All flight is based upon producing air pressure,
all flight energy consists in overcoming air pressure -- Otto Lilienthal
Biography
Otto Lilienthal was an aeronautical pioneer, experimenting with
wing gliders and flapping wing constructions. His books on the theory of
flight formed the basis for aeronautics. His work has formed the
inspiration of many aeronautical engineers, including the Wright
Brothers.
Lilienthal was born on May 23, 1848 in Anklam, Prussia (currently
Germany). Lilienthal developed an early interest in flight in grammar
school in Anklam, studying birds. He went on to study engineering
at the regional technical school in Potsdam (1864-1866), followed by
one year of practical training at the Schwarzkopf company in Berlin
as a mechanical engineer (1866-1867). Immediately following the
practical training, Lilienthal began his first studies on human
flight while enrolled at the Royal Technical Academy in Berlin (1867-
1870).
After graduation, Lilienthal first joined the army for one year, to
fight in the French-German war, followed by employment at several
engineering firms. Although Lilienthal was not working professionally on
gliders, human flight remained his greatest interest. Together with his
brother Gustav, he joined the Aeronautical Society
of Great Britain, and lectured about the theory of the flight of birds
(1873). From 1874, Otto and Gustav began a systematic study on the force
of air on wings, the aerodynamics of wind, and an experimental program
with kites and model gliders.
Lilienthal remained working as an engineer; he filed his first of 22
patents in 1866, involving a machine for mining purposes. During his
life, Lilienthal filed 4 patents dealing with aviation. Ultimately, he
started his own mechanical engineering company for boilers
and steam engines (1881). This eventually allowed him to
dedicate more studying machines for human flight. In 1889, he published a
groundbreaking book on aviation: "Der Vogelflug als Grundlage
der Fliegekunst" (Bird flight as a Basis of Aviation). The book
summarizes all the experiments he carried out, a treatise on the physics
of flight, rules for the construction of airplanes.
Having completed the book, Lilienthal was now ready to start building
man carrying gliders (1890). In 1891 he made his first flight of
approximately 80 feet, in Derwitz/Krilow (near Potsdam). In the
years following his first flight, he continued improving his gliders
eventually reaching a flight distance of 800 feet, from the Rhinower
hills (Stölln/Rhinow, 1893). Lilienthal also experimented with wing
flapping machines, but his major successes were with gliders; in 1894 he
started serial production of the normal glider.
Lilienthal made over 2000 flights with monoplane and biplane gliders.
On August 9, 1896 he made an unfortunate final flight. The steering
mechanism of his glider malfunctioned, and he crashed. Lilienthal died
one day later from his injuries.
Work
Lilienthals contributions to the field of aerodynamics, and
especially the aerodynamics of wings are significant:
- A conclusive account of the fundamental properties of work
required to lift a body in still air, compared to the flight work of
birds.
- Experimental work, and properties of curved wings. Lilienthal was
the first to interpret aerodynamic results using
streamlines.
- The physics of wing aerodynamics; decomposition of the resultant air
force in lift and drag components.
- The polar diagram; a method of plotting lift and drag that is still used today.
- Analysis of wing constructions in terms of aspect ratio, shape and profile.
- The development of equipment for air force measurements.
Compiled from the Otto-Lilienthal-Museum website and other
sources. The excellent website of the museum (including nice pictures
and documentation) can be found at:
http://home.t-online.de/home/LilienthalMuseum/ehome.htm