Karl Wilhelm Otto Lilienthal (German pronunciation: [ˈkaʁl ˈvɪlhɛlm ˈʔɔto ˈliːliəntaːl]; May 23, 1848 – August 10, 1896) was a German pioneer in aviation known as the "flying man." He was the first person to make carefully recorded, repeated, successful flights using gliders, proving that heavier-than-air aircraft could work. Newspapers and magazines shared pictures of Lilienthal flying, which helped people believe that flying machines could become practical.

Lilienthal’s work helped create the design of the modern airplane wing. His flights in 1891 marked the start of human flight. The "Lilienthal Normalsegelapparat" was the first airplane mass-produced, making the Maschinenfabrik Otto Lilienthal in Berlin the world’s first airplane production company. He is called the "father of aviation" and "father of flight."

On August 9, 1896, Lilienthal’s glider stalled, and he could not control it. He fell from about 15 meters (49 feet) and broke his neck. He died the next day.

Early life

Otto Lilienthal was born on May 23, 1848, in Anklam, Pomerania Province, in the German kingdom of Prussia. His parents were Gustav and Caroline, who was born into the Pohle family. He was baptized in the evangelical-Lutheran St. Nicholas Church and confirmed in St. Mary’s Church in Anklam. Lilienthal’s middle-class parents had eight children, but only three lived past infancy: Otto, Gustav, and Marie. The brothers worked together throughout their lives on technical, social, and cultural projects. Lilienthal attended grammar school and studied the flight of birds with his brother Gustav (1849–1933). Inspired by the idea of human flight, Lilienthal and his brother created strap-on wings, but their attempts to fly were unsuccessful. He studied for two years at the regional technical school in Potsdam and trained at the Schwarzkopf Company before becoming a professional design engineer. Later, he attended the Technische Hochschule in Berlin (now Technische Universität Berlin).

In 1867, Lilienthal began serious experiments to study the force of air, but he paused his work to serve in the Franco-Prussian War. After returning to civilian life, he worked as a staff engineer for several engineering companies and received his first patent for a mining machine. He later started his own company to manufacture boilers and steam engines.

On June 6, 1878, Lilienthal married Agnes Fischer, the daughter of a government official. Music helped bring them together; Agnes was trained in piano and voice, while Lilienthal played the French horn and had a strong tenor voice. After their marriage, the couple moved to Berlin and had four children: Otto, Anna, Fritz, and Frida. In 1889, Lilienthal published his famous book Birdflight as the Basis of Aviation.

Experiments in flight

Otto Lilienthal’s most important work was helping to develop heavier-than-air flight. He flew from an artificial hill he built near Berlin and from natural hills, especially in the Rhinow region.

In 1894, Lilienthal filed a U.S. patent that instructed pilots to hold a "bar" to carry and fly a hang glider. The A-frame design used by Percy Pilcher and Lilienthal is similar to the control frame used in modern hang gliders and ultralight aircraft. With his brother Gustav, Lilienthal made over 2,000 flights in gliders he designed, starting in 1891 with his first glider, the Derwitzer Glider, until his death in a gliding accident in 1896. His total flying time was five hours.

Lilienthal’s first flights took place in the spring of 1891 on a sand pit hill between the villages of Derwitz and Krielow in Havelland, west of Potsdam (52°24′48″N 12°49′22″E). This location is where the first human flight occurred. Later, he flew from an artificial hill near Berlin and mostly from the Rhinow Hills. In 1891, he achieved flights covering about 25 meters (82 feet). He used wind moving up a hill at 10 meters per second (33 feet per second) to stay in one place while shouting instructions to a photographer. In 1893, he flew up to 250 meters (820 feet) in the Rhinow Hills, a record that remained unbroken until his death.

Lilienthal studied how birds, especially storks, flew and used polar diagrams to describe the shape and movement of their wings. He conducted many experiments to collect reliable data about flight.

During his flying career, Lilienthal created 12 models of gliders, including monoplanes, wing-flapping aircraft, and two biplanes. His gliders were designed to balance weight evenly for stable flight. He controlled them by shifting his body to change the center of gravity, similar to how modern hang gliders are controlled. However, his gliders were hard to maneuver and often pitched downward, making it difficult to recover. This was partly because he held the glider by the shoulders instead of hanging from it like modern hang gliders. Only his legs and lower body could move, limiting how much he could shift his weight.

Lilienthal tried many ways to improve stability, such as building a biplane with a smaller wing span and adding a hinged tailplane that moved upward to help land more easily. He believed that flapping wings, like those of birds, might be needed for powered flight and began work on such an aircraft.

Although Lilienthal’s main goal was flight, he also invented a small engine that used tubular boilers. His engine was safer than others of the time, giving him financial freedom to focus on aviation. His brother Gustav (1849–1933) was in Australia until 1885, when he returned, and Lilienthal began his aviation experiments.

There are 25 known patents in Lilienthal’s name.

Lilienthal’s first gliding attempts happened in the spring of 1891 at a hill called "Spitzer Berg" near the villages of Krielow and Derwitz, west of Potsdam.

In 1892, his training area was a hill called "Maihöhe" in Steglitz, Berlin. He built a 4-meter-high tower-shaped shed on top of it, creating a 10-meter-high jumping-off point. The shed also stored his equipment.

In 1893, he began flying from the "Rhinower Berge" at "Hauptmannsberg" near Rhinow and later from "Gollenberg" near Stölln in 1896.

In 1894, Lilienthal built an artificial conical hill near his home in Lichterfelde, called Fliegeberg (flight hill). This hill was 15 meters high and allowed him to launch gliders into the wind from any direction. A crowd of people often gathered to watch his experiments.

Worldwide notice

News about Lilienthal's flights spread across Germany and other countries, with photos appearing in scientific and general interest magazines. People such as Ottomar Anschütz and American physicist Robert Williams Wood took pictures of him. He became known as the "father of flight" because he successfully controlled a heavier-than-air aircraft during long, steady flights.

Lilienthal was part of the Verein zur Förderung der Luftschifffahrt and often wrote about his experiences in the group's journal, the Zeitschrift für Luftschifffahrt und Physik der Atmosphäre, and in the popular weekly magazine Prometheus. These writings were translated into English, French, and Russian. Many people from around the world visited him, including Samuel Pierpont Langley from the United States, Russian scientist Nikolai Zhukovsky, Englishman Percy Pilcher, and Austrian Wilhelm Kress. Zhukovsky said Lilienthal's flying machine was the most important invention in aviation. Lilienthal wrote letters to many people, including Octave Chanute, James Means, Alois Wolfmüller, and other early flight pioneers.

Final flight

On August 9, 1896, Lilienthal went to the Rhinow Hills, as he often did on weekends. The weather was sunny and not too hot, with temperatures around 20°C (68°F). His first flights were successful, and he flew about 250 meters (820 feet) using his usual glider. During the fourth flight, his glider tilted upward and then quickly dropped. (It is believed the glider stalled.) Lilienthal had previously struggled to recover from this situation because the glider relied on shifting his body weight, which was hard to do when the glider was pointed downward. His attempts to control it failed, and he fell from a height of about 15 meters (49 feet) while still in the glider.

Paul Beylich, Lilienthal’s glider mechanic, took him by horse-drawn carriage to Stölln, where a doctor examined him. Lilienthal had broken his third neck bone and soon became unconscious. Later that day, he was transported by train to Lehrter train station in Berlin. The next morning, he was taken to the clinic of Ernst von Bergmann, one of Europe’s most well-known surgeons at the time. Lilienthal died there a few hours later, about 36 hours after the accident.

There are different stories about Lilienthal’s last words. A popular version, written on his tombstone, says, “Opfer müssen gebracht werden!” (“Sacrifices must be made!”). However, the director of the Otto Lilienthal Museum questions whether these were his actual last words. Otto Lilienthal was buried in the Lankwitz public cemetery in Berlin.

Guinness World Records recognizes Otto Lilienthal as the first person recorded to have died in a glider accident.

Legacy

Lilienthal’s research was known to the Wright brothers, and they gave him credit as a major influence for their decision to try flying with people. After two seasons of gliding, they stopped using his flight information and began using data from their own wind tunnel tests.

Before it closed in 2020, Berlin’s busiest airport, Berlin Tegel “Otto Lilienthal” Airport, was named after him.

In September 1909, Orville Wright was in Germany flying demonstrations at Tempelhof aerodrome. He visited Lilienthal’s widow and, on behalf of himself and Wilbur, honored Lilienthal for his impact on aviation and their early experiments in 1899.

In 1932, the Fliegeberg was redesigned by a Berlin architect, Fritz Freymüller, as a memorial to Lilienthal. On top of the hill, a small temple-like structure was built, with pillars holding up a slightly sloping round roof. Inside, a silver globe is placed, showing details about famous flights. Lilienthal’s brother Gustav and the old mechanic and assistant Paul Baylich attended the opening ceremony on August 10, 1932 (36 years after Otto’s death).

In 1938, the Federation Aviation Internationale (FAI) created an annual award called the Lilienthal Gliding Medal to honor recent achievements in gliding.

In 1972, Lilienthal was added to the International Air & Space Hall of Fame.

In 2013, an American aviation magazine called Flying ranked Lilienthal number 19 on its list of the “51 Heroes of Aviation.”

A German Air Force tanker, an Airbus A310 MRTT with registration 10–24, is named “Otto Lilienthal” in his honor.

The Lilium Jet, a prototype German electric vertical take-off and landing (eVTOL) airplane, and the company that designed it, Lilium GmbH, were named after him.

A real copy of the Normalsegelapparat made by the Otto Lilienthal Museum was tested by the German Aerospace Center in wind tunnel and flight experiments. The results showed that the glider is stable in pitch and roll and can be safely flown at moderate altitudes.

In 1989, a Soviet-era Ilyushin IL-62 passenger jet was flown to Gollenberg and landed in a nearby field. It now serves as a museum of early flight and is named “Frau Agnes” (German for “Lady Agnes”), after Lilienthal’s wife. The back of the aircraft is used as a registry office for marriages. The jet previously flew with East Germany’s state airline, Interflug.

In popular culture

• In 1953, Lilienthal was shown on a special postmark in Berlin.
• Lilienthal is an important character (even though he is not present) in Theodora Goss's short story "The Wings of Meister Wilhelm," which was nominated for a World Fantasy Award and included in her book collection In the Forest of Forgetting.
• A Lilienthal glider plays an important role in Paul Gazis's webserial The Airship Flying Cloud, R-505.
• "Lilienthals Traum" ("Lilienthal's Dream") is a song by Reinhard Mey that describes Lilienthal's flying experiences and death.
• "Lilienthal Berlin" is a German watch brand named after Otto Lilienthal.

Gallery

Lilienthal often had photographers with him when he wanted. Many of these photographers were famous, such as Ottomar Anschütz. After 1891, Lilienthal also took photographs of his flying machines. At least 145 photos show his test flights, some of very high quality. All of these photos can be seen online at the Otto Lilienthal Museum website. The original film, kept in the Deutsches Museum in Munich, was destroyed during World War II.

• Flight attempt using the Derwitzer Glider, Derwitz, 1891
• Lilienthal preparing for a Small Ornithopter flight, 16 August 1894
• Vorflügelapparat, 29 May 1895
• Normal soaring apparatus with the enlarged tail, 29 June 1895