Fliegeberg: Otto Lilienthal’s ‘Fly Mountain’

One of the major inspiration to the Wright brothers was the work of German pioneer of aviation, Otto Lilienthal, who repeatedly and successfully demonstrated the possibility of heavier-than-air flying machines more than ten years before the American brothers took to the air. To demonstrate these flights, Otto Lilienthal built an artificial conical hill in 1894 near his home in Lichterfelde, approximately 600 meters north of Berlin city limits. Called Fliegeberg, or the “Fly Mountain”, it allowed Lilienthal to launch his gliders into the wind no matter which direction it was coming from. The hill is 15 meters high and still stands as a memorial to Lilienthal.

Lilienthal started building and testing gliders in 1891. Initially he used a hill near the villages of Krielow and Derwitz from which he used to jump and glide down covering distances of about 25 meters. Lilienthal was also able to use the updraft of the wind against a hill to remain stationary with respect to the ground.

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Photo credit: Kaiser2102/Wikimedia

In 1892, Lilienthal moved to another hill formation in Steglitz, near Berlin. He built a 4 meters tall jumping platform at the top giving him an effective height of about 10 meters. In 1893, Lilienthal used another hill in Rhinow from which he was able to achieve flight distances as long as 250 meters — a record which remained unbeaten at the time of his death.

Lilienthal tried several other training areas outside of Berlin until he decided to build his own hill in Lichterfelde, on the site of a former brickyard, together with his brother Gustav. Lilienthal conducted more than a thousand test flights from Fliegeberg, attracting a regular crowd of people. His best recorded distance at Fliegeberg was 80 meters.

Original caption: Portrait of Otto Lilienthal --- Image by © Bettmann/CORBIS

Otto Lilienthal. Photo credit: A. Regis/public domain

During his short flying career, Lilienthal developed a dozen models of monoplanes, wing flapping aircraft and two biplanes. His gliders were carefully designed to distribute weight as evenly as possible to ensure a stable flight. Lilienthal controlled them by changing the center of gravity by shifting his body, much like modern hang gliders. However they were difficult to maneuver 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. This small design flaw proved fatal.

On 9 August 1896, Lilienthal was conducting tests at Rhinow Hills when his glider pitched forward and headed straight down to the ground. Lilienthal never got a chance to gain control of the glider. He fell from a height of 15 meters, breaking his neck. He died 36 hours later. His last words to his brother Gustav were "Opfer müssen gebracht werden!" (Sacrifices must be made!).

In 1932, the Fliegeberg was redesigned as a memorial to Lilienthal and his training ground became Lilienthalpark. On top of the hill, stands a bronze globe inscribed with Otto Lilienthal’s name and particulars of his famous flights.

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