m), ending with safe landings in the water by the boat-like fuselage. A. Pruckner affidavit: "I saw him make the flight across the Sound to which he refers." [ [http://www.deepsky.com/~firstflight/Pages/Pruckner.html Anton T. Pruckner - July 16, 1934 ] ]
* Orville & Wilbur Wright, United States — October 1902
*:Completed development of the three-axis control system with the incorporation of a movable rudder connected to the wing warping control on their 1902 Glider. They subsequently made several fully controlled heavier than air gliding flights, including one of 622.5 ft (189.7 m) in 26 seconds. The 1902 glider was the basis for their patented control system still used on modern fixed-wing aircraft.
* Richard Pearse, New Zealand — March 31, 1903
*: Reportedly first heavier-than-air powered flight in New Zealand. Several people witnessed Pearse make powered flights including one on this date of over convert|100|ft|m in a high-wing tricycle undercarriage monoplane powered by a convert|15|hp|abbr=on air-cooled horizontally-opposed engine. Flight ended with a crash into a hedgerow. In the mockumentary Forgotten Silver, director Peter Jackson recreated this flight, supposedly filmed by New Zealand filmmaker Colin McKenzie. The film was so convincing, Paul Harvey reported it as genuine on his syndicated "News and Comment" program.
* Karl Jatho, Germany — August 18, 1903
*: On August 18, 1903 he flew with his self-made motored gliding aircraft. He had four witnesses for his flight. The plane was equipped with a single-cylinder 10 horsepower (7.5 kW) Buchet engine driving a two-bladed pusher propeller and made hops of up to 200 ft (60 m), flying up to 10 ft (3 m) high.
* Orville & Wilbur Wright, United States — December 17 1903
*: First recorded controlled, powered, sustained heavier than air flight, in Wright Flyer. In the day's fourth flight, Wilbur Wright flew 279 meters (852 ft) in 59 seconds. First three flights were approximately 120, 175, and convert|200|ft|m|abbr=on, respectively. The Wrights laid particular stress on fully and accurately describing all the requirements for controlled, powered flight and put them into use in an aircraft which took off from a level launching rail, with the aid of a headwind to achieve sufficient airspeed before reaching the end of the rail.
* John Joseph Montgomery and Daniel Maloney, United States 1905
*: First high altitude flights with Maloney as pilot of a Montgomery tandem-wing glider design. The glider was launched by balloon to heights up to convert|4000|ft|m with Maloney controlling the aircraft through a series of prescribed maneuvers to a predetermined landing location in front of a large public gathering at Santa Clara, California.
* Wilbur Wright, United States — October 5, 1905
*: Wilbur Wright pilots Wright Flyer III in a flight of 24 miles (39km) in 39 minutes, a world record that stood until 1908.
* Traian Vuia, Romania — March 18, 1906
*: First European flight by a fully self-propelled, fixed-wing aircraft using an internal combustion engine and a single tractor propeller. He flew for 12 meters in Paris without the aid of external takeoff mechanisms, such as a catapult, a point emphasized in newspaper reports in France, the U.S., and the UK. The possibility of such unaided heavier-than-air flight was heavily contested by the Academy of Science in Paris, which had declined to assist Vuia with funding.
* Jacob Ellehammer, Denmark — September 12 1906
*:Built monoplane, which he tested with a tether on the Danish Lindholm island.
* Alberto Santos-Dumont, Brazil — October 23, 1906
*: the "14 Bis" at Bagatelle field, Paris. Aero Club of France certified the distance of 60 meters (197 ft); height was about 2-3 meters (6-10 ft). Winner of the Archdeacon Prize for first official flight of more than 25 meters. Described by some scholars as the first "sportsman of the air". As reported in previous years and months for Ader, Whitehead, Pearse, Jatho and Vuia, the 14-Bis flew and landed without a rail, catapult, or the presence of high winds, propelled by its own (internal combustion) engine.

cope of the entire claim

The people attempting to create the first flying machine were faced with many separate challenges, which required diverse skills:
# Develop theories on how flight works and invent a machine to fly. This requires the skills of a creative scientist.
# Construct the machine. This requires the skills of an engineer.
# Fly the machine. This requires a pilot, which — before flight is achieved — has to be someone intrepid, athletic and a quick learner — the skills of an explorer.
# Trial and error. This requires someone with a lot of time and resources — an investor.
# Recognition. This requires the skills of a marketeer.

Many of the people who attempted to create the first flying machine succeeded only in some of these challenges. Since all the challenges were difficult, these are notable achievements, rightfully touted in their respective cultures. But emphasizing one set of challenges or another leads to different claims to the title of "first flying machine".

The earliest attempts focused on the first challenges; they couldn't make much progress on the central challenges before the Industrial Revolution. Even then, most attempts borrowed from others' earlier work and still left work for others to finish. The next to last step, trial and error, can take years, and ideas can go back and forth between different groups, consciously or not.

It can be hard to determine the point at which particular inventions influenced others. Most early aviators worked by themselves developing their ideas, while occasionally corresponding with others. Some, such as Richard Pearse, produced outstanding work in such complete isolation that the world never heard about them until it was far too late to write them into the history books. The best that can be claimed is that certain inventions were pivotal steps to realising the age of flight. Even then, who first achieved which step can still be debated.

One thing does seem clear from the timeline above; by the early 1900s there were many early aviators around the world working on the problem of flight, and the technology had matured sufficiently for a determined experimenter to succeed. Even if all the 20th century aviators who are mentioned above had not existed, it seems fairly sure that a successful airplane would have been developed before 1920. It was an idea whose time had come.

Debate on what was invented

This is a major source of controversy for early flying machines. There are kites, parachutes, lighter than air craft (balloons/airships), gliders and powered aircraft, which all have some ability to fly. The first use of each of these is worthy of note, but the definition of each of these is not universally agreed upon. The performance of some gliders was little better than slow falling, and might be considered more a type of parachute. Most early flying craft were light and fragile, and required the right wind conditions to fly. A headwind can give a boost to their takeoff. A tailwind will lengthen the apparent flight. Either might be considered unfair help from nature; almost anything will fly if the wind is strong enough. Some powered aircraft still needed a starting height or catapults to get them started, which might classify them only as engine-assisted gliders. Some inventions focused only on staying in the air, and had little or no ability to steer the craft, which makes them useless for practical flight. Other controversies include aircraft that derive some lift from attaching themselves to other types of flying craft, becoming hybrids.

Debate on what was accomplished

Even the definition of "flight" is not agreed upon. If a given flight only achieved a couple of metres of altitude, the craft may be taking advantage of ground effect, which is an aerodynamic effect that adds lift when very close to the ground. If the flight is only a few dozen metres in length, then it may be more due to momentum than lift; these might be considered only "hops" and not qualify as true flight. If the takeoff was from a height or was otherwise assisted, then how much was due to the craft's own lift is debated even if the flight was longer. The flight of a craft with little ability to gain altitude on its own may not be considered a true powered flight. If the flight ends in a crash, some discount the flight; the crash might be due to shortcuts taken in the construction of the craft, reducing its function or strength, which made the construction easier even if it made the craft impractical. There are other, more technical details about flight that can be sources of endless technical debates.

On the other hand, rather than specific, technical achievements, some claims to flight are more general. With the myriad of different challenges surrounding flight, succeeding in some is still an accomplishment. In truth, the more successful inventors built on the works of those who preceded them; those that did the earlier work deserve some credit. This is true even if their craft didn't fly successfully, or was only prototype that wasn't flown, or was only a model, a design, or just a sketch or theory. But saying "whose work helped others..." is not as often claimed as titles like "Father of Flight" or "Discoverer of Aeronautics". When designs, rather than flight are claimed, the classification of the craft designed gets all the more debatable, as critical details may be missing.

Debate on veracity of claims

For a claim to be accepted there must be some credible evidence. The number, quality and possible bias of witnesses are analyzed. There may be language and cultural barriers to analyzing the witnesses' reports. There may be cultural and philosophical barriers of the witnesses to overcome to even understand, much less properly report, the event they witnessed. Inventors skilled at marketing may be favoured because of more substantial evidence, even though such skills aren't usually associated with inventing flying machines. There is even an opposite effect, where a skilled "showman" can be accused of inflating claims or even falsifying inventions. More weight is given to photos of the flight, even though this favours claims taking place after the invention of photography.

The number of flights is used to evaluate some claims in relation to others. If only a single flight was achieved by an invention, some dismiss this as a fluke. The more flights achieved, the more credible the evidence becomes, even though this favours inventors with more time and resources to invest. Damage to the aircraft on landings, and even injuries to the pilot, can be severe setbacks limiting the total evidence, even though they may be due to mere bad luck.

For inventors that focused on skills other than science, their inventions can be dismissed because of the non-scientific nature of the evidence. To answer this, there are sometimes attempts to provide the missing scientific aspects to the evidence by recreations after the fact. In the more extreme cases, rough sketches are turned into complete flying machines. But there is no way to prove that the re-creators' modern knowledge didn't influence details of the recreation, improving the original invention. The same problem arises when aircraft are recreated in attempts to perform new test flights years later.

Various governments and other organizations will often only give some claims an "official" approval in attempt to elevate one attempt over another, usually in the interest of a national or cultural pride. A great deal of disinformation and revisions can take place as well with some claims, both from individuals and governments, to adjust the level of importance of some respective claims. Minor mistakes or misinformation are sometimes widely reproduced without any further investigation. In the worst cases, some histories fail to mention the fact that counter-claims even exist, much less contrast them with a preferred claim.

Accuracy of historical record

Because so much litigation was involved in the early years of heavier-than-air flying, especially to discredit the Wright Brothers' patent on a means to control flight, it is sometimes hard to determine the accuracy of historical documentation. Much documentation was assembled for various court cases years or decades after the event in question, and may have been intentionally editorialized to make certain events seem more significant than they were in order to attempt to show prior art. Often the characterization of a given flight will differ dramatically between the contemporary accounts and the accounts later provided for evidence.

In addition, the secrecy surrounding the oft-competing inventors of flight often make documentation suspect. Many contemporary newspaper articles' accuracy were also hampered by the slow speed of news of the day, a tendency of some reporters to exaggerate or fabricate events, and the reticence of the inventors guarding their secrets.

Technical details of defining flight

Flight can be defined as simply not falling when in the air. To do this, some force is needed to counter gravity. If a craft's countering force is not as strong as gravity, then the craft still falls, although slower. To rise from a starting point, the force must be greater than gravity. Since medieval times, rockets were known to provide sufficient energy, but were usually seen as too hazardous for manned experiments. The more common method involved a craft that was, in total, less dense than air. Before treated or synthetic materials were invented, balloons had to be made of many small pieces of natural materials, which couldn’t be made completely airtight. This limited all early lighter than air craft to hot air balloons. However, such craft can only ascend and descend; they have little or no ability to steer, only work well in cold weather, and are quite susceptible to drifting away in even light breezes. Although balloons fly, they are of such limited use that people continued to search for something with a more practical ability to fly.

While useful flight is distinct from falling, there are many grey areas between them. Flying squirrels, for instance, can't sustain level flight, and may be doing little more than falling, yet what they achieve is certainly useful, since it is part of their natural adaptation for survival.

The type of falling that merely avoids injury on landing is usually termed "parachuting". This simply requires increasing air resistance to the point where terminal velocity is low enough to make landing safe. However, the slower one falls, the greater time in the air, and the greater the influence of other forces relative to gravity. This means it doesn't take much effort to achieve distance from initial momentum, or even steering from minor adjustments to the shape of whatever is providing the air resistance. In recent years, use of parasails, hang gliders and similar craft have erased most distinction between parachutes and gliders.

An aerofoil ("airfoil" in American English) is a surface that adds lift when air moves over it. By the shape of the aerofoil, the air over the top is forced to move faster than the air under. Slower air has more pressure, so there is a net upward pressure on the aerofoil, which is lift. The wings of most gliders and aircraft are aerofoils, but kites use the principles of aerofoils also.

There are various methods of getting air to move over an aerofoil. Forward motion makes the aerofoil move relative to the air. A headwind does the same. A kite is held stationary by a string, and wind moves the air over the kite. A rotorcraft uses rotating aerofoils.For flying machines that use aerofoils, the method of getting the air to move is used by some to classify the invention.

Anything that falls can easily trade height for some forward motion, and get lift from aerofoils. A glider is usually defined as an aerofoil craft that relies on starting height rather than its own generated energy. But having an internal source of energy (an engine) doesn't always mean it is an aircraft rather than a glider; the engine may be so weak that it doesn't influence the craft's flight. How strong does the engine have to be before it is considered a true aircraft? A good breakpoint would be if the craft provides enough energy that it doesn't lose speed or altitude for a long period. But taking off at the start of a flight is a different situation; this often requires trading speed for height even on modern craft. Treating the takeoff separate from the rest of the flight has complications, as many craft needed ramps to help convert potential energy to forward momentum, catapults to give an initial push, or a starting height to allow a quick trade-off to forward motion. It is difficult to determine how much influence these extra take-off assistances had on the rest of the flight. Some craft didn't seem to need any obvious assistance, yet still required a headwind to add to the effect of the aerofoils in order to take off.

ee also

*Timeline of aviation
*List of early flying machines
*Early flight
*List of years in aviation
*Aviation history
*Accidents and incidents in aviation
*World War I Aviation
*History by contract

Notes

References

* [http://www.aerospaceweb.org/question/history/q0159.shtml Aerospaceweb - Who was the first to fly?]
* [http://www.aerospaceweb.org/question/history/q0189.shtml Aerospaceweb - Why do Brazilians consider Alberto Santos-Dumont the first man to fly if he didn't fly until 1906 and the Wright brothers did so in 1903?]
* [http://www.flyingmachines.org/ Listing and descriptions of pre-wright flying machines]
* [http://www.centennialofflight.gov/essay/Prehistory/PH-OV.htm Prehistory of Flight]
*Octave Chanute, [http://invention.psychology.msstate.edu/i/Chanute/library/Prog_Contents.html "Progress in Flying Machines", 1891 - 1894]
*cite web|url=http://www.bondle.co.uk/personal_pages/jon/maxim/|title=The Maxim Flyer|accessdate=2007-06-26