Starting in 1891 Otto Lilienthal made the first well-documented, successful flights on a heavier-than-air aircraft under the control of a human being. In 1893 he patented the world’s first production aircraft, the ‘Normalsegelapparat’, a monoplane glider that he sold at least nine times to various places in Europe and America.
source/image(PrtSc): Markus Raffel
He made more than 2000 successful flights and his aerodynamic data and flight reports were circulated around the world. Others enthusiastically took his design, learned from it and then improved it to take flying to the next level./Markus Raffel
Good examples are here Pilcher, Chanute, the Wrights, Ferber, the Voisins, Zhukovsky and the list goes on.Samuel Langley as well as Octave Chanute and many others corresponded with Lilienthal.
Chanute, author of the other most influential book of that time and later friend of the Wright brothers, followed Lilienthal’s approach of carefully performed flight tests and lead several younger men to successful flights since 1896.via/read more: Markus Raffel