THROUGHOUT his childhood and early adult years, Otto Lilienthal would gaze for hours and hours at storks and other soaring birds, seeking to unlock the secret of their seeming weightlessness. No doubt he noted, as the poet William Cowper had 100 years before, that "the bird that flutters least is longest on the wing".
Lilienthal concluded that an arched, or cambered, wing was the most suitable design for flight, and he thereby developed the principle that allowed the art of gliding to become the sophisticated sport we know today.
Lilienthal was born in 1848 in the little Prussian town of Anklam. He trained to be an engineer, and it was his engineering knowledge applied to ornithology that led to his discovery. In 1889 he published his ideas in Der Vogelflug als Grundlage der Fliegekunste - "The Flight of Birds as a Basis for the Art of Flying" a book acknowledged to this day to be a seminal work on aerodynamics.
In 1891 Lilienthal put his ideas into practice. His first machine consisted of two curved fabric wings, to which he attached himself by his outstretched arms. When in the air he used the shifting weight of his hanging body to control the craft, a technique not dissimilar to hang gliding. This was only the first of many gliders Lilienthal built, and he clocked up more than 2000 flights, reaching heights of over 700 feet.
Lilienthal was not the first to master the technique of flight. That accolade is usually reserved for an Englishman named George Cayley, who designed a heavier than air machine in 1853. But Lilienthal perfected the design, and apart from his contribution to aerodynamics, it is to him that we owe the first appreciation of the importance to gliding of rising currents in the atmosphere.
In a static atmosphere, a glider inevitably drifts slowly back to earth; Lilienthal realised that if the aircraft is to gain height, it is necessary for the pilot to find areas of the sky where the lift provided by the air is greater than this tendency to sink - areas with "thermals", or where the air ascends to clear a ridge of elevated ground.
This magnificent obsession, however, had a very tragic end. Lilienthal died when one of his gliders caught a sudden gust of wind, and crashed near Rhinow in his native Germany, 100 years ago today on August 10th, 1896. His work, however, inspired a new generation of aviators, including the Wright brothers in the US, and it is fitting that nowadays one of the highest awards for soaring flight in gliding is the Lilienthal Medal.