Otto Lilienthal

Otto Lilienthal
Otto Lilienthal, c. 1896
Born	Karl Wilhelm Otto Lilienthal 23 May 1848 (1848-05-23) Anklam, Province of Pomerania
Died	10 August 1896 (1896-08-11) (48 years old) Berlin
Cause of death	Glider crash
Resting place	Lankwitz Cemetery, Berlin
Nationality	Prussian, German
Occupation	Engineer
Known for	Successful gliding experiments
Spouse	Agnes Fischer (1878)
Children	4
Relatives	Gustav Lilienthal, brother

Otto Lilienthal (May 23, 1848 – August 10, 1896) was a German pioneer of human aviation who became known as the Glider King. He was the first person to make well-documented, repeated, successful gliding flights. He followed an experimental approach established earlier by Sir George Cayley. Newspapers and magazines published photographs of Lilienthal gliding, favorably influencing public and scientific opinion about the possibility of flying machines becoming practical.

Personal life

Early life

Lilienthal was born in Anklam, Pomerania Province, Prussia. He attended the grammar school in Anklam, and also studied the flight of birds with his brother Gustav (1849–1933), fascinated by the idea of manned flight. Lilienthal and his brother made strap-on wings, but failed in their attempts to fly. He then attended the regional technical school in Potsdam for two years and trained at the Schwarzkopf Company before becoming a professional design engineer. He would later attend the Royal Technical Academy in Berlin.

In 1867 he began his experiments on the force of air in earnest, interrupted when he volunteered to serve in the Franco-Prussian War. As a staff engineer in various engineering companies, he received his first patent for a mining machine. Five years later, he founded his own company to make boilers and steam engines. Lilienthal published his famous book Birdflight as the Basis of Aviation in 1889.

Otto Lilienthal was born to middle-class parents. They had eight children, but only three of them survived infancy: Otto, Gustav, and Marie.Anderson, John D. (2001). A history of aerodynamics and its impact on flying machines (1. paperback ed., reprinted ed.). Cambridge [u.a.]: Cambridge Univ. Press. p. 156. ISBN 0521669553.  The brothers worked together all their lives on technical, social and cultural projects.

On June 6, 1878, Otto married Agnes Fischer, daughter of a deputy. Music brought them together, she was trained in piano and voice, and Otto played the French horn and had a good tenor voice.Anderson, John D. (2001). A history of aerodynamics and its impact on flying machines (1. paperback ed., reprinted ed.). Cambridge [u.a.]: Cambridge Univ. Press. p. 157. ISBN 0521669553.  After marriage they took up residence in Berlin. They had four children: Friedrich, Anna, Fritz and Frida."Family Tree of Otto Lilienthal". lilienthal-museum.de. http://www.lilienthal-museum.de/olma/estamm.htm. Retrieved 2012-01-08. 

Experiments in flight

Mechanics of White Stork flight in his Der Vogelflug als Grundlage der Fliegekunst (1889)

Lilienthal in mid-flight, c. 1895

Lilienthal's greatest contribution was in the development of heavier-than-air flight. He made his flights from an artificial hill he built near Berlin and from natural hills, especially in the Rhinow region.

A sketch toward a second hang glider in about 1891 involved a triangle control frame with a complex basebar that would lead to lower double kingposts while the apex of the triangle would serve as a single kingpost; his filing of a U.S. Patent in 1894 directed pilots to grip the "bar" for carrying and flying the hang glider. The A-frame of Percy Pilcher and Otto Lilienthal echoes in today's control frame for hang gliders and ultralight trike aircraft. Working in conjunction with his brother Gustav, he made over 2,000 flights in gliders of his design starting in 1891 with his first glider version, the Derwitzer, until his death in a gliding crash in 1896. His total flying time was five hours.

At the beginning, in 1891, he succeeded with jumps and flights covering a distance of about 24 metres (79 ft). In 1893, in the Rhinow Hills, he was able to achieve flight distances as high as 350 metres (1,150 ft). This record remained unbeated for him or anyone else at the time of his death.

He could use the updraft of a 10 m/s wind against a hill to remain stationary with respect to the ground, shouting to a photographer on the ground to manoeuvre into the best position for a photo.

Lilienthal did research in accurately describing the flight of birds, especially storks, and used polar diagrams for describing the aerodynamics of their wings. He made many experiments in an attempt to gather reliable aeronautical data.

Projects

Models of his gliders

During his short flying carreer, Lilienthal developed 18 different models (15 monoplanes and three biplanes). His gliders were carefully designed to distribute weight as evenly as possible to ensure a stable flight. Lilienthal controlled them by changing the centre of gravity by shifting his body, much like modern hang gliders. However they were difficult to maneuvre and had a tendency to pitch down, from which it was difficult to recover. One reason for this was that he held the glider by his shoulders, rather than hanging from it like a modern hang glider. Only his legs and lower body could be moved, which limited the amount of weight shift he could achieve.

Lilienthal made many attempts to improve stability with varying degrees of success. These included making a biplane which halved the wing span for a given wing area, and by having a hinged tail-plane that could move upwards to make the flare at the end of a flight easier. He speculated that flapping wings of birds might be necessary and had begun work on such a powered aircraft.

Aircraft produced by Otto Lilienthal
Name	Date	Wing			Glider		Notes
		Span (ft)	Area (sq ft)	Max. length (ft)	Length (ft)	Weight (kg)
Derwitzer Glider	1891	25 (later 18)	108 (later 84)	6.6	12.8	18	Wing curvature: 1/10 of length.
Südende Glider	1892	31	158	8.2	3.3	24	Wing curvature: 1/20 of length.
Maihöhe Rhinow Glider	1893	22 or 23	150	8.2	14.3	20
Small Ornithopter	1893-1896	22	129	8.2	5.5		Weight with CO2 cylinder: 10 kg.
Normal soaring apparatus	1894	22 - 23	140-146	7.9 / 8.2	16.1 - 17.4	20	At least 9 gliders sold. Original gliders are preserved in museums in London, Moscow, Munich (fragment) and Washington.
Sturmflügelmodell	1894	20	104	6.6	14.8		Original can be seen at the Technisches Museum Wien.
Vorflügelapparat	1895	29	204	9.8	18.4
Small Biplane	1895	19.7 / 17.1	104 / 105	7.2 / 6.9	15.7
Big Biplane	1895	21.6 / 20.7	146 / 112	7.5 / 7.5	16.1
Big Ornithopter	1896	27.9	188	8.2	17.4

The unveiling ceremony of the new monument in Berlin. Gustav (left) and Paul Baylich, August 1932

While his lifelong pursuit was flight, he was also an inventor and devised a small engine that worked on a system of tubular boilers. His engine was much safer than the other small engines of the time. This invention gave him the financial freedom to focus on aviation. His brother Gustav (1849–1933) was living in Australia at the time, and Lilienthal did not engage in aviation experiments until his brother's return in 1885.

There are 25 known patents of Otto Lilienthal.

Jumping-off places

At the beginning Lilienthal's training area was a hill formation called "Maihöhe", near the village of Rhinow. He built a 4 metres (13 ft) high shed, in the shape of a tower, on top of it. This way, he obtained a "jumping off" place 10 metres (33 ft) high. The shed served also for storing his apparatus.

In 1884 Lilienthal built an artificial conical hill in Lichterfelde (near his home), called "Fliegerberg". It allowed him to launch his gliders into the wind no matter which direction it was coming from. The hill is 15 metres (49 ft) high. There was a regular crowd of people that were interested in seeing his gliding experiments.

In 1932, the Fliegerberg was redesigned by a Berlin architect Fritz Freymüller as a memorial to Lilienthal. On top of the hill was built a small temple-like construction, consisting of pillars supporting a slightly sloping round roof. Inside is placed a silver globe inscribed with particulars of famous flights. Otto's brother Gustav and the old mechanic and assistant Paul Baylich attended the unveiling ceremony on August 10, 1932 (40 years after Otto's death).

Worldwide notice

Reports of Lilienthal's flights spread in Germany and elsewhere, with photographs appearing in scientific and popular publications. Among the those who photographed him were pioneers such as Ottomar Anschütz and American physicist Robert Williams Wood. He soon became known as the 'father of flight' as he had successfully controlled a heavier than air aircraft in sustained flight.

Lilienthal was a member of the Verein zur Förderung der Luftschifffahrt, and regularly detailed his experiences in articles in its journal, the Zeitschrift für Luftschifffahrt und Physik der Atmosphäre, and in the popular weekly publication Prometheus. These were translated in the United States, France and Russia. Many people from around the world came to visit him, including Samuel Pierpont Langley from the United States, Russian Nikolai Zhukovsky, Englishman Percy Pilcher and Austrian Wilhelm Kress. Zhukovsky wrote that Lilienthal's flying machine was the most important invention in the aviation field. Lilienthal corresponded with many people, among them Octave Chanute, James Means, Alois Wolfmüller and other flight pioneers.

Final flight

On August 9, 1896 Lilienthal went as usual to the Rhinow Hills. The day was very sunny, but not too hot (about 20°C). First flight was successful and he reached a distance of 350 metres (1,150 ft) in his "Normal Glider". During the second flight Lilienthal's glider stalled. He tried to re-establish lift by swinging his body back to correct the attitude of the glider. However, that maneuver failed and he fell from a height of 17 metres (56 ft), while still in the glider.

Paul Beylich, Lilienthal's glider mechanic, transported him by horse drawn carriage to Stölln, where he was examined by a physician. Lilienthal had a fracture of third cervical vertebra and soon became unconscious. Later that day he was transported in a cargo train to Lehrter train station in Berlin, and next morning to clinic of Ernst von Bergmann (one of the most famous and successful surgeons in Europe at the time). Lilienthal died there few hours later (about 36 h after the crash), his last words to his brother Gustav were "sacrifices must be made". The official cause of death was a fracture of the spine.

Otto Lilienthal was buried at Lankwitz public cemetery in Berlin.

Legacy

Lilienthal's research was well known to the Wright brothers, and they credited him as a major inspiration for their decision to pursue manned flight. However, they abandoned his aeronautical data after two seasons of gliding and began using their own wind tunnel data.

The Lilienthal monument, Berlin 2006

Of all the men who attacked the flying problem in the 19th century, Otto Lilienthal was easily the most important. ... It is true that attempts at gliding had been made hundreds of years before him, and that in the nineteenth century, Cayley, Spencer, Wenham, Mouillard, and many others were reported to have made feeble attempts to glide, but their failures were so complete that nothing of value resulted.

—Wilbur Wright

Berlin's busiest airport, Berlin Tegel "Otto Lilienthal" Airport, is named after him.

In September 1909 Orville Wright was in Germany making demonstration flights at Tempelhof aerodrome. He paid a call to Lilienthal's widow and on behalf of himself and Wilbur paid tribute to Lilienthal for his influence in aviation and on their own initial experiments in 1899.

Lilienthal in fiction

• Lilienthal plays a major part (in absentia) in Theodora Goss's short story "The Wings of Meister Wilhelm," nominated for a World Fantasy Award and published in her anthology In the Forest of Forgetting.
• A fictional characterization of Lilienthal was resurrected as an evil clone in the Japanese Read or Die (2001) novels, anime, and manga.
• A Lilienthal glider serves as a major plot element in Paul Gazis' Webserial "The Airship Flying Cloud, R-505".
• Lilienthal is mentioned as a "great scientist" in the video game Civilization Revolution.

Gallery

Otto Lilienthal was regularly joined by photographers at his request. Most of them are well known, like Ottomar Anschütz. Lilienthal was also constantly taking his own photographs of his flying machines after 1891.

There are at least 137 known photographs documenting his test flights, some of excellent quality. All of them are available online at Otto Lilienthal Museum website. The only negatives, preserved in the Deutsches Museum in Munich, were destroyed during World War II.

• 

  Flight atttempt of Lilienthal on the Derwitzer Glider,
  Derwitz, 1891

• 

  Lilienthal preparing for a Small Ornithopter flight,
  August 16, 1894

• 

  Vorflügelapparat,
  May 29, 1895

• 

  Normal soaring apparatus with the enlarged tail,
  June 29, 1895

See also

• Lilienthal Gliding Medal
• Otto Lilienthal Museum
• Aviation history
• Albrecht Berblinger
• Abbas Ibn Firnas
• George Cayley
• Jean-Marie Le Bris
• John Joseph Montgomery
• German inventors and discoverers

Bibliography

• Lilienthal, Otto (1911). Birdflight as the Basis of Aviation. reprinted 2001: ISBN 0-938716-58-1 (Translation from German edition, Berlin 1889: Der Vogelflug als Grundlage der Fliegekunst reprinted 2003: ISBN 3-9809023-8-2
• Crouch, Tom D (1989). The Bishop's Boys: A Life of Wilbur and Orville Wright. W. W. Norton & Company. ISBN 0-393-30695-X
• Nitsch, Stephan (1991). From the jump to the flight. Brandenburgisches Verlagshaus, Berlin. ISBN 3-327-01090-0

External links

• Biography / family tree of Otto Lilienthal
• Lilienthal's appendix from Chanute's book Progress in Flying Machines 1893.
• Movies and simulations
• Otto Lilienthal at Answers.com