There was never a more enthusiastic and consistent student of
the problems of flight than Otto Lilienthal, who was born in
1848 at Anklam, Pomerania, and even from his early school-days
dreamed and planned the conquest of the air. His practical
experiments began when, at the age of thirteen, he and his
brother Gustav made wings consisting of wooden framework covered
with linen, which Otto attached to his arms, and then ran
downhill flapping them. In consequence of possible derision on
the part of other boys, Otto confined these experiments for the
most part to moonlit nights, and gained from them some idea of
the resistance offered by flat surfaces to the air. It was in
1867 that the two brothers began really practical work,
experimenting with wings which, from their design, indicate some
knowledge of Besnier and the history of his gliding experiments;
these wings the brothers fastened to their backs, moving them
with their legs after the fashion of one attempting to swim.
Before they had achieved any real success in gliding the
Franco-German war came as an interruption; both brothers served
in this campaign, resuming their experiments in 1871 at the
conclusion of hostilities.

The experiments made by the brothers previous to the war had
convinced Otto that previous experimenters in gliding flight had
failed through reliance on empirical conclusions or else through
incomplete observation on their own part, mostly of bird flight.
From 1871 onward Otto Lilenthal (Gustav's interest in the
problem was not maintained as was his brother's) made what is
probably the most detailed and accurate series of observations
that has ever been made with regard to the properties of curved