"At the end I want to ask you not to take my achievements for more than they are. Through the photographic pictures, where you can see me flying high above in the sky, one can get the impression that the problem is already solved. That is not at all the case. I have to admit that it will still take quite a lot of work to turn this simple gliding into a long-term human flight. The achievements so far are for human flight nothing more than the first insecure steps of a child meant to imitate the walk of men."
Karl Wilhelm Otto Lilienthal was a German aviation pioneer. He was born in May 1848 in Anklam, a small town in the Kingdom of Prussia. As a boy in grammar school, he was fascinated by the idea of manned flight and studied the flight of birds. Otto and his younger brother Gustav made unsuccessful attempts to fly with strap-on wings. Undaunted by their initial failures, the two brothers continued to cooperate on various technical projects for most of their lives.
Upon completion of his studies at a regional technical school in Potsdam, Lilienthal trained as a professional design engineer. While attending the Royal Technical Academy in Berlin, he began serious studies on the physical aspects of human flight. As an engineer with various mechanical firms, Otto Lilienthal carried out systematic experiments on the force of air on artificial wings with models and kites.
In 1873, the Lilienthal brothers became members of the Aeronautical Society of Great Britain, where Otto Lilienthal gave his first public lecture on the theory of the flight of birds. In 1883, Otto founded his own mechanical engineering company for the production of boilers and steam engines. His patented design for a small steam engine, safer and more reliable than existing models, was so successful that he was able to introduce a 25% profit-sharing scheme for his workers. It also gave him enough financial independence to focus on aviation.
In 1886, Lilienthal became a member of the German Association for the Promotion of Airship Navigation and in 1889 published his book Birdflight as the Basis of Aviation. He gave detailed descriptions of the flight of birds, especially storks, and used polar diagrams to explain the aerodynamics of their wings.
Otto Lilienthal started making gliding jumps in 1891. His first glider model was the Derwitzer, about four meters long with a wingspan of about eight meters and weighing eighteen kilos. With this glider he flew a distance of twenty-five meters. With his later models, he extended his range to 250 meters. His first flights were from the top of hills around Potsdam, Berlin and other locations, but in 1894 he built a fifteen-meter tall hill near his home outside Berlin. Its conical shape allowed him to launch his gliders into the wind regardless of which direction it was blowing. He called his new testing area Flight Hill.
As he improved on the design and maneuverability of his gliders, Lilienthal regularly presented papers at academic conferences and in German technical journals that were also translated in the United States, France and Russia. Numerous articles and photographs of his work in scientific and popular publications swayed public and scientific opinion in favor of the new technology called aviation. Pioneers from around the world visited him, including Samuel Pierpont Langley from the United States, the Russian Nikolai Zhukovsky, Englishman Percy Pilcher and Austrian Wilhelm Kress*.
Unfortunately, Otto Lilienthal was fatally injured when his glider stalled and nosedived from a height of fifteen meters on 9th August 1896. He is known as “the father of flight” for having repeatedly flown heavier-than-air aircraft in controlled and sustained flights. He designed a dozen different models of monoplanes and biplanes, including two wing-flapping machines, and made over 2,000 flights in gliders. His fundamental research on birds and airfoils created the science of wing aerodynamics. The Wright brothers were very familiar with Lilienthal’s research and claimed he inspired them to pursue manned flight. In 1912, Wilbur Wright wrote “Of all the men who attacked the flying problem in the 19th century, Otto Lilienthal was easily the most important.”
Original gliders built by Lilienthal are on display in museums in London, Moscow, Munich, Washington and Vienna.
In 1972, Otto Lilienthal was inducted into the International Air and Space Hall of Fame.
By Giovanni Gregorat, Contributing Editor MFN